U.S. patent application number 11/951771 was filed with the patent office on 2008-06-12 for intrathecal catheter.
This patent application is currently assigned to MEDTRONIC, INC.. Invention is credited to William F. Kaemmerer, John G. Keimel, Mary M. Morris.
Application Number | 20080140008 11/951771 |
Document ID | / |
Family ID | 39245124 |
Filed Date | 2008-06-12 |
United States Patent
Application |
20080140008 |
Kind Code |
A1 |
Keimel; John G. ; et
al. |
June 12, 2008 |
INTRATHECAL CATHETER
Abstract
An intrathecal catheter for delivering fluid to, or withdrawing
fluid from, the cerebrospinal fluid compartment of a patient,
includes a proximal end and a distal portion. The distal portion
has an outer diameter of about 1 mm or less, a bending stiffness of
about 0.002 pounds per square inch or less, and a distal end. A
delivery region is located between the proximal end and the distal
end, and a lumen extends from the proximal end to the delivery
region. The catheter may further include a coiled structure region
to prevent dislodgement of the catheter from a tissue in which the
coiled structure is implanted, for example the cisterna magna. The
catheter may also include tines to anchor portions of the catheter,
for example to a portion of the spinal canal.
Inventors: |
Keimel; John G.; (North
Oaks, MN) ; Kaemmerer; William F.; (Edina, MN)
; Morris; Mary M.; (Shoreview, MN) |
Correspondence
Address: |
CAMPBELL NELSON WHIPPS, LLC
408 ST. PETER STREET, SUITE 240
ST. PAUL
MN
55102
US
|
Assignee: |
MEDTRONIC, INC.
Minneapolis
MN
|
Family ID: |
39245124 |
Appl. No.: |
11/951771 |
Filed: |
December 6, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60868901 |
Dec 6, 2006 |
|
|
|
60868904 |
Dec 6, 2006 |
|
|
|
Current U.S.
Class: |
604/158 ;
206/223; 604/508 |
Current CPC
Class: |
A61M 25/0102 20130101;
A61M 2025/0059 20130101; A61M 25/0108 20130101; A61M 27/006
20130101; A61M 2025/0063 20130101; A61M 2025/0293 20130101 |
Class at
Publication: |
604/158 ;
206/223; 604/508 |
International
Class: |
A61M 5/178 20060101
A61M005/178; A61M 31/00 20060101 A61M031/00; B65D 69/00 20060101
B65D069/00 |
Claims
1. An intrathecal catheter for delivering fluid to, or withdrawing
fluid from, the cerebrospinal fluid compartment of a subject, the
catheter comprising: a proximal end; a distal portion having an
outer diameter of about 1 mm or less, a bending stiffness of
between about 0.0005 pounds-inch squared to about 0.002 pounds-inch
squared, and a distal end; a delivery region located between the
proximal end and the distal end; and a lumen extending from the
proximal end to the delivery region, wherein the material forming
the distal portion of the catheter has sufficient hoop strength to
resist collapsing of the lumen when implanted in the cerebrospinal
fluid compartment.
2. The catheter of claim 1, further comprising a visualization
marker disposed in or about the distal portion in proximity to the
delivery region.
3. The catheter of claim 1, wherein the length of the catheter from
the proximal end to the delivery region is about 40 cm or more.
4. The catheter of claim 1, wherein the distal portion further
comprises a coiled structure region.
5. The catheter of claim 4, wherein the delivery region located in
the coiled structure region.
6. The catheter of claim 4, wherein the coiled structure region is
capable of being straightened upon insertion of a stylet into the
lumen of the catheter.
7. The catheter of claim 1, wherein the catheter is formed from a
polymeric material.
8. The catheter of claim 1, wherein the catheter is formed from a
material comprising polypropylene.
9. The catheter of claim 1, wherein the catheter is formed from a
material comprising polyethylene.
10. A kit comprising: a catheter according to claim 1; and a stylet
having a proximal end, and a distal portion, the distal portion
comprising a distal tip and being configured to be slidably
disposable in the lumen of the catheter.
