U.S. patent application number 15/065766 was filed with the patent office on 2016-07-14 for methods and systems for treating hydrocephalus.
The applicant listed for this patent is CEREVASC, LLC. Invention is credited to Carl Heilman, Adel M. Malek, David A. Rezac, Timothy W. Robinson, Joseph Ting.
Application Number | 20160199627 15/065766 |
Document ID | / |
Family ID | 54478289 |
Filed Date | 2016-07-14 |
United States Patent
Application |
20160199627 |
Kind Code |
A1 |
Heilman; Carl ; et
al. |
July 14, 2016 |
METHODS AND SYSTEMS FOR TREATING HYDROCEPHALUS
Abstract
Methods for treating hydrocephalus using a shunt, the shunt
having one or more CSF intake openings in a distal portion, a valve
disposed in a proximal portion of the shunt, and a lumen extending
between the one or more CSF intake openings and the valve, the
method comprises deploying the shunt in a body of a patient so that
the distal portion of the shunt is at least partially disposed
within a CP angle cistern, a body of the shunt is at least
partially disposed within an IPS of the patient, and the proximal
portion of the shunt is at least partially disposed within or
proximate to a JV of the patient, wherein, after deployment of the
shunt, CSF flows from the CP angle cistern to the JV via the shunt
lumen at a flow rate in a range of 5 ml per hour to 15 ml per
hour.
Inventors: |
Heilman; Carl; (Wayland,
MA) ; Malek; Adel M.; (Waltham, MA) ; Rezac;
David A.; (Westborough, MA) ; Robinson; Timothy
W.; (Sandown, NH) ; Ting; Joseph; (Framingham,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CEREVASC, LLC |
Boston |
MA |
US |
|
|
Family ID: |
54478289 |
Appl. No.: |
15/065766 |
Filed: |
March 9, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14929066 |
Oct 30, 2015 |
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15065766 |
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62073766 |
Oct 31, 2014 |
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62142895 |
Apr 3, 2015 |
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62156152 |
May 1, 2015 |
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Current U.S.
Class: |
604/8 |
Current CPC
Class: |
A61M 2039/242 20130101;
A61M 27/006 20130101; A61M 25/09 20130101; A61B 2018/00619
20130101; A61B 18/14 20130101; A61M 25/0155 20130101; A61B 18/1492
20130101; A61M 25/10 20130101; A61B 2018/1425 20130101; A61M
25/0067 20130101; A61B 18/1477 20130101; A61M 39/24 20130101; A61M
2210/06 20130101; A61M 25/0108 20130101; A61B 34/20 20160201; A61B
6/12 20130101; A61B 2018/00446 20130101; A61M 2039/2426
20130101 |
International
Class: |
A61M 27/00 20060101
A61M027/00; A61B 18/14 20060101 A61B018/14; A61M 25/10 20060101
A61M025/10; A61B 34/20 20060101 A61B034/20; A61M 25/00 20060101
A61M025/00; A61M 25/01 20060101 A61M025/01 |
Claims
1. A method for relieving a patient's elevated intracranial
pressure (ICP) by implanting a shunt in the patient, the shunt
comprising one or more cerebrospinal fluid (CSF) intake openings in
a distal portion of the shunt, a valve disposed in a proximal
portion of the shunt, and a lumen extending between the one or more
CSF intake openings and the valve, the method comprising:
introducing a deployment system including a tissue penetrating
element and the shunt from a venous access location in the patient;
navigating the deployment system, including the penetrating element
and shunt, from the venous access location to a target penetration
site within an inferior petrosal sinus (IPS) of the patient, via a
jugular vein (JV) of the patient; assessing a trajectory of the
tissue penetrating element at the target penetration site from the
IPS into a cerebellopontine (CP) angle cistern of the patient;
advancing the tissue penetrating element through dura and arachnoid
tissue layers at the target penetration site; advancing the distal
portion of the shunt into the CP angle cistern through an opening
in the respective dura and arachnoid tissue layers created by the
tissue penetrating element; deploying a distal anchoring mechanism
of the shunt in the CP angle cistern; withdrawing the delivery
system from the target penetration site towards the JV, wherein the
shunt is expelled from the delivery system and thereby deployed in
the IPS as the delivery system is withdrawn toward the JV;
deploying a proximal anchoring mechanism of the shunt about a
junction of the JV and IPS, such that the proximal portion of the
shunt is oriented away from a medial wall of the JV; and removing
the delivery system from the patient, wherein the deployed shunt
provides a one-way flow path for CSF to flow from the CP angle
cistern to the JV via the shunt lumen in order to maintain a normal
differential between the patient's ICP and venous system
pressure.
2. The method of claim 1, further comprising, advancing the tissue
penetrating element into the CP angle cistern and, prior to
withdrawing the delivery system from the patient, confirming that
the tissue penetrating element has accessed the CP angle cistern by
withdrawing CSF from the CP angle cistern through the delivery
system.
3. The method of claim 1, wherein the proximal portion of the
deployed shunt is disposed adjacent to a jugular bulb of the
patient.
4. The method of claim 1, wherein the distal portion of the shunt
is expanded or self-expands from a collapsed delivery configuration
to an expanded deployed configuration as or after it is advanced
into the CP angle cistern.
5. The method of claim 1, the delivery system comprising a delivery
catheter, and the tissue penetrating element comprises a tissue
penetrating tip of the delivery catheter, wherein advancing the
distal portion of the shunt into the CP angle cistern comprises
advancing the delivery catheter into the CP angle cistern with the
shunt positioned in a lumen of the delivery catheter.
6. The method of claim 5, the delivery catheter comprising a distal
portion that assumes a curved configuration that guides the tissue
penetrating tip into contact with the dura mater tissue at an angle
in a range of 30 degrees to 90 degrees thereto.
7. The method of claim 6, wherein the distal portion of the
delivery catheter comprises an expandable element or wall portion
that is expanded to cause the distal portion of the delivery
catheter to assume the curved configuration.
8. The method of claim 7, wherein the expandable element or wall
portion comprises a balloon that is inflated to cause expansion
thereof.
9. The method of claim 5, the delivery catheter comprising one or
more radiopaque markers located and dimensioned to indicate a
trajectory of the tissue penetrating element at the target
penetration site.
10. The method of claim 1, the tissue penetrating element
comprising an elongate pusher member having a tissue penetrating
tip, the elongate pusher member extending though the valve, lumen,
and distal opening of the shunt, respectively, wherein the elongate
pusher member is moveable relative to the shunt so that the tissue
penetrating distal tip may be advanced out of, and withdrawn into,
a distal opening of the shunt in communication with the shunt
lumen, wherein the distal portion of the shunt is advanced into the
CP angle cistern on the elongate pusher member.
11. The method of claim 10, the delivery system comprising a
delivery catheter having a lumen in which the respective shunt and
elongate pusher member are at least partially disposed when the
tissue penetrating tip of the elongate pusher member is advanced
through the respective dura and arachnoid tissue layers, the method
further comprising withdrawing the elongate pusher member through
the distal opening, lumen and valve of the shunt, respectively,
after the distal portion of the shunt is advanced into the CP angle
cistern, wherein CSF flows through the respective distal opening,
lumen and valve of the shunt after withdrawal of the elongate
pusher member.
12. The method of claim 1, further comprising imaging the shunt
while deploying the shunt in the patient.
13. The method of claim 1, wherein the proximal portion of the
deployed shunt is at least partially disposed within, or proximate
to, an intersection of a superior vena cava and right atrium of the
patient.
14. The method of claim 1, wherein the deployed distal anchoring
mechanism positions the distal portion of the shunt so as to
maintain the one or more CSF intake openings separated, apart
and/or directed away from an arachnoid layer of the CP angle
cistern.
15. The method of claim 1, wherein CSF flows from the CP angle
cistern to the JV via the shunt lumen at a flow rate in a range of
5 ml per hour to 15 ml per hour.
16. The method of claim 1, further comprising, delivering radio
frequency energy to the tissue penetrating element to advance the
tissue penetrating element through dura and arachnoid tissue layers
at the target penetration site.
17. The method of claim 1, further comprising, maintaining the
shunt at the target site, wherein a spring-like body of the shunt
applies a tensional force between the proximal and distal portions
of the shunt.
18. The method of claim 1, further comprising, stabilizing the
delivery system in the IPS lumen before advancing the tissue
penetrating element through dura and arachnoid tissue layers at the
target penetration site.
19. The method of claim 1, further comprising, guarding the
penetrating element with a shuttle while navigating to the target
penetration site.
20. The method of claim 19, further comprising, advancing the
shuttle to expose the penetrating element at the target penetration
site.
Description
RELATED APPLICATION DATA
[0001] The present application is a divisional of U.S. patent
application Ser. No. 14/929,066, filed Oct. 30, 2015, which claims
the benefit under 35 U.S.C. .sctn.119 to U.S. Provisional
Application Ser. No. 62/073,766, filed Oct. 31, 2014, 62/142,895,
filed Apr. 3, 2015, and 62/156,152, filed May 1, 2015. The
foregoing applications are hereby incorporated by reference into
the present application in their entirety.
FIELD OF THE INVENTION
[0002] The present disclosure pertains generally to systems and
methods for accessing cerebral cisterns and draining cerebrospinal
fluid (CSF), (e.g., to relieve elevated intracranial pressure),
using an endovascular approach. More particularly, the present
disclosure pertains to systems and methods for treatment of
hydrocephalus, pseudotumor cerebri, and/or intracranial
hypertension.
BACKGROUND
[0003] Hydrocephalus is one of the most common and important
neurosurgical conditions affecting both, children and adults.
Hydrocephalus, meaning "water on the brain," refers to the abnormal
CSF accumulation in the brain. The excessive intracranial pressure
resulting from hydrocephalus can lead to a number of significant
symptoms ranging from headache to neurological dysfunction, coma,
and death.
[0004] Cerebrospinal fluid is a clear, physiologic fluid that
bathes the entire nervous system, including the brain and spinal
cord. Cells of the choroid plexus present inside the brain
ventricles produce CSF. In normal patients, cells within arachnoid
granulations reabsorb CSF produced in the choroid plexus. Arachnoid
granulations straddle the surface of the intracranial venous
drainage system of the brain and reabsorb CSF present in the
subarachnoid space into the venous system.
[0005] Approximately 450 mL to 500 mL of CSF is produced and
reabsorbed each day, enabling a steady state volume and pressure in
the intracranial compartment of approximately 8-16 cm H2O. This
reabsorption pathway has been dubbed the "third circulation,"
because of its importance to the homeostasis of the central nervous
system.
[0006] Hydrocephalus occurs most commonly from the impaired
reabsorption of CSF, and in rare cases, from its overproduction.
The condition of impaired reabsorption is referred to as
communicating hydrocephalus. Hydrocephalus can also occur as a
result of partial or complete occlusion of one of the CSF pathways,
such as the cerebral aqueduct of Sylvius, which leads to a
condition called obstructive hydrocephalus.
[0007] A positive pressure gradient between the intracranial
pressure of the subarachnoid space and the blood pressure of the
venous system may contribute to the natural absorption of CSF
through arachnoid granulations. For example, in non-hydrocephalic
individuals ICPs can range from about 6 cm H20 to about 20 cm H20.
ICP greater than 20 cm H20 is considered pathological of
hydrocephalus, although ICP in some forms of the disease can be
lower than 20 cm H20. Venous blood pressure in the intracranial
sinuses and jugular bulb and vein can range from about 4 cm H20 to
about 11 cm H20 in non-hydrocephalic patients, and can be slightly
elevated in diseased patients. While posture changes in patients,
e.g., from supine to upright, affect ICP and venous pressures, the
positive pressure gradient between ICP and venous pressure remains
relatively constant. Momentary increases in venous pressure greater
than ICP, however, can temporarily disturb this gradient, for
example, during episodes of coughing, straining, or valsalva.
[0008] Normal pressure hydrocephalus (NPH) is one form of
communicating hydrocephalus. NPH patients typically exhibit one or
more symptoms of gait disturbance, dementia, and urinary
incontinence, which can lead to misdiagnosis of the disease. Unlike
other forms of communicating hydrocephalus, NPH patients may
exhibit little or no increase in ICP. It is believed that the
CSF-filled ventricles in the brain enlarge in NPH patients to
accommodate the increased volume of CSF in the subarachnoid space.
For example, while non-hydrocephalic patients typically have ICPs
ranging from about 6 cm H20 to about 20 cm H20, ICPs in NPH
patients can range from about 6 cm H20 to about 27 cm H20. It has
been suggested that NPH is typically associated with normal
intracranial pressures during the day and intermittently increased
intracranial pressure at night.
[0009] Other conditions characterized by elevated intracranial
pressure include pseudotumor cerebri (benign intracranial
hypertension). The elevated ICP of pseudotumor cerebri causes
symptoms similar to, but that are not, a brain tumor. Such symptoms
can include headache, tinnitus, dizziness, blurred vision or vision
loss, and nausea. While most common in obese women 20 to 40 years
old, pseudotumor cerebri can affect patients in all age groups.
[0010] Prior art techniques for treating communicating
hydrocephalus (and in some cases, pseudotumor cerebri) rely on
ventriculoperitoneal shunts ("VPS" or "VP shunt" placement), a
medical device design introduced more than 60 years ago. VPS
placement involves an invasive surgical procedure performed under
general anesthesia, typically resulting in hospitalization ranging
from two to four days. The surgical procedure typically involves
placement of a silicone catheter in the frontal horn of the lateral
ventricle of the brain through a burr hole in the skull. The distal
portion of the catheter leading from the lateral ventricle is then
connected to a pressure or flow-regulated valve, which is placed
under the scalp. A separate incision is then made through the
abdomen, into the peritoneal cavity, into which the distal portion
of a tubing catheter is placed. The catheter/valve assembly is then
connected to the tubing catheter, which is tunneled subcutaneously
from the neck to the abdomen.
[0011] VPS placement is a very common neurosurgical procedure, with
estimates of 55,000-60,000 VPS placements occurring in the U.S.
each year. While the placement of a VP shunt is typically
well-tolerated by patients and technically straightforward for
surgeons, VP shunts are subject to a high rate of failure in
treated patients. Complications from VP shunt placement are common
with a one-year failure rate of approximately 40% and a two-year
shunt failure rate reported as high as 50%. Common complications
include catheter obstruction, infection, over-drainage of CSF, and
intra-ventricular hemorrhage. Among these complications, infection
is one of the most serious, since infection rates in adults are
reported between 1.6% and 16.7%. These VPS failures require "shunt
revision" surgeries to repair/replace a portion or the entirety of
the VP shunt system, with each of these revision surgeries carrying
the same risk of general anesthesia, post-operative infection, and
associated cost of hospitalization as the initial VPS placement;
provided, however, that shunt infections often cost significantly
more, e.g., about three to five times more, than the cost of the
initial VP shunt placement. Often these infections require
additional hospital stays where the proximal portion of the VPS is
externalized and long-term antibiotic therapy is instituted. The
rate of failure is a constant consideration by clinicians as they
assess patients who may be candidates for VPS placement. Age,
existing co-morbidities and other patient-specific factors are
weighed against the likelihood of VP shunt failure that is
virtually assured during the first 4-5 years following initial VP
shunt placement.
[0012] Despite significant advances in biomedical technology,
instrumentation, and medical devices, there has been little change
in the design of basic VPS hardware since its introduction in
1952.
SUMMARY
[0013] Embodiments of the disclosed inventions include a method for
treating hydrocephalus using a shunt, the shunt having one or more
cerebrospinal fluid (CSF) intake openings in a distal portion of
the shunt, a valve disposed in a proximal portion of the shunt, and
a lumen extending between the one or more CSF intake openings and
the valve. The method comprises deploying the shunt in a body of a
patient so that the distal portion of the shunt is at least
partially disposed within a cerebellopontine (CP) angle cistern of
the patient, a body of the shunt is at least partially disposed
within an inferior petrosal sinus (IPS) of the patient, and the
proximal portion of the shunt is at least partially disposed within
or proximate to a jugular vein (JV) of the patient, wherein, after
deployment of the shunt, CSF flows from the CP angle cistern to the
JV via the shunt lumen at a flow rate in a range of 5 ml per hour
to 15 ml per hour.
[0014] In various embodiments of the method, deployment of the
shunt comprises: introducing the shunt percutaneously through a
venous access location in the patient, delivering of the shunt so
that the proximal portion of the deployed shunt is disposed
adjacent to a jugular bulb, advancing the distal portion of the
shunt from the IPS into the CP angle cistern using a tissue
penetrating member, and/or imaging the shunt while deploying the
shunt in the patient.
[0015] In other embodiments, the method includes that the distal
portion of the shunt is expanded or self-expands from a collapsed
delivery configuration to an expanded deployed configuration as, or
after, it is advanced into the CP angle cistern. The tissue
penetrating member is coupled to a distal end of the shunt, and
advancing the distal portion of the shunt from the IPS into the CP
angle cistern comprises advancing the tissue penetrating member and
distal portion of the shunt through a dura mater tissue wall of the
IPS, and through an arachnoid tissue layer, respectively, into the
CP angle cistern. Further, during advancement of the distal portion
of the shunt in this method, the distal portion of the shunt is at
least partially disposed in a delivery lumen of a delivery
catheter, the tissue penetrating member comprises a tissue
penetrating tip of the delivery catheter, and advancing the distal
portion of the shunt from the IPS into the CP angle cistern
comprises advancing the delivery catheter so that the tissue
penetrating tip penetrates through a dura mater tissue wall of the
IPS, and through an arachnoid tissue layer, respectively, into the
CP angle cistern.
[0016] In some embodiments of the method, the delivery catheter
includes a distal portion that assumes a curved configuration that
guides the tissue penetrating tip into contact with the dura mater
tissue at an angle in a range of 30 degrees to 90 degrees thereto.
The distal portion of the delivery catheter comprises an expandable
element or wall portion that is expanded to cause the distal
portion of the delivery catheter to assume the curved
configuration. The expandable element or wall portion comprises a
balloon that is inflated to cause expansion thereof. The balloon is
inflated to a first expanded state causing the tissue penetrating
tip to engage the dura, and thereafter inflated to a second
expanded state causing the tissue penetrating tip to penetrate
through the dura and arachnoid tissue layers, respectively, into
the CP angle cistern. The delivery catheter comprises one or more
radiopaque markers located and dimensioned to indicate a position
and orientation of the distal portion of the delivery catheter when
in the curved configuration. In deploying the shunt, the method
further comprises withdrawing the distal portion of the delivery
catheter from the CP angle cistern, while maintaining the distal
portion of the shunt at least partially disposed in the CP angle
cistern.
[0017] In some embodiments, where the method of deployment of the
shunt includes advancing the distal portion of the shunt from the
IPS into the CP angle cistern using a tissue penetrating member,
the tissue penetrating member comprising an elongate pusher member
having a tissue penetrating distal tip, the elongate pusher member
extends though the valve, lumen, and distal opening of the shunt,
respectively, wherein the elongate pusher member is moveable
relative to the shunt so that the tissue penetrating distal tip may
be advanced out of, and withdrawn into, a distal opening of the
shunt in communication with the lumen. Further, the method of
advancing the distal portion of the shunt from the IPS into the CP
angle cistern may include advancing the elongate pusher member so
that the tissue penetrating distal tip penetrates through a dura
mater tissue wall of the IPS, and through an arachnoid tissue
layer, respectively, into the CP angle cistern, with the distal
portion of the shunt being carried on the tissue penetrating
member. In these embodiments, deploying the shunt further
comprises, after advancing the distal portion of the shunt into the
CP angle cistern, withdrawing the tissue penetrating member through
the distal opening, lumen and valve of the shunt, respectively,
wherein CSF flows through the respective distal opening, lumen and
valve of the shunt after withdrawal of the tissue penetrating
member.
[0018] In various embodiments of the method, the shunt comprises a
first engaging member protruding and/or extending radially inward
from an inner wall of the shunt, the elongate pusher member
comprises a second engaging member protruding and/or extending
radially outward towards the inner shunt wall, where the second
engaging member engages the first engaging member to thereby
advance the distal portion of the shunt from the IPS into the CP
angle cistern on the tissue penetrating member. In these
embodiments, prior to advancing the tissue penetrating member into
the CP angle cistern, the method of deployment of the shunt further
includes adjusting a rotational orientation of the delivery
catheter about an axis of the delivery catheter so that the tissue
penetrating distal tip of the tissue penetrating member is
thereafter advanced out of the distal opening of the delivery
catheter into contact with the dura mater tissue at an angle in a
range of 30 degrees to 90 degrees thereto.
[0019] In some embodiments of the method, deployment of the shunt
further includes advancing a delivery catheter into the IPS with
the shunt and tissue penetrating member at least partially disposed
in a delivery lumen of the delivery catheter, the delivery catheter
having a distal opening in communication with the delivery lumen
through which the respective tissue penetrating member and shunt
may be advanced into the CP angle cistern.
[0020] In various embodiments of the method, deployment of the
shunt includes: introducing the shunt into the patient's body while
the shunt is at least partially disposed in a delivery catheter,
and where the delivery catheter is advanced over a guidewire
extending through a lumen of the delivery catheter, which may be a
same or different lumen in which the shunt is at least partially
disposed, until a distal portion of the delivery catheter is
positioned in the IPS. The proximal portion of the deployed shunt
is at least partially disposed within, or proximate to, an
intersection of a superior vena cava and right atrium of the
patient.
[0021] In other embodiments of the method, the distal portion of
the deployed shunt comprises a distal anchoring mechanism that
positions the distal portion of the shunt so as to maintain the one
or more CSF intake openings separated, apart and/or directed away
from an arachnoid layer of the CP angle cistern; and/or the
proximal portion of the deployed shunt comprises a proximal
anchoring mechanism that positions the proximal portion of the
shunt to thereby maintain a CSF outflow port and/or valve opening
disposed in the proximal portion of the shunt separated, apart
and/or directed away from a wall of the JV.
[0022] Embodiments of the disclosed inventions include a method for
relieving a patient's elevated intracranial pressure by implanting
a shunt in the patient, the shunt comprising one or more
cerebrospinal fluid (CSF) intake openings in a distal portion of
the shunt, a valve disposed in a proximal portion of the shunt, and
a lumen extending between the one or more CSF intake openings and
the valve. The method comprises: introducing a deployment system
including a tissue penetrating element and the shunt from a venous
access location in the patient; navigating the deployment system,
including the penetrating element and shunt, from the venous access
location to a target penetration site within an inferior petrosal
sinus (IPS) of the patient, via a jugular vein (JV) of the patient;
assessing a trajectory of the tissue penetrating element at the
target penetration site from the IPS into a cerebellopontine (CP)
angle cistern of the patient; advancing the tissue penetrating
element through dura and arachnoid tissue layers at the target
penetration site, and into the CP angle cistern; advancing the
distal portion of the shunt into the CP angle cistern through an
opening in the respective dura and arachnoid tissue layers created
by the tissue penetrating element; deploying a distal anchoring
mechanism of the shunt in the CP angle cistern; withdrawing the
delivery system from the target penetration site towards the JV,
wherein the shunt is expelled from the delivery system and thereby
deployed in the IPS as the delivery system is withdrawn toward the
JV; deploying a proximal anchoring mechanism of the shunt about a
junction of the JV and IPS, such that the proximal portion of the
shunt is oriented away from a medial wall of the JV; and removing
the delivery system from the patient, wherein the deployed shunt
provides a one-way flow path for CSF to flow from the CP angle
cistern to the JV via the shunt lumen in order to maintain a normal
differential pressure between the patient's subarachnoid space and
venous system.
[0023] In various embodiments, the method further comprises:
confirming that the tissue penetrating element has accessed the CP
angle cistern by withdrawing CSF from the CP angle cistern through
the delivery system, prior to withdrawing the delivery system from
the patient'; and/or imaging the shunt while deploying the shunt in
the patient.
[0024] In some embodiments of the method, the proximal portion of
the deployed shunt is disposed adjacent to a jugular bulb; and/or
the distal portion of the shunt is expanded or self-expands from a
collapsed delivery configuration to an expanded deployed
configuration as or after it is advanced into the CP angle cistern.
In further embodiments of the method, the delivery system comprises
a delivery catheter, and the tissue penetrating element comprises a
tissue penetrating tip of the delivery catheter, wherein advancing
the distal portion of the shunt into the CP angle cistern comprises
advancing the delivery catheter into the CP angle cistern with the
shunt positioned in a lumen of the delivery catheter.
[0025] In various embodiments of the method, the delivery catheter
comprises a distal portion that assumes a curved configuration that
guides the tissue penetrating tip into contact with the dura mater
tissue at an angle in a range of 30 degrees to 90 degrees thereto;
the distal portion of the delivery catheter comprises an expandable
element or wall portion that is expanded to cause the distal
portion of the delivery catheter to assume the curved
configuration; the expandable element or wall portion comprises a
balloon that is inflated to cause expansion thereof; the balloon is
inflated to a first expanded state causing the tissue penetrating
tip to engage the dura, and thereafter inflated to a second
expanded state causing the tissue penetrating tip to penetrate
through the dura and arachnoid tissue layers, respectively, into
the CP angle cistern. In the embodiments of the method, the
delivery catheter comprises one or more radiopaque markers located
and dimensioned to indicate a position and orientation of the
distal portion of the delivery catheter when in the curved
configuration.
[0026] In some embodiments of the method, the tissue penetrating
element comprises an elongate pusher member having a tissue
penetrating tip, the elongate pusher member extending though the
valve, lumen, and distal opening of the shunt, respectively,
wherein the elongate pusher member is moveable relative to the
shunt so that the tissue penetrating distal tip may be advanced out
of, and withdrawn into, a distal opening of the shunt in
communication with the shunt lumen, wherein the distal portion of
the shunt is advanced into the CP angle cistern on the elongate
pusher member. In these embodiments, the delivery system comprises
a delivery catheter having a lumen in which the respective shunt
and elongate pusher member are at least partially disposed when the
tissue penetrating tip of the elongate pusher member is advanced
through the respective dura and arachnoid tissue layers, the method
further comprising withdrawing the elongate pusher member through
the distal opening, lumen and valve of the shunt, respectively,
after the distal portion of the shunt is advanced into the CP angle
cistern, wherein CSF flows through the respective distal opening,
lumen and valve of the shunt after withdrawal of the elongate
pusher member.
[0027] In some embodiments, the method further comprises adjusting
a rotational orientation of the delivery catheter about an axis of
the delivery catheter so that the tissue penetrating tip of the
elongate pusher member is thereafter advanced out of a distal
opening of the delivery catheter into contact with the dura mater
tissue at an angle in a range of 30 degrees to 90 degrees thereto,
prior to advancing the tissue penetrating tip of the elongate
pusher member into the CP angle cistern.
[0028] In various embodiments of the method, the proximal portion
of the deployed shunt is at least partially disposed within, or
proximate to, an intersection of a superior vena cava and right
atrium of the patient, and/or the deployed distal anchoring
mechanism positions the distal portion of the shunt so as to
maintain the one or more CSF intake openings separated, apart
and/or directed away from an arachnoid layer of the CP angle
cistern.
[0029] Embodiments of the disclosed inventions include a method for
treating normal pressure hydrocephalus (NPH) using a shunt, the
shunt comprising one or more cerebrospinal fluid (CSF) intake
openings in a distal portion of the shunt, a valve disposed in a
proximal portion of the shunt, and a lumen extending between the
one or more CSF intake openings and the valve, the lumen having an
inner diameter in a range of 0.008'' to 0.014''. The method
comprises: deploying the shunt in a body of an NPH patient so that
the distal portion of the shunt is at least partially disposed
within a cerebellopontine (CP) angle cistern of the patient, a body
of the shunt is at least partially disposed within an inferior
petrosal sinus (IPS) of the patient, and the proximal portion of
the shunt is at least partially disposed within, or proximate to, a
jugular vein (JV) of the patient, wherein the shunt valve opens at
a pressure differential between the CP angle cistern and JV in a
range of 3 mm Hg to 5 mm Hg, so that, after deployment of the
shunt, CSF flows from the CP angle cistern to the JV via the shunt
lumen.
