U.S. patent application number 14/573244 was filed with the patent office on 2015-06-11 for vascular remodeling device.
The applicant listed for this patent is COVIDIEN LP. Invention is credited to Elad LEVY, Victoria SCHUMAN, Sanjay SHRIVASTAVA, Earl SLEE.
Application Number | 20150157331 14/573244 |
Document ID | / |
Family ID | 44309532 |
Filed Date | 2015-06-11 |
United States Patent
Application |
20150157331 |
Kind Code |
A1 |
LEVY; Elad ; et al. |
June 11, 2015 |
VASCULAR REMODELING DEVICE
Abstract
A generally spherical vascular remodeling device is permanently
positionable at a junction of afferent and efferent vessels of a
bifurcation having an aneurysm. After positioning the device at the
junction to substantially conform the device to the shape of the
junction, the device acts as a scaffolding to inhibit herniation of
objects out of the aneurysm and permits perfusion to the efferent
vessels. Positioning the device may include deployment and
mechanical or electrolytic release from a catheter. Embolic
material may be inserted in the aneurysm before or after
positioning the device. The device may have a first end, a second
end substantially opposite to the first end, and a plurality of
polymer filaments extending between and coupled at the first end
and the second end. Such devices may be football shaped, pumpkin
shaped, or twisted. The device may include a plurality of polymer
loops forming a generally spherical shape.
Inventors: |
LEVY; Elad; (Amherst,
NY) ; SCHUMAN; Victoria; (Minneapolis, MN) ;
SHRIVASTAVA; Sanjay; (Irvine, CA) ; SLEE; Earl;
(Laguna Niguel, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
COVIDIEN LP |
Mansfield |
CA |
US |
|
|
Family ID: |
44309532 |
Appl. No.: |
14/573244 |
Filed: |
December 17, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13016858 |
Jan 28, 2011 |
8926681 |
|
|
14573244 |
|
|
|
|
61299266 |
Jan 28, 2010 |
|
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Current U.S.
Class: |
606/191 |
Current CPC
Class: |
A61B 2017/12063
20130101; A61L 31/06 20130101; A61L 31/06 20130101; A61B 2017/00004
20130101; A61L 31/041 20130101; A61B 17/12172 20130101; A61B
17/1214 20130101; A61B 17/12145 20130101; A61B 17/12022 20130101;
A61B 2017/12054 20130101; A61F 2/07 20130101; A61B 2017/1205
20130101; A61L 2430/36 20130101; A61B 17/12118 20130101; A61L
31/148 20130101; A61B 17/12109 20130101; C08L 67/04 20130101 |
International
Class: |
A61B 17/12 20060101
A61B017/12 |
Claims
1. A vascular remodeling device comprising: a plurality of polymer
filaments; wherein proximal ends of the plurality of polymer
filaments are coupled together by a bioabsorbable coupling at a
proximal end of the device; wherein the coupling is configured to
bioabsorb more quickly than does the plurality of polymer
filaments; wherein the proximal ends of the plurality of polymer
filaments are configured to be released from the coupling after
bioabsorption of the coupling.
2. The device of claim 1, wherein at least some of the polymer
filaments comprise polyglycolic acid, polylactic acid,
poly(lactic-co-glycolic acid), poly-epsilon-caprolactone, or
naturally-derived bioabsorbable polymers.
3. The device of claim 1, wherein a first group of the polymer
filaments comprise a first polymer having a first rate of
bioabsorption and a second group of the polymer filaments comprise
a second polymer different than the first polymer, the second
polymer having a second rate of bioabsorption different that the
first rate of bioabsorption.
4. The device of claim 1, wherein the device is generally
football-shaped, the proximal end of the device extending outwardly
and a distal end extending outwardly.
5. The device of claim 1, wherein the device is generally
pumpkin-shaped, the proximal end of the device extending outwardly
and a distal end extending inwardly.
6. The device of claim 1, wherein a first porosity distally
increases between the second end and an approximate midpoint and
wherein a second porosity distally decreases between the midpoint
and the first end.
7. The device of claim 1, wherein the filaments are longitudinally
angled at the distal end.
8. The device of claim 1, wherein the plurality of filaments
comprises between about 6 filaments and about 12 filaments.
9. The device of claim 1, wherein the plurality of polymer
filaments are configured to extend towards an afferent vessel after
bioabsorption of the coupling.
10. A vascular remodeling device comprising: a first end; a second
end substantially opposite to the first end; and a plurality of
polymer filaments extending between the first end and the second
end and coupled at the first end and the second end, wherein a
first group of the polymer filaments comprises a first polymer
having a first rate of bioabsorption and a second group of the
polymer filaments comprises a second polymer different than the
first polymer, the second polymer having a second rate of
bioabsorption different than the first rate of bioabsorption.
11. The device of claim 10, wherein at least some of the polymer
filaments comprise polyglycolic acid, polylactic acid,
poly(lactic-co-glycolic acid), poly-epsilon-caprolactone, or
naturally-derived bioabsorbable polymers.
12. The device of claim 10, wherein the device is generally
football-shaped, the first end extending outwardly and the second
end extending outwardly.
13. The device of claim 10, wherein the device is generally
pumpkin-shaped, the first end extending outwardly and the second
end extending inwardly.
14. The device of claim 10, wherein a first porosity distally
increases between the second end and an approximate midpoint and
wherein a second porosity distally decreases between the midpoint
and the first end.
15. The device of claim 10, wherein the filaments are
longitudinally angled at the second end.
16. The device of claim 10, wherein the plurality of filaments
comprises between about 6 filaments and about 12 filaments.
17. The device of claim 10, wherein a proximal end of the device
comprises a bioabsorbable coupling.
18. The device of claim 17, wherein the coupling is configured to
bioabsorb more quickly than the plurality of polymer filaments.
19. The device of claim 18, wherein the plurality of polymer
filaments are configured to be released from the coupling after
bioabsorption of the coupling.
20. The device of claim 18, wherein the plurality of polymer
filaments are configured to extend towards an afferent vessel after
bioabsorption of the coupling.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. application Ser.
No. 13/016,858, filed Jan. 28, 2011, which claims priority benefit
of U.S. Provisional Patent Application No. 61/299,266, filed Jan.
28, 2010, which is incorporated herein by reference in its
entirety.
BACKGROUND
[0002] 1. Field
[0003] The present application generally relates to vascular
remodeling devices and to the manner of their positioning in
vessels, and, more particularly, to generally spherical remodeling
devices and to the matter of their positioning at the junction of
neurovascular bifurcations having an aneurysm.
[0004] 2. Description of Related Art
[0005] Neurovascular or cerebral aneurysms affect about 5% of the
population. Aneurysms may be located, for example, along arterial
side walls (e.g., the aneurysm 10 illustrated in FIG. 1) and at
arterial bifurcations (e.g., the aneurysm 20 illustrated in FIG.
2). The direction of fluid flow is generally indicated by the
arrows 16, 26. The aneurysms 10, 20 each have a fundus 12, 22, a
neck 14, 24, and a fundus-to-neck ratio or "neck ratio." If the
neck ratio is greater than 2 to 1 or if the neck 14, 24 is less
than 4 mm, the aneurysm 10, may be treated with embolization coils
alone because the coils will generally constrain themselves within
the aneurysm 10, 20 without herniating into parent vessels. If the
neck ratio is less than 2 to 1 or if the neck 14, 24 is greater
than 4 mm, the aneurysms 10, 20 may be difficult to treat with
embolization coils alone because the coils may be prone to
herniating into parent vessels, as illustrated in FIGS. 3A and 3B.