11. The kit of claim 10, further comprising a stop mechanism
configured to grippingly engage an outer surface of the stylet and
to engage the proximal end of the catheter as the stylet is
inserted into the lumen of the catheter to prevent the stylet from
being advanced into the lumen beyond a point where the distal tip
of the stylet extends through the lumen and beyond the delivery
region of the catheter.
12. The kit of claim 11, wherein the stop mechanism is capable of
being actuated between an open and a closed state, wherein the stop
mechanism in the open state is moveable relative to stylet and
wherein the stop mechanism in the closed state is configured to
grippingly engage the stylet.
13. The kit of claim 10, further comprising a stop mechanism
configured to grippingly engage an outer surface of the stylet and
to engage the proximal end of the catheter as the stylet is
inserted into the lumen of the catheter, wherein the length of
stylet from location of stop mechanism to distal tip is less than
length of the lumen from proximal end of catheter to delivery
region.
14. A system comprising: a catheter according to claim 1; and an
implantable infusion device operably couplable to the catheter such
that fluid is deliverable from the device to a patient via the
delivery region of the catheter when the system is implanted in the
patient.
15. A catheter comprising: a proximal end; a distal portion
including a delivery region and a coiled structure region; one or
more tines located proximal to the delivery region and the coiled
structure region; and a lumen extending from the proximal end to
the delivery region.
16. The catheter of claim 15, wherein the delivery region is
located within the coiled structure region.
17. The catheter of claim 15, wherein the delivery region is
located distal to the coiled structure region.
18. The catheter of claim 15, wherein the coiled structure region
is capable of being straightened upon insertion of a stylet into
the lumen of the catheter.
19. A system comprising: a catheter according to claim 15; and an
implantable infusion device operably couplable to the catheter such
that fluid is deliverable from the device to a patient via the
delivery region of the catheter when the system is implanted in the
patient.
Description
RELATED APPLICATIONS
[0001] This Application claims the benefit of Provisional
Application Ser. No. 60/868,901, filed Dec. 6, 2006, and of
Provisional Application Ser. No. 60/868,904, filed Dec. 6, 2006,
which applications are hereby incorporated herein by reference in
their respective entireties to the extent that they do not conflict
with the present disclosure.
FIELD
[0002] The present disclosure relates, inter alia, to implantable
medical catheters, and particularly to intrathecal catheters.
BACKGROUND
[0003] A variety of catheters are available for delivering
therapeutic agents to patients. Configurations of the catheters
vary according to the use for which they are intended. For example,
intravascular catheters may include a coiled region that presses
against the vasculature to hold the catheter in place during use.
The use of tines has also been employed for purposes of anchoring a
catheter relative to a tissue location. The materials and
properties of the catheters may be selected to be compatible with
the therapeutic agent being delivered and the tissue into which the
catheter is to be implanted.
[0004] Recently, therapies have been proposed for delivering
therapeutic agents to the cisterna magna. However, to date, no
catheters have been described that would be suitable for such
delivery, particular for long term delivery; e.g., as typically
associated with implantable infusion devices.
SUMMARY
[0005] The present disclosure describes catheters and kits and
systems suitable for delivering therapeutic agents to the cisterna
magna, particularly when the catheters are advanced rostrally
through the spinal canal to the cisterna magna.
[0006] In an embodiment, a catheter includes a proximal end and a
distal portion. The distal portion has an outer diameter of about 1
mm or less, a bending stiffness of between about 0.00005 pound inch
squared (1.4.times.10.sup.-8 kg-meter squared) to about 0.002 pound
inch squared (5.8.times.10.sup.-7 kg-meter squared), and a distal
end. A delivery region is located between the proximal end and the
distal end, and a lumen extends from the proximal end to the
delivery region. The material forming the distal portion of the
catheter imparts a sufficient hoop strength such that the lumen
resists collapsing when implanted in the cerebrospinal fluid
compartment of a subject. The catheter may further include a coiled
structure region to prevent dislodgement of the catheter from a
tissue in which the coiled structure is implanted, for example the
cisterna magna, or to allow for growth of the patient in height
when implanted in a young patient. The catheter may also include
tines to anchor portions of the catheter, for example to a portion
of the spinal canal.
