U.S. patent application number 15/451107 was filed with the patent office on 2017-06-22 for aneursym occlusion system and method.
This patent application is currently assigned to Penumbra, Inc.. The applicant listed for this patent is Penumbra, Inc.. Invention is credited to Dave Barry, Arani Bose, Vikas Gupta, Delilah Hui, Aleksandr Leynov, Stephen Pons.
Application Number | 20170172581 15/451107 |
Document ID | / |
Family ID | 49236029 |
Filed Date | 2017-06-22 |
United States Patent
Application |
20170172581 |
Kind Code |
A1 |
Bose; Arani ; et
al. |
June 22, 2017 |
ANEURSYM OCCLUSION SYSTEM AND METHOD
Abstract
An aneurysm occlusion system includes a device positionable
within a cerebral blood vessel covering a neck of an aneurysm on
the blood vessel. The device includes an expandable tubular element
having a lumen surrounded by a sidewall including a plurality of
gaps. When expanded, the tubular element includes longitudinal
standards arrayed helically in a proximal to distal direction. The
standards support struts and the gaps are defined between adjacent
struts and are sufficiently large to permit delivery of embolic
coils or other embolic materials therethrough.
Inventors: |
Bose; Arani; (New York,
NY) ; Gupta; Vikas; (San Leandro, CA) ; Barry;
Dave; (Livermore, CA) ; Hui; Delilah;
(American Canyon, CA) ; Pons; Stephen; (San
Francisco, CA) ; Leynov; Aleksandr; (Walnut Creek,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Penumbra, Inc. |
Alameda |
CA |
US |
|
|
Assignee: |
Penumbra, Inc.
Alameda
CA
|
Family ID: |
49236029 |
Appl. No.: |
15/451107 |
Filed: |
March 6, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13906714 |
May 31, 2013 |
9615832 |
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15451107 |
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13312816 |
Dec 6, 2011 |
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13906714 |
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11784236 |
Apr 6, 2007 |
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13312816 |
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61655116 |
Jun 4, 2012 |
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60790160 |
Apr 7, 2006 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/966 20130101;
A61F 2002/9665 20130101; A61B 17/12118 20130101; A61F 2230/0069
20130101; A61B 17/1215 20130101; A61F 2210/0014 20130101; A61F 2/91
20130101; A61M 2025/0681 20130101; A61F 2002/825 20130101; A61F
2230/0006 20130101; A61F 2/885 20130101; A61F 2/915 20130101; A61F
2230/0091 20130101; A61F 2230/008 20130101; A61F 2002/823 20130101;
A61F 2002/9505 20130101 |
International
Class: |
A61B 17/12 20060101
A61B017/12; A61F 2/88 20060101 A61F002/88 |
Claims
1. A system for treatment of intracranial aneurysm comprising: a
device for bridging the neck of an aneurysm of a cerebral vessel,
said device comprising a tubular element including a plurality of
standards, a plurality of bands connected to the standards, a
longitudinal axis, a reduced-profile delivery configuration and a
deployed configuration, wherein said standards are oriented at an
angle to said longitudinal axis when said tubular element is in
said deployed configuration so that the standards and the bands
together define a plurality of helical spines; an introducer for
introducing said tubular element into a vessel; and a delivery
device for delivering embolic material into the aneurysm.
2. The system according to claim 1 wherein said angle is between
15.degree. and 45.degree..
3. The system of claim 1 wherein the bands further comprise one or
more V-struts, wherein each V-strut comprises a first leg, a second
leg that is longer than said first leg, and an apex between said
legs.
4. The system of claim 1 wherein said standards comprise a width of
between 0.0020 inch and 0.0050 inch.
5. The system of claim 1 wherein said bands further comprise one or
more V-struts, wherein each V-strut comprises a first leg, a second
leg, and an apex between said legs, said first leg further
comprising an S-shaped connector disposed near, but not on, said
apex.
6. The system of claim 1 wherein said tubular element comprises
shape memory material and said system further comprises a sheath,
whereby said tubular element is retained in said low profile
delivery configuration, wherein withdrawal of said sheath permits
said tubular element to convert to its deployed configuration.
7. The system of claim 6 wherein said tubular element can be
returned to its delivery configuration within said sheath.
8. The system of claim 1 wherein said system further comprises a
sheath, and said tubular element can be withdrawn into said sheath
via said introducer.
9. The system of claim 1 the introducer further comprising a tip
comprising a central lumen, one or more legs, and at least one
aperture.
10. The system according to claim 9 wherein said first and second
standards further comprises at least one bump configured to engage
the at least one aperture.
11. A method of manufacture of an intravascular device, said method
comprising the steps of: providing a tube comprising one or more
shape memory materials, a longitudinal axis, a proximal end and a
distal end; cutting the tube according to a predetermined pattern,
wherein the predetermined pattern defines at least two parallel
elongate standards, bands, and gaps between said bands; applying a
circumferential twist to the cut tube to orient the elongate
elements at an angle to said longitudinal axis; and applying a
shape memory set to the twisted cut tube.
12. The method according to claim 11 wherein said shape memory
material is nitinol.
13. The method according to claim 11 wherein said predetermined
pattern defines only two parallel elongate standards.