Herniation of coils may cause arterial occlusion, stroke, and/or
death. Compared to the bifurcation illustrated in FIG. 2, the
efferent vessels of the bifurcation may be at substantially
different angles, have substantially different sizes, and/or be a
different quantity (e.g., three or more). Compared to the
bifurcation illustrated in FIG. 2, the aneurysm 20 of the
bifurcation may be offset with respect to the junction (e.g.,
having a neck substantially open to one efferent vessel), tilted
with respect to a plane created by the vessels (e.g., into or out
of the page), etc. Each of these would still be accurately
characterized as a "bifurcation" herein.
[0006] In order to inhibit such herniation, tubular neck remodeling
devices, for example Neuroform.TM., available from Boston
Scientific, and Enterprise.TM., available from Cordis
Neurovascular, may be used to keep coils or other materials within
the fundus of the aneurysm and out of the vessels. Tubular
remodeling devices generally consist of a braided wire or cut
metallic stent or stents covering the neck of the aneurysm so that
materials introduced into the fundus of the aneurysm do not
herniate out of the aneurysm. As illustrated in FIG. 4A, tubular
remodeling devices 40 are generally useful for side wall aneurysms
10. As illustrated in FIGS. 4B and 4C, tubular remodeling devices
42, 44 are generally less useful for aneurysms 20 at bifurcations,
for example because shaping the remodeling devices to preserve
blood flow through the afferent and efferent vessels while also
inhibiting herniation of coils 28 out of the aneurysm 20 can be
difficult.
SUMMARY
[0007] In some embodiments described herein, a generally spherical
vascular remodeling device is provided. The device is permanently
positionable at a junction of afferent and efferent vessels of a
bifurcation (e.g., a neurovascular bifurcation) having an aneurysm
having a fundus and a neck. Positioning may comprise deployment
from a catheter and mechanical or electrolytic release from the
catheter. After positioning the device at the junction, the device
can lock into place across the arterial ostia and the neck of the
aneurysm, substantially conforming to the shape of the junction.
After positioning the device at the junction, the device acts as a
scaffolding to inhibit or prevent herniation or prolapse of objects
such as embolization coils and thrombi out of the neck of the
aneurysm. Embolic material may be inserted in the fundus of the
aneurysm before or after positioning the device. After positioning
the device at the junction, the device permits perfusion of fluid
(e.g., blood) to the efferent vessels. The device may have a first
end, a second end substantially opposite to the first end, and a
plurality of polymer filaments extending between and coupled at the
first end and the second end. Certain such devices may be football
shaped, pumpkin shaped, or twisted. The polymer filaments may
comprise bioabsorbable polymers (e.g., polylactic acid,
polyglycolic acid, poly(lactic-co-glycolic acid),
poly-epsilon-caprolactone, and/or naturally-derived bioabsorbable
polymers). The device may comprise a plurality of loops (e.g.,
circular loops) or filaments forming a generally spherical shape,
each loop comprising a bioabsorbable polymer (e.g., polylactic
acid, polyglycolic acid, poly(lactic-co-glycolic acid),
poly-epsilon-caprolactone, and/or naturally-derived bioabsorbable
polymers). Radiopaque markers may be placed at one or both ends of
the device and/or at least one of the loops or filaments may
comprise a radiopaque material (e.g., platinum). In certain
embodiments, a method of treating an aneurysm at a junction of a
bifurcation having an afferent vessel and efferent vessels is
provided. The aneurysm has a neck and a fundus. The method
comprises advancing a catheter proximate to the junction of the
bifurcation. The catheter at least partially contains a generally
spherical vascular remodeling device in a compressed state. The
device comprises a plurality of polymer filaments. The method
further comprises positioning the device at the junction of the
bifurcation and withdrawing the catheter and leaving the device at
the junction of the bifurcation. The device acts as a scaffolding
to inhibit herniation of objects out of the neck of the aneurysm
after withdrawal of the delivery catheter. The device permits
perfusion of fluid to the efferent vessels.
[0008] In certain embodiments, a generally spherical remodeling
device comprises a first end, a second end substantially opposite
to the first end, and a plurality of polymer filaments extending
between the first end and the second end and coupled at the first
end and the second end. The device is configured to be positioned
at a junction of a bifurcation comprising at least one afferent
vessel, efferent vessels, and an aneurysm having a neck after
withdrawal of a delivery catheter. The device is configured to act
as a scaffolding to inhibit herniation of objects out of the neck
of the aneurysm. The device is configured to permit perfusion of
fluid to the efferent vessels.
[0009] In certain embodiments, a remodeling device comprising a
plurality of polymer arcuate loops forming a generally spherical
shape is provided. The device is configured to be positioned at a
junction of a bifurcation having an aneurysm after withdrawal of a
delivery catheter. The device is configured to act as a scaffolding
to inhibit matter from herniating out of the aneurysm. The device
is configured to permit perfusion of blood to efferent vessels of
the bifurcation.
[0010] For purposes of summarizing the invention and the advantages
achieved over the prior art, certain objects and advantages of the
invention are described herein. Of course, it is to be understood
that not necessarily all such objects or advantages need to be
achieved in accordance with any particular embodiment. Thus, for
example, those skilled in the art will recognize that the invention
may be embodied or carried out in a manner that achieves or
optimizes one advantage or group of advantages as taught or
suggested herein without necessarily achieving other objects or
advantages as may be taught or suggested herein.
[0011] All of these embodiments are intended to be within the scope
of the invention herein disclosed. These and other embodiments will
become readily apparent to those skilled in the art from the
following detailed description having reference to the attached
figures, the invention not being limited to any particular
disclosed embodiment(s).
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] These and other features, aspects, and advantages of the
present disclosure are described with reference to the drawings of
certain embodiments, which are intended to illustrate certain
embodiments and not to limit the invention.
[0013] FIG. 1 illustrates an example embodiment of a side wall
aneurysm.
[0014] FIG. 2 illustrates an example embodiment of a bifurcation
having an aneurysm.
[0015] FIG. 3A illustrates an example embodiment of a side wall
aneurysm with herniating embolization coils.
[0016] FIG. 3B illustrates an example embodiment of a bifurcation
having an aneurysm with herniating embolization coils.
[0017] FIG. 4A illustrates an example embodiment of a side wall
aneurysm treated with embolization coils and a tubular remodeling
device.
[0018] FIGS. 4B and 4C illustrates example embodiments of a
bifurcation having an aneurysm treated with embolization coils and
tubular remodeling devices.
[0019] FIG. 5 illustrates an example embodiment of a generally
spherical vascular remodeling device.
[0020] FIGS. 6A-6C illustrate an example embodiment of a method for
treating an aneurysm using the device of FIG. 5.
[0021] FIGS. 7A-7C illustrate another example embodiment of a
method for treating an aneurysm using the device of FIG. 5.
[0022] FIG. 8 illustrates another example embodiment of a generally
spherical vascular remodeling device.
[0023] FIGS. 9A-9C illustrate an example embodiment of a method for
treating an aneurysm using the device of FIG. 8.