[0007] In an embodiment, a catheter includes a proximal end and a
distal portion. The distal portion includes a delivery region and a
coiled structure region. A lumen extends from the proximal end to
the delivery region. One or more tines are located on the catheter
proximal to the delivery region and the coiled structure
region.
[0008] The catheters described herein provide one or more
advantages over existing catheters. For example, in various
embodiments, the catheters include a flexible distal end portion
that can reduce or prevent tissue damage when being advanced
through delicate tissue such as the cisterna magna. In various
embodiments, the catheters are configured to provide anchoring
within the cisterna magna or spinal canal to prevent dislodgement
of a delivery region of the catheter from the cisterna magna. These
and other advantages will become evident upon reading the
disclosure that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic longitudinal cross sectional view of a
representative catheter.
[0010] FIG. 2A is schematic side view of a representative
catheter.
[0011] FIG. 2B is a schematic exploded side view of a
representative catheter, adaptor, and second catheter.
[0012] FIG. 3 is a schematic longitudinal cross section of a distal
portion of a representative catheter.
[0013] FIG. 4 is a schematic longitudinal cross section of a
representative distal portion of a catheter with a stylet inserted
into a lumen of the catheter.
[0014] FIG. 5 is a schematic longitudinal cross section of a stylet
inserted into a lumen of a catheter.
[0015] FIG. 6 is a schematic longitudinal cross section of a
portion of a catheter including a visualization marker.
[0016] FIG. 7 is a schematic longitudinal cross section of a
representative distal portion of a catheter with a stylet inserted
into a lumen of the catheter.
[0017] FIG. 8 is a schematic perspective view of a coiled structure
region of a representative catheter.
[0018] FIG. 9 is a schematic longitudinal section of a portion of a
representative catheter having a coiled structure region and
tines.
[0019] FIG. 10 is a schematic side view of an implantable infusion
device with an attached catheter.
[0020] FIG. 11 is a schematic view of an infusion device and
associated catheter implanted in a patient.
[0021] The drawings are not necessarily to scale. Like numbers used
in the figures refer to like components, steps and the like.
However, it will be understood that the use of a number to refer to
a component in a given figure is not intended to limit the
component in another figure labeled with the same number.
DETAILED DESCRIPTION
[0022] In the following detailed description, reference is made to
the accompanying drawings that form a part hereof, and in which are
shown by way of illustration several specific embodiments of
devices, kits, systems and methods. It is to be understood that
other embodiments are contemplated and may be made without
departing from the scope or spirit of the present invention. The
following detailed description, therefore, is not to be taken in a
limiting sense.
[0023] Devices and methods for delivering large molecules to the
central nervous system (CNS) are discussed. The devices and methods
described allow for less invasive and more effective procedures to
be employed for delivering medications comprised of drugs, small
molecules, or large molecules to the brain.
Definitions
[0024] All scientific and technical terms used herein have meanings
commonly used in the art unless otherwise specified. The
definitions provided herein are to facilitate understanding of
certain terms used frequently herein and are not meant to limit the
scope of the present disclosure.
[0025] As used herein, "the cerebrospinal fluid compartment" of a
subject means the space within the central nervous system within
the anatomy of the subject that is filled with cerebrospinal fluid.
The cerebrospinal fluid compartment comprises the cisterna magna,
the lateral ventricles, the third ventricle, the fourth ventricle,
the foramen of Magendie, the foramen of Monro, the formina of
Luschka, the cerebral aquaduct, the subarachnoid space surrounding
the brain and the spinal cord, the dural venous sinuses, spaces
surrounding the cranial nerves, and other spaces of the central
nervous system containing cerebrospinal fluid.
[0026] As used herein, "visualization marker" means material that
is visible by surgical navigation instrumentation. A marker may be
a discrete band or may be in any other suitable form for
visualization purposes. Markers may comprise radiopaque material,
such as platinum, tungsten, gold or iridium. Markers may be
incorporated into catheter material or may be affixed to a portion
of a catheter.