14. The method according to claim 11 wherein said predetermined
pattern further defines a plurality of V-shaped bands having at
least one end connected to an elongate standard.
15. The method according to claim 14 wherein said V-shaped bands
comprise apexes and S-shaped connectors, wherein said S-connectors
are disposed near, but not upon, said apexes.
16. The method according to claim 11 wherein the step of applying a
circumferential twist to the cut tube is performed so that at least
one of the elongate standards crisscrosses a second elongate
standard at the distal end.
17. The method according to claim 11 wherein said angle is between
15.degree. and 45.degree..
18. A method of treating an aneurysm located in a blood vessel of a
subject, the method comprising the steps of: introducing an
elongate tubular delivery device into the blood vessel and
proximate the aneurysm, the delivery device suitable for delivery
of embolic material; introducing a tubular element for bridging the
neck of the aneurysm, the tubular element being radially expandable
from a compressed position to an expanded position, having a
proximal end, a distal end, a longitudinal axis, at least two
elongate standards and a plurality of bands attached thereto, the
bands having gaps therebetween and further comprising a first leg,
a second leg that is longer than said first leg, and an apex
between said first leg and said second leg, the elongate standards
arranged helically about the longitudinal axis from the proximal
end to the distal end when the tubular element is in the expanded
position, the elongate standards and bands together forming a first
helical spine and a second helical spine; bridging a neck of the
aneurysm with the tubular element; permitting the expandable
tubular element to expand; delivering one or more embolic materials
to the aneurysm; and withdrawing the tubular delivery device.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 13/906,714 (Attorney Docket No. 41507-714.201), filed May
31, 2013, now U.S. Pat. No. ______, which claims priority to U.S.
Provisional Application No. 61/655,116 (Attorney Docket No.
41507-714.101), filed Jun. 4, 2012; U.S. patent application Ser.
No. 13/906,714 (Attorney Docket No. 41507-714.201), filed May 31,
2013, now U.S. Pat. No. ______, is a continuation-in-part of U.S.
patent application Ser. No. 13/312,816 (Attorney Docket No.
41507-713.201), filed Dec. 6, 2011; and is also a
continuation-in-part of U.S. patent application Ser. No. 11/784,236
(Attorney Docket No. 41507-705.201), filed Apr. 6, 2007, which
claims priority to U.S. Provisional Application Serial No.
60/790,160 (Attorney Docket No. 41507-705.101), filed Apr. 7, 2006,
the disclosures of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to the fields of
systems and methods for treatment of aneurysm, including implanting
one or more intravascular devices for occlusion of the
aneurysm.
[0004] An aneurysm is an abnormal ballooning of a region of a blood
vessel wall due to weakening of the wall tissue. While aneurysms
can occur in any artery of the body, a large percentage of aneurysm
are found in the cerebral blood vessels. If left untreated, such
aneurysms can rupture, leading to life threatening hemorrhaging in
the brain which can result in death or severe deficit.
[0005] Aneurysms that do not rupture can form blood clots which can
break away from the aneurysm potentially causing a stroke. In some
patients, aneurysm can put pressure on nerves or brain tissue,
causing pain, abnormal sensations, and/or seizures.
[0006] One current practice for treatment of an aneurysm includes
surgical placement of an aneurysm clip across the aneurysm to
prevent blood flow into the aneurysm. Naturally, this procedure
requires highly invasive brain surgery and thus carries many
risks.
[0007] In a less invasive catheter-based technique for aneurysm
treatment, filler material is carried through the vasculature to
the site of the aneurysm and used to pack the aneurysm. Materials
used for this purpose include platinum coils and cellulose acetate
polymer to fill the aneurysm sac. While these techniques have had
some success, questions remain concerning their long-term
effectiveness, ease of use, as well as their potential for
rupturing the aneurysm or triggering clot formation. In addition,
there is some risk of post procedure migration of embolic material
from the aneurysm into the parent blood vessel.
[0008] According to another prior art aneurysm treatment, a mesh or
braided stent-like device is positioned within a blood vessel such
that it bridges the aneurysm, blocking flow of blood into the
aneurysm. A problem encountered with devices of this type is that
the sidewalls of the devices not only occlude blood flow into the
aneurysm, but they will also block flow between the blood vessel
and any side branch vessels that the stent happens to cover. See
FIG. 1A, which shows a blood vessel V, aneurysm A, and side branch
vessel B. In some prior art modifications to the stent-type
devices, the devices include sidewalls that are not occlusive
around the full circumference of the device. In implanting these
devices, the physician must make certain that the occlusive portion
of the device's circumference covers the aneurysm and not any of
the side branch vessels.
[0009] Returning to the aneurysm coil embolization solution
mentioned above, a typical procedure is illustrated in FIGS. 2A-2D.
A typical occlusion coil is a wire coil having an elongate primary
shape with windings coiled around a longitudinal axis. It is
constrained in an elongate configuration or primary shape within
the catheter for delivery through the interior of the catheter. The
catheter is introduced into the femoral artery and navigated
through the vascular system under fluoroscopic visualization. The
catheter distal end is positioned at the site of an aneurysm within
the vasculature of the brain. (See FIG. 2A, illustrating catheter
distal end D as it is being positioned at the site of aneurysm
A.)