[0030] Other and further aspects and features of embodiments will
become apparent from the ensuing detailed description in view of
the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a schematic diagram of a head of a human
patient;
[0032] FIG. 2 is a cross-sectional view of a portion of the head of
a human patient;
[0033] FIG. 3A is a cross-sectional view of a deployed endovascular
shunt according to embodiments of the disclosed inventions;
[0034] FIG. 3B is a side view of a delivery assembly according to
embodiments of the disclosed inventions;
[0035] FIGS. 4A-D are cross-sectional views of deployment of
endovascular shunt according to embodiments of the disclosed
inventions;
[0036] FIGS. 5A-J are side and cross-sectional views of deployment
of an endovascular shunt according to another embodiment of the
disclosed inventions;
[0037] FIG. 6 is a cross-sectional view of an endovascular shunt
according to embodiments of the disclosed inventions;
[0038] FIGS. 6A-T are side and cross-sectional views of features of
the endovascular shunt of FIG. 6 according to embodiments of the
disclosed inventions;
[0039] FIG. 7 is a cross-sectional view of an endovascular shunt
and a catheter interface according to embodiments of the disclosed
inventions;
[0040] FIG. 8 is a cross-sectional view of an endovascular shunt
according to embodiments of the disclosed inventions;
[0041] FIG. 9 is cross-sectional view of an endovascular shunt
according to another embodiment of the disclosed inventions;
[0042] FIG. 10 is a cross-sectional view of a delivery catheter
according to embodiments of the disclosed inventions;
[0043] FIGS. 11A-C are cross-sectional views of distal portions of
an endovascular and/or catheters, including experimental data,
according to embodiments of the disclosed inventions;
[0044] FIG. 12 is a cross-sectional view of a deployed endovascular
shunt and a conduit according to embodiments of the disclosed
inventions;
[0045] FIGS. 13A-13C are side views of prior art self-expanding
stent-grafts;
[0046] FIGS. 14A-14H are side and cross-sectional views of
deployment of a conduit and an endovascular shunt according to yet
another embodiment of the disclosed inventions;
[0047] FIGS. 15A-15D are cross-sectional and side views of
deployment an endovascular shunt according to one embodiment of the
disclosed inventions;
[0048] FIG. 16 is a side view of a deployed endovascular shunt
according to another embodiment of the disclosed inventions;
[0049] FIGS. 17A-B are cross-sectional views of an endovascular
shunt having a pre-curved configuration according to one embodiment
of the disclosed inventions;
[0050] FIGS. 18A-B are cross-sectional views of an endovascular
shunt having selective slots according to another embodiment of the
disclosed inventions;
[0051] FIGS. 19A-B are cross-sectional views of an endovascular
shunt having a elongate member according to yet another embodiment
of the disclosed inventions;
[0052] FIGS. 20A-F are cross-sectional views of an endovascular
shunt delivery assembly having an end cap and an stabilizing member
according embodiments of the disclosed inventions;
[0053] FIGS. 21A-E are cross-sectional views of another
endovascular shunt delivery assembly having a deflecting element
and a stabilizing member according embodiments of the disclosed
inventions;
[0054] FIGS. 22A-G are side and cross-sectional views of a deployed
endovascular shunt according to another embodiment of the disclosed
inventions;
[0055] FIGS. 23A-E are side and cross-sectional views of a deployed
endovascular shunt according to another embodiment of the disclosed
inventions;
[0056] FIGS. 24A-E are side views of deployed endovascular shunts
according to others embodiments of the disclosed inventions;
[0057] FIGS. 25A-G are side and cross-sectional views of a deployed
endovascular shunt according to yet another embodiment of the
disclosed inventions;
[0058] FIGS. 26A-G are side and cross-sectional views of a deployed
endovascular shunt according to another embodiment of the disclosed
inventions;
[0059] FIGS. 27A-E are side and cross-sectional views of a deployed
endovascular shunt according to another embodiment of the disclosed
inventions;
[0060] FIG. 28 is a side view of a deployed endovascular shunt
according to one embodiment of the disclosed inventions;
[0061] FIGS. 29A-G are side and cross-sectional views of an
alternative embodiment of the shunt constructed and implanted
according to embodiment of FIGS. 12 and 14A-H of the disclosed
inventions;
[0062] FIGS. 30A-F are side and cross-sectional views of a deployed
endovascular shunt according to another embodiment of the disclosed
inventions;
[0063] FIG. 31 is a side view an alternative embodiment of the
shunt constructed and implanted according to the embodiment of
FIGS. 22A-G of the disclosed inventions;
[0064] FIG. 32 is a side view an alternative embodiment of the
shunt constructed and implanted according to embodiment of FIG. 21E
of the disclosed inventions;
[0065] FIGS. 33A-33C are cross-section views of a surgical tool and
an endovascular shunt interface according to embodiments of the
disclosed inventions;
[0066] FIGS. 34A-34B are cross-section views of an endovascular
shunt according to another embodiment of the disclosed
inventions;
[0067] FIG. 35 is a perspective view of a system for testing
penetrating components of the endovascular shunt delivery assembly
according to embodiments of the disclosed inventions;
[0068] FIG. 36 is a perspective view of a tissue block of the
system of FIG. 35;
[0069] FIG. 37 is a perspective view of the tissue block shown in
FIG. 36;
[0070] FIG. 38 is a side view of a penetration test of the system
of FIG. 35;
[0071] FIG. 39 is an experimental data table according to
embodiments of the disclosed inventions;
[0072] FIG. 40 is a schematic flow diagram of an exemplary method
of assessing the patency of an implanted shunt according to the
disclosed inventions;
[0073] FIG. 41 is a schematic flow diagram of another exemplary
method of assessing the patency of an implanted shunt according to
the disclosed inventions;
[0074] FIGS. 42A-B are cross-sectional views of a deployed
endovascular shunt according to embodiments of the disclosed
inventions;
[0075] FIGS. 43A-D are perspective, side and cross-sectional views
of a delivery catheter, according to one embodiment of the
disclosed inventions;
[0076] FIGS. 44A-E are side and cross-sectional views of the
creation of anastomosis using the delivery catheter of FIGS.
43A-D;
[0077] FIGS. 45A-D are side and cross-sectional views of a piercing
element constructed according to one embodiment of the disclosed
inventions;
[0078] FIGS. 46A-G are side and cross-sectional views of a piercing
element constructed according to another embodiment of the
disclosed inventions;
[0079] FIGS. 47A-50B are perspective, side and cross-sectional
views of an expandable balloon constructed according to various
embodiments of the disclosed inventions;
[0080] FIGS. 51A-54C are perspective, side and cross-sectional
views of piercing elements constructed according to various
embodiments of the disclosed inventions;
[0081] FIGS. 55A-55E are perspective, side and cross-sectional
views of cuts in the elongated body of the shunt, constructed
according to one embodiment of the disclosed inventions;
[0082] FIGS. 56A-60C are perspective and side views of patterns of
the cuts in the elongated body of the shunt, constructed according
to various embodiments of the disclosed inventions;
[0083] FIGS. 61A-D are side and cross-sectional views of an
alternative embodiment of the shunt having a piercing element
cover, constructed according to one embodiment of the disclosed
inventions;
[0084] FIGS. 62A-D are cross-sectional views of a shuttle element
for covering piercing elements during delivery of the shunt,
according to an embodiment of the disclosed inventions;
[0085] FIGS. 63A-G are perspective and cross-sectional views of an
endovascular shunt according to yet another embodiment of the
disclosed inventions;
[0086] FIGS. 64A-C are cross-sectional views of a distal anchoring
mechanism of an endovascular shunt according embodiments of the
disclosed inventions;
[0087] FIGS. 65A-E are perspective, side and cross-sectional views
of a delivery catheter, according to another embodiment of the
disclosed inventions;
[0088] FIG. 66 is a perspective views of a guidewire, according to
one embodiment of the disclosed inventions; and
[0089] FIGS. 67A-D are cross-sectional views of delivery catheters,
according embodiments of the disclosed inventions.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0090] For the following defined terms, these definitions shall be
applied, unless a different definition is given in the claims or
elsewhere in this specification.
[0091] All numeric values are herein assumed to be modified by the
term "about," whether or not explicitly indicated. The term "about"
generally refers to a range of numbers that one of skilled in the
art would consider equivalent to the recited value (i.e., having
the same function or result). In many instances, the terms "about"
may include numbers that are rounded to the nearest significant
figure.
[0092] The recitation of numerical ranges by endpoints includes all
numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75,
3, 3.80, 4, and 5).
[0093] As used in this specification and the appended claims, the
singular forms "a", "an", and "the" include plural referents unless
the content clearly dictates otherwise. As used in this
specification and the appended claims, the term "or" is generally
employed in its sense including "and/or" unless the content clearly
dictates otherwise.
[0094] Various embodiments are described hereinafter with reference
to the figures. The figures are not necessarily drawn to scale, the
relative scale of select elements may have been exaggerated for
clarity, and elements of similar structures or functions are
represented by like reference numerals throughout the figures. It
should also be understood that the figures are only intended to
facilitate the description of the embodiments, and are not intended
as an exhaustive description of the invention or as a limitation on
the scope of the invention, which is defined only by the appended
claims and their equivalents. In addition, an illustrated
embodiment needs not have all the aspects or advantages shown. An
aspect or an advantage described in conjunction with a particular
embodiment is not necessarily limited to that embodiment and can be
practiced in any other embodiments even if not so illustrated.
[0095] References herein to the term "endovascular," such as
endovascular shunt or endovascular approach, generally refer to
minimally-invasive devices, systems, and procedures configured for
introduction into a patient's vasculature through a small access
device (e.g., needle or introducer sheath) without a large incision
or open surgical procedure, and using the vasculature to guide
various catheters, shunts, and other system elements described
herein percutaneously to a target procedural location disposed
within or about the patient's vasculature (e.g., intracranial
venous sinuses). It should be appreciated that the terms implanting
and/or deploying, and the terms implanted and/or deployed, are used
interchangeably herein. Additionally, the terms member or element
are interchangeably herein.
[0096] FIG. 1 is a schematic diagram showing the head 100 of a
human patient. Within each side of the patient's head, an inferior
petrosal sinus (IPS) 102 connects a cavernous sinus (CS) 104 to a
jugular vein 106 and/or a jugular bulb 108. For clarity, the
acronym "IPS" is used herein to refer generally to the inferior
petrosal sinus and more particularly to the interior space (or
lumen) of the inferior petrosal sinus. The IPS 102 facilitates
drainage of venous blood into the jugular veins 106. In some
patients, the junction of the IPS 102 and the jugular vein 106
occurs within the jugular bulb 108. However, in other patients,
this junction can occur at other locations in the jugular vein 106.
Moreover, while the IPS 102 in FIG. 1 is a single sinus passageway,
in some patients the IPS can be a plexus of separate channels that
connect the CS to jugular vein 106 (not shown) and/or jugular bulb
108.
[0097] Embodiments of the disclosed inventions are described with
respect to a target penetration site in the IPS 102 to access the
CSF-filled cerebellopontine (CP) angle cistern 138, which provide a
conduit for CSF to flow from the subarachnoid space 116 into the
jugular bulb 108, jugular vein 106, and/or the superior vena
cava-right atrium junction 105 (FIGS. 1, 2, and 42B). The delivery
assemblies and shunts described herein can access the target
penetration site in the IPS 102 through a venous access location in
the patient. The delivery assemblies and shunts described herein
can penetrate the dura mater IPS wall 114 and the arachnoid layer
115 to access the CP angle cistern 138 from within a superior
petrosal sinus (SPS) 122 (FIGS. 1 and 2) for delivery and
implantation of the shunt at the target site. The dura mater IPS
wall 114 is also referred to herein as the dura IPS wall 114, or
simply as the IPS wall 114. The SPS is a small diameter venous
sinus that connects from the sigmoid sinus (distally located to
jugular bulb 108) to the cavernous sinus 104 (FIG. 1). Further, the
delivery assemblies and shunts described herein can be advanced
through the IPS 102 and into the cavernous sinus 104, so that an
anastomosis (not shown) can be created in the upper portion or roof
of the cavernous sinus 104 to access the CSF-filled suprasellar
cistern 148, shown in FIG. 1, for implantation of the shunt at such
target site. Whether penetration to access a target site,
deployment and implantation of a shunt occurs from the lumen of the
SPS or cavernous sinus to access CSF in the subarachnoid space, the
embodiments of the inventions described herein provide a conduit
for CSF to flow from the subarachnoid space into the jugular bulb
108, jugular vein 106, and/or the superior vena cava-right atrium
junction 105.
[0098] FIG. 2 shows a cross-sectional view of a portion of head
100, including IPS 102, jugular vein 106, and jugular bulb 108. In
addition, basilar artery 110, brain stem 112, pia 112a, and IPS
wall 114 are also shown in FIG. 2. The IPS is a relatively small
diameter intracranial venous sinus that facilitates drainage of
cerebral venous blood into the jugular vein; the IPS is formed by a
cylindrical layer of dura mater, typically about 0.9 mm to 1.1 mm
thick for the portion of IPS wall 114 shown in FIG. 2, which
creates a hollow lumen through which blood flows. In the
cross-section view of FIG. 2, the hollow lumen of the IPS resides
between upper IPS wall 114 and a lower IPS wall 117, also comprised
of dura mater; the IPS itself lies in a bony groove or channel in
the clivus bone (not shown) beneath IPS wall 117 in FIG. 2.
[0099] A cross-section of the IPS 102 orthogonal to the plane
depicted in FIG. 2 would show that the cylindrical layer of dura
mater forming IPS 102 is surrounded by bone for about 270 degrees
of its circumference with the remaining portion of the IPS
circumference (i.e., IPS wall 114 in FIG. 2) covered by arachnoid
matter 115 and facing CP angle cistern 138. Arachnoid mater 115
(also referred to herein as the arachnoid tissue layer or the
arachnoid layer) is a delicate and avascular layer, typically about
0.05 mm to 0.15 mm thick, that lies in direct contact with the dura
mater comprising the exterior of IPS wall 114; arachnoid layer 115
is separated from the pia mater surrounding brain stem 112 by the
CSF-filled subarachnoid space 116 (e.g., CP angle cistern 138). The
lower portion of the IPS 102, opposite to the IPS wall 114 is the
IPS wall 117 formed by dura mater that sits in a channel in the
clivus bone (not shown).
[0100] It should be appreciated that for the embodiments of the
disclosed inventions, the methods and devices are configured to
create an anastomosis via an endovascular approach by piercing or
penetrating from within the hollow IPS 102 to pass through the dura
of IPS wall 114, and continue penetrating through the arachnoid
layer 115 until reaching the CSF-filled subarachnoid space 116
(e.g., CP angle cistern 138). For ease of illustration, it should
be appreciated that the arachnoid matter 115 covering the IPS wall
114 is present, although, not shown in certain figures.
[0101] The diameter d.sub.1 of IPS 102 is approximately 3 mm but
can range from approximately 1 mm to about 6 mm. As shown in FIG.
2, at the junction 118 between the IPS 102 and the jugular bulb 108
and/or jugular vein 106, the diameter d.sub.2 of the IPS 102 can
narrow. For example, d.sub.2 is approximately 2 mm, but can be as
small as about 0.5 mm. The length of the IPS 102 from the junction
118 with the jugular vein 106 to the cavernous sinus 104 (shown in
FIG. 1) is approximately in a range between 3.5 cm to 4 cm.
[0102] As shown in FIG. 1, most patients have two IPS 102 and two
jugular veins 106 (left and right). In a very small percentage of
patients (e.g., less than 1%), there is no connection between one
IPS and the corresponding jugular vein. It is highly unlikely,
however, that any given patient will lack connections to the
corresponding jugular veins on both left and right IPS.
[0103] Subarachnoid spaces are naturally occurring separations
between the pia mater and the arachnoid layer where the CSF pools.
Typically, the CSF is passed into a subarachnoid space over the
cerebral hemispheres and then into the venous system by arachnoid
granulations. The subarachnoid space 116 in FIG. 2 corresponds to a
cerebellopontine (CP) angle cistern 138, which acts as a reservoir
for CSF. In patients with hydrocephalus, a build-up of CSF within
the CP angle cistern 138 (in addition to other cisterns) can occur,
for example, if patients lack properly functioning arachnoid
granulations. If the excess CSF is not removed, the resulting
excess intracranial pressure can lead to symptoms such as headache,
neurological dysfunction, coma, and even death.
[0104] FIG. 3A illustrates an exemplary endovascular shunt 200
implanted in the IPS 102 according to the embodiments of the
disclosed inventions. The shunt 200 is delivered and implanted into
a patient percutaneously via a catheter inserted into the venous
system of the body through a needle hole (e.g., in the femoral or
jugular vein), without requiring boring into a patient's skull,
general anesthesia, or other open surgical techniques. The shunt
200 includes a tubular configuration having a proximal portion 204,
an elongate body 203, a distal portion 202, and an inner lumen 207
extending therebetween. When the shunt 200 is implanted in a target
site of the patient (e.g., inferior petrosal sinus), the distal
portion 202 of the shunt has accessed and is at least partially
disposed in the CSF-filled CP angle cistern 138, so that the body
203 of the shunt 200 is disposed in the IPS 102, and the proximal
portion 204 is at least partially disposed in the jugular bulb 108
and/or the jugular vein 106. The implanted shunt 200 provides a
fluid communication between the CP angle cistern 138 into the
jugular bulb 108 and/or jugular vein 106 so that CSF is drained
through the lumen 207 of the shunt 200 from the subarachnoid space
116 to the venous system (e.g., jugular vein 106). When the shunt
200 is deployed at the target site, CSF enters the distal intake
opening 251 (FIG. 6), flows through the lumen 207, and exits out
the proximal opening 205 (FIG. 6) of the shunt 200.
[0105] Shunt 200 capitalizes on a favorable pressure gradient
between the subarachnoid space 116 and venous system (e.g., jugular
vein 106) to drive CSF through the lumen 207. In patients without
hydrocephalus, the normal differential pressure between the
intracranial pressure of the subarachnoid space 116 (e.g., CP angle
cistern) and blood pressure of the venous system (e.g., IPS or
jugular vein) is about 5 to 12 cm H2O; this differential pressure
between the subarachnoid space and venous system can be
significantly higher in hydrocephalic patients. Once deployed and
implanted, the shunt 200 facilitates one-way flow of CSF from the
CP angle cistern 138 into the jugular bulb 108 and/or jugular vein
106 where CSF is carried away by venous circulation, similar to the
way that normally functioning arachnoid granulations drain CSF into
the venous system. Shunt 200 prevents backflow of venous blood
through inner lumen 207 into subarachnoid space 116 via one or more
one-way valves or other flow regulating mechanisms described
herein. The shunt 200 allows for a more physiologic drainage of CSF
by directing CSF into the cerebral venous system, a process that
occurs naturally in people without hydrocephalus. In this manner,
the pressure created by the excess CSF in the subarachnoid space
116 is relieved, and patient symptoms due to hydrocephalus can
thereby be ameliorated or even eliminated. The shunt 200 may also
include a flow regulating mechanism 209 configured to regulate
fluid flow through the shunt lumen 207.
[0106] The IPS 102 anatomy supports long-term stability of the
shunt 200 relative to other locations potentially suitable for
endovascular shunt deployment for treating hydrocephalus.
Particularly, the relatively long length and narrow diameter of the
IPS 102 (compared to other venous sinuses) provides a natural
housing for the shunt 200. The foundation provided by the grooved
portion of the clivus bone that surrounds about two-thirds of the
IPS circumference further supports long-term stability of the shunt
200, and presents a stable platform that delivery systems disclosed
herein can leverage during shunt implant procedures. Proximity to a
well-established, CSF-filled cistern such as the CP angle cistern
138 further supports IPS 102 as a preferred implant location
compared to other endovascular shunting techniques. Moreover,
occlusion of the IPS 102 from shunt 200 placement represents little
to no risk for the patient, as the IPS 102 plays a relatively
unimportant role in the overall intracranial venous blood
circulation scheme unlike larger diameter dural venous sinuses such
as the sagittal sinus, sigmoid sinus, straight sinus, and
transverse sinus.
[0107] The proximal portion 204 of the deployed shunt 200 that
extends from the junction 118 into the jugular bulb 108 and/or the
jugular vein 106 may be in a range between 1 mm to 5 mm (e.g., 2-3
mm), or any other suitable length configured to extend into the
jugular bulb 108 and/or the jugular vein 106 from the junction 118.
The proximal portion 204 of the deployed shunt 200 is disposed
adjacent to the jugular bulb 108. The circulation of venous blood
flow around the proximal portion 204 of the shunt 200, disposed in
the jugular bulb 108 and/or the jugular vein 106, constantly and
gently agitates the proximal portion 204, minimizing, deterring or
avoiding growth of endothelial cells and clogging of the lumen 207
opening 205 at the proximal portion 204 of the shunt 200. Venous
blood flow rates in jugular vein 106 can be significantly higher
than the blood flow rates in larger diameter dural venous sinuses
(i.e., sagittal, sigmoid, straight, transverse), which favor
long-term shunt patency of the disclosed embodiments.
[0108] Alternatively, the proximal portion 204 of the shunt 200
further extends from the jugular vein 106 and/or jugular bulb 108
into the superior vena cava-right atrium junction 105, in one or
more embodiments of the disclosed inventions, as shown in FIGS.
42A-B. In such embodiments, the implanted shunt 200 is configured
to extend from the CP angle cistern 138 through IPS 102 and jugular
vein 106 into the right atrium 107 of the heart 109 (FIG. 42A);
particularly, the proximal portion 204 having the proximal opening
205 in communication with the lumen 207 of the shunt 200, and/or
the valve 209, is disposed at the junction 105 between the superior
vena cava 101 and the right atrium 107 of the heart 109, preventing
or avoiding extending into the right atrium 107 (FIG. 42B).
Alternatively or additionally, the shunt 200 can include a tubular
extension 204' (e.g., silicone or other biocompatible material
catheter or the like) coupled to the proximal portion 204 of the
shunt 200 disposed in the jugular vein 106 and/or jugular bulb 108,
so that the proximal portion 204 further extends into the superior
vena cava-right atrium junction 105. In this embodiment, the
proximal portion 204 of the deployed shunt 200 is at least
partially disposed within, or proximate to, an intersection of a
superior vena cava and right atrium of the patient. In such
embodiments, the extended proximal portion 204, 204' of the shunt
200 relies on turbulent blood flow proximate to the superior vena
cava-right atrium junction 105 to maintain patency and avoid
clogging (e.g., by endothelial cell ingrowth) of the extended
proximal portion 204, 204' of the shunt 200. In this embodiment,
the valve 209 can be disposed in the extended proximal portion 204,
204' within the superior vena cava-right atrium junction 105.
[0109] The implanted shunt 200 may not occlude the IPS 102, for
example, when the diameter of the shunt 200 is smaller than the
diameter of the IPS 102, so that venous blood flow continues
through the IPS 102 into the jugular vein 106. Alternatively, the
implanted shunt 200 may occlude the IPS 102 preventing venous blood
flow from the cavernous sinus into the jugular vein 106. However,
it has been observed that an occluded IPS, whether resulting from a
surgical procedure or thrombosis, typically has no impact on a
patient's venous circulatory function.
[0110] FIG. 3B is a side view of a delivery assembly 300 for
delivering the shunt 200 into a target site of a patient,
constructed in accordance with embodiments of the disclosed
inventions. The delivery assembly 300 includes the shunt 200
detachably coupled to the delivery assembly 300. The delivery
assembly 300 and shunt 200 may be composed of suitable
biocompatible materials. The delivery assembly 300 is dimensioned
to reach remote locations of the vasculature and is configured to
deliver the shunt 200 percutaneously to the target location (e.g.,
inferior petrosal sinus). The delivery assembly 300 includes a
tubular member interface having an outer tubular member 320 (i.e.,
guide catheter) and an inner tubular member 304 (i.e., delivery
catheter/microcatheter) coaxially disposed within the outer tubular
member 320 and movable relative to the outer tubular member 320.
The delivery assembly 300 may include a guidewire 302 coaxially
disposed within the guide catheter 320 and/or the delivery catheter
304. The guidewire 302 can be, for example, 0.035 inches (0.889 mm)
in diameter. Additionally to the guidewire 302, the delivery
assembly 300 may include a delivery guidewire 308 disposed within
the delivery catheter 304. The delivery guidewire 308 has a smaller
diameter (e.g., approximately 0.010 inches--0.254 mm- to 0.018
inches--0.4572 mm--) compared to guidewire 302.
[0111] The guide catheter 320, delivery catheter 304, and
guidewires 302/308 may be formed of suitable biocompatible
materials, and may include markings for purposes of imaging (e.g.,
markers composed of radio-opaque materials). Further, the delivery
catheter 304 may include one or more anchoring mechanisms disposed
along the body of the catheter allowing temporary anchoring of the
catheter 304 within IPS 102 during the deployment of the shunt 200.
The anchoring mechanisms configuration and actuation may be similar
as the anchoring mechanisms of the shunt 200 described in further
detail below. For example, the anchoring mechanism of the delivery
catheter 304 may be actuated (e.g., engagement and disengagement
within the IPS 102) using a guidewire.
[0112] Various known and often necessary accessories to the
delivery assembly 300, e.g., one or more radiopaque marker bands 13
at the distal portion 324 of the guide catheter 320 to allow
viewing of the position of the distal portion under fluoroscopy and
a Luer assembly 17 for guidewires and/or fluids access, are shown
in FIG. 3B.
[0113] The delivery assembly 300 may include a tissue penetrating
element 306 coaxially disposed within the delivery catheter 304
and/or guide catheter 320 and/or shunt 200. The tissue penetrating
element 306 is configured to pierce the IPS wall 114 and arachnoid
layer 115 to access the CP angle cistern 138 for implantation of
the shunt 200. Alternatively, the shunt 200 includes a tissue
penetrating member 250 on the distal portion 202 of the shunt 200'
(e.g., FIGS. 5C-I and FIGS. 14F-H), so the tissue penetrating
element 306 is not required in the delivery assembly 300, since the
tissue penetrating member 250 incorporated in the shunt 200' is
configured to pierce the IPS wall 114 and arachnoid layer 115. (For
ease in illustration, the various embodiments of the shunt
disclosed and illustrated herein are given the reference number 200
or 200', although the embodiments may differ from each other in
certain aspects and features.)
[0114] FIGS. 4A-4D illustrate an exemplary method of delivering the
shunt 200 into the target site (e.g., inferior petrosal sinus) to
drain CSF from a cistern in the subarachnoid space 116 (e.g., CP
angle cistern 138) in accordance with embodiments of the disclosed
inventions. After gaining access to the vasculature of a patient
(e.g., via the femoral vein or the jugular vein 106), the guide
catheter 320 and/or the guidewire 302 of the delivery assembly 300
may be advanced through the vasculature into the IPS 102 or a
location proximate to the IPS 102 and IPS wall 114. When the
guidewire 302 is used for navigation of the delivery assembly 300
into the target site, the guidewire 302 is further advanced to
establish a pathway along which the delivery assembly 300 may be
advanced. After the guidewire 302 has been positioned in a desired
location, the guide catheter 320 may be advanced over the guidewire
302, so that a distal portion 324 of guide catheter 320 is within
the jugular bulb 108, near the junction 118 between the IPS 102 and
jugular vein 106. Alternatively, the guide catheter 320 may be
advanced to the location near the junction 118, and the guidewire
302 is further advanced into the IPS 102. In a further alternative
method, the guide catheter 320 is advanced to the desired location
near the junction 118 without the use of the guidewire 302.
[0115] With the guide catheter 320 positioned at or about the
junction 118 between jugular vein 106 and IPS 102, as shown in FIG.
4B, the delivery catheter 304 and the delivery guidewire 308,
disposed within the delivery catheter 304, are advanced within the
guide catheter 320. The delivery catheter 304 and delivery
guidewire 308 are further advanced to the distal portion 324 of
guide catheter 320, which is located in the jugular vein 106. The
delivery guidewire 308 is then passed through the junction 118
between jugular vein 106 and IPS 102 and into the opening of IPS
102 in the medial wall of the jugular dome. The delivery guidewire
308 is then further advanced within IPS 102 to the posterior aspect
of the cavernous sinus. The distal portion 334 of delivery
guidewire 308 may be more flexible than other portions of the
delivery guidewire 308 to facilitate navigation into the IPS 102
from jugular vein 106 and into the cavernous sinus.
[0116] Next, the delivery catheter 304 is advanced over the
delivery guidewire 308 and into IPS 102. Advancement of delivery
catheter 304 continues until a distal portion 344 of delivery
catheter 304 is positioned adjacent or proximate to a desired point
on IPS wall 114 where the shunt 200 is to be inserted to form an
anastomosis between the CP angle cistern 138 and the lumen of IPS
102. Alternatively, the delivery guidewire 308 and the delivery
catheter 304 may be advanced incrementally and sequentially into
the opening of the IPS 102 at junction 118 and through one or more
portions of the IPS 102.
[0117] Once the delivery guidewire 308 and delivery catheter 304
are located at a desired location within the IPS 102 for shunt
deployment, the delivery guidewire 308 can be advanced to the
posterior aspect of the cavernous sinus. The delivery guidewire 308
can serve as a support for the delivery catheter 304 within the IPS
102 and for shunt 200 deployment.
[0118] A variety of different imaging methods can be used to ensure
accurate positioning of the shunt 200, guide catheter 320,
guidewire 302, delivery catheter 304, and/or delivery guidewire
308, described above. Examples of suitable imaging methods include
biplane fluoroscopy, digital subtraction angiography with road
mapping technology, venous angiography with road mapping
technology, 3D-rotational angiography or venography (3DRA or 3DRV),
and cone-beam computed tomographic angiography or venography (CBCTA
or CBCTV). Both 3DRA/V and CBCTA/V enable volumetric reconstruction
showing the relationship between the bony anatomy, the venous
anatomy and the radiopaque catheters and guidewires used for shunt
deployment. The methods of deploying the shunt 200 comprise imaging
the shunt 200 while deploying the shunt 200 in the patient.
[0119] In some embodiments, positioning the delivery catheter 304
within the IPS 102 also includes rotating the delivery catheter 304
about its central axis to properly orient the delivery catheter 304
prior to deploying the shunt 200 or introducing the shunt 200 into
the distal portion 344 of the delivery catheter 304. As shown in
FIG. 4D (described in greater detail below), in certain
embodiments, the delivery catheter 304 is curved (e.g., pre-curved,
biasedly curved, flexible, drivable distal portion via control
wires, or the like, or combinations thereof) near the distal
portion 344 of the catheter so that when the delivery guidewire 308
and/or the shunt 200 are advanced through the delivery catheter
304, they approach and reach the IPS wall 114 at an angle relative
to a central axis 103 of IPS 102 (FIGS. 4B-C). The delivery
catheter 304 can be rotated, for example, by applying a rotational
force directly to the body of the delivery catheter 304, or to the
delivery guidewire 308 if the guide wire is connected to the
delivery catheter 304. Positioning the curved distal portion 344 of
the delivery catheter 304 in the desired orientation adjacent to
the IPS wall 114 can facilitate puncturing of the IPS wall 114 and
arachnoid layer 115 to access the CP angle cistern 138. When
deploying the shunt 200, the methods of deployment comprises
introducing the shunt 200 into the patient's body while the shunt
200 is at least partially disposed in the delivery catheter 304,
and wherein the delivery catheter 304 is advanced over guidewire
extending through a lumen of the delivery catheter 304, which may
be a same or different lumen in which the shunt 200 is at least
partially disposed, until a distal portion of the delivery catheter
304 is positioned in the IPS 102 (FIG. 4B).
[0120] Referring to FIG. 4C, prior to introducing the shunt 200, a
tissue penetrating element 306 located at a distal portion 354 of
an elongate pusher member 310 (e.g., piercing micro-wire) having a
penetrating member 306, can be used to pierce the IPS wall 114 and
arachnoid layer 115, creating anastomosis 140 (e.g., a connection
channel, hole, space into which the shunt 200 is later delivered
and implanted). The elongate pusher member 310 may be advanced
through either the guide catheter 320 or delivery catheter 304. By
applying a suitable mechanical force to the elongate pusher member
310, the penetrating member 306 can be advanced through the IPS
wall dura mater 114 and the arachnoid layer 115 that separate the
lumen of IPS 102 from subarachnoid space 116 (FIG. 2), creating the
anastomosis 140 for the shunt 200 deployment. For example, the
penetrating element 306 may include a needle tip with a rounded or
bullet-like configuration. The penetrating element 306 rounded or
bullet-like tip separates the dura fibers without damaging them
while the elongate pusher member 310 having sufficient stiffness
passes through the dura mater of IPS wall 114 and the arachnoid
layer 115 into the CP angle cistern 138.
[0121] Alternatively, the penetrating element 306 includes a
sharpened tip or trocar, which cuts through the IPS wall dura mater
114 and the arachnoid layer 115 to create the anastomosis 140 for
the shunt 200 deployment. In certain embodiments, the penetrating
element 306 includes a controllable radiofrequency ablation device
for creating the anastomosis 140 through the dura mater of IPS wall
114 and the arachnoid layer 115 to access the CSF-filled space of
the CP angle cistern 138.
[0122] Further, an interface between the penetrating element 306
and the shunt 200 is provided to collaboratively create the
anastomosis 140, which will be described in greater detail in FIG.