[0027] As used herein, "subject" means an animal into which a
catheter or a portion thereof may be implanted and includes
mammals, such as humans.
[0028] As used herein, "comprising", "including", and the like are
used in an open-ended fashion, and thus should be interpreted to
mean "including, but not limited to . . . "
[0029] As used in this specification and the appended claims, the
singular forms "a", "an", and "the" encompass embodiments having
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.
[0030] Abbreviations of units of measurements as used herein are
abbreviations commonly used in the art unless otherwise specified.
For example, "mm" means millimeter, "cm" means centimeter, and "kg"
means kilogram.
[0031] Described herein are catheters having properties that are
useful for delivering fluid to or withdrawing fluid from the
cisterna magna of a subject. However, it will be understood that
the properties of the catheters may be useful for delivering or
withdrawing fluid to other areas of a subject.
[0032] Referring to FIG. 1, catheter 100 has a proximal end 10 and
a distal portion 20. As used herein, "proximal" refers to the
portion of the catheter closer to a fluid delivery or withdrawal
device and "distal" refers to the portion of the catheter further
from the fluid delivery or withdrawal device when in use. Distal
portion 20 comprises a distal end 30 and a delivery region 40.
Catheter 100 comprises a lumen 50 extending from proximal end 10 to
delivery region 40. Delivery region 40 in FIG. 1 is depicted as a
side hole. However, it will be understood that delivery region 40
may be one or more side holes, one or more porous regions (not
shown) that extend around or substantially around a portion of
distal portion 20 of catheter 100, an opening (not shown) at distal
end 30, or the like. It may be desirable in many circumstances to
have more than one opening for fluid to be delivered or withdrawn
in case one or more openings becomes clogged during or following
implantation of catheter 100.
[0033] As shown in FIG. 1, distal portion 20 of catheter 100 has an
outer diameter (o.d.). In various embodiments o.d. of distal
portion 20 is less than about 1 mm. For example, o.d. may be less
than 0.75 mm or less than 0.62 mm. Catheter 100 having a distal
portion 20 with an o.d. of less than about 1 mm may tend to be too
limp to be pushed large distances within a subject's body, such as
from the intrathecal lumbar region to the cisterna magna,
particularly if made from certain polymeric materials. However,
such a limp catheter 100 tends to reduce the chance of damaging
tissue into which catheter 100 is inserted, such as the intrathecal
space. Accordingly, it may be desirable to employ a stylet 200
(see, e.g., FIG. 3) to direct catheter 100 to the appropriate
location within the subject. Of course, a long introducer (not
shown) or guiding catheter (not shown) may be used to provide a
guide through which the thinner catheter 100 could be pushed
without bending or going off course.
[0034] In various embodiments, distal portion 20 of catheter 100
has a bending stiffness low enough to avoid significant damage to
tissue, such as the arachnoid membrane, as distal portion 20 of
catheter 100 is advanced through the tissue. Bending stiffness can
be measured using the following formula:
M.rho.=E I, [0035] where M=bending moment; [0036] .rho.=radius of
curvature; [0037] E=Young's Modulus for the material selected; and
[0038] I=moment of inertia for the beam.
[0039] The moment of inertia for simple cross sections are readily
available to those skilled in the art, e.g., through textbooks or
handbooks. Otherwise, the moment of interia can be calculated as
follows:
I solidcylinder = .pi. 64 ( OD ) 4 ##EQU00001##
where OD is the outside diameter of the stylet, or
I hollowtube = .pi. 64 ( ( OD ) 4 - ( ID ) 4 ) ##EQU00002##
where OD is the outside diameter of the cannula and ID is the
inside diameter.