[0010] With proper positioning of catheter distal end D confirmed,
the coil is passed from the catheter into the aneurysm. The coil
reverts to a three dimensional configuration after release from the
distal end of the catheter into the interior of the aneurysm. Once
released from the catheter, the coil assumes a secondary shape
selected to optimize filling of the aneurysm cavity, and the
catheter may be withdrawn from the vessel. (See FIGS. 2B-2C,
illustrating the release of coil C into aneurysm A.) Multiple coils
may be introduced into a single aneurysm cavity for optimal filling
of the cavity. The deployed coils serve to block blood flow into
the aneurysm and reinforce the aneurysm against rupture. The
implants are intended to embolize the blood inside the aneurysm in
order to diminish additional blood flow into the aneurysm.
Eventually the embolization completely closes the aneurysm to
further flow of blood into the aneurysm. For a more detailed
description of embolic coils and related methods, see commonly
owned U.S. patent application Ser. No. 12/498,752 and Ser. No.
12/695,035.
[0011] In some cases, there is a significant risk of migration of
the coils or other implants out of the aneurysm and into the parent
vessel after delivery and deployment (or release or detachment) of
the coils. This is especially a risk in the case of a "wide neck"
aneurysm. (See FIG. 2D). Migration of a coil or coils into the
circulatory system is undesirable and can lead to occlusion of the
parent vessel, other vessels, as well as lead to other unintended
effects.
[0012] In such cases, it may be desirable to "bridge" the neck of
the aneurysm with a device prior to the delivery of embolic
implants. Such a bridge device may be a generally tubular structure
that is positionable via catheter within the parent vessel,
covering the neck of the aneurysm. Positioning of such a device is
typically performed with the assistance of a guidewire and
fluoroscopic visualization. The generally tubular aneurysm bridge
is deployed across the neck of the aneurysm and allowed to expand
into contact with the vessel walls. Embolic coils are then
delivered into the aneurysm through voids in the "walls" of the
tubular bridge.
[0013] Shortcomings of prior art attempts to bridge the neck of an
aneurysm prior to embolic coil delivery include difficulties with
tracking and deployment of the device, problems resheathing and
repositioning the device, entanglement between the coil delivery
catheter and the bridge device, and problems with portions of the
device "bulging" into the aneurysm. Therefore, there remains a need
for smooth, kink-free tracking, deployment, repositioning, and
reliable, uniform deployment. There also remains a need for a
sufficiently flexible device having adequate column strength.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 schematically illustrates an aneurysm in a blood
vessel and the corresponding blood flow.
[0015] FIG. 2A-2D illustrate some of the steps of a method of
implanting one or more embolic coils into an aneurysm in a blood
vessel.
[0016] FIGS. 3A-3E illustrate some of the steps of a method of
implanting a device to bridge the neck of an aneurysm and then
implanting one or more embolic coils into the aneurysm.
[0017] FIG. 4A-4G illustrate some of the steps of an alternative
method of implanting a device to bridge the neck of an aneurysm and
then implanting one or more embolic coils into the aneurysm.
[0018] FIG. 5 is a perspective view of a finished device according
to the invention, in a deployed configuration that results when the
device is not placed in a vessel prior to deployment, hereinafter
referred to as a "deployed in air".
[0019] FIG. 6 illustrates a side view of a device according to the
invention deployed within a curved, transparent model vessel.
[0020] FIG. 7 illustrates a truncated side elevational view of a
device according to the invention in a deployed in air
configuration.
[0021] FIGS. 7A-7C are cross-sectional end views of the embodiment
of FIG. 7 taken along section lines A, B, and C.
[0022] FIG. 8 is a perspective proximal end view of a finished
device according to the invention in a deployed in air
configuration.
[0023] FIG. 9 is a plan view of a cut pattern for manufacture of a
device according to the invention. Although devices according to
the invention are preferably cut from tubular structures, twisted
and shape set, FIG. 8 illustrates the cut tube as though it were
longitudinally cut and flattened into a sheet before twisting, so
that the pattern features may be more easily viewed.
[0024] FIG. 10 is a plan view of a cut pattern of an alternative
embodiment according to the invention. Although the bridge devices
are preferably tubular structures, cut from a tube, twisted and
shape set, FIG. 9 illustrates the device as though it were
longitudinally cut and flattened into a sheet before it is twisted,
so that its features may be more easily viewed.
[0025] FIG. 11 is a truncated plan view of an embodiment according
to the invention. Although the bridge devices are preferably
tubular structures, FIG. 11 illustrates the device as though, after
shape setting to include a right hand twist, it were longitudinally
cut and unrolled so that its features are more easily viewed.
[0026] FIGS. 11A-11B are enlarged views of Details A and B of FIG.
10.
[0027] FIG. 12 is a side elevation, partial cross sectional view of
the distal end of a pusher catheter according to the invention,
shown within a vessel and with the proximal end an aneurysm bridge
device according to the invention mounted thereon.
[0028] FIG. 13 is a perspective view of a pusher tip according to
the invention.