33A-C.
[0123] The location of the penetrating element 306 relative to the
IPS wall 114 can be monitored using any of the imaging techniques
described above, and/or can be detected based on a tactile feedback
communicated by the elongate pusher member 310 to a clinician. For
example, a clinician can detect a brief "click" or "snap" (e.g.,
tactile feedback) as the penetrating element 306 passes and creates
anastomosis 140 through IPS the wall 114. The elongate pusher
member 310 and/or penetrating element 306 can include one or more
radio-opaque markers 356, 366 to assist in vivo imaging and
guidance while the clinician creates the anastomosis 140 for shunt
deployment. For example, suitable markers can be included (e.g.,
embedded) or applied (e.g., coatings) to the outer surface of the
penetrating element 306 and/or elongate pusher member 310 in a
pattern that is readily/visually recognized by the clinician. An
example of a radio-opaque material that can be used to apply
suitable markings is barium sulfate.
[0124] Once the IPS wall 114 and arachnoid layer 115 are pierced
creating the anastomosis 140, the elongate pusher member 310 and
the penetrating element 306 are withdrawn. Next, as shown in FIG.
4D, the shunt 200 is advanced through the delivery catheter 304
(i.e., inner lumen 305 of the delivery catheter 304) into the
anastomosis channel 140 formed by piercing the IPS wall 114 and
arachnoid layer 115. Alternatively, when the shunt 200' that
includes a piercing element is used in the delivery assembly 300,
the shunt 200' pierces the IPS wall 114 and arachnoid layer 115
creating the anastomosis; so that the distal portion 202 of the
shunt 200' is disposed into the anastomosis channel 140 without
requiring withdrawal of the piercing element, elongate pusher
member 310 or penetrating element 306. The alternative method using
the shunt 200' having a piercing element will be described in
greater detail in FIGS. 5A-I and FIGS. 14F-H. As further
alternatives, the shunt 200 can accompany a penetrating element
through the dura of IPS wall 114 and arachnoid 115 (e.g., as
described in FIGS. 20A-F) or shunt 200 can be delivered through a
lumen of the penetrating element (e.g., as described in connection
with FIGS. 43, 44, 47), without an exchange or removal of delivery
system components between the penetration and shunt deployment
steps of the implant procedure.
[0125] Referring back to FIG. 4D, the shunt 200 can be delivered
through the delivery catheter 304 by advancing over the delivery
guidewire 308. The distal portion 202 of the deployed shunt 200
comprises a distal anchoring mechanism 229, as shown, for example
in FIG. 22A, that positions the distal portion 202 of the shunt so
as to maintain the one or more CSF intake openings 201 separated,
apart and/or directed away from an arachnoid layer 115 of the CP
angle cistern 138. The proximal portion 204 of the deployed shunt
200 comprises a proximal anchoring mechanism 227, as shown, for
example in FIG. 22A, that positions the proximal portion 204 of the
shunt to thereby maintain a CSF outflow port and/or valve 209
opening disposed in the proximal portion of the shunt 200
separated, apart and/or directed away from a wall of the jugular
vein 106. To facilitate placement of shunt 200 using a guidewire,
the body of shunt 200 can include an interior lumen 217, separate
from the lumen 215 used to communicate CSF (FIG. 8), which is
dimensioned to receive or slide over the delivery guidewire 308, or
a groove or rail (e.g., on an internal surface or on the external
surface of the shunt body) that mates in complementary fashion with
a corresponding structural feature of the delivery guidewire 308.
In addition to forward advancement of shunt 200 relative to the
delivery catheter 304, a connection interface 213 and 313 (FIG. 7)
between the delivery guidewire 308 and the shunt 200 permits
rotation (e.g., by rotating guidewire 308) of the shunt 200 about a
central axis of the shunt body 203 to ensure that the distal
portion 202 of shunt 200 is properly oriented to track toward a
deployment site in the CP angle cistern 138.
[0126] The delivery catheter 304 disposed within the IPS 102 and,
when present, the curved end distal portion 344 of the delivery
catheter 304, allows for the distal portion 202 of the shunt 200 to
be delivered into the anastomosis channel 140 and to extend into
the CP angle cistern 138, while allowing the body portion 203 of
shunt 200 to be disposed within the IPS 102, and the proximal
portion 204 of the shunt 200 to extend through the junction 118 and
into the jugular bulb 108 and/or jugular vein 106. After the shunt
200 is properly positioned, the delivery catheter 304, and any
remaining elements of the delivery assembly 300 (e.g., delivery
guidewire 308, guidewire 302, and guide catheter 320) are
withdrawn, leaving the implanted shunt 200 in situ, as shown in
FIG. 3A. The implanted shunt 200 provides a fluid communication
between the CP angle cistern 138 and into the jugular vein 106, so
that CSF is drained through the lumen 207 (or 215 when the shunt
200 includes multiple lumens) of the shunt 200. The CSF within the
CP angle cistern 138 enters the lumen 207 opening at the distal
portion 202 of the shunt 200, flows through the lumen 207 at the
body 203, and emerges from the lumen 207 opening at the proximal
portion 204 of the shunt 200, so that CSF is then carried away by
venous circulation within jugular bulb 108 and/or jugular vein
106.
[0127] As discussed above in connection with the guide catheter 320
and the delivery catheter 304, a variety of different imaging
techniques can be used to ensure proper or desirable deployment of
the shunt 200 within the CP angle cistern 138 and IPS 102. A
clinician deploying the shunt 200 can also rely on tactile
feedback, communicated through the delivery guidewire 308 or the
delivery catheter 304, to ensure proper positioning of the shunt
200. Typically, once properly deployed, the distal portion 202 of
the shunt 200 extends above arachnoid layer 115 into the CP angle
cistern 138 at a distance between 1 mm to 5 mm (e.g., 2-3 mm), or
any other suitable length configured to extend into the CP angle
cistern 138 while leaving suitable clearance between the distal tip
of the shunt 200 and the brain stem 112.
[0128] In some embodiments, the shunt 200 and/or penetrating member
of the delivery system includes measurement features to confirm
appropriate placement within the CP angle cistern 138 (e.g., an
electrical resistance detector configured to differentiate between
dura mater and CSF, a fluid composition detector configured to
differentiate between blood and CSF, and/or a light source and
sensor configured to differentiate between dura mater, blood, and
CSF based on reflected light). Further, in some embodiments a stop
member is proximally disposed to the penetrating element 306
(surgical tool or any other piercing element) preventing the
penetrating element 306 and/or the shunt 200/200' from being
deployed beyond a suitable distal length into the CP angle cistern
138, allowing suitable clearance between the distal tip of the
shunt 200/200' and the brain stem 112, while avoiding abutting or
the damaging brain stem 112. In some embodiments, a cover 260
slidably disposed over the tissue penetrating member 250 of the
shunt 200' is provided to cover the tissue penetrating member 250
after deployment of the shunt 200', which will be described in
greater detail in FIG. 61 A-D.
[0129] Before or after deployment of the shunt 200, confirmation
that the anastomosis 140 has been created between the CP angle
cistern 138 and IPS 102 may be performed. For example, CSF can be
withdrawn through the delivery catheter 320 using a syringe
connected to the Luer assembly 17 of the delivery assembly 300
(FIG. 3B), confirming that the wall 114 and arachnoid 115 have been
penetrated, the CP angle cistern 138 has been accessed, and/or the
anastomosis 140 has been created. In some embodiments, the delivery
catheter 320 includes measurement features to confirm that the
anastomosis 140 has been created with the CP angle cistern 138
(e.g., an electrical resistance detector configured to
differentiate between dura mater and CSF, a fluid composition
detector configured to differentiate between blood and CSF, and/or
a light source and sensor configured to differentiate between dura
mater, blood, and CSF based on reflected light).
[0130] FIGS. 4A-D disclose one exemplary method for deploying the
shunt 200 to treat hydrocephalus. According to the disclosed
inventions, the steps, sequence of steps, shunt, and delivery
assembly 300 elements to perform the steps, can be modified in a
variety of ways. For example, in an alternative method, the shunt
200 is deployed without using the delivery catheter 304. That is,
the shunt 200 is detachably coupled to the delivery guidewire 308
and advanced through the guide catheter 320 until it is properly
positioned within the CP angle cistern 138 and IPS 102. Then, the
delivery guidewire 308 can be detached from the shunt 200, and the
guidewire 308 and guide catheter 320 are withdrawn, allowing the
shunt 200 to remain in situ and facilitate flow of CSF from the CP
angle cistern 138 into jugular bulb 108 and/or jugular vein
106.
[0131] In a further alternative method, the delivery catheter 304
can be used to pierce IPS wall 114 creating all or a portion of the
anastomosis 140. For example, the distal portion 344 of delivery
catheter 304 can be cut at an angle with respect to a central axis
of the catheter body, forming a sharp, tapered, cannula-like end,
which will be described in greater detail below. By applying a
suitable force to the delivery catheter 304, the distal portion 344
can be pushed through and pierce the IPS wall 114 to create all or
a portion of the anastomosis 140. This method can be used together
with, or instead of, the use of the penetrating element 306
connected to the elongate pusher member 310 to complete the
connection between the lumen of IPS 102 and CP angle cistern
138.
[0132] It should be appreciated that more than one shunt 200 can be
implanted at the target site. For example, when the implanted shunt
200 does not completely occupy the IPS 102, a clinician may have
sufficient space within the IPS 102 to deploy a second shunt. The
second shunt may be implanted in the IPS 102 adjacently or
proximate to the previously implanted shunt 200.
[0133] FIGS. 5A-J illustrate an alternative method of delivering
and implanting the shunt 200 into the target site to drain CSF from
a cerebral cistern, in accordance with embodiments of the disclosed
inventions. For ease in illustration, the features, functions, and
configurations of the delivery assembly 300' are the same as in the
assembly 300 of FIGS. 4A-D are given the same reference numerals.
The delivery assembly 300' of FIGS. 5A-J includes the guide
catheter 320, the delivery catheter 304, the delivery guidewire 308
of the assembly 300. The delivery assembly 300' further includes a
detachably coupled shunt 200' having a tissue penetrating member
250 disposed on the distal portion 202 of the shunt 200'.
Alternatively, the tissue penetrating member 250 may be a cut of
the distal portion 202 of the shunt 200' to form an angled, sharp,
cannula-like end or include a tip needle or the like. Further, the
tissue penetrating member 250 may be detachably coupled to the
shunt 200' so that the tissue penetrating member 250 is detached
and removed from the shunt 200', once the anastomosis is created
and/or the shunt 200' implanted in the target site (e.g., as shown
in FIGS. 5H-J).
[0134] Once the delivery catheter 304 carrying the shunt 200' has
been advanced and positioned, using any of the methods described
above, adjacent or proximate to a desired point on the IPS wall 114
where the shunt 200' is to be implanted (FIG. 5B), the guidewire
308 may be withdrawn and the shunt 200' is advanced (FIG. 5C). The
clinician may verify the orientation of the shunt 200', confirming
the orientation of the tissue penetrating member 250 with any of
the methods described above (e.g., fluoroscopic) (FIG. 5D). The
method includes positioning the distal portion 344 (e.g.,
pre-curved, biasedly curved, flexible, drivable distal portion via
control wires, or the like, or combinations thereof) of the
delivery catheter 304 in the proper orientation relative to the IPS
wall 114 (e.g., so that the open distal end of delivery catheter
304 faces and/or abuts IPS wall 114) to facilitate puncturing of
the IPS wall 114 and arachnoid layer 115, and access to the CP
angle cistern 138 (FIG. 5E). The positioning of the distal portion
344 of the delivery catheter 304 may include adjusting the
rotational orientation of the delivery catheter 304; so that the
tissue penetrating member 250 carried on the distal portion 202' of
the shunt 200' pierces the IPS wall 114 and arachnoid layer 115
creating the anastomosis 140 at a target penetration site. In some
embodiments, the delivery catheter 304 contains a second opening
spaced proximally from the distal end 344 of the delivery catheter
304, on an axial location of the catheter body 304 (e.g., at the
location of reference line 304 in FIG. 5E). The second opening is
configured to allow the delivery guidewire 308 to emerge from the
delivery catheter 304 and extend through the IPS 102 (e.g., to the
posterior aspect of the cavernous sinus) beyond the shunt 200
deployment site. This configuration of the delivery catheter 304
and the delivery guidewire 308 allows the clinician to orient the
delivery catheter 304 about the proposed shunt 200' deployment
location in the IPS 102 and supports the delivery and piercing
assembly during penetration of the IPS wall 114 to create
anastomosis 140.
[0135] By applying suitable mechanical force to the shunt 200',
tissue penetrating member 250 and/or the delivery catheter 304, the
tissue penetrating member 250 can be advanced through the dura
mater of IPS wall 114 and arachnoid layer 115 that separates the
lumen of IPS 102 from the subarachnoid space 116 (FIG. 2), creating
the anastomosis 140 (FIG. 5F). Alternatively, the delivery
guidewire 308 may be advanced into the CP angle cistern 138 (FIG.
5G). The distal portion 202' of the shunt 200' is further advanced
into the CP angle cistern 138 (FIG. 5H); once the shunt 200' is in
the desired location, the distal portion 202' is secured against
the arachnoid layer 115 and within the CP angle cistern 138 (FIG.
5I). In some embodiments, deploying the shunt 200' comprises
advancing the distal portion 202' of the shunt 200' from the IPS
102 into the CP angle cistern 138 using the tissue penetrating
member 250. The tissue penetrating member 250 is coupled to a
distal end 202' of the shunt 200, so that advancing the distal
portion 202' of the shunt 200' from the IPS 102 into the CP angle
cistern 138 comprises advancing the tissue penetrating member 250
and distal portion 202' of the shunt 200' through the dura mater
tissue wall of the IPS 114, and through the arachnoid tissue layer
115, respectively, into the CP angle cistern 138. Verification of
the desired position of the distal portion 202' end of the shunt
200' may be performed with any of the methods described above.
[0136] The distal portion 202' of the shunt 200' may include an
anchoring mechanism 225 that extends from, or is adjacent to, the
distal portion 202'. The anchoring mechanism 225 has a delivery
configuration and a deployed configuration. In the delivery
configuration, the anchoring mechanism 225 is configured to advance
through the delivery assembly 300 (e.g., delivery catheter 304) and
pass through the anastomosis channel 140. In the deployed
configuration, the anchoring mechanism 225 is configured to secure
the distal portion 202' of the shunt 200 over the arachnoid layer
115 and/or within the CP angle cistern 138 to allow fluid
communication of CSF from the CP angle cistern 138 into the jugular
bulb 108 and/or jugular vein 106. The method depicted in FIG. 5I
includes actuating the anchoring mechanism 225 into the deployed
configuration to secure the shunt 200' against the arachnoid layer
115 and within the CP angle cistern 138. Alternatively, the
anchoring mechanism 225 is biased to its deployed, expanded
configuration (e.g., by heat setting Nitinol to a malecot form) and
constrained to a delivery configuration to pass through delivery
catheter 304 to the deployment site. As the anchoring mechanism 225
is advanced through the delivery catheter 304 and the anastomosis
140 into the CP angle cistern 138 where CSF pools, anchoring
mechanism 225 resumes its biased, deployed configuration to anchor
the shunt 200' in the subarachnoid space 116. The method may
include imaging the shunt 200' during positioning, securing and
implanting of the shunt 200'.
[0137] The distal portion 202' of the shunt 200' and/or the distal
portion 202 of the shunt 200, may include one or more openings 219
(e.g., hole, perforation, mesh, porous material, or the like, or a
combination thereof) that allow for fluid communication into the
lumen 207 of the shunt 200', so that CSF in the CP angle cistern
138 flows through the implanted shunt 200' into the jugular bulb
138 and/or jugular vein 106. Opening(s) 219 is placed closest the
distal end of shunt 200 such that, once deployed, opening 219 is
sufficiently spaced away from the arachnoid layer (e.g., 2 mm to 3
mm) to prevent arachnoid from creeping into or otherwise occluding
CSF flow into shunt lumen 207.
[0138] Alternatively, when the tissue penetrating member 250 is
detachably coupled to the shunt 200', the tissue penetrating member
250 is disengaged and removed from the implanted shunt 200' (e.g.,
via a guidewire, elongate pusher member 310, or the like), as shown
in FIG. 5J, once the anastomosis has been created. In this
embodiment, the lumen 207 of the shunt 200', particularly, the
lumen 207 opening at the distal portion 202 of the shunt 200'
remains in fluid communication with the CP angle cistern 138 for
drainage of CSF. In this embodiment, CSF enters the shunt lumen 207
through the distal tip of shunt 200' and openings 219.
[0139] It should be appreciated that the method disclosed in FIGS.
5A-J may include any steps and features disclosed herein, including
steps and features disclosed in connection with different
embodiments, in any combination as appropriate.
[0140] FIG. 6 shows a cross-sectional view of the shunt 200
constructed in accordance with embodiments of the disclosed
inventions. As described above, the shunt 200 includes proximal
portion 204, distal portion 202, and elongate body 203 extending
between the proximal portion 204 and the distal portion 202. The
lumen 207 extends within body 203 from a proximal end 204'' of the
proximal portion 204 to distal end 202'' of the distal portion 202,
allowing CSF to pass through the body of shunt 200. The shunt 200
includes a proximal opening 205 in the proximal end 204'' and/or
proximal portion 204, in fluid communication with the lumen 207.
The shunt 200 further includes a distal CSF intake opening 201 in
the distal end 202'' and/or distal portion 202 in fluid
communication with the lumen 207. The proximal opening 205 and the
distal CSF intake opening 201 may include one or more openings. The
shunt 200 has a length L.sub.2, measured along an elongate central
axis 231 of the shunt 200, selected so that shunt 200 extends from
the CP angle cistern 138 to the jugular bulb 108 and/or the jugular
vein 106. In one embodiment, L.sub.2 is in a range between 15 mm to
30 mm. In further embodiments, the elongate body 203 may have
variable L.sub.2 within said range of 15 mm to 30 mm, in which the
elongate body 203 includes expandable members, such as bellows
(FIG. 6A in a compressed configuration and FIG. 6B in an expanded
configuration), folds (FIG. 6C in a folded configuration and FIG.
6D in an unfolded/expanded configuration), slidably disposed
concentric tubular elements (FIG. 6E shorter L.sub.2 compared to
larger L.sub.2 of FIG. 6F), spring-like, coil-like (FIG. 6G more
tightly wound coil--shorter L.sub.2--than of FIG. 6H),
configurations, or the like, or combinations thereof.
[0141] In some embodiments, the distal portion 202 of the shunt 202
is expanded or self-expands from a collapsed delivery configuration
to an expanded deployed configuration as, or after, it is advanced
into the CP angle cistern 138.
[0142] The shunt lumen 207 has an inner diameter L.sub.1 measured
in a direction orthogonal to axis 231 depicted in FIG. 6. The
diameter L.sub.1 can range between 0.1 mm (0.004 inches) to 5 mm
(0.2 inches) in different embodiments, and preferably falls within
the range of about 0.2 mm (0.008 inches) to about 0.36 mm (0.014
inches). Further, L.sub.1 and/or L.sub.2 may have any suitable
dimension for implantation of the shunt 200 in the target site
(e.g., IPS, CP angle cistern, or the like).
[0143] In some embodiments of the inventions, a constriction in the
inner diameter L.sub.1 of shunt lumen 207 for a particular length
L.sub.2 is calculated based on the Hagen-Poiseuille equation to
enable shunt 200 to provide for a target flow rate of CSF (in a
range of about 5 ml per hour to about 15 ml per hour) through the
shunt 200 at a normal differential pressure, defined as being in a
range between about 5 cm H2O to about 12 cm H2O between the
subarachnoid space 116 and venous system, as:
.DELTA. P = 128 .mu. L Q .pi. d 4 .mu. : viscosity Q : flow rate
.DELTA. P : differential pressure L : length d : diameter
##EQU00001##
[0144] For example, constricting the inner diameter L.sub.1 of
shunt lumen 207 to 0.19 mm over a length L.sub.2 of 8 mm will
maintain a CSF flow rate of 10 mL/hour at a differential pressure
of 6.6 cm H20. In the shunt embodiments without a constriction in
the inner lumen, the same equation and approach can be used to
configure the inner diameter of the shunt lumen along the entire
length of the shunt body 203 to achieve a target flow rate (or
range) for a given differential pressure (or range).
[0145] In some embodiments, the shunt 200 may include one or more
valves to regulate the rate of CSF flow within the shunt 200, while
allowing flow of CSF only in one direction, i.e., from the distal
portion 202 to the proximal portion 204 of the shunt 200. FIG. 6
depicts a valve 209 disposed within the shunt body 203, in fluid
communication with the lumen 207 of the shunt 200. The valve 209
may be disposed at any suitable location within the body 203, for
example, proximate to or at the proximal portion 204, to the distal
portion 202, and/or in between said portions 202, 204. In certain
embodiments, multiple valves can be disposed at different locations
within the shunt 200.
[0146] Valve 209 can include a specific cracking pressure that,
when met or exceeded by the positive pressure gradient between the
subarachnoid space and venous system, opens the valve thereby
facilitating CSF flow from the CP angle cistern into the jugular
vein. For example, the cracking pressure of valve 209 can be
configured from about 3 mm Hg to about 5 mm Hg and/or when the
differential pressure between the subarachnoid space and venous
system reaches from about 3 mm Hg to about 5 mm Hg; however, other
cracking pressures can be configured in valve 209 depending on the
particular clinical needs of the patient.
[0147] The valve 209 may have a variety of suitable features. For
example, the valve 209 is a one-way valve, such as a duck-bill
valve, as shown in FIG. 6 and FIG. 6I. Other suitable valves 209
can be used in the shunt 200, such as umbrella valves, pinwheel
valves, ball and spring valves (FIGS. 6J-K), concentric tube valves
(FIG. 6L), slit valves, check valves, flapper valves (FIG. 6N-O) or
the like, or combinations thereof. In addition, a one-way valve can
be formed from electrolytically erodible materials that can be
selectively eroded to configure the flow rate through the valve by
applying current to the valve for a specific period of time.
Suitable materials, systems, and methods that can be used to
configure such an erodible valve are further described in U.S. Pat.
No. 5,976,131, the entire content of which is incorporated herein
by reference.
[0148] FIGS. 6P-6T illustrate the valve 209 constructed according
to one embodiment of the disclosed inventions. As shown in FIG. 6P,
the valve 209 comprises a molded silicone element configured to fit
over the proximal portion 204 of the shunt 200. The proximal
portion 204 of the shunt 200 has a narrowed outer diameter L.sub.4
(e.g., dotted line portion of FIG. 6P) relative to the outer
diameter L.sub.3 of the body 203 of the shunt 200, configured to
support the valve 209 over the proximal portion 204 (FIG. 6R). The
proximal portion 204 of shunt 200 includes a beveled edge that
terminates at a proximal end 204'' (e.g., tip) of the shunt 200
(FIGS. 6Q-T). As shown in FIG. 6R, the valve 209 includes a
protrusion 239 extending from an inner surface 299 of the valve
209. The protrusion 239 is dimensioned and configured to engage a
recess 238 formed in the outer surface 206 of the proximal portion
204 of the shunt 200. When the valve 209 is inserted over the
proximal portion 204 of the shunt 200, the protrusion 239 and
recess 238 engage, thereby securing the valve 209 over the proximal
portion 204 of the shunt 200. The valve 209 can include two or more
interlocking protrusions 239, spaced apart (e.g., or on opposing
sides of the valve 209 inner surface 299--FIG. 6R), and the shunt
200 includes corresponding recesses 238 in the outer surface 206
configured to engage the respective protrusions 239 of the valve
209. The valve 209 further includes a first portion 249 having a
closed configuration, in which the portion 249 seats and/or covers
the beveled edge and the proximal opening 205 of the shunt 200 in
communication with the lumen 207 stopping fluid flow out of the
lumen 207 (FIGS. 6P-R), and having an opened configuration in which
the portion 249 separates from the beveled edge and the proximal
opening 205 of the shunt 200 in communication with the lumen 207 in
a swing motion or hinged-like fashion, allowing fluid flow out of
the lumen 207 (FIG. 6S). The valve 209 includes a second portion
259 configured to cover a portion of the outer surface 206 of the
shunt 200, as shown in FIGS. 6R-T. The first 249 and second 259
portions of the valve 209 may be formed by creating a cut or slit
269 in the molded silicone element of the valve 209.
[0149] When the shunt 200 having the valve 209 of FIGS. 6P-T is
implanted at the target site in a patient, as previously described,
the first portion 249 can open from the closed configuration (FIGS.
6P-R) to the opened configuration (FIG. 6S) under positive
differential pressure conditions between the subarachnoid space 116
(e.g., CP angle cistern 138) and the venous system (e.g., jugular
vein 106). A relatively large surface area of first portion 249
provides a substantial swing motion when opening the valve 209 to
facilitate clearing of any aggregated materials inside shunt 200
(e.g., CSF proteins, arachnoid layer cells), and can accommodate a
wide range of flow rates with relatively low opening or cracking
pressure (e.g., about 3 mm Hg to about 5 mm Hg). The first portion
249 can also open to receive the guidewire 308, as shown in FIG. 6T
to assist with the navigation and deployment of the shunt 200, as
described herein. Under negative differential pressure conditions
(e.g., where venous blood pressure exceeds intracranial pressure in
subarachnoid space 116, such as during sneezing or coughing
events), the first portion 249 closes to seal, shut and/or close
the valve 209 (FIG. 6R) preventing venous blood from flowing back
through the shunt 200 into the subarachnoid space 116. The large
surface area of the first portion 249 provides a substantial area
for negative pressure (-P) to compress against and seal the valve
209 closed to prevent backflow of material through shunt 200 (FIG.
6R).
[0150] In addition to controlling flow of CSF from the subarachnoid
space to the venous system, shunt 200 preferably prevents backflow
of blood from the jugular bulb 108 and vein 106 through shunt lumen
207 into the subarachnoid space 116. Having one-way valves in the
shunt 200 are particularly advantageous, as they allow CSF to be in
fluid communication from the CP angle cistern 138 into the venous
circulatory system (e.g., the jugular bulb 108, jugular vein 106),
while preventing backflow of venous blood into the subarachnoid
space 116 (e.g., CP angle cistern 138).
[0151] In some embodiments, the one or more valves in the shunt 200
can be detachable from the shunt 200. For example, referring to
FIG. 6, the valve 209 includes an attachment mechanism 211 that
connects the valve 209 to the body 203 of the shunt 200. The valve
209 can be detached and removed from the shunt 200, even when the
shunt 200 is implanted, by activating the mechanism 211 (e.g., by
actuating the mechanism 211 using a guide wire inserted into shunt
200). In some embodiments, the shunt 200 includes a plurality of
different valves 209, where each valve allows for a different rate
of fluid flow. A clinician can control the rate at which CSF drains
from the CP angle cistern 138 into the jugular bulb 108 and/or the
jugular vein 106, for example, by selectively connecting one or
more suitable valves to the shunt 200.
[0152] The valve 209 (or a combination of valves), and/or another
type of flow regulating device (e.g., constriction of the inner
diameter of shunt 200 for a particular length as previously
described, compressed shunt body 203 narrowing lumen 207, FIG. 6M),
is configured to achieve a desired rate of flow of CSF from the CP
angle cistern 138 into the jugular bulb 108 and/or the jugular vein
106. For example, duckbill, slit, and windsock valve configurations
typically cannot regulate flow based on valve cracking pressure
alone; once opened, such valves continuously seep fluid and
therefore, can be combined with a constriction of the inner
diameter of shunt 200 for a particular length as previously
described to further regulate CSF flow. A desired rate of flow is
in a range between 5 ml per hour to 20 ml per hour and more
desirable between 10 ml per hour to 18 ml per hour. In some
embodiments, the desired flow rate of CSF is approximately 10 ml
per hour. In a 24-hour period, the flow of CSF through shunt 200
can be between 200 ml to 300 ml (e.g., 200, 225, 250, 275, or 300
cm.sup.3).
[0153] In some embodiments, the shunt 200 can include an
anti-thrombotic coating to prevent thrombosis induced by the
deployment of the shunt 200. For example, the shunt 200 may include
an anti-thrombotic coating 221 disposed along the length of the
shunt body 203. Anti-thrombotic coating 221 can generally be
applied to any one or more of the inner surfaces and/or outer
surface of the shunt 200. In addition, the anti-thrombotic coating
221 can be applied along the entire length of shunt 200, or
alternatively, only on selected portions of the inner and/or outer
surfaces of shunt 200 (e.g., in the proximate to or in the vicinity
of the end(s) of shunt 200). Suitable materials that can be used to
form anti-thrombotic coating 221 include, for example, Parylene,
polytetrafluoroethylene derivatives, and Heparin.
[0154] The shunt 200 is composed of biocompatible materials.
Suitable materials include, for example, platinum, Nitinol.RTM.,
gold, or other biocompatible metal and/or polymeric materials, for
example, silicon, or combinations thereof. In some embodiments, the
shunt 200 may include materials that are compatible with magnetic
resonance imaging and have radiopacity sufficient to allow imaging
with the use of the various techniques disclosed above. For
example, one or more markings formed of a radio-opaque material may
be applied to the surfaces of shunt 200 to assist in vivo imaging
of the shunt 200 during delivery and deployment (i.e., implantation
in target site). Suitable markers may be included (e.g., embedded)
or applied (e.g., coatings) to the outer surface 206 of the shunt
200 in a pattern that is readily recognized by a clinician. An
example of radio-opaque materials that can be applied for markings
is barium sulfate. Such markers can also be applied to the
catheters and/or guidewires used during a shunting procedure to
assist in vivo imaging of the various system components during
shunt 200 delivery and deployment.
[0155] In some embodiments, portions of the shunt 200 may be
composed of flexible materials, or the shunt 200 may have portions
of various degrees of flexibility. For example, the distal portion
202 is composed of a flexible material so that the distal portion
202 is more flexible than the body 203 of the shunt 200 (FIG. 6).
Suitable materials may compose the distal portion 202 of shunt 200,
which may include flexible, elastomeric materials such as silicone
or Nitinol (e.g., Nitinol hypotube with a reduced wall thickness or
an ePTFE-lined Nitinol hypotube with a latticed or relief cut
configuration to increase flexibility for navigating tortuous
anatomy). The flexible shunt 200, particularly the flexible distal
portion 202, facilitates bending of the shunt 200 within delivery
catheter 304, so that the shunt 200 creates and/or accesses the
anastomosis channel 140 into the CP angle cistern 138 at a suitable
angle relative to the IPS 102 (e.g., FIG. 4D). Referring back to
FIG. 6, the distal portion 202 composed of flexible materials
allows for bending of the portion 202 in an axis 233, so that the
distal portion 202 is configured to access the CP angle cistern 138
via the anastomosis channel 140, at an angle "A". The distal
portion 202 of the shunt 200 may be pre-curved, biasedly curved,
flexible, bendable via control wires or the like or combinations
thereof, in an angle with respect to the body 203 axis 231 to form
a suitable angle relative to the central axis 103 of the IPS 102
for penetration and/or implantation of the shunt 200 through the
anastomosis channel 140. The angle "A" may be in a range of 5
degrees to 80 degrees between axes 231 and 233.