[0040] In various embodiments, the bending stiffness of distal
portion 20 of catheter 100 may be about 0.002 pound-inch squared
(5.8.times.10.sup.-7 kg-meter squared) or less, such as about 0.001
pound-inch squared (2.9.times.10.sup.-7 kg-meter squared) or less,
to prevent significant damage to delicate tissue, such as the
tissue surrounding the spinal canal or the cisterna magna, as
distal portion 20 is being advanced through the tissue. In numerous
embodiments, the bending stiffness of distal portion 20 of catheter
100 is between about 0.002 pound-inch squared (5.8.times.10.sup.-7
kg-meter squared) and 0.00005 pound-inch squared
(1.4.times.10.sup.-8 kg-meter squared). Of course a catheter having
such a low bending stiffness may be difficult to advance through
the spinal canal. Accordingly, it may be desirable to use a stylet
200 (see, e.g., FIG. 3) to assist in directing catheter 100 to the
appropriate location within the subject. Distal portion 20 of
catheter 100 and stylet 200 disposed within lumen 50 of distal
portion 20 of catheter 100, in combination, should be sufficiently
stiff to advance distal portion 20 of catheter 100 through tissue.
If distal portion 20 of catheter 100 is to be advanced through the
spinal canal, distal portion 20 of catheter 100 and stylet 200
disposed within lumen 50 of distal portion 20 of catheter 100, in
combination, should have a bending stiffness of about 0.01 pounds
inch squared (2.9.times.10.sup.-6 kg meter squared) or greater.
[0041] It will be desirable for distal portion 20 of catheter 100
to have sufficient hoop strength to resist collapse of the lumen 50
when the catheter 100 is implanted in the cerebrospinal fluid
compartment of the subject. Examples of material that can impart
sufficient hoop strength at the diameters discussed above include
polypropylene and polyethylene.
[0042] Distal portion 20 of catheter 100 may vary in length to
achieve a desired effect; e.g., advancement into the cisterna magna
from a lumbar insertion. For example, the distal portion 20 may be
about 40 cm or longer, about 50 cm or longer, about 60 cm or
longer, about 70 cm or longer, about 80 cm or longer, about 90 cm
or longer, or about 100 cm or longer. The longer the distal portion
20 of catheter 100, which may have a small outer diameter, the less
likely that catheter 100 will damage tissue as catheter 100 is
advanced within a subject, and thus the more likely that it may be
advanced extended distances in delicate tissue. In addition, due to
a small outer diameter, distal portion 20 of catheter 100 may have
a small inner diameter, which will permit fine control of fluid to
be delivered. However, it should be noted that due to resistance to
fluid flow associated with smaller inner diameter, catheter 100
preferably has a sufficiently large inner diameter to permit bolus
delivery of fluid through the catheter 100. While it will be
understood that resistance may vary from solution to solution or
catheter to catheter, it may be difficult to deliver substantial
bolus amounts if the inner diameter of the catheter (i.e., the
lumen diameter) is less than about 0.127 mm.
[0043] In various embodiments, proximal end 10 of catheter 100 is
configured to be coupled to an infusion device 300 (see, e.g., FIG.
10). Proximal end 10 of catheter 100 may be coupled to infusion
device 300 using any known or future developed mechanism. In
embodiments wherein the outer diameter of distal portion 20 of
catheter 100 is small, catheter 100 may include a tapered portion
500 between proximal end 10 and distal end 30 to provide a proximal
end 10 with a larger outer diameter (see, e.g., FIG. 2A) to
facilitate coupling of the catheter 100 to the infusion device 300.
As shown in FIG. 2B, an adaptor 600 may be used to fluidly couple
the lumen of the catheter 100 to a second catheter 700, which may
then be coupled to the infusion device. Of course, the adaptor 600
may be configured to couple catheter 100 directly to the infusion
device.