[0029] FIG. 14 is a perspective view of an alternative embodiment
of the pusher tip of FIG. 11.
DETAILED DESCRIPTION OF THE DRAWINGS
[0030] Illustrative embodiments of the invention are described
below. In the interest of clarity, not all features of an actual
implementation are described in this specification. It will of
course be appreciated that in the development of any such actual
embodiment, numerous implementation-specific decisions must be made
to achieve the developers' specific goals, such as compliance with
system-related and business-related constraints, which will vary
from one implementation to another. Moreover, it will be
appreciated that such a development effort might be complex and
time-consuming, but would nevertheless be routine undertaking for
those of ordinary skill in the art having the benefit of this
disclosure. The aneurysm occlusion system disclosed herein boasts a
variety of inventive features and components that warrant patent
protection, both individually and in combination.
[0031] In FIG. 3A, a system for bridging the neck of an aneurysm
before delivering embolics to the aneurysm is illustrated during a
step of a method according to the invention. (An alternative
exemplary method is discussed below in relation to a description of
FIGS. 4A-4G.) FIG. 3A illustrates a system after the step of
positioning the system in a vessel V having aneurysm A. The
aneurysm bridge device and accompanying delivery system include
aneurysm bridge device 1, sheath 2 and pusher 5. A guide wire (not
pictured) may also be utilized in the step of positioning the
system in a vessel. Aneurysm bridge device is a generally tubular
device capable of being retained in a reduced profile delivery
configuration. The aneurysm bridge device 1 is proportioned to be
implanted within the cerebral vasculature including, but not
limited to, the Internal Carotid Artery, External Carotid Artery,
Vertebral Artery, Basilar Artery, Middle Cerebral Artery, Anterior
Cerebral Artery, and the Posterior Cerebral Artery.
[0032] Generally speaking, aneurysm bridge device 1 is a tubular
device having central lumen 6. It is retained in a reduced profile
delivery configuration by sheath 2, and it is capable of expanding
into contact with the vessel walls when released or deployed to a
larger diameter configuration. Preferred devices 1 are expandable
to an outer diameter in the range of 2.0 mm-6.0 mm. The user may be
provided with a set of multiple aneurysm bridge devices of
different diameters and different lengths so that the device with
the most appropriate dimensions may be chosen for the
procedure.
[0033] Suitable materials for device 1 include shape memory
materials including superelastic Nitinol or shape memory polymers,
or other materials such as stainless steel, composite materials, or
combinations of metals and polymeric materials. In a preferred
embodiment, the aneurysm bridge device 1 may be formed by laser
cutting features into a length of superelastic Nitinol tubing, then
chemically processing and shape-setting the material one or more
time using methods known to those skilled in the art. The device
may then be chilled to below its shape memory transition
temperature and loaded onto pusher 5 and retained by sheath 2.
[0034] In the example of a method according to the invention
illustrated beginning in FIG. 3A, proximal end 3 of aneurysm bridge
device 1 is disposed upon the distal end 4 of pusher 5 while being
retained by sheath 2. Sheath 2 is an elongate tubular catheter
preferably formed of a polymeric material such as Pebax nylon,
urethane, PTFE, Polyimide, metals such as Stainless Steel,
Platinum, etc., or other suitable material. A central lumen extends
the length of sheath 2. The sheath is proportioned for passage
through cerebral vasculature, and may have an outer diameter in the
range of 1 mm-3 mm.
[0035] Pusher 5 is an elongate tubular member having optional lumen
7. The pusher may be formed of suitable polymers, metals, and/or
composite materials. Distal end or tip 4 of pusher 5, which is
described in greater detail below in a description of FIGS. 11-14,
includes apertures 8. When loaded onto distal tip 4, device 1 is
threaded over pusher 5, and positioned so that bumps 9 of its
proximal end 3 are aligned with, or inserted into, apertures 8.
Bumps 9 may alternatively be projections, tabs, posts, clips, or
any structures, preferably male, that are suitable for engaging
apertures 8. Similarly, apertures 8 may alternatively be pockets,
holes, hollows, grooves, or any structures, preferably female, for
receiving bumps 9. Sheath 2 retains bumps 9 in engagement with
apertures 8 as it retains aneurysm bridge device 1 in a reduced
profile configuration. Device 1 remains in the reduced profile
configuration during tracking of the device under fluoroscopic
visualization to a treatment site within the vasculature of a
subject.
[0036] After positioning aneurysm bridge 1 across the opening of
aneurysm A, the device is then deployed and either temporarily or
permanently implanted in the vessel. As illustrated beginning with
FIGS. 3B, in order to deploy aneurysm bridge 1, sheath 2 is
withdrawn proximally to permit the device 1 to expand to its
unconstrained configuration into contact with the inner walls of
the parent vessel V. When sheath 2 is completely withdrawn from the
length of bridge device 1, device 1 expands to a deployed diameter,
as illustrated in FIG. 3C. Also, when sheath 2 is withdrawn from
along the length of device 1, bumps 9 are no longer retained in
apertures 8. Pusher 5 may then be withdrawn from the vessel V.