[0156] In some embodiments, the distal portion 202 of the shunt 200
can be cut in an angle to form a piercing element (e.g., sharp,
tapered, cannula-like end, or bevel, pencil, or Quincke tip)
allowing piercing the IPS wall 114 and the arachnoid layer 115. As
shown in FIG. 6, the angle "C" of the distal portion 202 with
respect to axis 233 can be selected as desired for a particular
"sharpness" of the piercing element. In some embodiments, angle "C"
is between 5 degrees to 80 degrees with respect to axis 233.
[0157] The shunt 200 can include one or more anchoring mechanisms
225 positioned along the body 203 of shunt 200, as shown in FIG. 6.
The anchoring mechanisms 225 allow the implanted shunt 200 to be
secured in the target site, and allow the shunt 200 to remain in
the implanted location (e.g., FIG. 3A). The anchoring mechanisms
225 can include one or more configurations, such as, hooks, barbs,
expandable arms, petal-like, coil-like, malecot, elliptecot, T-bar
features, or the like, or combinations thereof. The anchoring
mechanisms 225 can be disposed in one or more portions of the shunt
200. The anchoring mechanisms 225 include a delivery configuration
in which the mechanism 225 is radially constrained, and a deployed
configuration in which the mechanism 225 is radially expanded. The
anchoring mechanisms 225 may include self-expanding features so
that the mechanism radially expands when the shunt 200 is deployed
out of the delivery catheter 304 and/or guide catheter 320.
Additionally or alternatively, the anchoring mechanisms 225 may be
selectively actuated into the deployed configuration, for example,
with the use of a guidewire (e.g., guidewire 302, delivery
guidewire 308) inserted into the shunt 200.
[0158] In some embodiments, the shunt 200 may include one or more
anchoring mechanisms 225 disposed at the distal portion 202 of the
shunt 200, which secures the implanted shunt 200 in situ at the IPS
102, and particularly securing the distal portion 202 within CP
angle cistern 138. In some embodiments, the shunt 200 may further
include one or more anchoring mechanisms 225 disposed at the
proximal portion 204 of the shunt 200, which secures the implanted
shunt 200 in situ at the IPS 102, and particularly securing the
proximal portion 204 within the junction 118, jugular bulb 108
and/or jugular vein 106. The anchoring mechanism 225 can be
collapsible to allow for shunt retrieval and/or replacement. It
will be appreciated that combinations of different anchoring
mechanisms may be used in the proximal portion 204 and/or the
distal portion 202 of the shunt 200.
[0159] In some embodiments, the shunt 200 can include one or more
features that allow for accurate guidance, navigation and/or
control of the shunt 200, particularly when passing the shunt 200
from the jugular bulb 108 or jugular vein 106 through the junction
118 into the IPS 102, and/or into the anastomosis channel 140. FIG.
7 illustrates a cross-sectional view the shunt 200, according to
one embodiment of the disclosed inventions. The shunt 200 includes
a protruding rib 213 extending along an outer surface 206 of the
shunt 200. The rib 213 is dimensioned and configured to engage a
cooperating recess 313 in the delivery catheter 304. The recess 313
is formed within an inner surface 316 of the delivery catheter 304.
When the shunt 200 is inserted into the delivery catheter 304, the
rib 213 and recess 313 slidably engage, allowing the shunt 200 to
be guided in a desired orientation within delivery catheter 304.
The embodiment shown in FIG. 7 is an exemplary control feature that
can be implemented in connection with the shunt 200. In some
embodiments, the shunt 200 and the delivery catheter 304 can
include a plurality of such features (e.g., a plurality of ribs
that engage with a plurality of recesses). Although the shunt 200
includes a rib 213 in FIG. 7, in an alternative embodiment, the
delivery catheter 304 can include a rib, and the shunt 200 may
include a recess dimensioned and configured to slidably engage with
the delivery catheter 304.
[0160] Additionally or alternatively, the guide catheter 320 can
include features that engage with the control features of shunt 200
(e.g., one or more rails or recesses) and/or delivery catheter 304.
For example, the delivery catheter 304 and the guide catheter 320
can each include one or more features that engage with the control
features of shunt 200. Further, the delivery catheter 304 and the
guide catheter 320 can include control features (e.g., one or more
ribs or recesses) that cooperatively engage, allowing the catheters
304, 320 to move relative to one another in a controlled
orientation. Cooperatively engaging features can also be employed
between the delivery guidewire 308 and the delivery catheter 304,
and between the elongate pusher member 310 and the delivery
catheter 304 and/or the guide catheter 320. Examples of such
features include any of the features discussed above in connection
with shunt 200 and delivery catheter 304.
[0161] FIG. 8 illustrates a cross-sectional view of the shunt 200
having a first lumen 215 and a second lumen 217 constructed in
accordance with embodiments of the disclosed inventions. The first
lumen 215 is configured to allow flow of CSF from the CP angle
cistern 138 into the jugular bulb 139 and/or the jugular vein 106,
as discussed above. The second lumen 217 is configured to allow a
guidewire (e.g., guide wire 302, delivery guide wire 308, elongate
pusher member 310, tissue penetrating member 250, tissue
penetrating member 250, actuating guidewire or the like) to be
inserted and slidably disposed into, and through, the shunt 200.
The guidewire can be used by a clinician to assist with navigation
and deployment of the shunt 200 in a target site. Further, the
clinician can use the guidewire within the second lumen 217 to
access shunt components (e.g., valves, anchoring mechanisms). In
some embodiments, the clinician can use a penetrating element
(e.g., tissue penetrating member 306, 250, 350) attached to a
guidewire that passes through the second lumen 217 to pierce the
IPS wall 114 and access the CP angle cistern 138. Additionally, the
clinician can confirm that CSF flow path between the CP angle
cistern 138 and the jugular bulb 108 and/or the jugular vein 106
remains open, and/or dislodge any occlusions in either of the
lumens 215 and/or 217. In some embodiments, CSF can be withdrawn by
the clinician through either lumen 215 or 217 of the shunt 200,
confirming that the IPS wall 114 has been penetrated, the CP angle
cistern 138 accessed, and the anastomosis 140 has been created. In
other embodiments, the shunt 200 may include a plurality of lumens,
for example, more than the two lumens 215 and 217.
[0162] Additionally, the cross-sectional configuration of the shunt
200 may be of any suitable configuration for shunt implantation in
the IPS 102. For example, the cross-sectional configuration of the
shunt 200 may have a circular (FIG. 8), non-circular (e.g.,
elliptical), or any other regular or irregular configuration. FIG.
9 illustrates an elliptical cross-sectional configuration of the
shunt 200, according to the embodiments of the disclosed
inventions. The elliptical cross-sectional configuration of the
shunt 200 may be a better support for a sharp, tapered,
cannula-like end of the distal portion 202 of the shunt 200 than a
circular cross-sectional configuration.
[0163] FIG. 10 illustrates the delivery catheter 304 constructed
according to embodiments of the disclosed inventions. The catheter
304 includes an elongate body 345 that extends along an elongate
axis 331. The delivery catheter 304 includes a proximal portion
342, an elongate body 345, a distal portion 344, and a lumen 341
extending therebetween. The delivery catheter 304 includes a
proximal opening 348 in the proximal portion 342 in fluid
communication with the lumen 341. The delivery catheter 304 further
includes a distal opening 346 in the distal portion 344 in fluid
communication with the lumen 341. The distal portion 344 of
catheter 304 is curved (e.g., pre-curved, biasedly curved,
flexible, drivable distal portion via control wires or the like or
combinations thereof) relative to the catheter body 345 and/or axis
331. The distal portion 344 allows for bending in an axis 333, so
that the distal portion 344 is configured to access the CP angle
cistern 138 via the anastomosis channel 140 created during shunt
deployment, at an angle "B" for deployment of the shunt 200. The
angle "B" may be in a range of 5 degrees to 80 degrees between axes
331 and 333.
[0164] In accordance with the disclosed inventions, the distal
portions 202, 324, 344 of either of the shunt 200, guide catheter
320 and/or delivery catheter 304 are configured to curve and/or
bend. Exemplary variations of some of the largest and smallest
straight angles, as well as some the largest and smallest bend
angles, for an IPS 102 having a diameter ranging from 2 mm to 4 mm
are shown in FIGS. 11A-C. Such angles can also be used to assess
whether delivery system assembly 300 and penetrating element 250 or
350 configurations disclosed herein can achieve a desired
penetration angle into IPS wall 114 for a given IPS diameter. It
should be appreciated that the angle variations depicted in FIGS.
11A-C are exemplary and not intended to limit the embodiment of
FIGS. 11A-C.
[0165] FIG. 12 illustrates one embodiment of the shunt 200,
constructed in accordance with the disclosed inventions. The shunt
200 includes a plurality of anchoring mechanisms 225. An anchoring
mechanism 227 may extend from and/or be disposed on the proximal
portion 204 of the shunt 200, and an anchoring mechanism 229 may
extend from and/or be disposed on the distal portion 202 of the
shunt 200. The anchoring mechanism 227 has a delivery configuration
and a deployed configuration, as described above for the anchoring
mechanism 225. Alternatively or additionally, the anchoring
mechanism 227 and 229 may be disposed on a conduit 400 (e.g.,
collapsible barbs 425 depicted in FIG. 12).
[0166] The anchoring mechanism 227 may include any suitable
anchoring configuration, such as, a spring-loaded plug, stent,
mesh, malecot, or the like, coupled to the proximal portion 202.
The anchoring mechanism 227 may be composed of a shape-memory
material such as Nitinol.RTM., expandable material, such as
swellable polymeric foams, or the like or combinations thereof. The
anchoring mechanism 227 is configured to engage the junction 118
where the IPS 102 enters the jugular bulb 108 and/or jugular vein
106, and/or is configured to engaged the jugular bulb 108 or
jugular vein 106, securing and preventing movement of the shunt 200
when implanted, particularly, securing the proximal portion 204 of
the shunt 200 in situ. For example, prior to deployment of the
shunt 200, the anchoring mechanism 227 is radially constrained
allowing passage of the shunt 200 through the junction 118 in the
IPS 102. Once the shunt 200 is deployed, the anchoring mechanism
227 radially expands within the junction 118 (e.g., self-expansion,
swelling due to absorption of fluid and/or increased temperature)
to anchor shunt 200 at the proximal portion 204 as shown in FIG.
12. Additional embodiments of the anchoring mechanism 227 will be
described in further detail below.
[0167] The anchoring mechanism 229 that extends from the distal
portion 202 of the shunt 200 is configured to engage the arachnoid
layer 115 and/or the exterior portion of the IPS wall 114 when the
shunt 200 is implanted in the target site (e.g., IPS 102,
anastomosis channel 140, CP angle cistern 138). The anchoring
mechanism 229 has a delivery configuration and a deployed
configuration, as described above for the anchoring mechanism 227.
The anchoring mechanism 229 may include any suitable anchoring
configuration. For example, the anchoring mechanism 229 includes an
umbrella-type configuration having a plurality of wires aligned
approximately along the axis of shunt 200. Once the shunt 200
accesses the CP angle cistern 138, the anchoring mechanism 229 is
actuated, so that the mechanism 229 radially expands securing the
distal portion 202 of the shunt 200 in situ. Mechanism 229
advantageously compresses or pins down the arachnoid layer 115,
around the penetration site in the subarachnoid space 116, against
the dura mater comprising the exterior portion of IPS wall 114, to
prevent occlusion of the shunt lumen 207 (e.g., by arachnoid
mater). In some embodiments, the anchoring mechanism 229 may be
actuated using a guidewire inserted into shunt 200 and coupled to
the mechanism 229, so that retracting the guidewire forces the
mechanism wires in an outward radial direction from the axis of
shunt 200, thereby anchoring the shunt 200. Alternatively, the
anchoring mechanism 229 can be a collapsible, self-expanding
umbrella-type mechanism that remains radially constrained while in
the delivery catheter 304 and/or guide catheter 320, and radially
expands upon deployment from such catheters into the CP angle
cistern 138. In some embodiments, the anchoring mechanism 229 may
include a self-expanding circular basket with multiple collapsible
tines and/or a multi-filament globe-like.
[0168] The anchoring mechanism 229 forms an anchor by having a
diameter, in the deployed configuration (e.g., 3 mm to 5 mm),
larger than the diameter of the anastomosis channel 140. Therefore,
the deployed anchoring mechanism 229 is sufficiently wide to avoid
passage through the anastomosis channel 140, thereby securing the
shunt 200 within CP angle cistern 138. Additionally, the anchoring
mechanism 229 is configured to form a seal at the anastomosis
channel 140 preventing flow of blood into the CP angle cistern 138.
The seal formed by the anchoring mechanism 229 further prevents
occlusion or clogging of the shunt lumen 207 at the distal portion
202 by avoiding the access of blood into the CP angle cistern 138
from the IPS 102.
[0169] In some embodiments, the anchoring mechanism 227 and 229 can
be collapsible to facilitate shunt retrieval and/or replacement.
Additional aspects and features of suitable anchoring mechanisms
for use with shunt 200 are disclosed, for example, in U.S. Patent
Application Publication No. 2015/0196741 and published PCT
Application WO2015/108917, both filed on Jan. 14, 2015, the entire
contents of all of which are incorporated by reference. It will be
appreciated that combinations of different anchoring mechanisms may
be used in the proximal portion 204 and/or the distal portion 202
of the shunt 200/200'.
[0170] In some embodiments, a conduit 400 can be used to house the
shunt 200 when deployed within the IPS 102 (FIG. 12). The conduit
400 is composed of a biocompatible material configured to be
disposed within the IPS 102 prior to the deployment of the shunt
200 (FIGS. 14A-F). The shunt 200 is configured for deployment
within the conduit 400. The conduit 400 includes a tubular
configuration having a proximal portion 404, a distal portion 402
and a lumen 407 extending therebetween. The deployed conduit 400
extends proximally from a target penetration site in IPS wall 114
or from within the CP angle cistern 138 adjacent through IPS 102
into the jugular bulb 108 and/or jugular vein 106. The conduit 400
may include one or more anchoring mechanisms 425 that secure the
conduit 400 within the IPS 102. The anchoring mechanisms 425 may
have any suitable configuration, for example, hooks, barbs or the
like that engage the IPS wall 114 when the conduit 400 is deployed.
The distal portion 402 of conduit 400 may be curved in a manner
similar to the distal portion 202 of shunt 200 and/or delivery
catheter 304 to facilitate entry of shunt 200 into CP angle cistern
138 at a desired angle. The conduit 400 is composed of a suitable
expanding material, such as, biocompatible polymeric material that
expands when heated (i.e., upon deployment into IPS 102).
[0171] The conduit 400 may include an expandable stent-graft
configuration. FIGS. 13A-C are expandable stent-grafts known in the
art that may be used to construct the conduit 400. FIG. 13A
illustrates a stent-graft in a collapsed state, FIG. 13B in a
partially-expanded state, and FIG. 13C in an expanded state.
Further, the conduit 400 may include a self-expandable or
collapsible metal stent or metal mesh-like scaffold that supports a
biocompatible heat expandable fabric covering the scaffold.
[0172] FIGS. 14A-H illustrate an exemplary method of delivering the
shunt 200' within the conduit 400 according embodiments of the
disclosed inventions. Although, the shunt 200' incorporating a
piercing element is used to describe the method of deployment in
FIGS. 14A-H, it should be appreciated that any configuration of the
shunt 200 may be used in this method of deployment. The conduit 400
is deployed through a catheter (e.g., delivery catheter 304) in a
radially constricted configuration (FIG. 14A). The conduit 400
radially expands within the IPS 102, for example, after withdrawal
of the delivery catheter 304 if the conduit 400 is self-expanding,
or by heating the conduit 400, or the like, or combination thereof
(FIG. 14B). The expanded and implanted conduit 400 within the IPS
102 is shown in FIG. 14C. FIG. 14D is an insert of FIG. 14C and
illustrates a further detail of the curved distal portion 402 of
the conduit 400, which facilitates guidance of shunt 200' into CP
angle cistern 138 through the IPS wall 114 and arachnoid layer 115
to create the anastomosis channel 140. In FIG. 14E, the shunt 200'
is advanced through the delivery catheter 304 into the conduit 400
implanted in the IPS 102. The navigation and advancement of the
shunt 200' may be assisted by the use of a guidewire, as previously
disclosed. As shown in FIG. 14F, when the shunt 200' reaches the
curved the distal portion 402 of conduit 400, the distal portion
202 of the shunt 200' bends to follow the curved profile of the
conduit 400. As the shunt 200' is advanced within the conduit 400,
the shunt 200' is directed toward the IPS wall 114. Once the shunt
200' reaches the IPS wall 114, a clinician applies suitable force
to the shunt 200' (e.g. via a guidewire coupled to the shunt 200')
and the tissue penetrating member 250, incorporated in the shunt
200, penetrates and pierces the IPS wall 114 creating the
anastomosis channel 140, so that the distal portion 202 of shunt
200' accesses the CP angle cistern 138 (FIG. 14G). The creation of
the anastomosis 140 is also described above in FIGS. 5E-G. The
shunt 200' includes the anchoring mechanism 229; in particular, the
anchoring mechanism shown in FIGS. 14G-H is the distal portion
anchoring mechanism 229, which includes a plurality of deformable
elements 229a (e.g., arms) and a mesh 229b. The deformable
elements/arms 229 are expandable members that may include any
suitable configuration to allow outward, radial expansion, such as
members composed of bendable or deformable materials (e.g.
Nitinol.RTM.). The mesh 229b allows for fluid communication into
the lumen 207 of the shunt 200' so that CSF in the CP angle cistern
138 flows through the implanted shunt 200' into the jugular bulb
108 and/or jugular vein 106. The mesh 229b functions as the distal
opening 219 of the shunt 200', as shown in FIG. 5I, and may
comprise any other suitable configurations (e.g. perforations,
porous material or the like). The arms 229a are coupled to the
tissue penetrating member 250, so that when a retrograde force 229c
is applied (e.g. via a guidewire), the tissue penetrating member
250 retracts causing the arms 229a to bend, expand or deform in a
radially outward direction 229d, as shown in FIG. 14H, anchoring
the distal portion 202 of shunt 200' within CP angle cistern
138.
[0173] Alternatively, the arms 229a are detachably coupled to the
tissue penetrating member 250, so that the tissue penetrating
member 250 may be detached and removed from the implanted shunt
200', as shown in FIG. 5J.
[0174] FIGS. 15A-D illustrate detailed cross-sectional views of an
alternative embodiment of the anchoring mechanism 229 and, an
exemplary method of delivering the shunt 200 at the target site
according embodiments of the disclosed inventions. As shown in FIG.
15A, the anchoring mechanism 229 includes an inner sheath 229f, a
deformable element 229e, and an outer sheath 229g slidably disposed
over the inner sheath 229f and element 229e. The deformable element
229e (e.g., arms, wires, loops, layer, or the like) includes a
radially constrained delivery configuration (e.g., outer sheath
229g disposed over element 229e, as shown in FIGS. 15A-B), and a
radially expanded deployed configuration (e.g., withdrawn outer
sheath 229g as shown in FIG. 15D). The deformable element 229e are
composed of shape memory material, e.g., Nitinol.RTM., of any
suitable biocompatible metal, alloys, polymeric materials or
combinations thereof. The elements 229e are coupled to the inner
sheath 229f, for example, by adhesive, thermal bonding, welding or
the like, or combinations thereof, or by any other suitable
methods. The deployed configuration of the deformable element 229e
is configured to expand, anchor and secure the distal portion 202
of the shunt 200 at the IPS wall 114 within the CP angle cistern
138. The tissue penetrating member 250, disposed within the
anchoring mechanism 229, is detachably coupled to the anchoring
mechanism 229 and/or the shunt 200, so that the tissue penetrating
member 250 is detached and removed when the shunt 200 is delivered
and implanted at the target site.
[0175] After the tissue penetrating member 250 has created the
anastomosis channel 140 in the IPS wall 114, the distal portion 202
of the shunt 200, including the anchoring mechanism 229, is
advanced by applying suitable force in a distal direction
(indicated by the arrow in the top left portion FIG. 15B). Portions
of the inner sheath 229f and the outer sheath 229g extend into the
CP angle cistern 138 via the anastomosis channel 140. Once inside
the CP angle cistern 138, the tissue penetrating member 250 is
detached and withdrawn from the shunt 200 by applying suitable
force in a proximal direction (indicated by the arrow in the top
right portion of FIG. 15B). The outer sheath 229g is also
withdrawn, therefore exposing the deformable element 229e in the
deployed configuration, and further exposing the inner sheath 229f
that defines the lumen 207 of shunt 200, as shown in FIG. 15B. The
deformable element 229e, shown in FIGS. 15C-D, includes a plurality
of Nitinol.RTM. wires that radially expand in the deployed
configuration, and are configured to anchor and secure the shunt
200 distal portion 202 against arachnoid layer 115 and/or the
exterior of IPS wall 114 (i.e., dura mater), and within CP angle
cistern 138.
[0176] FIG. 16 illustrates a side view of an alternative distal
anchoring mechanism 229 in accordance to embodiments of the
disclosed inventions. The anchoring mechanism 229 includes a body
251 (e.g., pre-curved, biasedly curved, flexible, drivable distal
portion via control wires, or the like, or combinations thereof)
composed of shape memory materials (e.g., Nitinol.RTM.) or other
deformable materials, or combinations thereof. The anchoring
mechanism 229 comprises a delivery configuration (e.g., elongated
for advancement through the delivery assembly 300 and/or conduit
400) and a deployed configuration (e.g., curved or arc between 180
degrees to 340 degrees). The anchoring mechanism 229 further
includes an angled tissue penetrating member 250 configured to
facilitate the piercing of the IPS wall 114 and arachnoid layer at
a first point of entry from within the lumen of IPS 102 into the CP
angle cistern 138, creating a first anastomosis channel 140a, and
at a second point of entry from the CP angle cistern 138 returning
into the lumen of IPS 102, creating a second anastomosis channel
140b. Particularly, after the first anastomosis channel 140a is
created and as the body 251 curves and further advances, the tissue
penetrating member 250 once again contacts and pierces the IPS wall
114 at the second point of entry creating the second anastomosis
140b. Therefore, the distal portion 202 of the shunt 200 is
anchored and secured in situ by having portions of the body 251 of
the anchoring mechanism 229 disposed through both anastomosis
channels 140a and 140b, preventing dislodging of the implanted
shunt 200.
[0177] The body 251 of the anchoring mechanism 229 includes
openings 253 (i.e., holes, porous, perforations, or the like, or
combinations thereof), allowing fluid communication into the lumen
207 of the shunt 200, so that CSF disposed in the CP angle cistern
138 is drained when the shunt 200 is implanted, according to the
embodiments of the disclosed inventions. The openings 253 are
formed in the body 251 of the anchoring mechanism 229 configured to
be disposed within the CP angle cistern 138 when the shunt 200 is
implanted. It should be appreciated that portions of the body 251
of the anchoring mechanism 229 that are configured to be disposed
within the IPS wall 114 at the anastomosis channels 140a and 140b
and/or within the IPS 102 (e.g., distal and proximal portions the
anchoring mechanism 229), do not include any openings 253, so that
blood flow through the shunt 200 is prevented or avoided. The size
and position of the openings 253 can be selected to alter the
physical properties of the body 251, for example, varying the
extent of the curvature, and the stiffness of the body 251 of the
anchoring mechanism 229.
[0178] FIGS. 17A-B, 18A-B, and 19A-B describe exemplary embodiments
of the distal portion 202 of the shunt 200' having the tissue
penetrating member 250, configured to achieve a suitable angle for
piercing the IPS wall 114 and the arachnoid layer 115 for
implantation of the shunt 200' and creating the anastomosis channel
140 into CP angle cistern 138. It should be appreciated that the
aspects and features of the embodiments described in FIGS. 17A-B,
18A-B, and 19A-B can be incorporated into the distal portion 202 of
the shunt 200, the distal portion 344 of the delivery catheter 304,
the distal portion 324 of the guide catheter 320, the distal
portions of the guidewires (308, 304, 310) and/or any other element
of the delivery assembly 300 configured to be disposed in the
proper angle and orientation relative to the IPS wall 114 for
penetration and/or implantation, according to the disclosed
embodiments.
[0179] FIGS. 17A-B illustrates an exemplary distal portion 202 of
the shunt 200' according to the embodiments of the disclosed
inventions. The distal portion 202 of the shunt 200' is composed of
shape-memory materials, such as super-elastic nickel titanium
alloy, known as Nitinol.RTM. or other suitable deformable material,
so that the distal portion 202 has a pre-curved or biasedly curved
configuration (FIG. 17B). The distal portion 202 of the shunt 200'
comprises a delivery configuration, in which the distal portion 202
is elongated for advancement through the delivery catheter 304
(FIG. 17A) or the delivery assembly 300 and/or conduit 400, and a
deployed configuration, in which the distal portion 202 assumes its
curved configuration when the delivery catheter 304 is withdraw
(FIG. 17B), or any other element of the delivery assembly 300 that
may radially constrict the distal portion 202 of the shunt 200 is
withdrawn. The distal end 202 of the shunt 200 is biasedly curved
in a suitable angle towards and/or configured to be oriented
towards the IPS wall 114, so that the distal end 202 having the
tissue penetrating member 250 is configured for piercing the IPS
wall 114 and arachnoid layer 115 creating anastomosis 140 and/or
for implantation of the shunt 200' into the CP angle cistern
138.
[0180] FIGS. 18A-B illustrates another exemplary distal portion 202
of the shunt 200' according to the embodiments of the disclosed
inventions. The distal portion 202 of the shunt 200' includes the
flexible elongate tubular structure according to the disclosed
inventions, and further comprises a plurality of slots 254 (e.g.,
cuts, openings, perforations, or the like, or combinations thereof)
formed within the tubular structure (FIG. 18A). The slots 254 are
configured to selectively weaken the axial and flexural strength of
the tubular structure causing the distal portion 202 to be more
susceptible to bending or folding, when the distal portion 202 is
subjected to an external force, for example, when the distal end
202 comes in contact with an object, such as the conduit 400 of
FIGS. 12 and 14A-F. As shown in FIG. 18B, the slots 254 are
configured to remain closed due to the bend of the distal portion
202 of the implanted shunt 200', so that blood flow through the
shunt 200' is prevented or avoided.
[0181] FIGS. 19A-B illustrates yet another exemplary distal portion
202 of the shunt 200' according to the embodiments of the disclosed
inventions. The distal portion 202 includes an elongated member 280
(e.g., leg, kickstand, or the like) configured to position the
distal portion 202 of the shunt 200' in the proper angle and
orientation relative to the IPS wall 114. The elongated member or
leg 280 includes a first end 281 coupled to the distal portion 202
of the shunt 200' in a hinge-like configuration, and a second end
282 coupled to a pull wire 288. The leg 280 further includes a
stand or foot 283 at the second end 282 configured to assist and
stabilize the distal end 202 of the shunt 200' at the desired
position within the IPS 102 (FIG. 19B). The leg 280 is composed of
any suitable biocompatible material, according to the disclosed
inventions. The leg 280 may be attached to the distal portion 202
of the shunt 200' at the first end 281 (e.g. hinge, bonded, welded
or other movable attachment) or may be a cut-out of the shunt 200'
tubular structure. The leg 280 comprises a delivery configuration
for advancement through the delivery catheter 304 or any other
elements of the delivery assembly 300 (FIG. 19A), and a deployed
configuration, in which the leg 280 assists and stabilizes the
distal end 202 of the shunt 200' at the desired position within the
IPS 102 (FIG. 19B). By application of suitable retrograde force to
the pull wire 288 coupled to the second end 282 of the leg 280, the
leg 280 moves in a backward direction so that the foot 280 contacts
the lower portion of the IPS 102 (e.g., "stands" on the IPS wall
117 opposite to the IPS wall 114), supporting and stabilizing the
distal end 202 of the shunt 200', as shown in FIG. 19B.
[0182] FIGS. 20A-F illustrate the delivery assembly 300 in
accordance with one embodiment of the disclosed inventions. The
delivery assembly 300 includes the delivery catheter 304, the shunt
200 coaxially disposed within the delivery catheter 304, and the
elongate pusher member 310 310 coaxially disposed within the shunt
200. The tissue penetrating member 306 (e.g., surgical tool) is
disposed on the distal portion 354 of the elongate pusher member
310 (e.g., piercing micro-wire). The elongate pusher member 310
includes one or more engaging members 312 disposed on an outer
surface 311 of the elongate pusher member 310, and the shunt 200
includes one or more engaging members 242 disposed on an inner wall
surface 208 of the shunt 200 to form a mechanical interaction with
the one or more engaging members 312 of the elongate pusher member
310 (FIG. 20A). The engaging member 242 of the shunt 200 (i.e.,
first engaging member) protrudes and/or extends radially inward
from the inner wall 208 of the shunt 200, the engaging member 312
of the elongate pusher member 310 (i.e., second engaging member)
protrudes and/or extends radially outward towards the inner shunt
wall 208. The second engaging member engages the first engaging
member to thereby advance the distal portion 202 of the shunt 200
from the IPS 102 into the CP angle cistern 138 on the tissue
penetrating member 306 (FIG. 20E). The engaging members 312 and 242
may include protrusions, balls, collars, or the like, or
combinations thereof, or any other suitable configurations. When
the engaging members 312 of the elongate pusher member 310 and the
engaging members 241 of the shunt 200 meet and engage with each
other (FIGS. 20B and 20E), advancement of the elongate pusher
member 310 and penetrating element 306 simultaneously advances the
shunt 200 into the target or target penetration site, according to
the disclosed inventions. The engaging members 312 and 242 are
configured to be engaged in a one-way direction (i.e., forward in
the direction of the penetration site of the IPS wall 114, distally
toward the subarachnoid space 116--FIGS. 20B, 20D and 20E), so that
the engaging members 312 and 242 are disengaged when the elongate
pusher member 310 having the penetrating element 306 is withdrawn
from the delivery catheter 304 or moved proximally (FIG. 20F).