[0024] FIGS. 10A-10C illustrate another example embodiment of a
method for treating an aneurysm using the device of FIG. 8.
[0025] FIG. 11 illustrates yet another example embodiment of a
generally spherical vascular remodeling device.
[0026] FIG. 12 illustrates an example embodiment of treating an
aneurysm using the device of FIG. 11.
[0027] FIG. 13 illustrates still another example embodiment of a
generally spherical vascular remodeling device.
[0028] FIG. 14 illustrates an example embodiment of a generally
spherical vascular remodeling device at a stage of an example
manufacturing process.
DETAILED DESCRIPTION
[0029] Although certain embodiments and examples are described
below, those of skill in the art will appreciate that the invention
extends beyond the specifically disclosed embodiments and/or uses
and obvious modifications and equivalents thereof. Thus, it is
intended that the scope of the invention herein disclosed should
not be limited by any particular embodiments described below.
[0030] FIG. 5 illustrates an example embodiment of a generally
spherical vascular remodeling device 50. It will be appreciated
that the device 50 may be more compliant than the vasculature in
which it is deployed such that it may be somewhat misshapen (e.g.,
non-spherical, for example as illustrated in FIG. 6B) after being
deployed, and that the phrase "generally spherical" describes the
shape of the device 50 when in an expanded (e.g., fully expanded)
state. Additionally, the phrase "generally spherical" distinguishes
the device 50, which is generally uniform in each dimension in an
expanded state, from tubular stents having a small radial dimension
and a large longitudinal dimension in an expanded state. In some
embodiments of a generally spherical device, an outer periphery of
the device has a shape that deviates by between about 10% and about
25% from an outer periphery of a mathematically perfect sphere. In
some embodiments, the device 50 has a length and a width that are
within less than about 33% of each other (e.g., having a length of
6 mm and a width of 8 mm, having a length of 6 mm and a width of 8
mm). Embodiments in which the width is greater than the length may
be advantageous due to a difference in porosity at a midpoint and
an end proximate to an aneurysm. Embodiments in which the length is
greater than the width may be advantageous for positioning a
portion of the device 50 in a portion of the aneurysm 20 (e.g., to
aid in embolization).
[0031] In the embodiment illustrated in FIG. 5, the device 50
comprises a plurality of generally circular loops 52 coupled
together. Coupling of the loops 52 may comprise adhering, welding,
soldering, interlacing (e.g., some loops 52 being over or under
other loops 52), intertwining, meshing, combinations thereof, and
the like. In the embodiment illustrated in FIG. 5, the device 50
comprises a lead or tail 53, which may be used for releasing and/or
retracting the device 50 after deployment, as described herein. In
some embodiments, the device 50 comprises a cut metallic sphere, a
single filament, a plurality of non-circular filaments (e.g.,
arcuate segments), etc. In some embodiments, each loop 52 forms a
plane and the intersections of the planes are substantially
parallel (e.g., as illustrated in FIG. 7A).
[0032] In some embodiments, at least some of the loops 52 or
filaments comprise a self-expanding and/or a shape-memory material
(e.g., comprising Nitinol, CoCr alloy, etc.), thereby causing the
device 50 to be self-expanding under certain conditions (e.g., not
restrained by a catheter). In some embodiments, at least one of the
loops 52 comprises a different material than others of the loops 52
(e.g., some loops 52 comprising Nitinol and some loops 52
comprising Nitinol and platinum). In some embodiments, at least one
of the loops 52 comprises a radiopaque material (e.g., platinum).
In certain such embodiments, an even number of loops 52 (e.g., two,
four, etc.) comprises a radiopaque material (e.g., platinum). In
some embodiments, at least one of the loops 52 comprises a
radiopaque material (e.g., platinum) at least partially wrapped
(e.g., coiled) around a self-expanding material (e.g., Nitinol). In
some embodiments, at least one of the loops 52 comprises a
self-expanding material with a radiopaque core (e.g., Nitinol with
a platinum core) or a radiopaque coating (e.g., Nitinol coated with
platinum, tantalum, etc. by physical vapor deposition, chemical
vapor deposition, plating, etc.). It will be appreciated that the
amount and type of radiopaque material used may depend, inter alia,
on price, desired level of radiopacity, mechanical properties of
the radiopaque material, and corrosion properties of the radiopaque
material. In certain embodiments, the loops 52 have a substantially
circular or ovoid cross section (e.g., embodiments, in which the
loops 52 comprise separate wires). In some embodiments, the loops
52 have a substantially rectangular or flat cross section (e.g.,
embodiments, in which the loops 52 comprise uncut portions of a
metallic tube). Other shapes of loops 52 and combinations of shapes
of loops 52 are also possible. In certain embodiments, the
plurality of loops 52 comprises between about six and about twelve
loops 52. In certain embodiments, the plurality of loops 52
comprises at least about six loops 52, at least about eight loops
52, or at least about twelve loops 52. Other numbers of loops 52
are also possible.
[0033] In certain embodiments, at least some of the loops 52 or
filaments comprise a polymer. In some embodiments, at least some of
the loops 52 or filaments comprise a polymer that is bioabsorbable.
In certain embodiments, at least some of the loops 52 or filaments
comprise polyglycolic acid (PGA), polylactic acid (PLA),
poly(lactic-co-glycolic acid) (PLGA), poly-epsilon-caprolactone
(PCL), naturally-derived bioabsorbable polymers (NDB), or
combinations thereof (e.g., a first group of the loops 52
comprising PGA and a second group of the loops 52 comprising PLA,
PLGA, PCL, and/or NDB, a first group of the loops 52 comprising PLA
and a second group of the loops 52 comprising PGA, PLGA, PCL,
and/or NDB, a first group of the loops 52 comprising PLGA and a
second group of the loops 52 comprising PLA, PGA, PCL, and/or NDB,
a first group of the loops 52 comprising PCL and a second group of
the loops 52 comprising PGA, PLA, PLGA, and/or NDB, a first group
of the loops 52 comprising NDB and a second group of the loops 52
comprising PGA, PLA, PLGA, and/or PCL, etc.). Other polymers are
also possible. PGA, PLA, PLGA, PCL, and NDB are all bioabsorbable;
however they have different rates of bioabsorption. The
bioabsorption rates of a single polymer can also vary based on, for
example, blood characteristics, blood flow, loop 52 dimensions,
etc. PLA has the longest bioabsorption rate. In some embodiments,
the bioabsorption rate of PLA is at least about ten months. In some
embodiments, the bioabsorption rate of PLA is at least about one
year. In some embodiments, the bioabsorption rate of PLA is at
least about fourteen months. In some embodiments, the bioabsorption
rate of PLA is between about 10 months and about 14 months (e.g.,
about one year). In some embodiments, the bioabsorption rate of PGA
is between about 1 week and about 3 weeks. In some embodiments, the
bioabsorption rate of PGA is between about 2 weeks and about 4
weeks. The bioabsorption rates of PLGA, PCL, and NDB are generally
between the bioabsorption rates of PLA and PGA, and may depend on
parameters such as, for example, molecular weight (e.g., generally
the higher the molecular weight, the longer the bioabsorption
rate), structure (e.g., depending on the arrangement of repeating
units), etc. of the polymer. In some embodiments, PLGA, PCL, and
NDB may have a bioabsorption rate between about 4 weeks and about 1
year. The bioabsorption rate generally refers to the time lose
about 50% of strength. The polymer(s) used in the device 50 may be
selected based on the amount of time an aneurysm may take to
thrombose (e.g., based on fundus size, neck width, etc.). For
example, if an aneurysm is expected to take one month to thrombose
and the device 50 is expected to persist through thrombosis but not
long thereafter, PGA may be selected. The polymer(s) used in the
device 50 may be selected based on the amount of time an aneurysm
may take to obliterate (e.g., based on fundus size, neck width,
etc.). For example, if an aneurysm is expected to take one year to
obliterate and the device 50 is expected to persist through
obliteration, PLA may be selected. Other polymers or combinations
of polymers can be selected based on the particular aneurysm to be
treated and the desired action and/or persistence of the device 50
with respect to the aneurysm. Other selection criteria are also
possible. Different combinations of polymers with different rates
of bioabsorption can allow for selection of a desired rate of
bioabsorption for the device 50. For example, a device 50 with a
combination of PGA and PLA loops 52 may have a rate of
bioabsorption in between the rate of bioabsorption of a device 50
comprising only loops 52 comprising PGA and the rate of
bioabsorption of a device 50 comprising only loops 52 comprising
PLA.