Alternatively, pusher 5 may be left positioned in vessel V, and
central lumen 7 may be utilized as a conduit or passage in a
subsequent step. Further, if the user wishes to reposition device
1, sheath 2 can be advanced distally in order to resheath device 1.
The steps of positioning and deploying device 1 described above can
then be repeated.
[0037] Voids in the walls of the tubular device 1 permit the
catheter-based delivery of embolic coils through the walls and into
the aneurysm. (Alternatively, embolic coils may be implanted
according to a method in which the coils are not delivered through
the voids in the wall of device 1, as described in greater detail
below.) As illustrated in FIG. 3D, delivery catheter D may be
positioned within vessel V (and/or alternatively within pusher
lumen 7). Embolics including one or more embolic coils may then be
delivered to the aneurysm, in much the same manner as described
above in relation to FIGS. 2A-2C, except that they are delivered
through the voids in the "walls" of the bridge 1. The position of
the device 1 across the neck of the aneurysm prevents the
unintended escape of embolic materials out of the aneurysm and into
the parent vessel following the conclusion of the procedure (See
FIG. 3E). The device remains in place in the parent vessel across
the aneurysm neck during the delivery of coils, thereafter, and if
desired, permanently.
[0038] Turning now to an alternative method according to the
invention, FIGS. 4A-4G illustrate exemplary steps according to the
alternative method. In the steps illustrated in FIGS. 4A-4G, the
aneurysm bridge 1 described above in relation to FIGS. 3A-3E is
again utilized, but according to a somewhat different method than
that described in the foregoing paragraphs. FIG. 4A illustrates an
early step according to the invention following the introduction of
delivery catheter D into a vessel V having aneurysm A. One or more
embolic coils, in the elongate configuration, is constrained by and
carried within delivery catheter D. The distal end of delivery
catheter D is positioned proximate aneurysm A.
[0039] Following positioning of delivery catheter D proximate
aneurysm A, the aneurysm bridge device 1 and accompanying delivery
system are introduced into the vessel V and positioned proximate
aneurysm A, generally as illustrated in FIG. 4B. In addition to
aneurysm bridge device 1, the delivery system includes sheath 2
that was illustrated and discussed above. Sheath 2 retains aneurysm
bridge device 1 in a reduced profiled configuration. Device 1 is
capable of expanding into contact with the vessel walls, or
released or deployed to a larger diameter configuration, when
sheath 2 is withdrawn.
[0040] There are many similarities between the delivery system
illustrated in FIG. 3B and FIG. 4B. However, the system illustrated
in FIG. 4B includes alternative pusher 14. Pusher 14 may be formed
of suitable polymers, metals, and/or composite materials. Pusher 14
may include any of the materials and dimensions of pusher 5
described above, but pusher 14 does not include a central lumen. A
guide wire (not pictured) may also be utilized in the step of
positioning the system in a vessel.
[0041] Prior to introduction into vessel V, the proximal end 3 of
aneurysm bridge device 1 is disposed upon the distal end of pusher
14. Exemplary distal tips of pusher 14 are described in greater
detail below in a description of FIGS. 11-14. Distal tip 4 again
includes apertures 8. When loaded onto distal tip 4, device 1 is
threaded over pusher 14, and positioned so that bumps 9 of its
proximal end 3 are aligned with, or inserted into, apertures 8.
Bumps 9 may alternatively be projections, tabs, posts, clips, or
any structures, preferably male, that are suitable for engaging
apertures 8. Similarly, apertures 8 may alternatively be pockets,
holes, hollows, grooves, or any structures, preferably female, for
receiving bumps 9. Sheath 2 retains bumps 9 in engagement with
apertures 8 as it retains aneurysm bridge device 1 in a reduced
profile configuration. Device 1 remains in the reduced profile
configuration during tracking of the device under fluoroscopic
visualization to a treatment site within the vasculature of a
subject.
[0042] After positioning aneurysm bridge 1 across the opening of
aneurysm A, and proximate the distal end of delivery catheter D,
the device is then deployed. As illustrated beginning with FIGS.
4C, in order to deploy aneurysm bridge 1, sheath 2 is withdrawn
proximally to permit the device 1 to expand to its unconstrained
configuration into contact with the inner walls of the parent
vessel V. When sheath 2 is completely withdrawn from the length of
bridge device 1, device 1 expands to a deployed diameter, as
illustrated in FIG. 4D. If the user wishes to reposition device 1,
sheath 2 can be advanced distally in order to resheath device 1.
The steps of positioning and deploying device 1 described above can
then be repeated. Pusher 5 may then be either withdrawn from the
vessel V or may be left positioned in vessel V. As illustrated in
FIGS. 4C and 4D, delivery catheter D remains in place proximate the
aneurysm during the steps of the method described herein.
[0043] As illustrated in FIG. 4E-4F, one or more embolic coils (or
other embolic material) may then be delivered to the aneurysm, in
much the same manner as described above, except that they are
delivered directly into the aneurysm, instead of through the voids
in the "walls" of the bridge 1. The position of the device 1 across
the neck of the aneurysm prevents the unintended escape of embolic
materials out of the aneurysm and into the parent vessel following
the conclusion of the procedure (See FIG. 4G). The device remains
in place in the parent vessel across the aneurysm neck during the
delivery of coils, thereafter, and if desired, permanently.