[0183] The tissue penetrating member 306 comprises the elongate
pusher member 310 and a tissue penetrating distal tip, the elongate
pusher member 310 extends though the valve 209, lumen 207, and
distal opening 201 of the shunt 200, respectively, wherein the
elongate pusher member 310 is moveable relative to the shunt 200 so
that the tissue penetrating 306 distal tip may be advanced out of,
and withdrawn into, a distal opening 201 of the shunt 200 in
communication with the lumen 207, wherein advancing the distal
portion 202 of the shunt 200 from the IPS 102 into the CP angle
cistern 138 comprises advancing the elongate pusher member 310 so
that the tissue penetrating 306 distal tip penetrates through the
dura mater tissue wall of the IPS 114, and through the arachnoid
tissue layer 115, respectively, into the CP angle cistern 138, with
the distal portion 202 of the shunt 200 being carried on the tissue
penetrating member 306 (FIGS. 20A-E). When deploying the shunt 200,
the method further comprises, after advancing the distal portion of
the shunt into the CP angle cistern, withdrawing the tissue
penetrating member 306 through the distal opening 202, lumen 207
and valve of the shunt 200, respectively, wherein CSF flows through
the respective distal opening 201, lumen 207 and valve 209 of the
shunt 200 after withdrawal of the tissue penetrating member 206
(FIG. 20F). When deploying the shunt 200, the method further
comprises advancing the delivery catheter 304 into the IPS 102 with
the shunt 200 and tissue penetrating member 306 at least partially
disposed in the delivery lumen 305 of the delivery catheter 304,
the delivery catheter 304 having a distal opening in communication
with the delivery lumen 305 through which the respective tissue
penetrating member 306 and shunt 200 may be advanced into the CP
angle cistern 138. The method of deploying the shunt further
comprises, adjusting a rotational orientation of the delivery
catheter 304 about an axis of the delivery catheter 304 so that the
tissue penetrating distal tip of the tissue penetrating member 306
is thereafter advanced out of the distal opening of the delivery
catheter 304 into contact with the dura IPS wall 114 at an angle in
a range of 30 degrees to 90 degrees thereto, prior to advancing the
tissue penetrating member 306 into the CP angle cistern 138. The
method further comprises imaging the shunt while deploying the
shunt in the patient.
[0184] It should be appreciated that the aspects, features and
functions of the engaging members 312 of the elongate pusher member
310 and the engaging members 241 of the shunt 200, described in
FIGS. 20A-B, may be incorporated into the delivery assembly 300',
so that the tissue penetrating member 250 coupled to a guidewire
assists with the advancement of the shunt 200' into the target site
(FIGS. 5E-I), and is configured to be disengaged and removed from
the implanted shunt 200' (FIG. 5J).
[0185] Referring back to FIGS. 20A-F, the delivery catheter 304
includes a deflecting element 370 coupled to or disposed on the
distal portion 344 of the delivery catheter 304. The deflecting
element 370 includes a tubular configuration having an angled inner
ramp 375 and a side aperture 377. The deflecting element 370 is
formed of suitable biocompatible metals, alloys, polymers or their
like, or combinations thereof. The deflecting element 370 and
particularly, the ramp 375, may be formed of relatively stiff and
non-deformable materials, or be covered with a relatively stiff
polymeric coating (e.g., polytetrafluoroethylene "PTFE",
polyethyleneterephthalate "PET"). The deflecting element 370 may
further include radio-opaque materials or include markings for
purposes of imaging, according to the disclosed inventions. The
deflecting element 370 and ramp 375 are configured to deflect the
tissue penetrating element 306, elongate pusher member 310, and
shunt 200 engaged to the elongate pusher member 310, towards the
aperture 377, so that the tissue penetrating element 306, elongate
pusher member 310, and shunt 200 are advanced out of the distal
portion 344 of the delivery catheter 304 in a suitable angle for
piercing the IPS wall 114 and the arachnoid layer 115 for
implantation of the shunt 200 into the target site (FIG. 20B),
according to the disclosed inventions.
[0186] Prior to the piercing of the IPS wall 114 to create
anastomosis and access the CP angle cistern 138, the proper
orientation of the distal portion 344 of the delivery catheter 304,
particularly, the proper orientation of the deflecting element 370
and/or aperture 377, may be verified according to the imaging
methods previously disclosed. When needed, the positioning and
orientation of the deflecting element 370 disposed on the distal
portion 344 of the delivery catheter 304 may be adjusted, for
example, by applying a rotational force directly to the body of the
delivery catheter 304, or to the elongate pusher member 310, if the
member 310 is engaged to the delivery catheter 304.
[0187] Alternatively, a stabilizing element 380 may be used for
positioning, orienting, and/or stabilizing the distal end 344 of
the delivery catheter 304, and/or the aperture 377 of the
deflecting element 370 within the IPS 102, as shown in FIGS. 20C-D.
The stabilizing element 380 of the delivery assembly 300 may be
coaxially disposed with the guide catheter 320, and includes a
distal portion 382 configured to radially expand and engage the IPS
102 walls 114, 117 (i.e., diameter d.sub.1, as shown in FIG. 2)
when the stabilizing element 380 is advanced out of the distal
portion 324 of the guide catheter 320 and/or the guide catheter 320
is withdrawn exposing the distal portion 382 of the stabilizing
element 380. The stabilizing element 380 may be composed of any
suitable biocompatible shape memory and/or expandable materials
according to the disclosed inventions.
[0188] In the embodiments of FIGS. 20C-D, the distal portion 382 of
the stabilizing element 380 includes a spiral configuration. In
other embodiments, the distal portion 382 of the stabilizing
element 380 may include any suitable configuration, such as a coil,
stent, expandable foams, balloons, or combinations thereof,
configured to engage the IPS 102 walls 114, 117 and assist with the
position, orientation, and/or stability of the distal end 344 of
the delivery catheter 304, and/or the aperture 377 of the
deflecting element 370 within the IPS 102. When deployed, the
stabilizing element 380 stabilizes the position of the distal end
344 of the delivery catheter 304, and/or the aperture 377 of the
deflecting element 370 preventing movement of the catheter distal
end 344 and deflecting element 370 within the IPS 102 while the IPS
wall 114 is being pierced (FIG. 20D).
[0189] FIG. 20E illustrates the further advancement of the shunt
200 into the target site by the advancement of the elongate pusher
member 310 (i.e., via engagement of the respective engaging members
312 and 242) of the embodiments of FIGS. 20A-D, along with the
withdrawal of the delivery catheter 304 (not shown). Once the shunt
200 is deployed in the target site, the elongate pusher member 310
having the tissue penetrating element 306 is withdrawn (i.e.,
disengagement of the respective engaging members 312 and 242), as
shown in FIG. 20F. Additionally, the anchoring mechanism 229 of the
shunt 200 is deployed to secure the distal portion 202 of the shunt
200 in the target site, according to the disclosed inventions.
[0190] FIGS. 21A-D illustrate the delivery assembly 300' having one
or more stabilizing element 380 in accordance with one embodiment
of the disclosed inventions. The delivery assembly 300' includes
the guide catheter 320, the delivery catheter 304 and the delivery
guidewire 308. The delivery catheter 304 of the delivery assembly
300' includes the stabilizing element 380 that extends from or is
disposed on the distal portion 344 of the delivery catheter 304,
and the deflecting element 370 disposed in the distal portion 344
of the delivery catheter 304. As shown in FIG. 21A, the stabilizing
element 380 comprises a first stabilizing element 380a, a second
stabilizing element 380b, and the deflecting element 370 disposed
between the stabilizing elements 380a and 380b. The stabilizing
elements 380a and 380b include inflatable balloons that may be
inflated with contrast dye for imaging proposes, according to the
disclosed inventions. In some embodiments, the stabilizing elements
380a and 380b may include expandable coils, stent, foams, or the
like, or combinations thereof. The deflecting element 370 includes
the inner angle ramp 375 and the side aperture 377, according to
the disclosed inventions (FIGS. 20A-D).
[0191] As shown in FIG. 21A, the stabilizing elements 380a and 380b
are deflated and/or radially constricted in the delivery
configuration within the IPS 102. Once the proper position and
orientation of the distal portion 344 of the delivery catheter 304
and/or of the aperture 377 is achieved according to the methods of
the disclosed inventions, the stabilizing elements 380a and 380b
are inflated and/or radially expanded, as shown in FIG. 21B,
stabilizing the delivery catheter 304 and/or the aperture 377
within the IPS 102. As shown in FIGS. 21C-D, the shunt 200'
incorporating the tissue penetrating member 250 is advanced through
the delivery catheter 304, meeting the ramp 375 of the deflecting
element 370, so that the shunt 200' is deflected towards the
aperture 377 and the tissue penetrating member 250 contacts and
pierces the IPS wall 114 and the arachnoid layer 115 in a suitable
angle for creation of the anastomosis 140 and implantation of the
shunt 200' into the target site (FIG. 21E), according to the
disclosed inventions. As shown in FIG. 21E, the distal anchoring
mechanism 229 incorporated in shunt 200' expands, anchoring the
shunt 200' within the CP angle cistern 138 and further allowing CSF
drainage through the shunt 200'. In the embodiments of FIGS. 21C-E,
the shunt 200' comprises an elliptecot configuration that will be
described in further detail below. It should be appreciated that
the embodiments and methods disclosed in FIGS. 21A-E can include
any features and steps disclosed herein, including features and
steps disclosed in connection with different embodiments (e.g.,
shunt 200, delivery assembly 300), in any combination as
appropriate.
[0192] FIGS. 22A-G illustrate an exemplary shunt 200 constructed
and implanted according to embodiments of the disclosed inventions.
The shunt 200 includes the anchoring mechanism 227 and a duck-bill
valve 209 in the proximal portion 204, the anchoring mechanism 229
in the distal portion 202, and the elongate body 203 extending
therebetween. The anchoring mechanisms 227 and 229 include a
malecot configuration having a plurality of respective deformable
elements 227a and 229a (e.g., arms) that are disposed radially
outward in the deployed configuration (FIGS. 22A and 22F-G). The
anchoring mechanism 227 and 229 are formed by concentric parallel
or radially spaced cuts 222 along the length of the respective
proximal 204 and distal 202 portions of the shunt 200, forming the
arms 227a and 229a (FIGS. 22B-D). FIGS. 22C-D illustrate exemplary
patterns and dimensions of the cuts 222 in the respective proximal
204 (FIG. 22C) and distal 202 (FIG. 22D) portions. It should be
appreciated that the patterns and dimensions of the cuts 222 in the
proximal portion 204 may be similar or dissimilar from the patterns
and dimensions of the cuts 222 in the distal portion 202. Each
deformable element 227a and 229a has a respective hinge-like point
227b and 229b (e.g., living hinge, joint, or the like). As shown in
FIG. 22A, the hinge-like points 227b and 229b are configured to
move radially outward from the axis of the shunt 200 in a
hinge-like fashion, allowing the arms 227a and 229a to be outwardly
disposed so that the shunt 200 is anchored at the target site.
Anchoring mechanisms can have a preformed expanded or deployed
configuration (e.g., configuration of FIGS. 22A, 22F-G), for
example, when constructed from super-elastic materials such as
Nitinol. The deployed anchoring mechanism 227 engages the jugular
bulb 108, the IPS wall 117, and/or another portion of the IPS 102,
anchoring the proximal portion 204 of the shunt 200 within the
jugular vein 106, so that the valve 209 is disposed within the
jugular vein 106. Alternatively, the anchoring mechanism 227 may
engage the IPS walls 114 and 117 at the junction 118 (not-shown).
The deployed anchoring mechanism 229 secures the distal portion 202
of the shunt 200 within the CP angle cistern 138 (FIGS. 5H-J), so
that CSF flows through the implanted shunt 200 into the jugular
vein 106.
[0193] Additionally, the shunt 200 may include an interlocking
element 294 (e.g., clasp) coupled to the proximal portion 204 of
the shunt 200 (FIGS. 22B and 22E). The interlocking element 294 is
configured to engage and disengage with an interlocking element
coupled to the distal portion of the delivery assembly (not shown)
for deployment of the shunt 200 at the target site. FIG. 22E
illustrates an exemplary pattern used for laser cutting a tubular
portion of super-elastic material to form an embodiment of the
interlocking element 294.
[0194] Dimensions referenced in FIG. 22B, are provided in inches.
It should be appreciated that the dimensions depicted in FIG. 22B
are exemplary dimensions of the shunt 200, which are not intended
to limit the embodiment of FIGS. 22A-G.
[0195] FIGS. 23A-E illustrate another exemplary shunt 200
constructed and implanted according to embodiments of the disclosed
inventions. As shown in FIG. 23A, the shunt 200 includes the
anchoring mechanism 227 and the duck-bill valve 209 in the proximal
portion 204, the anchoring mechanism 229 in the distal portion 202,
and the elongate body 203 extending therebetween. The body 203 of
the shunt 200 comprises slidably disposed concentric tubular
elements, as shown in FIGS. 6E-F, for selective elongation and/or
adjustment of the shunt length L.sub.2 (FIG. 6) according to the
anatomy of the patient (i.e., target site for implantation of the
shunt 200. The anchoring mechanisms 227 and 229 include a
flower-like configuration having a plurality of respective
deformable elements 227a and 229a (e.g., petals) that are disposed
radially outward in the deployed configuration. The deformable
petals 227a and 229a are formed by concentric parallel and/or
radially spaced cuts 230 along the length of the respective
proximal 204 and distal 202 portions of the shunt 200, as shown in
FIG. 23B. The number of petals 227a and 229a depend on the number
of cuts 230 formed into the respective proximal 204 and distal 202
portions. The petals 227a and 229a are configured to invert, fold
and/or expand into their deployed configurations when the shunt 200
is implanted, as shown in FIGS. 23A, and 23C-D. As shown in FIGS.
23C-D, the distal anchoring mechanism 229 is deployed by
advancement of the shunt 200 and/or withdrawal of the delivery
catheter 304, so that the petals 229a invert, fold and/or expand,
engaging the arachnoid layer 115 and securing the distal portion
202 of the shunt 200 within the CP angle cistern 138, as shown in
FIG. 23D.
[0196] FIGS. 24A-E illustrate yet another exemplary shunt 200
constructed and implanted according to embodiments of the disclosed
inventions. The shunt 200 includes the anchoring mechanism 227 and
an interlocking valve 209 in the proximal portion 204, the
anchoring mechanism 229 in the distal portion 202, and the elongate
body 203 extending therebetween. The body 203 of the shunt 200
comprises a spring/coil-like body, as shown in FIG. 6GH, for
selective elongation and/or adjustment of the shunt length L.sub.2
(FIG. 6) according to the anatomy of the patient (i.e., target site
for implantation of the shunt 200). Further, the spring/coil-like
body 203 of the shunt 200 is configured to apply tensional force,
at least, between the proximal portion 204 and the distal portion
202 of the shunt 200 maintaining the implanted shunt 200 properly
anchored in the target site (e.g., preventing movement of shunt or
a loosely anchored shunt). The shunt 200 is composed of
shape-memory materials, such as super-elastic nickel titanium
alloy, known as Nitinol.RTM. or other suitable material, so that
the proximal portion 204 forming the anchoring mechanism 227, and
the distal portion 202 forming the anchoring mechanism 229,
comprise helical-coil or spring-like configurations when deployed,
as shown in FIGS. 24A-C. The shunt 200 is elongated for advancement
through the delivery assembly 300 in the delivery configuration
(FIG. 3B), and assumes the deployed configuration when the delivery
assembly 300 that radially constricts the shunt 200 is withdrawn
and/or the shunt 200 is advanced out of the delivery assembly 300
(FIGS. 24A-C), so that the anchoring mechanisms 227 (FIGS. 24A and
24C) and 229 (FIGS. 24A-B) are deployed, securing the implanted
shunt 200 in the target site. CSF flows through the implanted shunt
200, from the CP angle cistern 138 entering the shunt lumen 207
from distal portion 202 of the shunt (FIG. 24B) and out of valve
209 at the proximal portion 204 of the shunt (FIG. 24D) into the
jugular vein 106. As shown in FIG. 24D, the valve 209 comprises a
concentric gland seal housed on the proximal portion 204 of the
shunt 200 with a slit exposing the opening of the valve, as also
shown in FIG. 6L. FIG. 24E illustrates an alternative embodiment of
the shunt 200 of FIG. 24A, in which the shunt 200 comprises the
spring/coil-like configuration in substantially the entire length
L.sub.2 of the shunt 200 (i.e., from the proximal portion 204 to
the distal portion 202, including the body 203) in the deployed
configuration.
[0197] FIGS. 25A-G illustrate yet another exemplary shunt 200
constructed and implanted according to embodiments of the disclosed
inventions. As shown in FIG. 25A, the shunt 200 includes the
anchoring mechanism 227 and the duck-bill valve 209 in the proximal
portion 204, the anchoring mechanism 229 in the distal portion 202,
and the elongate body 203 extending therebetween. The body 203 of
the shunt 200 comprises slidably disposed concentric tubular
elements, as shown in FIGS. 6E-F, for selective elongation and/or
adjustment of the shunt length L.sub.2 (FIG. 6) according to the
anatomy of the patient (i.e., target site for implantation of the
shunt 220). The deployed anchoring mechanism 227 disposed on the
proximal portion 204 of the shunt 200 comprises a spiral
configuration for anchoring the proximal portion 204 of the shunt
200 within the jugular vein 106 by engaging the jugular bulb 108,
the IPS wall 117 and another portion of the IPS 102, so that the
duck-bill valve 209 is disposed within the jugular vein 106 (FIG.
25G). Alternatively, the anchoring mechanism 227 may engage the IPS
wall 114 and 117 at the junction 118 (not shown). The anchoring
mechanism 229 of the distal portion 202 of the shunt 200 comprises
a retrograde-barb configuration (FIGS. 25A-F), so that when the
anchoring mechanism 229 is in the delivery configuration, the
tissue penetrating member 250 formed of an elongated cannula is
folded over a portion 202'' of the distal portion 202 of the shunt
200 (e.g., radially constrained by the delivery catheter 304, FIGS.
25B-C), and when the anchoring mechanism 229 is in the deployed
configuration, the tissue penetrating member 250 unfolds or expands
from the portion 202'' in a hinge-like fashion (FIGS. 25A and
25E-F). The portion 202'' of the distal portion 202 is configured
to radially expand in the deployed configuration, supporting and
stabilizing the distal end 202 of the shunt 200 within the IPS 102
(FIGS. 25A and 25E-F). As shown in FIGS. 25B-C, the anchoring
mechanism 229 is advanced thorough the delivery catheter 304 into a
target site within the IPS 102 (e.g., at a location proximate the
jugular bulb 108 or the jugular tubercle (not shown)). The
anchoring mechanism 229 is further advanced within the IPS 102
and/or the delivery catheter 304 is withdrawn (FIG. 25C), so that
the tissue penetrating member 250 unfolds (FIG. 25D). By
application of suitable retrograde force to the shunt 200, the
unfolded tissue penetrating member 250, in contact with the IPS
wall 114, pierces the dura mater of the IPS wall 114 and the
arachnoid layer 115 creating anastomosis 140 into the CP angle
cistern 138 (FIGS. 25E-F). The expanded portion 202'' of the
anchoring mechanism 229 supports and stabilizes the distal end 202
of the deployed shunt 200 (e.g., contacting/"seating on" the IPS
wall 117), as shown in FIGS. 25A and 25E-F.
[0198] FIGS. 26A-G illustrate another exemplary shunt 200
constructed and implanted according to embodiments of the disclosed
inventions. As shown in FIG. 26A, the shunt 200 includes the
anchoring mechanism 227 and valve 209 in the proximal portion 204,
the anchoring mechanism 229 in the distal portion 202, and the
elongate body 203 extending therebetween. As shown in FIG. 26A, the
body 203 and distal portion 202 of the shunt 200 comprise a
self-expandable stent having an elastomeric/polymeric cover/liner,
and/or stent-graft configuration, as shown in FIGS. 12 and 13A-C
for the conduit 400. The shunt 200 is elongated for advancement
through the delivery catheter 304 in the delivery configuration
(FIG. 26B), and assumes the deployed/expanded configuration when
the delivery catheter 304 that radially constricts the shunt 200 is
withdrawn and/or the shunt 200 is advanced out the distal portion
344 (e.g. distal end opening 346) of delivery catheter 304 (FIGS.
26A, 26C-E), so that the anchoring mechanism 229 (FIGS. 26A and
26C-E) self-expands, securing the implanted shunt 200 in the target
site. The anchoring mechanism 227 secures the proximal portion 204
of the shunt 200 within the jugular vein 106 by engaging the
jugular bulb 108 and/or the jugular vein 106, the IPS wall 117 and
another portion of the IPS 102, so that the valve 209 is disposed
within the jugular vein 106 (FIGS. 26A and 26H). CSF flows through
the implanted shunt 200, from the CP angle cistern 138 entering the
shunt lumen 207 from distal portion 202 of the shunt (FIGS. 26A and
26C) and out of valve 209 at the proximal portion 204 of the shunt
(FIG. 26A) into the jugular vein 106. As shown in FIGS. 26A and
26F-G, the valve 209 comprises a concentric gland seal housed on
the proximal portion 204 of the shunt 200 with a slit exposing the
opening of the valve, as also shown in FIG. 6L. The delivery
assembly 300 further comprises an interlocking mechanism 290
configured to detachably couple the shunt 200 to the delivery
catheter 304, as shown in FIG. 26F. The interlocking mechanism 290
includes a first interlocking element 292 (e.g., clasp) coupled to
the delivery assembly 300 (e.g., via a push wire) and a second
interlocking element 294 (e.g., clasp) coupled to the shunt 200
proximal portion 204 (e.g., attached to the valve 209). Once the
shunt 200 is properly disposed at the target site, withdrawal of
the delivery catheter 304 allows the interlocking mechanism 290 to
be uncoupled (FIG. 26G). The interlocking element 294 coupled to
the shunt 200 proximal portion 204 also allows for subsequent
capture, recovery and/or withdrawal of the implanted shunt 200
(e.g., snare catheter).
[0199] FIGS. 27A-E illustrate another exemplary shunt 200
constructed and implanted according to embodiments of the disclosed
inventions. As shown in FIG. 27A, the shunt 200 includes the
anchoring mechanism 227 and valve 209 in the proximal portion 204,
the anchoring mechanism 229 in the distal portion 202, and the
elongate body 203 extending therebetween. As shown in FIGS. 27A-B,
the body 203 of the shunt 200 comprises a self-expandable stent
having an elastomeric/polymeric cover/liner, and/or stent-graft
configuration, as shown in FIGS. 12, 13A-C and 26A-E. The deployed
anchoring mechanisms 227 and 229 of the shunt 200 comprises a
radially expanded configuration (e.g., mesh or wired sphere,
elliptic, wired frame or basket, or the like, or combinations
thereof) for anchoring the shunt 200 at the target site (FIG.
27A-B). The anchoring mechanisms 227 and 229 (FIGS. 27A-D)
self-expand when the shunt 200 is implanted, thereby securing the
implanted shunt 200 in the target site. The anchoring mechanism 227
of the proximal portion 204 of the shunt incorporates the valve
209. The valve 209 comprises a wire frame partially covered with an
elastomeric/polymeric liner, so that the CSF flow is regulated by
the percentage of liner covering over the wire frame (FIGS. 27A and
27C). For example, the flow rate is lower when the wire frame is
substantially covered by the liner, as shown in FIG. 27C, and the
flow rate is larger when the wire frame has less liner coverage, as
shown in FIG. 27A. As shown in FIGS. 27C-E, the delivery assembly
300 further comprises an interlocking mechanism 290 configured to
detachably couple the shunt 200 to the delivery catheter 304. The
interlocking mechanism 290 includes a first interlocking element
292 (e.g., claw) coupled to the delivery catheter 304 and a second
interlocking element 294 (e.g., ring) coupled to the shunt 200
proximal portion 204 (e.g., attached to the valve 209). Once the
shunt 200 is properly disposed at the target site, withdrawal of
the delivery catheter 304 and uncoupling of the interlocking
mechanism 290 (e.g., disengaging the claw, as shown in FIG. 27E)
allows deployment of the shunt 200 (FIG. 27D). The interlocking
element 294 (e.g., ring) coupled to the shunt 200 proximal portion
204 also allows for subsequent capture, recovery and/or withdrawal
of the implanted shunt 200 (e.g., claw tool/catheter) or revision
of valve 209 in proximal portion 204.
[0200] Alternatively, the embodiment of shunt 200 depicted in FIGS.
27A-E can be configured for deployment in IPS 102 using a two-step
process. First, the body 203 of the shunt 200 comprising a
self-expandable elastomeric/polymeric cover/liner, and/or
stent-graft configuration, can be deployed in IPS 102. In some
embodiments, the cover/liner or stent-graft element resides only
within the IPS 102, while in other embodiments, deployment of the
cover/liner or stent-graft element includes the step of creating
the anastomotic connection between the IPS 102 and the CSF-filled
subarachnoid space of the CP angle cistern 138 (e.g., FIGS. 26B-E).
In a second step, a self-expanding wire form (e.g., comprising the
proximal and distal anchoring mechanisms 227 and 229, respectively,
and a stent-like body portion configured to reside within the cover
liner or stent-graft) can be delivered through the previously
deployed cover/liner and/or stent graft (e.g., FIG. 27B). The
anchoring mechanisms 227 and 229 (FIGS. 27B-D) self-expand as the
wire form is deployed out the cover/liner and/or stent graft in the
CP angle cistern 138 (i.e., mechanism 229) and jugular vein 106
(i.e., mechanism 227), thereby securing the implanted shunt 200 in
the target site. A partially covered wire frame comprising the
proximal anchoring mechanism 227 forms valve 209 with the
cover/liner and/or stent graft as previously disclosed.
[0201] FIG. 28 illustrates an exemplary shunt 200 constructed
according to embodiments of the disclosed inventions. The shunt 200
includes the anchoring mechanism 227 and a duck-bill valve 209 in
the proximal portion 204, the anchoring mechanism 229 in the distal
portion 202, and the elongate body 203 extending therebetween, and
further including an anchoring mechanism 223. The anchoring
mechanisms 223, 227 and 229 include a plurality of respective
deformable elements 223a, 227a and 229a (e.g., wires, loops) that
are disposed radially outward in the deployed configuration. The
deformable elements 223a, 227a and 229a are self-expanding (i.e.,
expanding from the delivery configuration into the deployed
configuration) and configured to move radially outward from the
axis of the shunt 200 allowing the shunt 200, including the body
203, to be anchored at the target site. The anchoring mechanism 227
is configured to engage the jugular bulb 108, the jugular vein 106,
the IPS wall 117, and/or another portion of the IPS 102, anchoring
the proximal portion 204 of the shunt 200 within the jugular vein
106, so that the valve 209 is disposed within the jugular vein 106.
The anchoring mechanism 223 is configured to engage the IPS walls
114 and 117, anchoring the body 203 within the IPS 102, and the
anchoring mechanism 229 is configured to engage the arachnoid layer
115 anchoring the distal portion 202 of the shunt 200 within the CP
angle cistern 138.
[0202] FIGS. 29A-G illustrates an alternative embodiment of the
shunt 200 constructed and implanted according to embodiments of
FIGS. 12 and 14A-H of the disclosed inventions. In the embodiment
of FIGS. 29A-G, the shunt 200 is coupled to the conduit 400; the
shunt 200 further includes the valve 209 in the proximal portion
204. Dual conical Nitinol coils 229a form a piercing cone (not
shown) when constrained by the delivery catheter 304 and conduit
400; coils 229a of the piercing cone (e.g., pencil tip
configuration) are delivered to IPS 102 in a constrained delivery
configuration, thereby providing a sharp penetrating member that
passes through dura of IPS wall 114 and arachnoid layer 115. Coils
229a can be self-expanding to separate from the penetrating cone
form and expand within the subarachnoid space after passing through
the dura 114 and arachnoid 115 to compress or pin down the
penetrated arachnoid layer 115 within the CP angle cistern 138.
Alternatively, the coils 229a can be mechanically actuated from a
penetrating cone to a deployed configuration, according to
previously disclosed embodiments of the anchoring mechanism 229. As
shown in FIGS. 29A, 29C-D, and 29F-G, the anchoring mechanisms 227
and 229 are incorporated or disposed on the conduit 400. The
conduit 400 comprises a self-expandable stent having an
elastomeric/polymeric cover/liner, and/or stent-graft
configuration, as shown in FIG. 12. The anchoring mechanism 229
comprises a plurality of deformable elements 229a (e.g., coils) and
a tubular neck 229b (FIGS. 29A, 29C-D). The plurality of deformable
elements 229a are configured to move radially outward from the axis
of the shunt 200 and/or conduit 400, and alternatively, the
elements 229a are also configured to move downwards (FIGS. 29A,
29C-D). The neck 229b is configured to be disposed within the
anastomosis channel 140 in the deployed configuration (FIGS. 29A,
29C-D). Additionally, the anchoring mechanism 229 includes engaging
members 229k (e.g., spring wires, balloons, claws, barbs, or the
like, or combinations thereof) coupled to the tubular neck 229b and
configured to move radially outward and upwards (FIG. 29D).
Further, the neck 229b and/or engaging members 229k comprise a
penetration stop preventing the penetrating member (e.g., 306, 250,
350, penetrating cone) and/or the shunt 200/200' from being
deployed beyond a suitable distal length into the CP angle cistern
138, allowing suitable clearance between the distal tip of the
shunt 200/200' and the brain stem 112, while avoiding abutting or
the damaging brain stem 112.
[0203] As shown in FIG. 29D, the anchoring mechanism 229 is
configured to compress or pin down the arachnoid layer 115 with the
deployed elements 229a against the dura mater IPS wall 114 with the
deployed members 229k, to prevent occlusion of the shunt lumen 207
(e.g., by arachnoid mater). The deployed anchoring mechanism 227
engages the jugular bulb 108, the jugular vein 106, the IPS wall
117, and/or another portion of the IPS 102, anchoring the proximal
portion 204 of the shunt 200 and/or conduit 400 within the jugular
vein 106, so that the valve 209 is disposed within the jugular vein
106 (FIGS. 29A, 29F-G). Valve 209 can have a windsock-like
configuration, formed from a collapsible, mesh-like framework of
biocompatible polymeric material (e.g., PTFE, ePTFE, i.e., expanded
polytetrafluoroethylene, PET). In its open form (e.g., under normal
differential pressure between the subarachnoid space and venous
system), CSF flows from the CP angle cistern 138 through the shunt
lumen 207 and out through the pores of windsock valve 209 into the
jugular vein 106. Windsock valve 209 can collapse on itself (e.g.,
where venous blood pressure exceeds the intracranial pressure in
the subarachnoid space such during coughing or sneezing events) to
prevent the backflow of blood through shunt 200 into the
subarachnoid space 116. As shown in FIG. 29G, the circulation of
venous blood flow around the proximal portion 204 of the shunt 200
agitates the valve 209, minimizing, deterring, or avoiding growth
of endothelial cells and clogging of the lumen 207 opening at the
proximal portion 204 of the shunt 200. As previously disclosed with
the embodiments of shunt 200 depicted in the FIG. 27, the
embodiments of shunt 200 shown in FIG. 29 can be deployed in a
two-step process (e.g., deployment of conduit 400 in at least the
IPS 102 in a first step, and deployment of a self-expanding wire
form comprising the proximal and distal anchoring mechanisms 227
and 229, a stent-like body portion, and valve 209 in a second
deployment step).