[0034] In certain embodiments, the device 50 is configured to be
positioned at a junction of a bifurcation (e.g., a neurovascular
bifurcation) comprising at least one afferent vessel, efferent
vessels, and an aneurysm having a fundus and a neck. For example,
in some embodiments, the device 50 is suitably dimensioned to fit
in a junction of a bifurcation (e.g., having a diameter between
about 2 mm and about 12 mm, having a diameter between about 6 mm
and about 8 mm, having a diameter less than about 12 mm, having a
diameter greater than about 2 mm). For another example, in some
embodiments, the device 50 is less rigid than a junction of a
bifurcation (e.g., due to the number of loops 52, the material of
the loops 52, the thickness of the loops 52, the spacing of the
loops 52, the shape of the loops 52, combinations thereof, and the
like). In certain embodiments, the device 50 is configured to act
as a scaffolding to inhibit or prevent herniation or prolapse of
objects (e.g., embolization coils, thrombi, etc.) out of a neck of
an aneurysm. For example, in some embodiments, the loops 52 are
dense enough at the neck of the aneurysm that objects cannot pass.
In certain embodiments, the device 50 is configured to permit
perfusion of fluid (e.g., blood) to efferent vessels of a
bifurcation. For example, in some embodiments, the device 50 is
substantially devoid of a covering, mesh, or other material between
the loops 52, thereby allowing fluid to flow substantially
unimpeded.
[0035] The device 50 comprises a plurality of perforations or cells
54 between the loops 52. In certain embodiments, a percentage of
the outer surface of the device 50 covered by the loops 52 is
between about 25% and about 40%. In certain embodiments, a
percentage of the outer surface of the device 50 covered by the
cells 54 is between about 60% and about 75%. Other porosities are
also possible. In some embodiments (e.g., in embodiments in which
the device 50 comprises loops 52 that form a plane and in which the
intersections of the planes are substantially parallel (e.g., as
illustrated in FIG. 7A)), porosity distally increases between a
proximal end of the device 50 and an approximate midpoint and
distally decreases between the approximate midpoint and a distal
end of the device 50. In some embodiments, the device 50 further
comprises one or more radiopaque markers (e.g., comprising or at
least partially covering a portion of a loop 52, at a proximal end
of the device 50, at a distal end of the device 50, etc.).
[0036] FIGS. 6A-6C illustrate an example embodiment of a method for
treating an aneurysm 20 using the device 50. FIG. 6A illustrates a
confluence of afferent and efferent vessels or "junction" at a
bifurcation 60 having an aneurysm 20. In some embodiments, the
vessels are neurovascular or cranial. The aneurysm 20 is
illustrated with a plurality of embolization coils 62 having been
inserted in the fundus 22 of the aneurysm 20. It will be
appreciated that the embolization coils 62 may be a single
embolization coil or other embolic material. A catheter 64 (e.g., a
microcatheter), at least partially containing a constricted or
compressed device 50, is also shown in the afferent vessel. The
catheter 64 is small enough and flexible enough to be routed
through the vasculature and situated proximate to the aneurysm 20.
In some embodiments, the embolization coils 62 are inserted in the
fundus 22 of the aneurysm 20 using the catheter 64. In some
embodiments, the embolization coils 62 are inserted in the fundus
22 of the aneurysm 20 using a different catheter. In certain such
embodiments, a guidewire may be used to guide both catheters.
[0037] FIG. 6B illustrates the bifurcation 60 after the device 50
has been deployed from the catheter 64 (e.g., by being pushed out
with a plunger, by retracting the catheter 64 while the device 50
remains stationary, etc.). After being deployed from the catheter
64, the device 50 may expand. In some embodiments, the device 50
comprises a self-expanding and/or a shape-memory material that
automatically expands towards an uncompressed state or does so upon
the application of warm fluid (e.g., saline). The device 50 may
substantially conform to the shape of the junction of the
bifurcation 60 (e.g., not substantially including portions
extending into the afferent and efferent vessels) and locks into
place across the ostia of the afferent and efferent vessels and the
neck 24 of the aneurysm 20. The device 50 at least partially covers
the neck 24 of the aneurysm 20 as well as the afferent and efferent
vessels, but does not need to divert flow. The device 50 acts as a
scaffolding to inhibit or prevent herniation or prolapse of objects
such as the embolization coils 62 and/or thrombi out of the
aneurysm 24. The device 50 also allows perfusion of fluid (e.g.,
blood) from the afferent vessel(s) to the efferent vessel(s).
[0038] FIG. 6C illustrates the bifurcation 60 after the device 50
has been released from the catheter 64. In some embodiments, the
device 50 is released mechanically (e.g., by a release mechanism).
In some embodiments, the device 50 is released electrolytically
(e.g., by applying a small current until a portion of the tail 53
proximal to the device 50 corrodes away, as illustrated by the gap
65). The catheter 64 is then withdrawn from the bifurcation 60,
thereby leaving or permanently positioning the device 50 at the
junction of the bifurcation 60.
[0039] It will be appreciated that the term "permanently" does not
mean that the device 50 is impossible to remove at a later time. In
some embodiments, the device 50 may be retracted into the catheter
64 after being deployed from the catheter 64 (e.g., by pulling on
the tail 53). The device 50 may then be deployed, for example at a
new angle, at a new rotational position, more proximal or distal to
an afferent vessel and/or an efferent vessel, etc. For example,
although the device 50 expands towards an uncompressed state after
deployment, the resulting shape of the device 50 at the junction of
the bifurcation 60 may vary depending on the details of the
deployment from the catheter 64 because the device 50 adapts to the
shape of the anatomy (e.g., due to the size, shape, number, etc. of
the loops 52). Once the user is satisfied with properties of the
device 50 (e.g., position, tilt, rotation, shape, interaction with
the vessels, etc.), the device 50 may be released as described
herein.
[0040] Combinations of the steps described above are also possible.
In some embodiments, the embolization coils 62 may be inserted in
the fundus 22 of the aneurysm 20 after the device 50 has been
deployed from the catheter 64 (e.g., using the catheter 64 to
insert the embolization coils 62). In some embodiments, the
embolization coils 62 may be inserted in the fundus 22 of the
aneurysm 20 after the device 50 has been released from the catheter
64 (e.g., using the catheter 64 to insert the embolization coils
62).