[0044] Referring to FIG. 3 and in accordance with various
embodiments, the lumen 50 of the catheter is configured to slidably
receive a stylet 200. In the depicted embodiment, distal portion 20
of catheter 100 has a side hole delivery region 40. Disposed within
lumen 50 is a stylet 200 including a distal end 210. As used
herein, "stylet" means an elongated device capable of being
inserted into lumen 50 of catheter 100 and assisting the movement
of distal portion 20 of catheter 100 to a desired location in a
subject, and includes a guidewire and the like. Stylet 200 may be
used to push distal portion 20 of catheter 100 or may be used to
impart stiffness to distal portion 20 of catheter 100 to allow
catheter 100 to be positioned within a subject, e.g., where the
stylet 200 and the catheter 100 are advanced together. It will
generally be desirable for excess catheter material to extend
beyond distal end 210 of stylet 200 to allow material softer than
stylet 200 to be exposed to tissue as distal portion 20 of catheter
100 and stylet 200 are advanced. Any way to ensure that distal end
210 of stylet 200 does not extend beyond distal end 30 of catheter
100 may be used. As shown in FIG. 3, a catheter 100 having a closed
distal end 30 may be one way of preventing stylet 200 from
extending beyond distal end 30 of catheter 100. Alternatively,
catheter may be squeezed, e.g. by a user's fingers, to apply
sufficient pressure to prevent relative longitudinal movement of
stylet 200 to distal portion 20 of catheter 100 as distal portion
20 of catheter 100 and stylet 200 are advanced together.
[0045] FIG. 4 depicts an embodiment of a catheter 100 having a
feature 70 to prevent accidental extension of stylet 200 beyond
distal end 30 of catheter 100 or accidental protrusion of stylet
200 through side hole delivery region 40. As shown in FIG. 4,
excess catheter material 80 may be present between the feature 70
and distal end 30 of catheter 100 to allow a material softer than
stylet 200 to be exposed to tissue as catheter 100 and stylet 200
are being advanced. In the depicted embodiment, feature 70 is
configured to receive distal end 210 of stylet 200, which may be
useful in circumstances where it is desirable to use stylet 200 to
push distal portion 20 of catheter 100.
[0046] Referring to FIG. 5, an alternative embodiment for
preventing accidental extension of stylet 200 beyond distal end 30
of catheter 100 is shown. As shown in FIG. 5, stylet 200 may
include a stop 230 or handle at the proximal region of stylet 200
that prevents distal end 210 of stylet 200 from extending beyond
distal end 30 of catheter 100 during use. In various embodiments,
the length of stylet 200 from stop 230 to distal end 210 of stylet
200 is less that the length of catheter 100 (if straightened) from
proximal end 10 to distal end 30. In various embodiments, the
length of stylet 200 from stop 230 to distal end 210 of stylet 200
is less than the length of catheter 100 (if straightened) from
proximal end 10 to an opening of delivery region 40. It may be
desirable for the length of stylet 200 to be shorter than the
length of catheter 100 by an amount to allow sufficient excess
catheter material to extend beyond distal end 210 of stylet 200
while catheter 200 is being advanced within a subject. The position
of stop 230 on stylet 20 may be fixed or adjustable to the desired
length.
[0047] Generally, stop 230 is configured to grippingly engage an
outer surface of stylet 20 and to engage the proximal end of the
catheter. If stop 230 is moveable along stylet 20, the stop 230 may
exist in an open state and a closed or engaged state. In the open
state the stop 230 is moveable. In the closed state the stop 230 is
fixed relative to the stylet 20. In various embodiments, the stop
230 is actuatable between the open and closed states. Suitable
actuatable mechanisms for stops 230 are well known and include set
screws, squeezable handles or the like.
[0048] In various embodiments, kits including a catheter 100 as
described herein and a stylet 200 are provided. Any suitable stylet
200, such as a stylet as described above, may be included in the
kit. In numerous embodiments, the catheter 100 and the stylet 200
of the kit are provided in a single package.
[0049] Referring to FIG. 6, a cross-sectional representation of an
embodiment of distal portion 20 of catheter 100 is shown. As shown
in FIG. 6, a visualization marker 60 may be disposed in or about a
portion of catheter 100 in proximity to delivery region 40 to serve
as a proxy for identification of the location of the delivery
region. Visualization marker 60 may be in the form of a band as
shown in FIG. 6, or may take any other suitable form to serve as a
means for localizing the placement of delivery region 40 by
surgical navigation visualization techniques.