[0204] FIGS. 30A-F illustrate another exemplary shunt 200
constructed and implanted according to embodiments of the disclosed
inventions. The shunt 200 includes the anchoring mechanism 227 and
the duck-bill 209 in the proximal portion 204, the anchoring
mechanism 229 and tissue penetrating member 250 in the distal
portion 202, and the elongate body 203 extending therebetween. The
body 203 of the shunt 200 comprises a spring/coil-like body, as
shown in FIG. 6GH, for selective elongation and/or adjustment of
the shunt length L.sub.2 (FIG. 6) according to the anatomy of the
patient (i.e., target site for implantation of the shunt 220).
Further, the spring/coil-like body 203 of the shunt 200 is
configured to apply tensional force, at least, between the proximal
portion 204 and the distal portion 202 of the shunt 200 maintaining
the implanted shunt 200 properly anchored in the target site (e.g.,
limiting movement of shunt or loosely anchored shunt). The shunt
200 may be composed of thermoplastic elastomer (TPE), and the
anchoring mechanisms 227 and 229 may be composed of shape-memory
materials, such as super-elastic nickel titanium alloy, known as
Nitinol.RTM. or other suitable material. The shunt 200 is elongated
for advancement through the delivery catheter 304 (FIG. 30B). The
anchoring mechanisms 227 and 229 comprise a T-bar tubular
configuration, as shown in FIGS. 30A-F. The anchoring mechanism 229
includes a first anchoring element 229a configured to be disposed
in the CP angle cistern 138, anchoring and/or holding the distal
portion 202 of the shunt 200 against the arachnoid layer 115 so
that the tissue penetrating member 250 is disposed and held
adjacently to the arachnoid layer 115 when the shunt 200 is
deployed (FIGS. 30A and 30C). The anchoring mechanism 229 further
includes a second anchoring element 229b configured to be disposed
within the IPS 102 contacting the IPS wall 114, further anchoring
and holding the distal end 202 of the shunt 200 when interfacing
with the first anchoring element 229a, as shown in FIGS. 30A and
30C. The deployed anchoring mechanism 227 engages the jugular bulb
108, the jugular vein 106, the IPS wall 117, and/or another portion
of the IPS 102, anchoring the proximal portion 204 of the shunt 200
within the jugular vein 106, so that the valve 209 is disposed
within the jugular vein 106, as shown in FIGS. 30A and 30-D-F. The
delivery assembly 300 further comprises an interlocking mechanism
290 configured to detachably coupled the shunt 200 to the delivery
catheter 304, as shown in FIGS. 30D-F. The interlocking mechanism
290 includes a first interlocking element 292 (e.g., double clasps,
claws) coupled to the delivery assembly 300 and a second
interlocking element 294 (e.g., annular recess) coupled to the
shunt 200 proximal portion 204. Once the shunt 200 is properly
disposed at the target site, withdrawal of the delivery catheter
304 and uncoupling of the interlocking mechanism 290 (e.g.,
disengaging the claw 292 from the recess 294, as shown in FIG. 30E)
allows deployment of the shunt 200 (FIGS. 30A and 30F). The
interlocking element 294 (e.g., annular recess) disposed in the
proximal portion 204 of the shunt 200 also allows for subsequent
capture, interrogation, repair, recovery and/or withdrawal of the
implanted shunt 200 (e.g., claw tool/catheter).
[0205] FIG. 31 illustrates an alternative embodiment of the shunt
200 constructed and implanted according to the embodiment of FIGS.
22A-G. The implanted shunt 200 shown in FIG. 31 includes an
anchoring mechanism 227 and a duck-bill valve 209 in the proximal
portion 204, an anchoring mechanism 229 in the distal portion 202,
and an elongate body 203 extending therebetween. The anchoring
mechanism 227 includes a pre-curved configuration (e.g., "S" like
shape) and may further include a stent disposed within the jugular
vein 106, which may be attached to the proximal portion 204 of the
shunt 200. The stent portion of the anchoring mechanism 227
maintains the proximal portion of shunt 200 and duck-bill valve 209
in a relatively high blood flow area of the jugular vein to prevent
occlusion of valve 209. Such stent portion prevents proximal
portion 204 and valve 209 from being incorporated into the wall of
the jugular bulb and vein by endothelial cells overgrowing the
proximal portion 204 of the shunt 200, which can lead to shunt
clogging and failure.
[0206] FIG. 32 illustrates an alternative embodiment of the shunt
200 constructed and implanted according to embodiment of FIG. 21E.
The implanted shunt 200 includes the anchoring mechanism 229 and
the tissue penetrating member 250 in the distal portion 202 of the
shunt 200. The anchoring mechanism 229 comprises an elliptecot
configuration, as previously disclosed.
[0207] FIGS. 33A-33C depict one embodiment of an interface between
the tissue penetrating element 306 and the shunt 200 constructed
according to embodiments of the disclosed inventions. The tissue
penetrating element 306 includes a hollow tubular trocar configured
to be coaxially disposed within the lumen 207 of shunt 200. The
tissue penetrating element 306 includes a curved distal portion
(e.g., pre-curved, biasedly curved--heat-set Nitinol, flexible,
drivable distal portion via control wires, or the like, or
combinations thereof) with a sharpened, beveled tip configured to
penetrate the IPS wall 114 and the arachnoid layer 115. The shunt
200 also includes a curved distal portion 202 (e.g., pre-curved,
biasedly curved--heat-set Nitinol, flexible, or the like, or
combinations thereof). As shown in FIG. 33A, the respective curved
distal portions of the tissue penetrating element 306 and the shunt
200 are depicted in an opposite directions. The lumen 207 of the
shunt 200 is configured to allow passage of the tissue penetrating
element 306 thereof, as shown in FIG. 33B. When the tissue
penetrating element 306 and the shunt 200 are disposed in a
destructive interference (e.g., opposed respective curved distal
portions) the tissue penetrating element 306 and shunt 200 create a
straightened configuration, as shown in FIG. 33B. In this straight
configuration, the tissue penetrating element 306 and the shunt 200
can be navigated through the vasculature via the delivery catheter
304 until reaching the desired deployment location along the IPS
wall 114. At such location, the tissue penetrating element 306 can
be rotated relative to the shunt 200 such that the respective
curved distal portions of the tissue penetrating element 306 and
the shunt 200 align along the same arcuate path having a
constructive interface cooperatively bending towards the IPS wall
114, as shown in FIG. 33C. The tissue penetrating element 306 can
be advanced distally from the shunt 200 to penetrate through IPS
wall 114 and arachnoid layer 115 into the subarachnoid space 116,
as previously described. The shunt 200 can then be advanced over
the tissue penetrating element 306 and be anchored in CP angle
cistern 138 (e.g., before, as, or after the tissue penetrating
element 306 is withdrawn from the delivery assembly 300). The
tissue penetrating element 306 and shunt 200 configuration of FIGS.
33A-33C advantageously allows the tissue penetrating element 306
and shunt 200 to be delivered in a straight configuration while
tracking through the vasculature to the IPS 102, and then rotated
to a constructive interference of the curved distal portions of the
tissue penetrating element 306 and the shunt 200 having a combined
strength for penetrating through the IPS wall dura mater 114 and
arachnoid layer 115.
[0208] FIGS. 34A-34B illustrate another exemplary shunt 200
constructed and implanted according to embodiments of the disclosed
inventions. FIGS. 34A-B depict side views of the shunt 200 having
the anchoring mechanism 227 extending from the proximal portion 204
of the shunt 200 comprising a shepherd's hook or "J" like shape in
the deployed configuration, and the anchoring mechanism 229
extending from the distal portion 202 of the shunt 200 also
comprising a shepherd's hook or "J" like shape in the deployed
configuration. The anchoring mechanisms 227 and 229 include
respective curved (e.g., pre-curved, biasedly curved, flexible, or
the like, or combinations thereof) proximal 204 and distal 202
portions of the shunt 200, forming their respective shepherd's
hooks or "J" like shape in the deployed configuration. FIG. 34B
depicts a cross-section view of the shunt 200 deployed and
implanted in the IPS 102, providing a conduit for one-way flow of
CSF from the CP angle cistern 138 into the jugular vein 106. The
anchoring mechanisms 227 and 229 are configured to secure and
anchor the shunt 200 in a desired location by engaging the tissue
in the CP angle cistern 138 and jugular vein 106, respectively, as
previously described. The shepherd's hooks or "J" like shape of the
anchoring mechanisms 227 and 229 in the deployed configuration
minimize and/or prevent shunt occlusion and clogging by maintaining
the opening into the lumen 207 of the shunt 200 of the distal
portion 202 (e.g., CSF inflow portion) separated, apart, or away
from the arachnoid layer 115 (FIG. 34B) and the opening out of the
lumen 207 of the shunt 200 of the proximal portion 204 (e.g., CSF
outflow portion, valve 209) separated, apart, or away from the wall
of the jugular vein 106 (FIG. 34B). The shunt 200 comprises a
spring/coil-like body 203, as shown in FIGS. 34A and 34B
(interrupted line), for selective elongation and/or adjustment of
the shunt 200 length L.sub.2 according to the anatomy of the
patient (i.e., target site for implantation of the shunt 200).
Further, the spring/coil-like body 203 of the shunt 200 is
configured to apply tensional force, at least, between the proximal
portion 204 and the distal portion 202 of the shunt 200 maintaining
the implanted shunt 200 properly anchored in the target site.
[0209] Several embodiments of the shunt 200 and/or the delivery
system 300 have been previously described for penetrating the dura
mater of the IPS wall 114 and the arachnoid layer 115 with a
penetrating element (e.g., elongate pusher member 310, delivery
catheters 304/304'/304'', piercing elements 306/250/350, shunt
200', and/or system 300'). It should be appreciated that factors
(e.g., design and clinical aspects) can be considered as to
determine the embodiments, aspects and configurations of the
penetrating element of the system 300, for example: (a) the peak
force required to penetrate through tissue (i.e., IPS wall 114 dura
mater from within the IPS 102 and the arachnoid layer 115 into the
CP angle cistern 138), which force is translated through the
delivery system 300 from a peripheral access point such as a
delivery catheter inserted at the femoral vein (e.g., proximal
portion of a delivery guide wire, catheter, or tool); (b) the
tissue damage and severity of the trauma caused from the
penetrating/piercing step or force (a) applied to the IPS wall 114
dura mater and arachnoid layer 115; (c) the extent to which the
penetration site seals around the deployed shunt or has potential
for leaking blood or CSF through the anastomosis 140; (d) the
extent of tissue deformation during the penetrating/piercing step
or force (a) applied to the IPS wall 114 dura mater and arachnoid
layer 115 (e.g., the extent that IPS wall 114 dura mater and/or
arachnoid layer 115 expand toward brain stem 116 before the
penetrating element passes through the tissue); and (e) the extent
that the penetrating element resists bending or buckling while
penetrating tissue and/or that such penetrating element requires
additional support (e.g., an outer sheath) to translate the forces
required to penetrate tissue.
[0210] FIG. 35 depicts a test system 400 for evaluating the
aforementioned design and clinical considerations of the
penetrating elements of the system 300, according to embodiments of
the disclosed inventions. The test system 400 includes a load
displacement apparatus 410, and a load cell 420 fitted to a
cross-head of the load displacement apparatus 410. The load cell
420 includes a connector 420A for affixing a penetrating element
425 (e.g., elongate pusher member 310, delivery catheter 304,
tissue penetrating member 306/250/350, shunt 200') as shown in
FIGS. 35, 36, and 38. The connector 420A is sized and configured to
fit and hold a variety of penetrating elements 425. A bath fixture
430 is coupled to or mounted on a heating platform 473; the heating
platform 473 is coupled to or mounted on stage members 463A and
463B that control the location of the bath fixture 430 relative to
the load displacement apparatus 410 in the X (463A) and Y (463B)
planes. A tissue block 490 is disposed inside the bath fixture 430,
and includes a tissue sample 486 (e.g., human dura, pig dura, a
dura surrogate such as Dura-Guard.RTM. dural repair patch from
Synovis Surgical Innovations, St. Paul, Minn.) clamped in the
tissue block 490 for testing the penetrating element 425, as shown
in FIGS. 35-38. Alternatively or additionally, an arachnoid tissue
or a suitable surrogate for arachnoid layer 115 (e.g., human
arachnoid, pig arachnoid, pig mesentery) can also be clamped in the
tissue block 490 for testing the penetrating element 425. The load
displacement apparatus 410 can control and vary the speed that
penetrating element 425 advances towards the tissue sample 486. The
load cell 420 measures the forces generated from the penetrating
element 425 piercing tissue samples 486, as well as the forces
generated when withdrawing the penetrating element 425 from the
pierced tissue sample 486.
[0211] As shown in FIG. 36, the tissue block 490 is coupled to a
block stand 474 disposed within the bath fixture 430. The tissue
block 490 and block stand 474 are rotatably coupled allowing an
operator to adjust the orientation of the tissue block 490 relative
to the block stand 474 and therefore, relative to the piercing
element 425, in the clockwise and counterclockwise directions. The
relative rotation of the tissue block 490 and block stand 474
allows the operator to adjust and set a desired angle for the
penetrating element 425 to pierce or penetrate the tissue sample
486 clamped in the tissue block 490 when the load displacement
apparatus 410 drives penetrating element 425 towards the clamped
tissue sample 486 (piercing direction represented by arrow 425A in
FIG. 36).
[0212] The tissue block 490 includes an upper plate 481 having a
plurality of channels 484; the plate 481 is coupled to a lower
support block 487, and the lower support block 487 includes a
connection port 483 (FIGS. 36 and 37). The tissue sample 486 is
clamped under the upper plate 481 and over the lower support block
487 creating a chamber 488 between the sample 486 and the support
block 487, as shown in FIGS. 36 and 37. The lower support block 487
can be constructed using a clear material to observe the
penetrating element 425 during testing (e.g., observe the extent of
tissue deformation or whether arachnoid layer "tents" above the
dura surrogate before piercing). The bath fixture 430 can be filled
with a temperature controlled solution (e.g., saline) and/or the
heating block 473 can be used to control the temperature of the
solution within the bath fixture 430. The chamber 488 of the tissue
block 490 disposed within the bath fixture 430 can be pressurized
with the temperature controlled solution (or other CSF surrogate)
via the port 483, such that the chamber 488 represents the
subarachnoid space into which penetrating element 425 will pierce
during testing. The pressure of the CSF surrogate in the chamber
488 can be controlled to create a differential pressure between the
CSF surrogate solution and the temperature controlled solution in
the bath fixture 430, which mimics the pressure differential
between the subarachnoid space and venous system in patients (e.g.
5-12 cm H20 for non-hydrocephalic patients).
[0213] FIG. 37 depicts the tissue sample 486 clamped between the
upper plate 481 and the lower support block 487 of the tissue block
490, according to the disclosed inventions. Screws 485 (or other
suitable fasteners) secure the upper plate 481 to lower support
block 487 clamping the tissue sample 486 between the upper plate
481 and the lower support block 487 to create the chamber 488. The
upper plate 481 channels 484 mimicking the IPS 102 (i.e., lumen)
such that, the tissue sample 486 represents the IPS wall 114 for
testing the penetrating element 425 of the system 300. The channels
484 are configured to expose the clamped tissue sample 486 and
allow contact with the penetrating element 425 driven by the load
displacement apparatus 410 in the piercing direction 425A (FIG.
36). For example, FIG. 38 shows a tissue sample 486 and the
penetrating element 425 (e.g., beveled needle) oriented in the
piercing direction 425A to penetrate the tissue sample 486 at a
10-degree penetration angle A.sub.1.
[0214] Testing the penetrating element 425 having certain
configurations, such as shape (e.g., shape of the piercing tip,
needle, beveled, or the like), sizes (i.e., gauge number), and
material (e.g., stainless steel, Nitinol, or the like) at various
penetration speeds ranging from 0.1 mm/s to 5 mm/s and various
ranges of penetration angles using the test system 400 as
previously described, yielded the exemplary data summarized in FIG.
39. Of the penetrating element 425 tested, the data generally
indicates that: (1) blunt needles require a higher force to
penetrate dura mater, impose higher deformation on the tissue prior
to puncture, and show a risk of coring the tissue during piercing
dura mater; (2) pencil tip and beveled needles show consistent
retraction forces that translate to the best seal of the
anastomotic connection between the IPS 102 and CP angle cistern 138
(e.g., no CSF surrogate leaked between chamber 488 and bath fixture
430 up to a differential pressure of 100 cm H20); and (3) Quincke
and pencil tip needles require the least amount of force to
puncture dura mater. While other penetrating elements 425 were
evaluated and tested with test system 400, the test data showed
that the quincke, pencil, and bevel shape penetrating element 425
may be preferred for embodiments of the disclosed inventions based
on the relatively low tissue penetration force require to pierce
dura mater, minimal tissue damage caused during tissue penetration,
the sealing characteristics of the penetration tract through the
tissue, minimal tissue deformation during penetration, and minimal
additional support requirements of the penetrating element 425 to
prevent buckling or bending during penetration.
[0215] Methods can be used to assess the patency of the shunt 200
or 200' (e.g., of lumen 207 and valve 209) after deployment and
implantation of the shunt 200 or 200', according to embodiments of
the disclosed inventions. In one exemplary method of accessing the
patency of the implanted shunt 200 or 200', with reference to FIG.
40, a clinician can inject an iodinated contrast agent into the
lumbar thecal sac of the patient by a lumbar puncture or spinal tap
500. After the injection step 500 (e.g., approximately five to ten
minutes after 500), the contrast agent will disperse from the
lumbar subarachnoid space into the CSF in the intracranial
subarachnoid space around the brain stem from the circulation of
CSF within the subarachnoid space. Using one or more of the imaging
methods previously described herein, the presence of contrast agent
in the CSF will be apparent by the clinician (e.g., highlight in an
imaging system) 510. If the imaging step 510, detects the presence
of contrast agent 520 throughout shunt lumen 207 and/or in the
venous system immediately adjacent the proximal portion 204 of the
shunt 200, then shunt 200 is patent (i.e., not occluded) 530, as
evidenced by the contrast agent dispersing from the flow of CSF in
the CP angle cistern through the shunt 200. If the imaging step 530
does not detect the presence of contrast agent throughout shunt
lumen 207 and/or in the venous system immediately adjacent the
proximal portion 204 of the shunt 200, then shunt 200 is not patent
(i.e., occluded) 540. Additionally, during the lumbar puncture step
500, a CSF pressure measurement can be obtained 550. A pressure
measurement within normal ranges further confirms that the deployed
shunt 200 is draining CSF from the intracranial subarachnoid space
into the venous system, and a pressure measurement higher than the
normal ranges further confirms that the deployed shunt 200 is or
may be occluded.
[0216] In another exemplary method of assessing the patency of the
implanted shunt 200 or 200', with reference to FIG. 41, a clinician
can evaluate CSF flow through the deployed shunt 200 or 200' by
injecting 600 radioactive or neutron-activated microspheres (e.g.,
microspheres from BioPAL, Worcester, Mass.) into the CSF via a
lumbar puncture or by accessing the subdural space in the cranium.
Microspheres with a diameter of 15 microns or larger would not pass
through the arachnoid granulations, which absorb CSF from the
subarachnoid space into the venous system, yet should be selected
such that the microspheres can pass through lumen 207 of a deployed
shunt (e.g., having a diameter ranging from 0.1 mm to 2 mm).
Assuming a properly functioning deployed shunt 200 according to the
disclosed inventions, the presence of microspheres in the CSF would
only enter the blood stream via a patient shunt 200; a venous blood
sample or tissue sample from the lungs can be collected and
assessed for the presence of microspheres 610. The number of
microspheres obtained via a venous sampling at various points in
time reflects the flow rate through the shunt 200 and the number of
microspheres injected into the CSF 620. Samples obtained via a
biopsy of lung tissue are also proportional to the total flow of
microspheres through the shunt and the number of microsphere
injected into the CSF. Collected samples without any microspheres
suggest that CSF is not flowing through the deployed shunt 200, and
the shunt 200 is occluded 630. For example, the venous blood sample
can be obtained from the guide or delivery catheter in the
vasculature for shunt deployment and within 15 to 20 minutes of
injecting microspheres into the CSF. This sampling technique can
provide a sensitive measurement of the CSF flow through the shunt
200 if assessed by radioactive or neutron-activated microspheres
because it maximizes the collection of microspheres flowing through
the shunt 200. The neutron activated microsphere assay is extremely
sensitive with the limits of detection almost down to 1
microsphere. Venous blood or lung tissue samples can be sent to a
commercial testing service, such as BioPAL, that uses neutron
activation technology to measure the microsphere content of the
sample.
[0217] FIGS. 43A-D illustrate an alternative delivery catheter 304'
for delivering the shunt 200 into a target site of a patient,
constructed in accordance with embodiments of the disclosed
inventions. For ease in illustration, the features, functions, and
configurations of the delivery catheter 304' that are the same as
in the assembly 300 of FIGS. 3B and 4A-D and/or are the same as in
the assembly 300' of FIGS. 5A-J are given the same reference
numerals. The delivery catheter 304' is dimensioned to reach remote
locations of the vasculature and is configured to deliver the shunt
200 percutaneously to the target location (e.g., inferior petrosal
sinus). The delivery catheter 304' may comprise variable stiffness
sections (e.g., varying ratio of material, including selective
reinforcement, such as braids, coils, or the like) suitable to
provide sufficient "pushability" and "torqueability" to allow the
catheter 304' to be inserted, advanced and/or rotated in the
vasculature to position the distal portion 344 of the catheter at
the target site within the IPS 102. Further, the distal portion 344
should have sufficient flexibility so that it can track and
maneuver into the target site. Variable stiffness in the catheter
304' is achieved, for example, by locally varying the properties or
distribution of the materials used and/or varying the durometer or
thickness of the materials during the process of manufacturing. By
way of non-limiting examples, the materials used in manufacturing
the catheter 304' may include polyether block amide (Pebax.RTM.)
and Nylon. Other suitable materials that may be contemplated for
making the catheter 304' include homopolymers, copolymers or
polymer blends containing polyamides, polyurethanes, silicones,
polyolefins (e.g., polypropylenes, polyethylenes), fluoropolymers
(e.g., FEP, TFE, PTFE, ETFE), polycarbonates, polyethers, PEEK,
PVC, and other polymer resins known for use in the manufacture of
catheters. It should be appreciated that when appropriate, the
delivery catheter 304' may be used in combination with the delivery
assembly 300/300' previously described.
[0218] The delivery catheter 304' comprises a tissue penetrating
member 350 coupled to the distal portion 344 of the catheter 304'.
The tissue penetrating member 350 comprises a tubular configuration
having a lumen 355 fluidly coupled to the lumen 305 of the delivery
catheter 304' (FIG. 43C), which allows the shunt 200 (i.e.,
slidably disposed in the lumen 305 of the catheter 304') to be
deployed into the target site when the anastomosis channel 140 is
created (not shown). The tissue penetrating member 350 comprises a
piercing edge 351 and a piercing tip 352 (FIGS. 43A, 43C-D), which
will be described in further detail below. It should be appreciated
that when using the delivery catheter 304' to deliver and deploy
the shunt 200 into the target site, the tissue penetrating element
306 of the delivery assembly 300 and/or the tissue penetrating
member 250 incorporated in the shunt 200' may not be required.
[0219] The delivery catheter 304' further comprises an expandable
element 390 coupled to, or disposed on the distal portion 344 of
the delivery catheter 304'. The expandable element 390 is
proximately disposed to the piercing tip 352 of the tissue
penetrating member 350, as to drive and/or advance the tissue
penetrating member 350 into the IPS wall 114 to create anastomosis
between the IPS 102 and the CP angled cistern 138 (FIG. 44C). The
expandable element 390 may comprise an expandable balloon, foam,
stent, or combinations thereof. In the embodiments of FIGS.
43A-44C, the expandable element 390 is an expandable balloon. The
expandable element 390 comprises a collapsed configuration (i.e.,
deflated, as shown in FIGS. 43A-D and 44A), a first expanded
configuration (e.g., partially inflated or first expanded state, as
shown in FIG. 44B), and a second expanded configuration (i.e.,
inflated or second expanded state, as shown in FIG. 44C). It will
be appreciated that the expandable element 390 provides an off-axis
expanded configuration (FIGS. 44B-C). In other embodiments, the
expandable element 390 may include any suitable expandable
configuration, such as, a conical, tapered, accordion-like, angled
configurations, or combinations thereof.
[0220] The expandable element 390, when expanded/inflated to the
first expanded state, the expandable element 390 causes the tip of
the tissue penetrating element 350 to engage the dura matter of the
IPS wall 114, and thereafter inflated to the second expanded state
causes the tissue penetrating element 350 and tip to penetrate
through the IPS wall 114 and arachnoid layer 115, respectively,
into the CP angle cistern 138, as shown in FIGS. 44B-E. Further,
when the expandable element 390 is expanded/inflated to the first
expanded state, the element 390 orients the tissue penetrating
member 350 towards the IPS wall 114 and initiates tissue engagement
as shown in FIG. 44B thereby locking delivery catheter 304' in the
IPS 102 relative to the target penetration site in the IPS wall
114. By way of example, the height of the bulb portion of
expandable element 390 expandable element 390 (e.g.,
inflation/volume of an interior cavity 391 of the expandable
element 390 expandable element 390) in its first expanded state
shown in FIG. 44B, as measured from IPS wall 117, can be between
0.5 mm to 2.5 mm (e.g., 1.5 mm). Additional expansion/inflation of
expandable element 390 expandable element 390 from its first
expanded configuration to its second expanded configuration
advances the tissue penetrating member 350 through the IPS wall 114
as shown in FIG. 44C. Again, by way of example, the height of the
bulb portion of expandable element 390 expandable element 390
(e.g., inflation/volume of the balloon's interior 391) in its
second expanded state shown in FIG. 44C, as measured from IPS wall
117, can be between 2.5 mm to 4.0 mm (e.g., 3.0 mm). It should be
appreciated that the height of the bulb portion of expandable
element 390 may also be smaller than 2.5 mm in patients with
smaller diameter IPS 102, or larger than 4.0 mm in patients with
larger diameter IPS 102.
[0221] Additionally, while the expandable element 390 is being
expanded/inflated to transition from the deflated configuration
(FIG. 44A) to the partially inflated configuration (FIG. 44B), and
into the fully inflated configuration (FIG. 44C), the tissue
penetrating member 350 transitions from being disposed
substantially parallel relative to the IPS wall 114 (FIG. 44A) into
being disposed in angles of interaction relative to the IPS wall
114 (FIGS. 44B-C). The angles of interaction of the tissue
penetrating member 350 from the delivery configuration may vary
from approximately 0.degree. to approximately 150.degree. relative
to the IPS wall 114, preferably from approximately 5.degree. to
approximately 90.degree..
[0222] The delivery catheter 304' further comprises an inflation
lumen 309 fluidly coupled to the interior 391 of the expandable
element 390 (FIGS. 43B-C), and to a source of inflation media (not
shown) for supplying fluid and/or gas to selectively inflate and
deflate the expandable element 390. For example, the inflation
media source may have a predetermined volume of fluid/gas to
adequately inflate the expandable element 390 causing the
advancement of the tissue penetrating member 350 into the IPS wall
114. Additionally, the source of inflation media may include
aspiration means to deflate the expandable element 390 by
withdrawing the fluid/gas from the expandable element 390. The
inflation media source may optionally include a pressure sensor to
measure the inflation pressure to ensure adequate inflation without
over inflation of the expandable element 390. The expandable
element 390 may be inflated with one or more fluids (e.g., saline,
contrast agent, or the like) or with gas (e.g., air), and/or a
combination thereof. For example, the expandable element 390 may be
inflated with a mixture of saline and contrast agent (i.e., fluid
containing radio-opaque materials) for purposes of imaging,
according to the disclosed inventions (e.g., mixture comprising 50%
saline and 50% contrast agent).
[0223] The expandable element 390 coupled to the delivery catheter
304' may be made of or otherwise include compliant, semi-compliant,
or non-compliant polymeric materials, such as silicone, urethane
polymer, thermoplastic elastomer rubber, santoprene, nylon,
polytetrafluoroethylene "PTFE", polyethylene terephthalate "PET",
and other suitable materials or combinations thereof. In
embodiments comprising compliant materials, the expandable element
390 is preferably composed of urethanes (e.g., Pellethane or
Chronoprene).
[0224] In another embodiment, the expandable element 390 is
composed of a non-compliant material, such as polyurethane
terephthalate "PET", which allows and facilitates inflation of the
expandable element 390 by a source of inflation media filled with a
predetermined volume of fluid/gas. The predetermined volume of
fluid/gas may correspond to, for example, a preformed volume of the
expandable element 390, which will be described in further detail
below. Having a source of inflation media filled with a
predetermined volume of fluid to inflate the noncompliant material
of expandable element 390 reduces the risk of overinflating and
overextending of the expandable element 390 in its deployed
configuration. Additionally, the expandable element 390 composed of
non-compliant material is configured to withstand higher inflation
pressure without deforming or overextending, as compared to
balloons composed of compliant materials.
[0225] FIGS. 44A-C illustrate a method for creating anastomosis via
an endovascular approach to deliver and implant the shunt 200 into
the target site using the delivery catheter 304', in accordance
with embodiments of the disclosed inventions. The distal portion
344 of the delivery catheter 304' having the tissue penetrating
member 350 in a delivery orientation, and the expandable element
390 in the collapsed configuration, is advanced into the target
site within the IPS 102, as shown in FIG. 44A. Prior to the
piercing of the IPS wall 114 and the arachnoid layer 115 to create
anastomosis and access the CP angle cistern 138, proper orientation
of the distal portion 344 of the delivery catheter 304',
particularly, proper orientation of the tissue penetrating member
350 and the expandable element 390, may be verified prior to
actuation according to the imaging methods previously disclosed.
For example, markers may be used for positioning and orienting the
distal portion 344 of the delivery catheter 304'. When needed, the
positioning and orientation of the tissue penetrating member 350
and the expandable element 390 disposed on the distal portion 344
of the delivery catheter 304' may be adjusted, for example, by
applying a rotational force directly to the body of the delivery
catheter 304'.