[0041] In certain embodiments, the loops 52 or filaments comprise a
bioabsorbable polymer. This bioabsorbability can be advantageous in
conjunction with permanent placement of the device 50. For example,
after thrombosis of the aneurysm following treatment, the device 50
may no longer be needed to inhibit herniation of material. Certain
bioabsorbable embodiments of the device 50 may advantageously
inhibit herniation during thrombosis of the aneurysm, but bioabsorb
when they may no longer be needed to inhibit herniation. This can
make permanent placement, or release of the device 50, a less
consequential procedure as a device 50 comprising bioabsorbable
filaments 52 will not remain in the vasculature permanently.
[0042] FIGS. 7A-7C illustrate another example embodiment of a
method for treating an aneurysm 20 using the device 50. In the
method described with respect to FIGS. 6A-6C, the device 50 was
pre-assembled outside of the vasculature prior to positioning. By
contrast, in the method described with respect to FIGS. 7A-7C, the
device 50 is introduced piecemeal and is constructed within the
patient at the bifurcation 60. FIG. 7A illustrates a first loop 66
and a second loop 68 positioned across the neck 24 of the aneurysm
20 and the ostia of the afferent and efferent vessels. In some
embodiments, the first loop 66 is positioned and the second loop 68
is then positioned inside the first loop 66. In some embodiments, a
plane defined by the positioned first loop 66 is substantially
perpendicular to the plane of the neck 24 of the aneurysm 20 and a
plane defined by the positioned second loop 68 is substantially
perpendicular to the plane of the neck 24 of the aneurysm 20. In
certain embodiments, the first loop 66 and the second loop 68 are
positioned via deployment from a same catheter. In certain
embodiments, the first loop 66 is positioned via deployment from a
first catheter, the second loop 68 is positioned via deployment
from a second catheter, and so on. In some embodiments, the device
50 is not released from a catheter, but each loop 52 is released
(e.g., mechanically, electrolytically, etc.) from a catheter. FIG.
7B illustrates the device 50 after it has been fully constructed by
positioning additional loops 52. Embolization coils 62 may be
inserted in the fundus 22 of the aneurysm 20 prior to construction
of the device 50, for example as described above with respect to
FIG. 6A, or after construction of the device 50 (e.g., as
illustrated in FIG. 7C).
[0043] Combinations of methods described herein are also possible.
For example, a partially constructed device 50 may be positioned at
the junction of the bifurcation 60, and then the device 50 may be
fully constructed at the junction of the bifurcation 60. In certain
such embodiments, a partially constructed device 50 having some
missing loops 52 may allow better access to the aneurysm 20 for
easier placement of the embolization coils 62.
[0044] FIG. 8 illustrates another example embodiment of a generally
spherical vascular remodeling device 80. It will be appreciated
that the device 80 may be more compliant than the vasculature in
which it is deployed such that it may be somewhat misshapen (e.g.,
non-spherical, for example as illustrated in FIG. 9B) after being
deployed, and that the phrase "generally spherical" describes the
shape of the device 80 when in an expanded (e.g., fully expanded)
state. Additionally, the phrase "generally spherical" distinguishes
the device 80, which is generally uniform in each dimension in an
expanded state, from tubular stents having a small radial dimension
and a large longitudinal dimension in an expanded state. In some
embodiments of a generally spherical device, an outer periphery of
the device has a shape that deviates by between about 10% and about
25% from an outer periphery of a mathematically perfect sphere. In
some embodiments, the device 80 has a length and a width that are
within less than about 33% of each other (e.g., having a length of
6 mm and a width of 8 mm, having a length of 6 mm and a width of 8
mm). Embodiments in which the width is greater than the length may
be advantageous due to a difference in porosity at a midpoint and
an end proximate to an aneurysm. Embodiments in which the length is
greater than the width may be advantageous for positioning a
portion of the device 80 in a portion of the aneurysm 20 (e.g., to
aid in embolization).
[0045] The device 80 comprises a first or distal end 81 and a
second or proximal end 82 substantially opposite the first end 81.
The device 80 further comprises a plurality of filaments 84
extending between the first end 81 and the second end 82. The first
end 81 extends outwardly and the second end 82 extends outwardly to
form a generally spherical (e.g., oval or oblong) shape similar to
a football, a rugby ball, or a watermelon. In certain embodiments,
the filaments 84 are coupled at the first end 81 and/or the second
end 82 (e.g., by adhering, welding, soldering, combinations
thereof, and the like). In the embodiment illustrated in FIG. 8,
the device 80 comprises a lead or tail 83, which may be used for
releasing and/or retracting the device 80 after deployment, as
described herein. In certain embodiments, the device 80 comprises a
cut metallic sphere, a single filament, etc.
[0046] In certain embodiments, the device 80 is configured to be
positioned at a junction of a bifurcation (e.g., a neurovascular
bifurcation) comprising at least one afferent vessel, efferent
vessels, and an aneurysm having a fundus and a neck. For example,
in some embodiments, the device 80 is suitably dimensioned to fit
in a junction of a bifurcation (e.g., having a diameter between
about 2 mm and about 12 mm, having a diameter between about 6 mm
and about 8 mm, having a diameter less than about 12 mm, having a
diameter greater than about 2 mm). For another example, in some
embodiments, the device 80 is less rigid than a junction of a
bifurcation (e.g., due to the number of filaments 84, the material
of the filaments 84, the thickness of the filaments 84, the spacing
of the filaments 84, the shape of the filaments 84, combinations
thereof, and the like). In certain embodiments, the device 80 is
configured to act as a scaffolding to inhibit or prevent herniation
or prolapse of objects (e.g., embolization coils, thrombi, etc.)
out of a neck of an aneurysm. For example, in some embodiments, the
filaments 84 are dense enough at the neck of the aneurysm that
objects cannot pass. In certain embodiments, the device 80 is
configured to permit perfusion of fluid (e.g., blood) to efferent
vessels of a bifurcation. For example, in some embodiments, the
device 80 is substantially devoid of a covering, mesh, or other
material between the filaments 84, thereby allowing fluid to flow
substantially unimpeded.
[0047] In some embodiments, at least one of the filaments 84
comprises a self-expanding and/or a shape-memory material (e.g.,
comprising Nitinol, CoCr alloy, etc.), thereby causing the device
80 to be self-expanding under certain conditions (e.g., not
restrained by a catheter). In some embodiments, at least one of the
filaments 84 comprises a different material than others of the
filaments 84 (e.g., some filaments 84 comprising Nitinol and some
filaments 84 comprising Nitinol and platinum). In some embodiments,
at least one of the filaments 84 comprises a radiopaque material
(e.g., platinum). In certain such embodiments, an even number of
filaments 84 (e.g., two, four, etc.) comprises a radiopaque
material (e.g., platinum). In some embodiments, at least one of the
filaments 84 comprises a radiopaque material (e.g., platinum) at
least partially wrapped (e.g., coiled) around a self-expanding
material (e.g., Nitinol). In some embodiments, at least one of the
filaments 84 comprises a self-expanding material with a radiopaque
core (e.g., Nitinol with a platinum core) or a radiopaque coating
(e.g., Nitinol coated with platinum, tantalum, etc. by physical
vapor deposition, chemical vapor deposition, plating, etc.). It
will be appreciated that the amount and type of radiopaque material
used may depend, inter alia, on price, desired level of
radiopacity, mechanical properties of the radiopaque material, and
corrosion properties of the radiopaque material. In certain
embodiments, the filaments 84 have a substantially circular or
ovoid cross section (e.g., embodiments, in which the filaments 84
comprise separate wires). In some embodiments, the filaments 84
have a substantially rectangular or flat cross section (e.g.,
embodiments, in which the filaments 84 comprise uncut portions of a
metallic tube, as described below). Other shapes of filaments 84
and combinations of shapes of filaments 84 are also possible. In
certain embodiments, the plurality of filaments 84 comprises
between about six and about twelve filaments 84. In certain
embodiments, the plurality of filaments 84 comprises at least about
six filaments 84, at least about eight filaments 84, or at least
about twelve filaments 84. Other numbers of filaments 84 are also
possible.