[0050] As shown in FIG. 7, stylet 200 may comprise visualization
marker 220 at or near distal end 210 to further enhance
visualization of navigation and placement of delivery region 40 of
catheter 100. Visualization marker 220 may be in the form of a band
as shown in FIG. 7, or may take any other suitable form to serve as
a means for localizing distal end 210 of stylet 200, which may
serve as a proxy for placement of delivery region 40 by surgical
navigation visualization techniques. Visualization marker 220 may
also be used to verify that distal end 210 of stylet 200 is not
extended beyond distal end 30 of catheter 100 (as indicated by
visualization marker 60 of catheter 100) during placement of
catheter 100.
[0051] In various embodiments, at least a portion of distal portion
20 of catheter 100 comprises a coiled structure 90 when relaxed, as
shown in FIG. 8. A "coiled structure", as used herein, may have one
or more loops or other nonlinear portions (e.g., a sigma structure)
that may serve to anchor distal portion 20 of catheter 100 within a
location of the body, such as the cisterna magna. Such a coiled
structure 90 may be desirable in situations where catheter 100 is
likely to undergo a strain due to body movements of the subject.
For example, if catheter 100 is introduced into the intrathecal
space of the spinal canal through a lumbar puncture and advanced
rostrally so that distal portion 20 of catheter 100 is located in
the cisterna magna, movement of the subject's head or neck may tend
to dislodge distal portion 20 of catheter 100 from the cisterna
magna. As such, a coiled structure portion 90 of distal portion 20
of catheter 100 may serve to provide strain relief to prevent
pulling or dislodging of distal portion 20 of catheter 100. Such a
coiled structure portion 90 may also be beneficial when catheter
100 is implanted in an infant or child, where growth of the spine
may otherwise tend to dislodge distal portion 20 of catheter 100
from its desired location, e.g. the cisterna magna. The coiled
structure portion 90 of distal portion 20 of catheter 100 is
sufficiently pliable to be straightened when a stylet 200 is
inserted into lumen 50 of catheter 100 and extended through coiled
portion 90 of catheter 100. In addition to providing strain relief,
coiled structure portion 90 may also serve to anchor distal portion
20 of catheter 100 in place.
[0052] It may be desirable to include one or more visualization
markers 60 (not shown in FIG. 8) on coiled structure portion 90 to
verify that the coiled structure portion 90 has been appropriately
implanted or navigated. Alternatively, it may be desirable to
incorporate radiopaque material into catheter material of coiled
structure portion 90 to allow for visualization during or after
implant.
[0053] Referring to FIG. 9, a representation of an embodiment of
distal portion 20 of catheter 100 as it may appear implanted in a
subject is shown. Distal portion 20, which may be implanted in the
cisterna magna, comprises a coiled structure portion 90 comprising
distal end 30 of catheter 100. Included in the depicted coiled
structure portion 90 are delivery regions 40 and visualization
marker 60. Placement of delivery region 40 within the coiled
structure region 90 may serve to keep delivery region located away
from a tissue of the subject, rather than allowing the delivery
region to contact or be in close proximity to tissue of the subject
when implanted. Such a configuration may be desirable to prevent
granulomas that may occur with certain intrathecally delivered
drugs.
[0054] While not shown, it will be understood that it may be
desirable for coiled structure region 90 to comprise more than one
visualization marker 60 or to have a visualization marker 60 extend
over a substantial portion of coiled structure region 90, e.g., by
incorporating a radiopaque material into the catheter at coiled
structure region 90.
[0055] Distal portion 20 of catheter 100 may comprise one or more
tines 110 to assist in anchoring distal portion 20, and more
particularly delivery region 40. Tines 110 may be located at any
location along catheter 100 that may result in anchoring the
catheter 100 or reduce movement of delivery region 40. As shown in
FIG. 9, tines 110 may be located further from distal end 30 of
catheter 100 than coiled structure portion 90 (e.g., the tines are
located proximal to the coiled structure region), e.g. at a
location of catheter 100 to be implanted within a spinal canal.