[0226] Once proper positioning and orientation of the distal
portion 344 of the delivery catheter 304' is achieved, the
expandable element 390 is inflated transitioning into its partially
expanded configuration and bending the distal portion 344 of
delivery catheter 304' away from IPS wall 117 so as to orient the
tissue penetrating member 350 into the IPS wall 114 at a suitable
angle, as shown in FIG. 44B. Continuing inflation until the
expandable element 390 reaches its fully expanded configuration
advances the tissue penetrating member 350 causing piercing and
penetration of IPS wall 114, and penetration through the arachnoid
layer 115 until reaching the CSF-filled subarachnoid space 116
and/or the CP angle cistern 138 creating the anastomosis channel
140, as shown in FIG. 44C. Simultaneously or consecutively with the
creation of the anastomosis channel 140, the shunt 200 is advanced,
deployed and implanted at the target site, as previously described.
Once the shunt 200 is implanted, the balloon 290 is
deflated--preferably after the deployment of the distal anchoring
mechanism 229 of shunt 200- and the delivery catheter 304' is
withdrawn out of the patient (not shown). As illustrated in FIGS.
44A-C, expansion of expandable element 390 inside the lumen of IPS
102 limits the penetration depth of tissue penetrating member 350
into CP angle cistern 138; that is, the configuration of expandable
element 390 and the anatomical confines from the lumen of IPS 102
and IPS wall 114 prevent expandable element 390 in its expanded
configuration, from further expansion that could advance the
coupled tissue penetrating member 350 too far distally into the
subarachnoid space 116 and/or the CP angle cistern 138. The
penetration depth limit illustrated in FIGS. 44C and 44E, in turn,
maintains adequate space in CP angle cistern 138 between arachnoid
layer 115 and brain stem 112 (not shown) or expansion envelope for
a distal portion of the shunt and/or distal anchoring mechanism to
deploy in the subarachnoid space without damage critical anatomical
structures.
[0227] FIGS. 44A-C depict tissue penetrating member 350 as it
transitions through a 90-degree turn (e.g., in a range of 30
degrees to 90 degrees) from its delivery orientation (i.e., coaxial
with the longitudinal axis of delivery catheter 304' and IPS lumen
102) to a fully penetrated orientation (i.e., orthogonal to IPS
wall 114) as expandable element 390 transitions to a fully expanded
configuration. For illustration purposes, FIGS. 44D-E are
perspective views of FIGS. 44B-C respectively, depicting a top-side
view of the tissue penetrating member 350 transitioning into an
expanded configuration which facilitates full penetration of the
IPS wall 114 and arachnoid layer 115 into the CP angle cistern 138.
The narrow diameter and/or tortuous pathway of the IPS lumen may
not allow tissue penetrating member 350 to penetrate orthogonal to
IPS wall 114 in all patients; thus, the tissue penetrating member
350 may only transition through about a 30-degree turn to 70-degree
turn while expandable element 390 expands before completely
penetrating IPS wall 114. For example, the clinician may expand
expandable element 390 to a first expanded state where penetrating
element 350 engages the dura of IPS wall 114 at an angle of about
45 degrees or less, without fully penetrating into the CP angle
cistern 138, as shown in FIG. 44B. At this step, the clinician can
confirm the trajectory of the penetrating element 350 (e.g., using
one or more of the imaging methods described herein) before
completing the penetration step of the procedure. If unsatisfied
with the trajectory presented, the clinician can deflate expandable
element 390 to its collapsed or delivery configuration, adjust the
position or orientation of delivery catheter 304', and re-expand
expandable element 390 to a first expanded configuration where
penetrating element 350 engages IPS wall 114 on a suitable
trajectory for further penetration through the IPS wall into CP
angle cistern 138. Thereafter, the clinician can further expand
expandable element 390 until the penetrating element 305 has
completely penetrated through the IPS wall 114 and arachnoid layer
115 underlying the CP angle cistern 138. (e.g., at an angle of
about 70 degrees).
[0228] Additionally to the method for creating anastomosis 140 via
an endovascular approach of FIGS. 44A-C, a clinician may apply a
suitable mechanical force to the delivery catheter 304' further
assisting with the advancement of tissue penetrating member 350
driven by the expandable element 390 into the IPS wall 114.
[0229] Additionally to the expandable element 390 disclosed above,
delivery catheter 304' may include a second expandable balloon,
foam, stent, or combination thereof, located proximally from the
distal end of the catheter (e.g., about 1 cm to about 3 cm from the
distal end of the catheter). The second expandable member (not
shown), when expanded from a collapsed to expanded configuration,
further secures delivery catheter 304' about the target penetration
site in IPS wall 114. In embodiments where the second expandable
member is a balloon, the balloon can be composed of non-compliant
or compliant materials and communicate fluidly with inflation lumen
309 or a similar yet fluidly distinct lumen. Further, the second
balloon can be configured within the dimensional ranges previously
disclosed with respect to expandable element 390. The second
expandable member can extend circumferentially around the exterior
of the delivery catheter or may comprise a smaller portion of the
delivery catheter circumference (e.g., approximately 25%,
approximately 50%, approximately 75%). In embodiments where the
second expandable member comprises a smaller portion of the
delivery catheter circumference, such expandable member can be
located on the opposite side of delivery catheter 304' when
compared to the expandable element 390 or, alternatively, on the
same side of delivery catheter 304' as the expandable element 390,
or in some relative clocking between fully aligned and fully
opposed orientations.
[0230] In some embodiments, deploying the shunt 200 comprises
advancing the distal portion 202 of the shunt 200 from the IPS 102
into the CP angle cistern 138 using the tissue penetrating member
350. The tissue penetrating member 350 may be coupled to a distal
portion 202 of the shunt 200, so that advancing the distal portion
202 of the shunt 200 from the IPS 102 into the CP angle cistern 138
comprises advancing the tissue penetrating member 350 and distal
portion 202 of the shunt 200' through the dura mater tissue wall of
the IPS 114, and through the arachnoid tissue layer 115,
respectively, into the CP angle cistern 138. During advancement of
the distal portion 202 of the shunt 200, the distal portion 202 of
the shunt 200 is at least partially disposed in the delivery lumen
305 of the delivery catheter 304', the tissue penetrating member
350 comprising a tissue penetrating tip of the delivery catheter
304', and where advancing the distal portion 202 of the shunt 200
from the IPS 102 into the CP angle cistern 138 comprises advancing
the delivery catheter 304 so that the tissue penetrating tip
penetrates through the dura mater tissue wall of the IPS 114, and
through the arachnoid tissue layer 115, respectively, into the CP
angle cistern 138. The delivery catheter 304' distal portion 344
assumes a curved configuration that guides the tissue penetrating
tip into contact with the dura mater of the IPS 114 at an angle in
a range of 30 degrees to 90 degrees, as shown in FIGS. 44B-C. As
shown in FIGS. 44A-E, the distal portion 344 of the delivery
catheter 304' comprises the expandable element 390 (or wall portion
that is expanded) to cause the distal portion of the delivery
catheter 304' to assume the curved configuration. The delivery
catheter 304' comprising one or more radiopaque markers located and
dimensioned to indicate a position and orientation of the distal
portion 344 of the delivery catheter when in the curved
configuration. Deploying the shunt 200 further comprises
withdrawing the distal portion of the delivery catheter 304' from
the CP angle cistern 138, while maintaining the distal portion 202
of the shunt 200 at least partially disposed in the CP angle
cistern 138.
[0231] FIGS. 45A-D illustrate an exemplary tissue penetrating
member 350 constructed according to embodiments of the disclosed
inventions. The tissue penetrating member 350 comprises a tubular
configuration having a proximal end portion 353 and a distal end
portion 357, and lumen 355 extending therebetween (FIG. 45B). The
distal end portion 357 of the tissue penetrating member 350
comprises a tapered/beveled piercing edge 351 that terminates in
the piercing tip 352 (FIGS. 45A-B). FIGS. 45D and 46G illustrate
exemplary dimensions (in inches), angles and properties of the
tissue penetrating member 350, which are not intended to limit the
embodiment of FIGS. 45A-C.
[0232] FIGS. 46A-G illustrate other exemplary piercing elements 350
constructed according to embodiments of the disclosed inventions.
The proximal end portion 353 of tissue penetrating member 350
further extends (FIGS. 46E-F) or it is coupled to an elongated
tubular member 359 (FIGS. 46A-D). The elongated tubular member 359
comprises a smaller outer diameter and profile than the outer
diameter and profile of the proximal end portion 353 of the tissue
penetrating member 350 (FIGS. 46A-D). The elongated tubular member
359 of FIGS. 46A-D and the extending proximal portion 353 of FIGS.
46E-F are shaped and dimensioned to be disposed within the lumen
305 of the distal portion 344 of the delivery catheter 304'. The
tissue penetrating member 350 embodiment shown in FIGS. 46E-F
includes cut portions along the length of the tubular member 359
shown as a spiral cut pattern in FIGS. 46E-F. The cut portions
advantageously provide sufficient flexibility for the penetrating
element, for example, to bend from a delivery to expanded
configuration if incorporated into the expandable element 390
embodiment shown in FIGS. 43, 44, and 47, while maintaining
sufficient column strength of the tissue penetrating member 350 to
penetrate through dura and arachnoid tissues. In the embodiments of
FIGS. 46A-D, the outer diameter and profile of tissue penetrating
member 350 may match the outer diameter and profile of the distal
portion 344 of the delivery catheter 304'.
[0233] It should be appreciated that the dimensions, angles and
properties of the tissue penetrating member 350 of FIGS. 45A-46D
may be incorporated into the tissue penetrating element 306 of the
delivery assembly 300 and/or the tissue penetrating member 250 of
the shunt 200'.
[0234] FIGS. 47A-49C illustrate expandable expandable element 390
constructed according to various embodiments of the disclosed
inventions. The expandable expandable element 390 is shown in a
preformed molded configuration (FIGS. 47A, 48A and 49A) before it
is mounted on or coupled to the distal portion 344 of the delivery
catheter 304'. The expandable element 390 includes a first-end
portion 392 (e.g., proximal), a middle-body portion 393 (e.g.,
expandable) and a second-end portion 394 (e.g., distal),
collectively defining an interior 391 of the expandable element 390
through which the delivery catheter 304' or other type of elongate
structure extends. The first-end portion 392 and second-end portion
394 of the expandable element 390 may include respective tubular or
other suitable configurations to be coupled to the distal portion
344 of the delivery catheter 304' by adhesive, thermal bonding or
the like, interlocking geometries, mechanical fastening, sutures or
combinations thereof.
[0235] In comparison to the expandable expandable element 390
embodiment of FIG. 47A-C where a shunt is delivered through a lumen
of the expandable element 390, the balloon embodiments of FIGS.
48A-D, 49A-D, when in an expanded configuration, provide a ramp to
deflect a penetrating element 306 of the elongate pusher member
310, penetrating element 250 of the shunt 200' or penetrating
element 350 of the delivery catheter 304' toward IPS wall 114,
similar to the deflecting element 370 coupled to or disposed on the
distal portion 344 of the delivery catheter 304 described in
connection with FIGS. 20A-F. In an expanded configuration, the
transition from first-end portion 392 to middle-body portion 393 of
the expandable element 390 of FIGS. 48A-D, 49A-D deflects the
piercing element away from the central axis of the delivery
catheter to penetrate IPS wall 114. That is, the piercing element
or a sheath housing the piercing element can emerge from delivery
catheter 304 at a location proximal to first-end portion 392 of the
balloon; as the piercing element advances distally; the
transitioned portion of the inflated balloon directs the piercing
element into the tissue of IPS wall 114 (FIGS. 48D and 49D). As
described herein, the piercing element used with the balloon
embodiments of FIGS. 48A-D, 49A-D can be configured such that the
shunt is delivered through a lumen of the piercing element or such
that the piercing element extends through the shunt lumen to deploy
the shunt distal end (e.g., anchor 229) within the CP angle
cistern.
[0236] The expandable element 390 may be composed of material
previously described that may have a shore durometer range between
40 A to 90 A, and/or a shore durometer range between 25 A to 100 A.
For example, the expandable element 390 may be manufactured with
standard processing equipment to obtain a molded balloon having a
wall thickness of approximately between 0.00025 inches (0.00635 mm)
to 0.003 inches (0.0762 mm) in the middle expandable portion 393.
Further, the wall thickness of the expandable element 390 may vary
from thicker, in and around the first-end portion 392 and in and
around the second-end portion 394 to thinner in and around the a
middle-body portion 393 at least. For example, the first-end
portion 392 may have a wall thickness greater than a wall thickness
of the middle-body portion 393.
[0237] Portions 392, 393, and/or 394 of expandable element 390 can
have a non-uniform thickness. For the expandable element 390
embodiment shown in FIGS. 43, 44, 47 and with reference to FIG. 47,
a central region of middle portion 393 comprises a thicker wall
thickness than the first and second end regions of middle portion
393; the localized thinning of expandable element 390 at the end
regions of middle portion 393 provides the eccentric expansion of
expandable element 390 depicted in FIGS. 43-44. In some embodiments
of expandable element 390, the central region of middle portion 393
comprises the thickest portion of expandable element 390.
[0238] In embodiments of the invention and with the use of standard
blow and/or dip molding principles, an angled (FIGS. 47A-C), an
off-axis (FIGS. 44A-E, 48A-C), or a conical molded configuration
(FIGS. 49A-C) of the expandable element 390 may be manufactured. By
way of example, the expandable element 390 can have a variety of
shapes in the molded, mounted or inflated configurations, including
but not limited to: diamond, circular, oval, multi-sided, or
irregular shapes, and/or angles that are adapted to orient and
advance the tissue penetrating member 350 into the IPS wall 114 and
arachnoid layer 115 to create the anastomosis channel 140, as
previously described. For example, FIGS. 50A-B depict a straight
mounted configuration of the expandable element 390, in which FIG.
50A shows the collapsed configuration and FIG. 50B shows the
expanded configuration of the expandable element 390. In addition,
penetrating element 350 can be folded further inward than as
depicted in FIG. 50A, proximally along the length of expandable
element 390 such that the tip of penetrating element 350 does not
extend past or emerge from the distal end of expandable element 390
in a collapsed or delivery configuration. As the balloon is
inflated, the length of expandable element 390 unfurls causing
penetrating element 350 to emerge from the infolded balloon to its
expanded configuration shown in FIG. 50B.
[0239] FIGS. 47A-50B illustrate exemplary dimensions, angles and
properties of the expandable element 390, which are not intended to
limit the embodiments of expandable element 390. FIG. 47D
illustrates exemplary tabulated material properties of the
expandable element 390 depicted in 47A-C, which are not intended to
limit the embodiment of FIGS. 47A-C.
[0240] FIGS. 51A-54C illustrate further exemplary piercing elements
for creating anastomosis via the endovascular approach, constructed
in accordance with embodiments of the disclosed inventions. The
tissue penetrating member 250 comprises a stylet (i.e., solid
elongated element with a piercing distal tip), as shown in FIGS.
51A-54C. Alternatively, the tissue penetrating member 250 may
comprise a needle (i.e., hollow tubular element with a piercing
distal tip), as shown in FIGS. 45A-46D, which may be incorporated
and/or detachably coupled to the shunt 200', previously described.
The tissue penetrating member 250 further comprises a proximal
portion 258, an elongated body portion 252, and a distal portion
255 that terminates in a distal tip 255'. The distal end tip 255 is
configured for piercing the IPS wall 114 and arachnoid layer 114
and creating the anastomosis channel 140, as shown, for example in
FIGS. 5C-J. Embodiments of the tissue penetrating member 250 of
FIGS. 51A-54C can be incorporated into the distal end of the
various delivery assembly 300 or delivery catheter 304 embodiments
disclosed herein.
[0241] The distal portions 255 of the tissue penetrating member 250
of FIG. 51A and FIG. 53A terminate in a straight point distal tips
255'. FIGS. 51B, 52B, 53B and 54B are cross-section views of a
portion of tissue penetrating member 250 along the respective axis
B-B shown in FIGS. 51A, 52A, 53A and 54A. The diameter of the
tissue penetrating member 250, along the distal portion 255 and/or
elongated body 252 can range from approximately 0.006 inches
(0.1524 mm) to 0.030 inches (0.762 mm). It should be appreciated
that other suitable diameters of the tissue penetrating member 250
may be provided, as long as the shunt 200 and the delivery assembly
300 accommodate the dimensions of the tissue penetrating member
250. FIG. 51C and FIG. 53C depict a perspective view of the distal
portion 255 of tissue penetrating member 250 having the straight
point distal tips 255'. Alternatively, the distal portions 255 of
the tissue penetrating member 250 of FIG. 52A and FIG. 54A
terminates in a rounded distal tip 255' (e.g., bullet-nose,
elliptical cross-section, blunt configuration). The cross-sectional
views of the tissue penetrating member 250 in FIG. 52C and FIG. 54C
depict exemplary elliptical curvatures of the rounded distal tips
255'.
[0242] Further, the tissue penetrating member 250 may comprise a
neck portion 257 proximately disposed to the distal portion 255, as
shown in FIGS. 53A, 53C and FIGS. 54A, 54C. The neck portion 257
comprises a smaller outer diameter relative to the elongated body
252 and distal portion 255 of the tissue penetrating member 250.
The outer diameter of the neck portion 257 can be, for example,
approximately 25% to 75% smaller than the outer diameter of the
elongated body 252 and distal portion 255 of the tissue penetrating
member 250. The neck portion 257 provides a recess in the tissue
penetrating member 250 for the distal portion 202 and/or the distal
anchoring mechanism 229 of the shunt 200/200' to reside in a
delivery configuration as the tissue penetrating member 250 passes
through the IPS wall 114. The distal portion shunt 200 is
detachably coupled to neck portion 257 of the tissue penetrating
member 250 200', and once the anastomosis channel 140 is created,
the shunt 200' implanted in the target site (e.g., as shown in
FIGS. 5H-J).
[0243] In some embodiments, the tissue penetrating member 250 may
have a more abrupt transition between the distal portion 255 of the
tissue penetrating member 250 and the neck portion 257, compared to
the transition of the elongated body portion 252 of the tissue
penetrating member 250 and the neck portion 257, as shown in FIGS.
53A and 54A. These transitions or curved profile of neck portion
257 (e.g., as shown in FIGS. 53A, 53C, 54A, and 54C) facilitate the
delivery of shunt 200 through IPS wall 114 in a collapsed or
delivery configuration. Optionally, an outer sheath (not shown) can
be used to hold shunt 200 over the tissue penetrating member 250 in
a delivery configuration as the tissue penetrating member 250 and
shunt 200 are advanced through the patient's vasculature. For
example, the distal end of the sheath covering the shunt disposed
over the piercing element can be advanced to the target penetration
site in IPS wall 114 such that the distal end of the sheath abuts,
but does not pass through, the IPS wall 114 as tissue penetrating
member 250 and the shunt 200 penetrate the IPS wall 114 and the
arachnoid layer 115 into CP angle cistern 138.
[0244] In other embodiments, the proximal portion 258 and/or the
elongated body portion 252 of the tissue penetrating member 250 can
have a greater outer diameter than distal portion 255 of tissue
penetrating member 250 (e.g., an outer diameter of approximately
25% to 75% greater than the outer diameter of body or distal
portions of the piercing element). The increased outer diameter of
the proximal portion 258 and/or the elongated body portion 252 of
the tissue penetrating member 250 prevents the shunt 200 from
sliding proximally over the tissue penetrating member 250 during
navigation through the patient's vasculature and the penetration
step, and serves as a penetration stop by preventing the tissue
penetrating member 250 (and accompanying delivery system) from
passing beyond IPS wall 114 and arachnoid layer 115 into the
subarachnoid space 116. Once a distal portion of shunt 200 and/or
distal anchoring mechanism 229 has been deployed in CP angle
cistern 138, the tissue penetrating member 250 can be withdrawn
from the shunt lumen 207, delivery assembly 300.
[0245] In some embodiments, the tissue penetrating member 250 may
be coupled to an energy source (not shown) to facilitate the
piercing and/or advancement through the IPS wall 114 and arachnoid
layer 115 that separates the lumen of IPS 102 from the subarachnoid
space 116/CP angle cistern 138. The energy source can provide one
or more energy types, including, but not limited to, radio
frequency energy (RF), thermal energy, acoustic energy or the like.
For example, the piercing elements 250 of FIGS. 51A-54C,
particularly, the piercing elements 250 having the bullet-nose tip
255' of FIGS. 52A, 52C and FIG. 54A, 54C may be coupled to a source
of high frequency RF energy to assist with the advancement through
the IPS wall 114 and arachnoid layer 115 to create anastomosis 140
between IPS 102 and CP angle cistern 138. The use of RF energy in
the piercing elements 250 coagulates tissue while creating the
anastomosis channel 140 thereby eliminating or reducing bleeding
into the subarachnoid space, and can eliminate the need for a
sharpened penetrating element facing brainstem 112 after passing
through the IPS wall 114 and arachnoid layer 115 into the CP angle
cistern 138.
[0246] By way of non-limiting example, the tissue penetrating
member 250 of FIGS. 51A, 51C that includes the straight point
distal tip 255' for delivering RF energy to penetrate the IPS wall
114 and arachnoid layer 115. The straight point distal tip 255' can
focus the RF energy at the distal most point of tissue penetrating
member 250 to facilitate penetrating through the IPS wall 114 and
arachnoid layer 115, without dispersing electrical current to
nearby tissue or structures. The gradual transition from straight
point distal tip 255' to distal portion 255 of the tissue
penetrating member 250 gently dilates the tissue of IPS wall 114
during the penetration step to minimize tissue damage during the
delivery and deployment of shunt at the target site. In some
embodiments, the tissue penetrating member 250 of FIGS. 51A-54C is
configured to pass through shunt lumen 207 of the various
embodiments of shunt 200 disclosed herein such that the shunt can
be delivered through the IPS wall 114 as the tissue penetrating
member 250 penetrates through the IPS wall 114 and arachnoid layer
115 into CP angle cistern 138.
[0247] The tissue penetrating member 250 of FIGS. 51A-54C can be
made from Nitinol or other conductive materials. The tissue
penetrating member 250 can be a straight, rigid piece of material
incorporated into the distal end of a delivery catheter 304 or
other element of delivery assembly 300. Alternatively, the tissue
penetrating member 250 can be primarily flexible, similar to
flexible micro guide wires known in the art. Shunt 200 disposed
over a flexible tissue penetrating member 250 can provide
sufficient column strength to the combination of the shunt/piercing
element, which allows navigation through the patient's vasculature,
to the target penetration site in IPS wall 114, and into CP angle
cistern 138. The flexible configuration of tissue penetrating
member 250 provides additional safety if the tissue penetrating
member 250 advances too far distally into the cistern 138; the
floppy, guide wire-like configuration further reduces the risk that
the tissue penetrating member 250 will damage local critical
structures such as the brain stem or cranial nerves.
[0248] The tissue penetrating member 250 of FIGS. 51A-54C and
delivery assembly 300 can be configured for use with an
electrosurgical unit that generates and supplies RF energy to the
distal tip of tissue penetrating member 250. Several manufacturers
and distributors provide electrosurgical units suitable for use
with embodiments of the disclosed inventions (e.g., Aaron.RTM.
Product Line, Bovie Medical Corporation, Clearwater, Fla.). As will
be appreciated by those of skill in the art, all but the distal
most portion of the tissue penetrating member 250 (e.g., distal
most 1 mm to 15 mm) may be insulated such that only the distal tip
255' or distal portion 255 of the tissue penetrating member 250
delivers RF energy to IPS wall 114 (and not the delivery assembly
300 and/or delivery catheter 304). Standard electrosurgical units
provide multiple settings that can optimize the use of such systems
for use with the disclosed embodiments. For example, monopolar
versus bipolar operation focuses the RF energy around a pinpoint
penetration site from the distal tip 255' and/or distal portion 255
of tissue penetrating member 250 in IPS wall 114, without damaging
nearby tissue or structures. Coagulation and/or blended settings,
as opposed to pure cut, can further pinpoint the RF energy to the
contact point between the distal tip 255' and/or distal portion 255
of the tissue penetrating member 250 and IPS wall 114 without
generating excess heat and vaporizing cells. Such coagulation or
blended settings advantageously provide a controlled delivery of RF
energy to pass the tissue penetrating member 250 through the target
penetration site, without dispersing RF energy to the surrounding
tissues, while also coagulating the tissue to prevent localized
bleeding from IPS wall 114. Adjustable power settings allow for
further optimization of electrosurgical units with the disclosed
embodiments. For example, with a coagulation setting, a power
setting from about 5 watts to about 20 watts, and preferably from
about 8 watts to about 12 watts, can be used with tissue
penetrating member 250 to penetrate from IPS 102 into CP angle
cistern 138. In addition, an electrosurgical unit can be configured
to stop the delivery of RF energy to the tissue penetrating member
250 upon detecting a change in impedance; a detector on the tissue
penetrating member 250 can provide impedance feedback to the
electrosurgical unit to differentiate between dura mater and CSF as
the distal tip 255' of the tissue penetrating member 250 emerges
from the IPS wall 114 and arachnoid layer 114 into the CSF-filled
subarachnoid space 116 and/or CP angle cistern 138.
[0249] FIGS. 55A-E illustrate an exemplary elongated portion 203 of
the shunt 200, according to embodiments of the disclosed
inventions. As described above, the shunt 200 includes the proximal
portion 204, the distal portion 202, and the elongate body 203
extending therebetween. The shunt 200 further includes lumen 207
extending from the proximal opening 205 to the distal opening 201
of the shunt 200. In the embodiment of FIGS. 55A, 55D, length
L.sub.2, measured along the elongate central axis 231 of the shunt
200, is approximately 0.5 inches (1.27 cm) in the delivery
configuration. In other embodiments, L.sub.2 may range between 10
mm to 30 mm in the delivery configuration. Further, in the
embodiment of FIG. 55D, the inner diameter (ID) of the shunt 200
(e.g., lumen 207) measured in a direction orthogonal to axis 231,
is approximately 0.0144 inches (0.3657 mm). In other embodiments,
the ID of the shunt 200 may range between 0.002 inches (0.0508 mm)
to 0.020 inches (0.508 mm). It should be appreciated that the ID,
L.sub.2 and any other length, width, or thickness may have any
suitable dimension for implantation of the shunt 200 in the target
site (e.g., IPS, CP angle cistern, or the like).
[0250] As previously described, the shunt 200 may be composed from
any number of biocompatible, compressible, elastic materials or
combinations thereof, including polymeric materials, metals, and
metal alloys, such as stainless steel, tantalum, or a nickel
titanium alloy such as a super-elastic nickel titanium alloy known
as Nitinol. The shunt 200, particularly the elongated body 203 of
FIGS. 55A-E, is composed of Nitinol. The shunt 200 further
comprises one or more cuts 210 (e.g., kerfs, slots, key-ways,
recesses, or the like) along the elongated body 203. The cuts 210
of the elongated body 203 may have a variety of suitable patterns,
as shown in FIGS. 55A-60C. The cuts 210 and their patterns are
preferably manufactured by laser cutting the elongated body 203 of
the shunt 200. Alternatively, the cuts 210 and their patterns may
be manufactured by etching or other suitable techniques. In the
embodiment of FIG. 55C, each cut 210 may have a width of 0.001
inches (0.0254 mm). The width, length and depth of each cut 210 and
patterns in the elongated body 203 of the shunt 200, may comprise
any suitable dimensions. The cuts 210 of the elongated body 203 are
configured to increase the flexibility of the shunt 200 for
navigating tortuous anatomy during delivery and/or to assume a
pre-determined configuration (e.g., secondary shape, for example
helical/coil shape of FIGS. 6G-H, 24A, 24E, 34A-B) when deployed
and implanted at the target site.
[0251] Additionally, the shunt 200 comprises an inner liner 212 and
an outer jacket 214, as better seen in FIG. 55E. The inner liner
212 and outer jacket 214 are composed of suitable implantable
polymeric materials, such as polytetrafluoroethylene "PTFE",
polyethyleneterephthalate "PET", High Density Polyethylene "HDPE",
expanded polytetrafluoroethylene "ePTFE", urethane, silicone, or
the like. Preferably, inner liner 212 is composed of materials that
resist aggregation of CSF proteins and cells flowing through shunt
lumen 207 to maintain long-term shunt lumen patency such as HDPE,
PET, PTFE, or silicone. The inner liner 212 and outer jacket 214
are configured to cover--completely or partially--the cuts 210 of
the elongated body 203, from within shunt lumen 207 and over shunt
body 203, respectively; in such configuration, the elongated body
203 becomes a frame that supports the inner liner 212 and outer
jacket 214. Shunt 200 with its inner liner 212, shunt body frame
203, and outer jacket 214 is impermeable to venous and sinus blood
flow, and the integrated liner-frame-jacket configuration maintains
the flexibility and pre-determined configuration that the cuts 210
provide to the shunt 200.
[0252] Inner liner 212 provides a smooth surface within shunt lumen
207 and maintains a laminar flow profile for CSF flowing through
the shunt under normal differential pressure (5-12 cm H2O) between
the subarachnoid space 116 and cistern 138. In addition to material
selection criteria for liner 212 previously described, maintaining
laminar flow within shunt lumen 207 further eliminates or reduces
the risk of occlusion from protein accumulation and cell
aggregation. Liner 212 can be configured to line the interior of
shunt body 203 using an extrusion process. Alternatively, the liner
material can de deposited (e.g., using a dispersion technique) on a
mandrel (e.g., nickel coated copper); thereafter, the liner-coated
mandrel can be placed within shunt body 203 for application of
outer jacket 214 and adhering inner liner 212 to shunt body 203,
after which the mandrel can be withdrawn from shunt 200 leaving
inner liner 212 in place within shunt lumen 207. Without an inner
liner 212, cuts 210 inside the lumen 207 can provide surfaces for
proteins and cells to accumulate, which could occlude lumen 207 and
prevent CSF from flowing from the subarachnoid space into the
venous system.
[0253] Outer jacket 214 provides a smooth exterior surface to shunt
200, which reduces the risk of thrombus formation in the IPS 102
compared to shunt 200 with cuts 210 on the exterior surface of
shunt body 203. As noted above, the outer jacket 214 can comprise
one or more implant-grade polymers including, but not limited to,
polyurethane or silicone-polyurethane blends. In some embodiments,
a gas or liquid dispersion of polymer is applied to shunt body 203
and inner liner 212, which forms the outer jacket 214 and bonds the
inner liner 212, the shunt body 203, and outer jacket 214 together
in an integrated configuration of shunt 200, for example, as shown
in FIG. 55E.