[0048] In certain embodiments, at least some of the filaments 84
comprise a polymer. In some embodiments, at least some of the
filaments 84 comprise a polymer that is bioabsorbable. In certain
embodiments, at least some of the filaments 84 comprise
polyglycolic acid (PGA), polylactic acid (PLA),
poly(lactic-co-glycolic acid) (PLGA), poly-epsilon-caprolactone
(PCL), naturally-derived bioabsorbable polymers (NDB), or
combinations thereof (e.g., a first group of the filaments 84
comprising PGA and a second group of the filaments 84 comprising
PLA, PLGA, PCL, and/or NDB, a first group of the filaments 84
comprising PLA and a second group of the filaments 84 comprising
PGA, PLGA, PCL, and/or NDB, a first group of the filaments 84
comprising PLGA and a second group of the filaments 84 comprising
PLA, PGA, PCL, and/or NDB, a first group of the filaments 84
comprising PCL and a second group of the filaments 84 comprising
PGA, PLA, PLGA, and/or NDB, a first group of the filaments 84
comprising NDB and a second group of the filaments 84 comprising
PGA, PLA, PLGA, and/or PCL, etc.). Other polymers are also
possible. PGA, PLA, PLGA, PCL, and NDB are all bioabsorbable;
however they have different rates of bioabsorption. The
bioabsorption rates of a single polymer can also vary based on, for
example, blood characteristics, blood flow, filament 84 dimensions,
etc. PLA has the longest bioabsorption rate. In some embodiments,
the bioabsorption rate of PLA is at least about ten months. In some
embodiments, the bioabsorption rate of PLA is at least about one
year. In some embodiments, the bioabsorption rate of PLA is at
least about fourteen months. In some embodiments, the bioabsorption
rate of PLA is between about 10 months and about 14 months (e.g.,
about one year). In some embodiments, the bioabsorption rate of PGA
is between about 1 week and about 3 weeks. In some embodiments, the
bioabsorption rate of PGA is between about 2 weeks and about 4
weeks. The bioabsorption rates of PLGA, PCL, and NDB are generally
between the bioabsorption rates of PLA and PGA, and may depend on
parameters such as, for example, molecular weight (e.g., generally
the higher the molecular weight, the longer the bioabsorption
rate), structure (e.g., depending on the arrangement of repeating
units), etc. of the polymer. In some embodiments, PLGA, PCL, and
NDB may have a bioabsorption rate between about 4 weeks and about 1
year. The bioabsorption rate generally refers to the time lose
about 50% of strength. The polymer(s) used in the device 80 may be
selected based on the amount of time an aneurysm may take to
thrombose (e.g., based on fundus size, neck width, etc.). For
example, if an aneurysm is expected to take one month to thrombose
and the device 80 is expected to persist through thrombosis but not
long thereafter, PGA may be selected. The polymer(s) used in the
device 80 may be selected based on the amount of time an aneurysm
may take to obliterate (e.g., based on fundus size, neck width,
etc.). For example, if an aneurysm is expected to take one year to
obliterate and the device 80 is expected to persist through
obliteration, PLA may be selected. Other polymers or combinations
of polymers can be selected based on the particular aneurysm to be
treated and the desired action and/or persistence of the device 80
with respect to the aneurysm. Other selection criteria are also
possible. Different combinations of polymers with different rates
of bioabsorption can allow for selection of a desired rate of
bioabsorption for the device 80. For example, a device 80 with a
combination of PGA and PLA filaments 84 may have a rate of
bioabsorption in between the rate of bioabsorption of a device 80
comprising only filaments 84 comprising PGA and the rate of
bioabsorption of a device 80 comprising only filaments 84
comprising PLA. In some embodiments, the coupling of the filaments
84 may also comprise a bioabsorbable polymer. For example, the
filaments 84 may be coupled at the proximal end 82 of the device 80
by intertwining the bioabsorbable filaments 84 or the filaments 84
may be coupled at the proximal end 82 of the device 80 using a
separate bioabsorbable component.
[0049] The device 80 comprises a plurality of perforations or cells
86 between the filaments 84. In certain embodiments, a percentage
of the outer surface of the device 80 covered by the filaments 84
is between about 25% and about 40%. In certain embodiments, a
percentage of the outer surface of the device 80 covered by the
cells 86 is between about 60% and about 75%. Other porosities are
also possible. In some embodiments, porosity distally increases
between the second end 82 and an approximate midpoint (e.g.,
approximately at the line A-A in FIG. 8) and distally decreases
between the approximate midpoint and the first end 81. For example,
cross-sections taken along the lines A-A and B-B in FIG. 8 each
have the same number of filaments 84, but at the cross-section A-A
the filaments 84 are spaced further apart from each other than at
the cross-section B-B. As an example, if the device comprises ten
filaments 84 each having a thickness of 0.5 mm, the porosity at the
cross-section A-A would be about 80% with an example circumference
of about 25 mm:
100%.times.[1-(.apprxeq.0.5 mm/filament.times.10
filaments/.apprxeq.25 mm)]80%
and the porosity at the cross-section B-B would be about 33% with
an example circumference of about 7.5 mm:
100%.times.[1-(4.5 mm/filament.times.10 filaments/.apprxeq.7.5
mm)]33%.
High porosity proximate to a midpoint of the device 80 may provide
good fluid flow to efferent vessels. Low porosity proximate to the
first end 81 of the device 80 may provide good scaffolding
properties.
[0050] In some embodiments, the device 80 further comprises a
radiopaque marker 88 proximate to the first end 81 and/or a
radiopaque marker 89 proximate to the second end 82. In certain
embodiments, the radiopaque marker 88 may extend at least partially
into the aneurysm 20 when the device 80 is positioned at the
junction of a bifurcation. In some embodiments, the radiopaque
markers 88, 89 may comprise a sleeve positioned or wrapped around
the filaments 84, thereby coupling the filaments 84. The radiopaque
markers 88, 89 may aid in positioning the device 80 at the junction
of a bifurcation.
[0051] In some embodiments, the device 80 further comprises a
covering (e.g., comprising a porous or non-porous polymer)
proximate to the first end 81. In some embodiments, the covering
improves the scaffolding properties of the device 80 by reducing
the porosity at the first end 81, thereby further inhibiting the
herniation or prolapse of embolic material from the aneurysm 20. In
certain embodiments, the covering may be attached to the device 80
by sewing the covering from a pre-formed thin film. In certain
embodiments, the covering may be mechanically attached (e.g.,
wrapped around, looped through, etc.) the filaments 84. In certain
embodiments, the covering may be deposited (e.g., via physical
vapor deposition, chemical vapor deposition, etc.) on the filaments
84. Other portions of the device 80 may also comprise a
covering.