Also shown in FIG. 9, is that excess 120 catheter 100 may be placed
in the spinal canal to provide slack to allow for growth of a
subject, such as a child. Tines 110 may be made of any material
that can provide sufficient anchoring to inhibit movement of the
catheter relative to the tissue in which the tines 110 are
anchoring the catheter. In the depicted embodiment, the tines 110
are oriented to allow rostral advancement of the catheter in the
spinal canal but to inhibit caudal withdrawal or movement of the
distal portion 20 of the catheter. However, the tines 110 may be
retractable, as is known in the art, to prevent damage to the
spinal canal upon withdrawal of the catheter. One example of
retractable tines is presented in U.S. Pat. No. 6,695,861.
[0056] Referring to FIG. 10, catheter 100 is shown operably coupled
to an infusion device 300. Catheter 100 may be connected to
infusion device 300 via catheter connector 330. Infusion device 300
shown in FIG. 10 comprises a refill port 310 in fluid communication
with a reservoir (not shown) for housing a fluid to be infused to
into a subject via catheter 100, which is in fluid communication
with reservoir. Infusion device 300 as depicted in FIG. 10 also
comprises an injection port 320, which is in fluid communication
with catheter. Fluid, e.g. fluid containing therapeutic agent, may
be injected into injection port 320, e.g. to deliver a bolus of
therapeutic agent. Examples of infusion devices 300 having
injection ports 310 in fluid communication with reservoirs and
having injection ports 320 are Medtronic, Inc.'s SynchroMed.RTM.
series of infusion devices. While not shown, it will be understood
that infusion device 300 may be any device that is capable of
delivering a fluid through catheter 100, such as a syringe, a
device having a pump (e.g., osmotic, peristaltic, piston, etc.), an
access port, and the like.
[0057] Referring to FIG. 11, a programmable infusion device 300,
such as Medtronic, Inc.'s SynchroMed.RTM. series of infusion
devices, is shown implanted in a human. As shown in FIG. 11, distal
end 30 of catheter 100 may be inserted into a subject's spinal
canal through a lumbar puncture and advanced rostrally through the
spinal canal to a desired location. Proximal end 10 of catheter 100
is coupled to infusion device 300, which is typically implanted in
the subject at a subcutaneous location. Infusion device 300
comprises a receiver 42 (or transmitter) which is capable of
telemetric communication (or any other suitable form of
communication) with programmer 400. Programmer 400 may communicate
with an implantable infusion device 300 to adjust the amount of
therapeutic agent delivered. Communication may be unidirectional;
e.g., programmer 400 to infusion device 300, or bi-directional.
Generally, programmer 400 is placed over skin in an area where
infusion device 300 is implanted to communicate with device 300.
While not shown, it will be understood that one or more sensors may
be operably coupled to infusion device 300 to alter the rate at
which therapeutic agent is delivered. Programmable infusion devices
are particularly amenable to alteration of infusion rate via
sensors. One advantage of the use of programmable infusion devices
over non-programmable devices is that the rate of delivery of
therapeutic agent from infusion device 300 may be altered as a
patient's condition warrants or to optimize therapeutic
efficacy.
[0058] In general, it will be understood that catheter 100, or
portions thereof, may be made of any material that is compatible
with a subject in which catheter 100 is implanted and with fluid to
be delivered through catheter 100. Material selection for the
catheter may be based on mechanical properties of the tubing, drug
stability (changes in the drug due to the catheter material), drug
compatibility (changes in the catheter material due to the drug),
biostability (changes in the material due to the in vivo
environment), biocompatibility (effects of the material on the
patient), and the like. Generally catheter 100 or portions thereof
will be made of polymeric material such as silicone, polyurethane,
polyethylene, polypropylene, or the like. If polypeptides are to be
delivered via catheter 100, it may be desirable to use polymeric
materials other than silicone, as the polypeptide may adhere to or
be absorbed into the silicone or may be degraded.
[0059] Thus, embodiments of the INTRATHECAL CATHETER are disclosed.
One skilled in the art will appreciate that the present invention
can be practiced with embodiments other than those disclosed. The
disclosed embodiments are presented for purposes of illustration
and not limitation, and the present invention is limited only by
the claims that follow.
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