[0044] Details of an aneurysm bridge device according to the
invention are illustrated in FIG. 5. Aneurysm bridge 10 is
illustrated in a deployed "in air" configuration. Aneurysm bridge
10 is a more or less tubular device capable of being retained in a
constrained form or shape prior to deployment, and then expanded
(or permitted to expand) into contact with the walls of a vessel
when deployed. Consequently, it may be positioned and delivered
using a variety of methods similar to those summarized above in
conjunction with the description of FIGS. 3A-4G. As described in
detail below, aneurysm bridge 10 has many advantages over prior art
devices for improved delivery, deployment, retraction,
repositioning, and redeployment .
[0045] Aneurysm bridge 10 may be constructed from any number of
compositions having suitable biocompatibility and strength
characteristics. In the embodiment illustrated in FIG. 5, aneurysm
bridge 10 is constructed from Nitinol.RTM. with "shape memory" or
superelastic characteristics to optimize self expansion of the
device upon deployment. Aneurysm bridge 10 is constructed by
cutting features into a Nitinol tube. For example, a tube of 3.5 mm
outer diameter and 0.005 inch thickness may be cut in a
predetermined pattern of bands, struts, and/or connectors. Examples
of suitable patterns are illustrated below in FIGS. 9 and 10,
though variations on the patterns are within the scope of the
invention. After the features are cut into the tube, the tube is
twisted and shape set. It has been found that a helical arrangement
resulting from the twist helps the deployed device conform to the
vessel walls, and it also improves the ability of the device to
resist kinking.
[0046] An aneurysm bridge according to the invention may be
dimensioned in any number of suitable sizes and lengths, depending
upon the location of the aneurysm, variances in patient anatomy,
and the size and shape of the aneurysm. Aneurysm bridge 10 of FIG.
5 in its expanded configuration is approximately 2.0-6.0 mm at its
maximum outer diameter, and between 10-45 mm in length. Aneurysm
bridge 10 can be described while viewing FIG. 5 from left to right,
with its proximal end 15 on the left side of the figure, its distal
end 18 on the right, and a central region 11 disposed therebetween.
As described in greater detail below in conjunction with a
description of FIGS. 7-7C, generally tubular aneurysm bridge 10 has
a generally ovular shaped cross section at its proximal end 15 and
its distal end 18 when it is deployed in air. It is however
generally circular in cross section throughout most of its central
region 11. When bridge 10 is deployed in a vessel, it generally
takes the shape and cross section of the vessel.
[0047] In FIG. 5, two standards 20 and 22 can be seen extending in
a helical fashion from proximal end 15 to distal end 18, more or
less the entire length of tubular element 10, though alternative
embodiments may have a greater number of standards. The helical
array of aneurysm bridge 10 may be imparted to a cut tube by
grasping standards 20 and 22 and applying a circumferential twist.
(The extent of circumferential twist can be characterized in terms
of the resulting angle of standards 20 and 22 to the longitudinal
axis of device 10, and is illustrated in FIG. 7 below). Standards
20 and 22 have a width in the range of 0.0020-0.0050 inch,
preferably between 0.0030-0.0045 inch, and impart axial and
columnar strength upon aneurysm bridge 10. The standards may also
be used to provide axial force to the device if it is necessary to
reposition the device after partial deployment within the vessel as
discussed above. Standards 20 and 22 may further be equipped with
features to facilitate loading of the finished device 10 into a
sheath.
[0048] Standard 22 defines a portion of first helical spine 25.
First helical spine 25 extends in a helical fashion along the
length of aneurysm bridge 10 from proximal end 15 to distal end 18
as a result of the circumferential twist applied to standards 20
and 22. Similarly, standard 22 defines a portion of second helical
spine 27. Second helical spine 27 extends in a helical fashion from
proximal end 15 to distal end 18 of aneurysm bridge 10. First
helical spine 25 and second helical spine 27 impart columnar
strength and uniform, reduced size gap spacing along the length of
the device 10. The specific features that define first helical
spine 25 and second helical spine 27 will be described in detail in
relation to FIGS. 8 and 9, in which the features are more easily
viewed.
[0049] Among the advantages of the invention herein are its
superior, kink-resistant, reversible trackability and reversible
deployability within tortuous vasculature. In order to illustrate
the superior tracking and reliable deployment of the system, device
10 is shown deployed within a transparent vessel model 30 in FIG.
6. Transparent model vessel 30 has a curved configuration and model
aneurysm 34 located on the "outer" side of curve 36. Device 10 was
tracked through curve 36 and across the neck of aneurysm 34.
Aneurysm bridge 10 was permitted to expand radially outwardly to
closely meet the walls of the vessel model. And despite the curved
configuration of the vessel model, aneurysm bridge device readily
deploys to contact the walls of the lumen. Moreover, when deployed
in a curved vessel, the features of device 10, (which are described
more specifically below in conjunction with a discussion of FIG. 9)
are disposed in a uniform, orderly configuration. No portion of
aneurysm bridge device 10 bulges or protrudes into aneurysm 34.