[0052] FIGS. 9A-9C illustrate an example embodiment of a method for
treating an aneurysm 20 using the device 80. FIG. 9A illustrates a
confluence of afferent and efferent vessels or "junction" at a
bifurcation 60 having an aneurysm 20. In some embodiments, the
vessels are neurovascular or cranial. The aneurysm 20 is
illustrated with a plurality of embolization coils 62 having been
inserted in the fundus 22 of the aneurysm 20. It will be
appreciated that the embolization coils 62 may be a single
embolization coil or other embolic material. A catheter 92 (e.g., a
microcatheter), at least partially containing a constricted or
compressed device 80, is also shown in the afferent vessel. The
catheter 92 is small enough and flexible enough to be routed
through the vasculature and situated proximate to the aneurysm 20.
In some embodiments, the embolization coils 62 are inserted in the
fundus 22 of the aneurysm 20 using the catheter 92. In some
embodiments, the embolization coils 62 are inserted in the fundus
22 of the aneurysm 20 using a different catheter. In certain such
embodiments, a guidewire may be used to guide both catheters.
[0053] FIG. 9B illustrates the bifurcation 60 after the device 80
has been deployed from the catheter 92 (e.g., by being pushed out
with a plunger, by retracting the catheter 92 while the device 80
remains stationary, etc.). After being deployed from the catheter
92, the device 80 may expand. In some embodiments, the device 80
comprises a self-expanding and/or a shape-memory material that
automatically expands towards an uncompressed state or expands
towards an uncompressed state upon the application of warm fluid
(e.g., saline). The device 80 may substantially conform to the
shape of the junction of the bifurcation 60 (e.g., not
substantially including portions extending into the afferent and
efferent vessels) and locks into place across the ostia of the
afferent and efferent vessels and the neck 24 of the aneurysm 20.
The device 80 at least partially covers the neck 24 of the aneurysm
20 as well as the afferent and efferent vessels, but does not need
to divert flow. The device 80 acts as a scaffolding to inhibit or
prevent herniation or prolapse of objects such as the embolization
coils 62 and/or thrombi out of the aneurysm 24. The device 80 also
allows perfusion of fluid (e.g., blood) from the afferent vessel(s)
to the efferent vessel(s).
[0054] FIG. 9C illustrates the bifurcation 60 after the device 80
has been released from the catheter 92. In some embodiments, the
device 80 is released mechanically (e.g., by a release mechanism).
In some embodiments, the device 80 is released electrolytically
(e.g., by applying a small current until a portion of the tail 83
proximal to the device 80 corrodes away, as illustrated by the gap
95). The catheter 92 is then withdrawn from the bifurcation 60,
thereby leaving or permanently positioning the device 80 at the
junction of the bifurcation 60.
[0055] It will be appreciated that the term "permanently" does not
mean that the device 80 is impossible to remove at a later time. In
some embodiments, the device 80 may be retracted into the catheter
92 after being deployed from the catheter 92 (e.g., by pulling on
the tail 83). The device 80 may then be deployed, for example at a
new angle, at a new rotational position, more proximal or distal to
an afferent vessel and/or an efferent vessel, etc. For example,
although the device 80 expands towards an uncompressed state after
deployment, the resulting shape of the device 80 at the junction of
the bifurcation 60 may vary depending on the details of the
deployment from the catheter 92 because the device 80 adapts to the
shape of the anatomy (e.g., due to the size, shape, number, etc. of
the loops 82). Once the user is satisfied with properties of the
device 80 (e.g., position, tilt, rotation, shape, interaction with
the vessels, etc.), the device 80 may be released as described
herein.
[0056] In the embodiment illustrated in FIGS. 9A-9C, the
embolization coils 62 are inserted in the fundus 22 of the aneurysm
20 before the device 80 has been deployed from the catheter 92
(e.g., using the catheter 92 to insert the embolization coils 62).
In the embodiments illustrated in FIGS. 10A-10C, the embolization
coils 62 are inserted in the fundus 22 of the aneurysm 20 after the
device 80 has been released from the catheter 92 (e.g., using the
catheter 92 to insert the embolization coils 62). Combinations are
also possible. For example, the embolization coils 62 may be
inserted in the fundus 22 of the aneurysm 20 after the device 80
has been deployed from the catheter 92, but prior to the device 80
being released from the catheter 92. For another example, the
embolization coils 62 may be inserted into the fundus 22 of the
aneurysm 20 after the device 80 has been deployed from the catheter
92 (e.g., in a coil state), and the device 80 may be retracted and
redeployed from the catheter 92 (e.g., in a final state).
[0057] In certain embodiments, the filaments 84 comprise a
bioabsorbable polymer. This bioabsorbability can be advantageous in
conjunction with permanent placement of the device 80. For example,
after thrombosis of the aneurysm following treatment, the device 80
may no longer be needed to inhibit herniation of material. Certain
bioabsorbable embodiments of the device 80 may advantageously
inhibit herniation during thrombosis of the aneurysm, but bioabsorb
when they may no longer be needed to inhibit herniation. In certain
embodiments in which the coupling of the proximal end 82 of the
device 80 comprises a bioabsorbable polymer, the coupling may
absorb over time, releasing the filaments 84. Once released, the
filaments 84 may extend towards and may flatten against the wall of
the afferent vessel. This capability may advantageously clear the
interior section of the afferent vessel, restoring normal blood
flow therein (e.g., in embodiments in which the coupled proximal
end may have altered blood flow). In some embodiments, this
capability may clear the interior section of the afferent vessel
before bioabsorption of the filament 84 is complete. In certain
such embodiments, the coupling may comprise a material that
bioabsorbs faster than the filaments (e.g., the coupling comprising
PGA and the filaments comprising PLA). This can make permanent
placement, or release of the device 80, a less consequential
procedure as a device 80 comprising bioabsorbable filaments 84 will
not remain in the vasculature permanently.
[0058] FIG. 11 illustrates yet another example embodiment of a
generally spherical vascular remodeling device 110. It will be
appreciated that the device 110 may be more compliant than the
vasculature in which it is deployed such that it may be somewhat
misshapen (e.g., non-spherical, for example as illustrated in FIG.
12) after being deployed, and that the phrase "generally spherical"
describes the shape of the device 110 when in an expanded (e.g.,
fully expanded) state. Additionally, the phrase "generally
spherical" distinguishes the device 110, which is generally uniform
in each dimension in an expanded state, from tubular stents having
a small radial dimension and a large longitudinal dimension in an
expanded state. In some embodiments of a generally spherical
device, an outer periphery of the device has a shape that deviates
by between about 10% and about 25% from an outer periphery of a
mathematically perfect sphere. In some embodiments, the device 110
has a length and a width that are within less than about 33% of
each other (e.g., having a length of 6 mm and a width of 8 mm,
having a length of 6 mm and a width of 8 mm). Embodiments in which
the width is greater than the length may be advantageous due to a
difference in porosity at a midpoint and an end proximate to an
aneurysm. Embodiments in which the length is greater than the width
may be advantageous for positioning a portion of the device 110 in
a portion of the aneurysm 20 (e.g., to aid in embolization).