[0254] Outer jacket 214 can completely cover the exterior surface
of shunt body 203; however, in other embodiments, the outer jacket
can be placed selectively along portions of shunt body 203 to
adhere inner liner 212 to shunt body 203. By way of non-limiting
example, a liquid dispersion of polymer or an epoxy-based adhesive
can be placed at discrete locations along the length of shunt body
203 (e.g., proximal portion, middle portion, and/or distal portion
of shunt body 203). Alternatively, the exterior surface of inner
liner 212 can be coated with polymer or adhesive, and then placed
within shunt body 203; the polymer or adhesive can seep into cuts
210, completely or partially filling some or all of the cuts 210
along shunt body 203. In these embodiments, exterior portions of
the shunt body 203 material are exposed to the implant site within
the patient.
[0255] In the embodiment of FIG. 55E, the inner liner 212 may have
a thinness of 0.0007 inches (0.01778 mm), the elongated body 203
wall may have a thinness of 0.0018 inches (0.04572 mm) and, the
outer jacket 214 may have a thickness of 0.0005 inches (0.0127 mm).
It should be appreciated that the inner liner 212, elongated body
203 and outer jacket 214 may comprise any suitable dimensions.
[0256] FIGS. 56A-60C illustrate exemplary patterns of the cuts 210
of the elongated body 203 of the shunt 200, according to
embodiments of the disclosed inventions. As shown in FIGS. 56A-60C,
the elongated bodies 203 of shunts 200 comprise a variety of
exemplary patterns of the cuts 210. In these embodiments, the
patterns of the cuts 210 are achieved by laser cutting the
elongated body 203 while rotating the body at a selected angle as
the laser and body move with respect to one another. For example,
with a laser oriented orthogonal to the longitudinal axis of the
body 203 and with a laser capable of holding body 203 while
rotating and advancing the body relative to the fixture, the laser
can be activated and deactivated to form specific cut patterns in
shunt body 203. FIGS. 56B, 57C, 58C, 59C and 60C depict exemplary
cut patterns in a two dimensional view of their respective tubular
elongated bodies 203 of FIGS. 56A, 57A, 58A, 59A and 60A. In the
embodiments of FIGS. 56A-58C, the laser cutting of the elongated
body 203 creates 1.5 cuts 210 per rotation of the body, having a
cut balance of about 210.degree. of rotation with laser on, and
then 30.degree. of rotation with laser off. In the embodiments of
FIGS. 59A-C, the laser cutting of the elongated body 203 creates
2.5 cuts 210 per rotation, having a cut balance of about
116.degree. of rotation with laser on, followed by 28.degree. of
rotation with laser off. In the embodiments of FIGS. 60A-C, the
laser cutting of the elongated body 203 creates 2.5 cuts 210 per
rotation, having a cut balance of about 116.degree. on, 28.degree.
off. Further, while the pitch of the cut pattern is approximately
0.0070 inches (0.1778 mm) in the embodiments of FIGS. 56A-59C, each
cut 210 may have a variety of widths; for example 0.0010 inches
(0.0254 mm) (FIGS. 56A-B), 0.0022 inches (0.05588 mm) (FIGS.
57A-C), 0.0049 inches (0.12446 mm) (FIGS. 58A-C) or 0.0039 (0.09906
mm) (FIGS. 60A-C). In the embodiment of FIGS. 60A-C, each cut 210
has a width of 0.00399 inches (0.10134 mm) and is oriented
orthogonal to the tube's longitudinal axis, illustrating a
zero-pitch pattern. It should be appreciated that the above
disclosed units are exemplary dimensions, angles and properties of
the cuts 210 and their patterns, which are not intended to limit
the embodiment of FIGS. 56A-60C.
[0257] FIGS. 61A-D illustrate an exemplary shunt 200', constructed
in accordance with embodiments of the disclosed inventions. In
these embodiments, the tissue penetrating member 250 is fixedly
coupled to the distal portion 202 of the shunt 200'. The shunt 200'
further comprises a cover 260 disposed over and slidably coupled to
the tissue penetrating member 250 and to the distal portion 202 of
the shunt 200'. The cover 260 comprises a first configuration, in
which the cover 260 is withdrawn, exposing the tissue penetrating
member 250 of the shunt 200' (FIGS. 61A-B). The cover 260 further
comprises a second configuration, in which the cover 260 is
advanced, covering or hiding the tissue penetrating member 250
(FIGS. 61C-D). The cover 260 may be actuated from the first to the
second configuration by the deployment of the shunt 200' into the
target site. For example, the cover 260 is disposed in the first
configuration (FIGS. 61A-B) while the tissue penetrating member 250
is piercing the IPS wall 114 and arachnoid layer 115 creating the
anastomosis channel 140, as previously described (e.g., FIGS.
5E-I). The distal portion 202 of the shunt 200' including the
tissue penetrating member 250 and the cover 260 are further
advanced into the CP angle cistern until the cover 260 is also
disposed within the cistern (not shown). Then, suitable withdrawal
forces are applied to the shunt 200' creating an interface between
the arachnoid layer 115 and the cover 260, actuating the cover 260
into the second configuration (FIGS. 61C-D), so that the tissue
penetrating member 250 is covered and hidden by the cover 260 when
the shunt 200' is deployed and implanted in the target site (not
shown). Alternatively, the cover 260 may be actuated from the first
to the second configuration using an actuation member (e.g., tether
261, or the like) coupled to the cover 260, or any other suitable
methods. As a further alternative, penetrating element 250 can be
made from bioresorbable/bio-absorbable materials (e.g., comprising
magnesium or zinc) that degrade over time and mitigate the risk of
leaving a sharp element implanted within the patient.
[0258] FIGS. 62A-D illustrate a shuttle element 570 for guarding
piercing elements during delivery of the shunt into a target site,
in accordance with embodiments of the disclosed inventions. As
shown in FIG. 62A, the shuttle element 570 comprises a proximal
portion 574 having a proximal end opening 575 and a lumen 576, and
a distal portion 572 having a bumper 573. The proximal portion 574
forms a cover or sleeve-like configuration suitable for a nesting
interface with the puncture element 250. The shuttle 570 is
composed of any suitable biocompatible materials, previously
described. Further, the bumper 573 is composed of any suitable
material configured to withstand meeting and engaging the piercing
element without being pierced, torn, and/or broken prematurely.
Further, the bumper 573 may be covered or coated with a suitable
polymeric material that may assist the bumper 373 to withstand the
engagement with the piercing element (e.g., polyurethane, silicone,
ePTFE) and/or assist with the advancement of the bumper 373 through
the vasculature (e.g., hydrophilic coatings or their like).
[0259] The shuttle 570 is configured to cover and guard piercing
elements during delivery of the shunt 200 to the target site,
protecting the patient's vasculature from unintended tear or
puncturing during delivery from the venous access point in the
patient to the target penetration site in the IPS wall 114. The
shuttle 570 may be used in combination with any piercing element,
for example, the tissue penetrating member 250 of the shunt 200',
the tissue penetrating element 306 of the delivery system 300,
and/or the tissue penetrating member 350 of the delivery catheter
304'. Additionally, the shuttle 570 may be used, for example, with
the embodiments of FIGS. 43A-44E and 47A-50B, such that the shuttle
570 may cover the deflated expandable element 390 (not shown)
during the delivery of the shunt into the target site. It can be
appreciated from FIGS. 44A and 62B-C that incorporation of the
shuttle into embodiments involving expandable balloons may further
aid in balloon folding and reduce effective crossing profile while
tracking through the vasculature.
[0260] FIGS. 62B-D depict an exemplary interface of the shuttle 570
with the shunt 200' and tissue penetrating member 250. As shown in
FIG. 62B, the tissue penetrating member 250 is disposed within the
lumen 576 of the shuttle 570 during advancement of the shunt 200'
through the delivery catheter 304. The proximal portion of the
shuttle 570 covers and protects the tissue penetrating member 250
during advancement into the target site. The tissue penetrating
member 250 may meet and engage the bumper 573 of the shuttle 570
during delivery of the shunt 200'. The shuttle 570 is advanced by
the engagement and advancement of the tissue penetrating member 250
(e.g., pushing the shuttle), by being coupled to the delivery
guidewire 308 (e.g., axial translation of the guidewire), by being
advanced with a plunger or push element (not shown), or any other
suitable actuation mechanisms and methods. For example, the shuttle
570 may be slidably coupled to the guidewire 308 comprising a first
stop 308' and a second stop 308'', as shown in FIG. 62D. In the
embodiments where the shuttle 570 is slidably disposed over the
exemplary guidewire 308 of FIG. 62D, the bumper 573 is disposed
between the first 308' and second 308'' stops, so that advancement
of the guidewire 308 causes the first stop 308' to engage the
bumper 573 thus advancing the shuttle 570 (FIG. 62D), and
withdrawal of the guidewire 308 causes the second stop 308'' to
engage the bumper 573 therefore withdrawing the shuttle 570 (not
shown). The first stop 308' and second stop 308'' may be
constructed for varying degrees of interference with the bumper 573
such that a predetermined amount of tensile or compressive force
would allow the bumper 573 to bypass the first stop 308' or second
stop 308'' selectively throughout the course of a given procedure.
Once the shunt 200' is disposed within the IPS 102, shown in FIG.
62B, the delivery catheter 340 and/or shunt 200' are withdrawn
exposing the tissue penetrating member 250, or the shuttle 570 is
advanced exposing the tissue penetrating member 250. Alternatively,
the withdrawal of the delivery catheter 340 and/or shunt 200', and
the advancement of the shuttle 570 occurs simultaneously or
consecutively to expose the tissue penetrating member 250.
Additionally, the shuttle 570 may be configured with a slit along
its longitudinal axis that facilitates side-exit of the tissue
penetrating member 250 through the application of sufficient axial
and/or bending loads. The tissue penetrating member 250 is then
oriented and advanced towards the IPS wall 114, with any of the
methods described herein, to pierce the IPS wall 114 and the
arachnoid layer 115 creating the anastomosis channel 140 (FIG.
62D).
[0261] FIGS. 63A-G illustrate another exemplary shunt 200
constructed and implanted according to embodiments of the disclosed
inventions. The shunt 200 includes the anchoring mechanism 227 in
the proximal portion 204, the anchoring mechanism 229 in the distal
portion 202, and the elongate body 203 extending therebetween. The
anchoring mechanisms 227 and 229 include a flared-basked
configuration (FIGS. 63A-C). The flared-basked anchoring mechanisms
227 and 229 include a plurality of respective elements 227a and
229a manufactured by selective cutting the respective proximal 204
and distal 202 portions of the shunt 200 (FIGS. 63D-F), using any
suitable cutting method (e.g., laser cutting). FIGS. 63E-F depicts
detailed exemplary patterns of the cuts of the respective proximal
204 and distal 202 portions of the shunt 200. The plurality of
respective elements 227a and 229a can be biased into a radially
outward configuration for deployment (e.g., as shown in FIG. 63G),
and compressed in a delivery configuration until deployment of the
shunt 200. While the plurality of respective elements 227a and 229a
do not incorporate an liner or outer jacket as shown in FIG. 63G,
in alternate embodiments the plurality of respective elements 227a
and 229a and the elongated body 203 of the shunt 200 are covered by
a coating and/or liner, as for example, the liner 214 described in
FIG. 55E. The liner is configured to allow the respective elements
227a and 229a to expand radially outward in the deployed
configuration of the shunt 200, assuming the flared-basked
configuration of the anchoring mechanisms 227 and 229, as for
example, shown in FIGS. 63A-C, 63G. Alternatively, or in addition
to the lined anchoring mechanisms 227 and 229, the inner liner 212
extends out the longitudinal axis of shunt body 203 at the proximal
and/or distal end of shunt body 203 by a predetermined distance
ranging from one to several millimeters. For example, on the distal
end portion 203 of the shunt, the liner can extend approximately 3
mm above the portion of anchoring mechanism 229 that rests atop
arachnoid layer 115, thereby maintaining the shunt lumen 207
separated or away from arachnoid cells. By way of further example,
in the proximal end portion 204 of the shunt, the liner can extend
from shunt body 203 into or onto valve 209, without lining proximal
anchoring mechanism 227.
[0262] As shown in FIG. 63A, the deployed anchoring mechanism 227
engages the jugular bulb 108, the IPS wall 117, and/or another
portion of the IPS 102, anchoring the proximal portion 204 of the
shunt 200 within the jugular vein 106, so that the valve of the
proximal portion 204 (not shown) is disposed within the jugular
vein 106. Alternatively, the anchoring mechanism 227 may engage the
IPS walls 114 and 117 at the junction 118 (not-shown). The deployed
anchoring mechanism 229 secures the distal portion 202 of the shunt
200 within the CP angle cistern 138, so that CSF flows through the
implanted shunt 200 into the jugular vein 106. FIG. 63B-C depict
further perspective views of the shunt 200.
[0263] FIGS. 64A-C illustrate another exemplary distal anchor of
the shunt, constructed and implanted according to embodiments of
the disclosed inventions. As shown in FIG. 65A, the tissue
penetrating member 250 is advanced from the IPS 102, piercing the
IPS wall 114 and arachnoid layer 115, creating the anastomosis
channel 140 into the CP angle cistern 138. The distal portion 202
of the shunt 200' is advanced into the CP angle cistern, so that
the distal anchoring mechanism 229 is deployed, securing the distal
portion 202 of the shunt 200' at the target site. The deployed
anchoring mechanism 229 expands the distal portion 202 of the shunt
200', and is configured to assume a larger inner diameter ID.sub.1
than the inner diameter ID.sub.2 of the elongated body 203 of the
shunt 200', as shown in FIG. 64B. The anchoring mechanism 229
comprises a distal edge 229' configured to invert and/or be
disposed radially inward in the deployed configuration (FIG. 64B).
Alternatively, the anchoring mechanism distal edge 229' may be
configured to evert and/or be disposed radially outward in the
deployed configuration (FIG. 64C). It should be appreciated that
the anchoring mechanism 229 of FIGS. 64B-C may be used with any of
the embodiments of the shunts described herein, as appropriate.
[0264] FIGS. 65A-D illustrate an exemplary delivery catheter 304''
for delivering the shunt 200 into a target site of a patient,
constructed in accordance with embodiments of the disclosed
inventions. For ease in illustration, the features, functions, and
configurations of the delivery catheter 304'' that are the same as
in the assembly 300 of FIGS. 3B and 4A-D, in the assembly 300' of
FIGS. 5A-J, and/or in the catheter 304' of FIGS. 43A-D, are given
the same reference numerals. The delivery catheter 304'' is
dimensioned to reach remote locations of the vasculature and is
configured to deliver the shunt 200 percutaneously to the target
location (e.g., inferior petrosal sinus). The delivery catheter
304'' may comprise variable stiffness sections (e.g., varying ratio
of material, including selective reinforcement, such as braids,
coils, or the like) suitable to provide sufficient "pushability"
and "torqueability" to allow the catheter 304'' to be inserted,
advanced and/or rotated in the vasculature to position the distal
portion 344 of the catheter at the target site within the IPS 102.
Further, the distal portion 344 should have sufficient flexibility
so that it can track and maneuver into the target site. Variable
stiffness in the catheter 304'' is achieved, for example, by
locally varying the properties and/or distribution of the materials
used and/or varying the durometer or thickness of the materials
during the process of manufacturing. By way of non-limiting
examples, the materials used in manufacturing the catheter 304''
may include polyether block amide (Pebax.RTM.) and Nylon, and any
other suitable materials, such as the materials previously
described for manufacturing the catheter 304'. It should be
appreciated that when appropriate, the delivery catheter 304'' may
be used in combination with the delivery assembly 300/300' also
previously described.
[0265] The distal portion 344 of the delivery catheter 304''
comprises the tissue penetrating member 350 having lumen 355
fluidly coupled to the lumen 305 of the delivery catheter 304''
(FIG. 65C). The shunt 200 is configured to be deployed into the
target site via lumens 305, 355, when the anastomosis channel 140
is created (not shown). It should be appreciated that when using
the delivery catheter 304'' to deliver and deploy the shunt 200
into the target site, the tissue penetrating element 306 of the
delivery assembly 300 and/or the tissue penetrating member 250
incorporated in the shunt 200' may not be required.
[0266] The delivery catheter 304'' further comprises a lumen 314
configured for advancement of a guidewire 318, supplying and/or
withdrawing fluid to the vasculature and/or any other suitable
function (FIGS. 65B-E). The elongated guidewire 318 includes a
flattened profile, as seen in the cross-sectional views of the wire
318 in FIG. 65B and FIG. 66, and the wire 318 is formed of Nitinol.
In other embodiments, the wire 318 may comprise any suitable
profile and materials. The delivery catheter 304'' may be advanced
over the wire 318 extending through the lumen 314, until the distal
end portion 344 of the delivery catheter 304 is positioned in the
IPS 102 (not shown).
[0267] FIGS. 67A-D illustrate exemplary cross-sectional views of
the delivery catheters for delivering the shunt 200 into a target
site of a patient, constructed in accordance with embodiments of
the disclosed inventions. FIG. 67A depicts a cross-sectional view
of the delivery catheter 304 comprising a tubular interface having
an outer tubular member 364 and an inner tubular member 365
coaxially disposed within the outer tubular member 364. The coaxial
tubular interface of the catheter 304 comprises the lumen 305
configured to deliver the shunt 200 into the target site, and the
lumen 314 configured for advancement of guidewires, supplying
and/or withdrawing fluid to expandable members (e.g., balloons, or
their like) or to the vasculature and/or any other suitable
function. FIG. 67B depicts a cross-sectional view of the previously
described delivery catheter 304'' of FIGS. 65A-E. FIGS. 67C-D
depict cross-sectional views of the delivery catheter 304'
comprising the lumen 305 configured to deliver the shunt 200 into
the target site, and two additional lumens, a guidewire lumen 315
and an inflation lumen 317. It should be appreciated that any other
configuration of the delivery catheter and lumens suitable for
delivering the shunt 200 into the target site may be used.
[0268] Lumens of the catheter embodiments depicted in FIGS. 65A-67D
can be configured to conform to the various delivery assembly 300
elements used such catheters. Lumen 314 of delivery catheter 304''
depicted in FIG. 65B comprises a crescent shaped profile, distinct
from the flattened profile of wire 318. In other embodiments, the
profile of all or a portion of lumen 314 can be configured to more
closely match the exterior profile of wire 318. For example, the
bottom left and right portions of lumen 314 shown in FIG. 65D can
be formed to match the straight and angled edges on the bottom
portion of the wire 318. As another example, lumen 314 can match
the profile of the wire 318 depicted in FIG. 66. Conformed catheter
lumens can eliminate the risk that the element passing through
inadvertently changes orientation or trajectory within the catheter
during the shunt implant procedure. In addition, any combination of
conformed lumens can be used with or in place of the circular and
crescent lumen 314 embodiments shown in FIG. 67A-D. It will be
appreciated by those of skill in the art, however, that certain
lumen 314 configurations (e.g., crescent lumen versus rectangular
lumen of equal size) can conserve more cross-sectional area of the
catheter to accommodate other lumens and componentry.
[0269] The lumens of the catheter embodiments depicted in FIGS.
65A-67D and disclosed elsewhere in this application (e.g., delivery
catheter 304, guide catheter 320) can include a liner to increase
the lubricity of the delivery assembly 300 and reduce friction
between the specific catheter lumen and delivery system components
delivered through such lumen. The catheter liner may comprise
homopolymers, copolymers or polymer blends containing polyam ides,
polyurethanes, silicones, polyolefins (e.g., polypropylenes,
polyethylenes), fluoropolymers (e.g., FEP, TFE, PTFE, ETFE),
polycarbonates, polyethers, PEEK, PVC, and other polymer resins.
The liner thickness can range from approximately 0.0005 inches to
0.003 inches. In addition, the catheter embodiments can include
hydrophilic coatings commonly known in the art to further increase
the lubricity and navigability of the delivery assembly 300
components within the patient.
[0270] In the embodiments of the disclosed inventions, a method for
relieving a patient's elevated intracranial pressure by implanting
the shunt 200/200' in the patient is provided. The shunt 200/200'
comprising one or more cerebrospinal fluid (CSF) intake openings
201 in a distal portion 202 of the shunt 200/200', the valve 209
disposed in a proximal portion 204 of the shunt 200/200', and the
lumen 207 extending between the one or more CSF intake openings 201
and the valve 209 (e.g., as shown in FIG. 6). The method comprises:
introducing the deployment system 300/300' including the tissue
penetrating element 306/250/350 and the shunt 200 from a venous
access location in the patient; navigating the deployment system
300/300', including the penetrating element 306/250/350 and shunt
200/200', from the venous access location to a target penetration
site within the IPS 102 of the patient, via the jugular vein (JV)
106 of the patient; assessing a trajectory of the tissue
penetrating element 306/250/350 at the target penetration site from
the IPS 102 into the angle cistern 138 of the patient; advancing
the tissue penetrating element 306/250/350 through dura IPS wall
114 and arachnoid tissue layer 115 at the target penetration site,
and into the CP angle cistern 138; advancing the distal portion 202
of the shunt 200/200' into the CP angle cistern 138 through an
opening (e.g., anastomosis channel 140) in the respective dura IPS
wall 114 and arachnoid tissue layer 115 created by the tissue
penetrating element 306/250/350; deploying the distal anchoring
mechanism 229 of the shunt 200/200' in the CP angle cistern 138;
withdrawing the delivery system 300/300' from the target
penetration site towards the JV 106, wherein the shunt 200/200' is
expelled from the delivery system 300/300' and thereby deployed in
the IPS 102 as the delivery system 300/300' is withdrawn toward the
JV 106; deploying the proximal anchoring mechanism 227 of the shunt
200/200' about a junction 118 of the JV 106 and IPS 102, such that
the proximal portion 204 of the shunt 200/200' is oriented away
from a medial wall of the JV 106; and removing the delivery system
300/300' from the patient, wherein the deployed shunt 200/200'
provides a one-way flow path for CSF to flow from the CP angle
cistern to the JV 106 via the shunt lumen 207 in order to maintain
a normal differential pressure between the patient's subarachnoid
space and venous system. The method may further comprise confirming
that the tissue penetrating element 306/250/350 has accessed the CP
angle cistern 138 by withdrawing CSF from the CP angle cistern 138
through the delivery system 300/300' prior to withdrawing the
delivery system 300/300' from the patient.
[0271] In the embodiments of the disclosed inventions, a method for
treating normal pressure hydrocephalus (NPH) using the shunt
200/200' is provided. The shunt 200/200' comprising one or more
cerebrospinal fluid (CSF) intake openings 201 in the distal portion
202 of the shunt 200, the valve 209 disposed in the proximal
portion 204 of the shunt 200/200', and the lumen 207 extending
between the one or more CSF intake openings 201 and the valve 209,
the lumen 207 having an inner diameter in a range of 0.008'' to
0.014''. The method comprises: deploying the shunt 200/200' in a
body of an NPH patient so that the distal portion 202 of the shunt
200/200' is at least partially disposed within the CP angle cistern
138 of the patient, the body 203 of the shunt 200/200' is at least
partially disposed within the IPS 102 of the patient, and the
proximal portion 204 of the shunt is at least partially disposed
within, or proximate to, the jugular vein (JV) 106 of the patient,
wherein the shunt valve 209 opens at a pressure differential
between the CP angle cistern 138 and JV 106 in a range of 3 mm Hg
to 5 mm Hg, so that, after deployment of the shunt 200/200', CSF
flows from the CP angle cistern 138 to the JV 106 via the shunt
lumen 207.
[0272] When the shunt 200/200' is deployed, the proximal portion
204 of the shunt 200/200' may be disposed adjacent to a jugular
bulb 108.
[0273] The methods and devices disclosed herein provide a number of
significant advantages relative to other methods and systems
intended to treat hydrocephalus or relieve elevated ICP.
[0274] Conventional VP shunt placement surgery is an invasive
procedure performed under general anesthesia and typically requires
about three to five days hospitalization. During the procedure, the
physician makes a bore hole in the patient's skull and then passes
a catheter through such hole and further, through brain tissue
(e.g., cerebral cortex grey matter, brain white matter, ventricles)
to access CSF within the cerebral ventricles. Ventricular catheter
placement typically requires coagulating the cortex of the brain
and passing the catheter through cerebral cortex and subcortical
white matter one or several times. Thereafter, the ventricular
catheter is attached to an inflow portion of a valve mechanism that
the physician implants underneath the patient's scalp, often behind
the ear. The outflow portion of the valve mechanism is attached to
a silicone catheter that is tunneled under the patient's skin down
through the neck and into the abdomen. The implanted shunt provides
a one-way flow path for CSF to travel from the patient's ventricle
and into the peritoneal cavity.
[0275] VP shunts are prone to clogging, particularly in the
ventricular catheter and peritoneal tubing. As excess CSF is
removed from the ventricles through the catheter, the ventricles
become smaller. Often, as the ventricles shrink, the choroid and
other cells of the surrounding ventricle shrink down around the CSF
inlets of the catheter and obstruct the flow of CSF into the VP
shunt. The peritoneal tubing often clogs from cell ingrowth (e.g.,
endothelial cells) and/or clogs from incorporation into the
abdominal wall. VP shunt placement surgery has a relatively high
rate of infection especially when compared to minimally invasive,
endovascular procedures. VP shunts are subject to a siphoning
effect due to the long, hydrostatic column created between the CSF
inflow (i.e., ventricle) and outflow (i.e., peritoneum) locations
of the implanted shunt. Draining CSF too rapidly or draining too
much CSF from the ventricles presents significant risk to the
patient from, e.g., collapsed ventricles or subdural hematoma.
Complicated anti-siphoning valves have been developed in attempt to
mitigate the siphoning effect in VP shunts.
[0276] In contrast, by using an endovascular deployment method and
deploying shunt 200 from within IPS 102 into CP angle cistern 138
such that CSF drains into the jugular bulb or vein, the risks and
clogging complications due to invasive surgery, surrounding brain
tissues, infection, and siphoning effect can be eliminated or
significantly mitigated. In many patients, particularly those less
than 70 years old, there is little or no space between the
arachnoid layer and brain parenchyma within the subarachnoid space
to accommodate an endovascular shunt in a venous sinus other than
IPS 102. In such cases, shunt deployment techniques and shunt
features move brain parenchyma and/or create or augment a cistern
in the subarachnoid space for CSF to pool for inflow to the shunt.
Such techniques increase the risk of injury to brain tissue and
increase the risk of subsequent shunt clogging at the proximal end
from surrounding brain tissue. The methods, systems, and devices
disclosed herein significantly reduce or eliminate these risks.
[0277] Some advantages of the endovascular access system and method
for navigating a catheter into a target site (e.g., inferior
petrosal sinus) and placing an endovascular shunt to drain CSF from
a cerebral cistern (e.g., cerebellopontine (CP) angle cistern) to
treat communicating hydrocephalus including NPH, and pseudotumor
cerebri, are disclosed herein, thereby minimizing undesired effects
of traditional VPS placement, avoiding boring into a patient's
skull, coagulating the cortex of the brain, passing a shunt
catheter through cerebral cortex and subcortical white matter one
or several times, and other invasive surgical techniques used in
current hydrocephalus treatments.
[0278] The anatomy of CP angle cistern 138 and its proximity to IPS
102 make it a preferred location for deploying an endovascular CSF
shunt, compared to the sigmoid sinus or other intracranial venous
sinuses (e.g., the transverse sinus, the cavernous sinus, the
sagittal sinus, and/or the straight sinus). CP angle cistern 138
typically features a large CSF-containing space and a greater
separation between the arachnoid layer and the closest surrounding
brain parenchyma than any other CSF cisterns accessible from venous
conduits. Accordingly, positioning shunt 200 within CP angle
cistern 138 is easier and more fault tolerant than positioning the
shunt within other cisterns, and the rate at which CSF can be
communicated to venous circulation is greater on account of the
larger pool of CSF within CP angle cistern 138.
[0279] Venous blood flow rates in jugular vein 106 can be
significantly higher than the blood flow rates in larger diameter
dural venous sinuses (i.e., sagittal, sigmoid, straight,
transverse), which favor long-term shunt patency of the disclosed
embodiments compared to other implant locations.
[0280] In addition, the anatomy of IPS 102 facilitates long-term
stability of shunt 200. The relatively long length and narrow
diameter of IPS 102 provides a natural housing to accommodate shunt
200 along its length. The foundation provided by the grooved
portion of the clivus bone that surrounds about two-thirds of the
IPS circumference further supports long-term stability of the shunt
200, and presents a stable platform that delivery systems disclosed
herein can leverage during shunt implant procedures. The situation
differs in the other venous sinuses, which are not as well adapted
naturally to house a shunt. Further, if IPS 102 occludes due to
occupation by shunt 200, thereby restricting or preventing blood
flow through IPS 102, there is little to no risk to the patient
given the relatively minor role of IPS 102 in the overall
intracranial venous blood circulation system. Occlusion of larger
diameter venous sinuses (e.g., sagittal, sigmoid, straight,
transverse), on the other hand, poses a serious risk for the
patient.
[0281] Further, despite the advantages of the endovascular approach
to deliver and implant the shunt according to the disclosed
inventions, it should be appreciated that other delivery methods
may be used to deliver and implant the shunts described herein,
such as, using open and/or invasive surgical procedures.
[0282] It should be appreciated that prior to use in humans, the
embodiments of the disclosed inventions can be deployed and tested
in suitable animal surrogates having venous vascular and
intracranial subarachnoid features that resemble or closely
approximate the IPS and CP angle cistern in humans. Pigs (e.g.,
Yorkshire pigs or Yucatan mini-pigs) have a suitable deployment
site for testing embodiments of the disclosed inventions. In the
pig model, the system can navigate a shunt to the basilar sinus
(e.g., via the internal jugular vein or venous vertebral plexus),
and deploy the shunt through dura and arachnoid tissues to access
CSF-filled subarachnoid space (e.g., basilar cisterns, pontine
cisterns) for testing. Suitable surrogates for the IPS and CP angle
cistern in humans are feasible in other animal models (e.g., dogs
and primates).
[0283] Although particular embodiments have been shown and
described herein, it will be understood by those skilled in the art
that they are not intended to limit the present inventions, and it
will be obvious to those skilled in the art that various changes,
permutations, and modifications may be made (e.g., the dimensions
of various parts, combinations of parts) without departing from the
scope of the disclosed inventions, which is to be defined only by
the following claims and their equivalents. The specification and
drawings are, accordingly, to be regarded in an illustrative rather
than restrictive sense. The various embodiments shown and described
herein are intended to cover alternatives, modifications, and
equivalents of the disclosed inventions, which may be included
within the scope of the appended claims.
* * * * *