Consequently, aneurysm bridge device 10 can be repositioned and
redeployed readily if needed, or withdrawn completely from the
vessel. And aneurysm bridge device 10 provides orderly gaps between
struts or bands through which occlusion coils (not pictured) may be
both delivered to aneurysm 34 and prevented from escape
therefrom.
[0050] FIG. 7 illustrates other aspects of aneurysm bridge 10 from
a truncated side elevational view. Firstly, the twist angle
mentioned above in relation to FIG. 5 is more easily viewed in FIG.
7. Twist angle a is illustrated as the angle between standard 20
and longitudinal axis x of device 10. Twist angle a is between
15.degree. and 40.degree., and preferably between 20.degree. and
35.degree., in either a clockwise or a counterclockwise direction.
A particular twist angle may be imparted on device 10 after pattern
features illustrated in FIGS. 9 and 10 below are cut into a Nitinol
tube.
[0051] FIGS. 7A-7C illustrate cross sectional shapes of device 10
(when it is deployed in air), along lines A, B and C of FIG. 7
above. FIG. 7A illustrates the cross section of proximal end 15 at
Detail A. At proximal end 15 of aneurysm bridge 10, standard 20 is
generally opposite standard 22. FIG. 7B illustrates the cross
section of central region 11 at Detail B. And FIG. 7C illustrates
the cross section of aneurysm bridge 10 at detail C. At distal end
18, standards 20 and 22 intersect one another along a wall of
aneurysm bridge 10. Apexes 24 are disposed opposite one another, at
the narrowest portions of the oval. Central lumen 28, which extends
the length of tubular element 10, is consequently ovular in cross
section at the proximal and distal ends of aneurysm bridge 10, and
circular in cross section in the central region of the device.
[0052] FIG. 8 illustrates aneurysm bridge 10 from a perspective
view of proximal end 15, revealing central lumen 28. (For clarity,
the portion of bridge 10 on the "back side" of lumen 28 is
illustrated merely by dotted helical lines.) Distal end 18 is
essentially facing away from the viewer in FIG. 8. Bridge 10 is
again shown deployed in air, and proximal end 15 has a generally
ovular cross section. At proximal end 15, the proximal-most ends of
standards 20 and 22 lie essentially opposite one another, along the
narrowest portions of the oval.
[0053] FIG. 9 illustrates an example of a cut pattern used to make
a device according to the invention. Although an aneurysm bridge
according to the invention is a generally tubular device shape set
into a twisted configuration, FIG. 9 illustrates the device as
though, before being shape set into a twist, it has been cut along
its length and laid flat so that its features may be more easily
viewed. Cut pattern 50 has a proximal end 52 and a distal end 53.
Cut pattern 50 also has standards 55 and 57. Standard 55 and
standard 57 have a similar set of features arrayed in a repeating
pattern. For ease of reference, these features will be described
especially in relation to standard 55, though standard 57 is also
oriented to bands, struts or connectors having generally the same
features. Extending laterally or diagonally from standard 55 is a
plurality of bands 60. Bands 60 have strut widths in the range of
0.00050-0.00150 inch, and preferably between 0.00060-0.00120 inch.
Bands 60 in turn extend to define S-connectors 65. Standard 55,
bands 60 and S-connectors 65 define a first spine 68. Second spine
69 is defined by the corresponding features in conjunction with
standard 57. In the cut pattern 50, spines 68 and 69 are generally
straight. In a finished device, however, a circumferential twist
will be shape set into the device, placing spines 68 and 69 in a
helical configuration.
[0054] Connected to the other ends of S-connectors 65 are bands
referred to as V-struts 70. Each V-strut 70 includes a short leg
71, a long leg 72, and an apex 73 therebetween. Apexes 73 are
disposed pointing toward distal end 53. Though other geometries are
possible within the scope of the invention, the resulting lattice
of first spine 68, V-struts 70, second spine 69 and V-struts 74
will define the skeletal "walls" of the generally tubular aneurysm
bridge and the shape and size of voids within the walls.
[0055] The function of S-connectors 65 can be described as limiting
the expansion between bands 60. The expansion limiting function can
most easily be viewed in FIG. 6. Aneurysm bridge 10, deployed in
curved model vessel 30, has bands 12 and S-connectors 13. The
tighter spacing between bands 12 is illustrated in comparison to
the wider spacing of V-struts 19. S-connectors 13 tighten the gaps
in the walls of the device, effectively reducing the size of gaps
26 by roughly half, thereby providing a barrier to coils that may
be implanted into aneurysm 34. S-connectors 13 also prevent bands
12 and V-struts 19 from "poking" or protruding into aneurysm 34, an
important advantage if the device must be repositioned, especially
when the aneurysm is disposed in a curved vessel, as in the example
of FIG. 6. The closely spaced and generally uniform array imparted
by S-connectors 13 is imparted along the length of first helical
spine 25 (and second helical spine 27, which is not visible in FIG.
5), and consequently along the length of aneurysm bridge 10.
[0056] The function of V-struts 19 can be characterized as
maximizing the flexibility of the device 10. The flexibility
imparted by V-struts 19 is very important for accommodating the
flexure of the device both prior to deployment and over the life of
the device. Prior to deployment of the device, most of the stress
imparted on the device occurs during crimping down and loading the
device into a sheath, and then tracking the crimped device through
tortuous vasculature while crimped down and sheathed. Following
deployment of the device within the vessel, most of the stress
imparted on the device is a result of the ongoing, long term
expansion and contraction due to pulsation of the vessel. In both
configurations, the majority of the stress on the device is
absorbed by the V-struts 19. It is desirable for the device to be
able to flex at the "V"; otherwise the stress may break the device,
or deform the device beyond its ability to recover, or otherwise
cause the device to fail.
[0057] The specific structures of bands 12, S-connectors 13 and
V-struts 19 of FIGS. 5-8 are similar to the corresponding features
of FIGS. 9 and 10, but can be most easily viewed in FIG. 10. FIG.
10 illustrates an alternative embodiment according to the
invention. Similar to FIG. 9, it illustrates a cut pattern of a
generally tubular device as though it were cut along the length of
the tube before the tube has been shape set, and laid flat so that
the features of the pattern may be more easily viewed. Cut pattern
90 has proximal end 92, distal end 93, and standards 95 and 97. Cut
pattern 90 has a lesser number of bands 100 than does cut pattern
50 described above. Cut pattern 90 has a correspondingly fewer
number of S-connectors 105 and V-struts 110. Cut pattern 90
accordingly will form a shorter length device than cut pattern
50.
[0058] An important similarity between the embodiment of FIG. 10
and other embodiments is that S-connectors 105 perform the same
gap-limiting function without sacrificing needed flexibility. In
order to perform this function, S-connectors 105 are disposed
between bands 100 and V-struts 110, and specifically very near
apexes 112 of V-struts 110. V-struts 110 consequently have a short
leg 114 and a long leg 116. S-connectors 110 thereby maintain close
spacing between bands 100, while permitting flexure of apexes 112.
Because most of the stress during flexure of the device made from
cut pattern 90 is absorbed by apexes 112, it is important that the
S-connector not completely prevent flexure of apexes 112. The
positioning of S-connectors illustrated in FIG. 9 help define first
spine 94 and second spine 96, yet permit flexure of V-struts 110.
Apexes 112 additionally point in the direction of distal end 93,
facilitating resheathing of the device if needed.
[0059] FIG. 11 illustrates a truncated view of a cut pattern to
which a right hand twist has been applied. Cut pattern 130 is
illustrated as though a twisted tubular aneurysm bridge according
to the invention were cut along its axis and unrolled to better
display its features. More easily viewed in FIG. 11A, Detail A,
taken from a distal portion of cut pattern 130 of FIG. 11, reveals
the structure of bands 150, S-connectors 155, and V-struts 160.
Also visible in FIG. 11A is marker 165, which is disposed on the
distal end of standard 170. The distal extension 175 of standard
170 is between 0.0200-0.110 inch, and preferably between 0.0300 and
0.1050 inch in length.
[0060] FIG. 11B is an enlarged view of Detail B, taken from a
proximal region of FIG. 11, to better illustrate some of its
features. Again S-connectors 155 are visible, as are V-struts 160,
and standard 170. Affixed near the proximal end of standard 170 is
bump 180 (shown from a top view of bump 180). As mentioned above,
bump 180 is useful in loading a finished device on the distal end
of a pusher prior to retaining the device with a sheath (see FIGS.
3A-3C).
[0061] See also FIG. 12, showing an enlarged schematic illustration
of a device 200 according to the invention mounted on a pusher and
retained by a sheath. Proximal end 201 of aneurysm bridge 200 is
shown mounted on the distal end of a pusher 202. Bumps 205 are seen
in engagement with apertures 210. Sheath 215 retains aneurysm
bridge 200 in its reduced profile delivery configuration, and
consequently keeps bumps 205 in engagement with apertures 210 until
either proximal withdrawal of sheath 215, or until pusher 202
pushes the device out of the end of sheath 215.
[0062] FIG. 13 is a perspective view of a pusher tip 300 that is
not affixed to the distal end of a pusher. Pusher tip 300 has a
central lumen 305, and three apertures 310. A greater or lesser
number of apertures are within the scope of the invention. Similar
to the apertures described in relation to FIGS. 10-11 above,
apertures 310 permit the engagement of bumps on the proximal end of
an aneurysm bridge device. Legs 315 and eyelets 317 permit the
attachment of pusher tip 300 onto the distal end of a pusher.
[0063] FIG. 13 is a perspective view of an alternative embodiment
of a pusher tip according to the invention. Pusher tip 400 has
central lumen 405 and two apertures 410 which can accommodate bumps
on the proximal end of an aneurysm bridge device, to enhance
retention of the device on the distal end of a pusher until
deployment of the device at a desired time. Legs 415 and eyelets
417 enhance attachment of pusher tip 400 on the distal end of a
pusher.
[0064] It should be recognized that a number of variations of the
above-identified embodiments will be obvious to one of ordinary
skill in the art in view of the foregoing description. Accordingly,
the invention is not to be limited to those specific embodiments
and methods of the present invention illustrated and described
herein. Rather, the scope of the invention is to be defined by the
claims and their equivalents.
* * * * *