[0059] The device 110 comprises a first or distal end 111 and a
second or proximal end 112 substantially opposite the first end
111. The device 110 further comprises a plurality of filaments 114
extending between the first end 111 and the second end 112. In the
device 110 illustrated in FIG. 11, the first end 111 extends
inwardly and the second end 112 extends outwardly to form a
generally spherical shape similar to a pumpkin, a garlic bulb, or a
rutabaga. In some embodiments, the filaments 114 are coupled at a
position proximal to a bend at a distal end of the device 110
(e.g., as illustrated by the dimension d in FIG. 11). In certain
embodiments, the filaments 114 are coupled at the first end 111
and/or the second end 112 (e.g., by adhering, welding, soldering,
combinations thereof, and the like). In the embodiment illustrated
in FIG. 11, the device 110 comprises a lead or tail 113, which may
be used for releasing and/or retracting the device 110 after
deployment, as described herein. In certain embodiments, the device
110 comprises a cut metallic sphere, a single filament, etc. It
will be appreciated that a device in which the first end extends
outwardly and the second end extends inwardly and a device in which
the first end extends inwardly and the second end extends inwardly
are also possible.
[0060] In certain embodiments, the device 110 is configured to be
positioned at a junction of a bifurcation (e.g., a neurovascular
bifurcation) comprising at least one afferent vessel, efferent
vessels, and an aneurysm having a fundus and a neck. For example,
in some embodiments, the device 110 is suitably dimensioned to fit
in a junction of a bifurcation (e.g., having a diameter between
about 2 mm and about 12 mm, having a diameter between about 6 mm
and about 8 mm, having a diameter less than about 12 mm, having a
diameter greater than about 2 mm). For another example, in some
embodiments, the device 110 is less rigid than a junction of a
bifurcation (e.g., due to the number of filaments 114, the material
of the filaments 114, the thickness of the filaments 114, the
spacing of the filaments 114, the shape of the filaments 114,
combinations thereof, and the like). In certain embodiments, the
device 110 is configured to act as a scaffolding to inhibit or
prevent herniation or prolapse of objects (e.g., embolization
coils, thrombi, etc.) out of a neck of an aneurysm. For example, in
some embodiments, the filaments 114 are dense enough at the neck of
the aneurysm that objects cannot pass. In certain embodiments, the
device 110 is configured to permit perfusion of fluid (e.g., blood)
to efferent vessels of a bifurcation. For example, in some
embodiments, the device 110 is substantially devoid of a covering,
mesh, or other material between the filaments 114, thereby allowing
fluid to flow substantially unimpeded.
[0061] In some embodiments, at least one of the filaments 114
comprises a self-expanding and/or a shape-memory material (e.g.,
comprising Nitinol, CoCr alloy, etc.), thereby causing the device
110 to be self-expanding under certain conditions (e.g., not
restrained by a catheter). In some embodiments, at least one of the
filaments 114 comprises a different material than others of the
filaments 114 (e.g., some filaments 114 comprising Nitinol and some
filaments 114 comprising Nitinol and platinum). In some
embodiments, at least one of the filaments 114 comprises a
radiopaque material (e.g., platinum). In certain such embodiments,
an even number of filaments 84 (e.g., two, four, etc.) comprises a
radiopaque material (e.g., platinum). In some embodiments, at least
one of the filaments 84 comprises a radiopaque material (e.g.,
platinum) at least partially wrapped (e.g., coiled) around a
self-expanding material (e.g., Nitinol). In some embodiments, at
least one of the filaments 84 comprises a self-expanding material
with a radiopaque core (e.g., Nitinol with a platinum core) or a
radiopaque coating (e.g., Nitinol coated with platinum, tantalum,
etc. by physical vapor deposition, chemical vapor deposition,
plating, etc.). It will be appreciated that the amount and type of
radiopaque material used may depend, inter alia, on price, desired
level of radiopacity, mechanical properties of the radiopaque
material, and corrosion properties of the radiopaque material. In
certain embodiments, the filaments 114 have a substantially
circular or ovoid cross section (e.g., embodiments, in which the
filaments 84 comprise separate wires). In some embodiments, the
filaments 114 have a substantially rectangular or flat cross
section (e.g., embodiments, in which the filaments 84 comprise
uncut portions of a metallic tube). Other shapes of filaments 114
and combinations of shapes of filaments 114 are also possible. In
certain embodiments, the plurality of filaments 84 comprises
between about six and about twelve filaments 114. In certain
embodiments, the plurality of filaments 114 comprises at least
about six filaments 114, at least about eight filaments 114, or at
least about twelve filaments 114. Other numbers of filaments 114
are also possible.
[0062] In certain embodiments, at least some of the filaments 114
comprise a polymer. In some embodiments, at least some of the
filaments 114 comprise a polymer that is bioabsorbable. In certain
embodiments, at least some of the filaments 114 comprise
polyglycolic acid (PGA), polylactic acid (PLA),
poly(lactic-co-glycolic acid) (PLGA), poly-epsilon-caprolactone
(PCL), naturally-derived bioabsorbable polymers (NDB), or
combinations thereof (e.g., a first group of the filaments 114
comprising PGA and a second group of the filaments 114 comprising
PLA, PLGA, PCL, and/or NDB, a first group of the filaments 114
comprising PLA and a second group of the filaments 114 comprising
PGA, PLGA, PCL, and/or NDB, a first group of the filaments 114
comprising PLGA and a second group of the filaments 114 comprising
PLA, PGA, PCL, and/or NDB, a first group of the filaments 114
comprising PCL and a second group of the filaments 114 comprising
PGA, PLA, PLGA, and/or NDB, a first group of the filaments 114
comprising NDB and a second group of the filaments 114 comprising
PGA, PLA, PLGA, and/or PCL, etc.). Other polymers are also
possible. PGA, PLA, PLGA, PCL, and NDB are all bioabsorbable;
however they have different rates of bioabsorption. The
bioabsorption rates of a single polymer can also vary based on, for
example, blood characteristics, blood flow, filament 114
dimensions, etc. PLA has the longest bioabsorption rate. In some
embodiments, the bioabsorption rate of PLA is at least about ten
months. In some embodiments, the bioabsorption rate of PLA is at
least about one year. In some embodiments, the bioabsorption rate
of PLA is at least about fourteen months. In some embodiments, the
bioabsorption rate of PLA is between about 10 months and about 14
months (e.g., about one year). In some embodiments, the
bioabsorption rate of PGA is between about 1 week and about 3
weeks. In some embodiments, the bioabsorption rate of PGA is
between about 2 weeks and about 4 weeks. The bioabsorption rates of
PLGA, PCL, and NDB are generally between the bioabsorption rates of
PLA and PGA, and may depend on parameters such as, for example,
molecular weight (e.g., generally the higher the molecular weight,
the longer the bioabsorption rate), structure (e.g., depending on
the arrangement of repeating units), etc. of the polymer. In some
embodiments, PLGA, PCL, and NDB may have a bioabsorption rate
between about 4 weeks and about 1 year. The bioabsorption rate
generally refers to the time lose about 50% of strength. The
polymer(s) used in the device 110 may be selected based on the
amount of time an aneurysm may take to thrombose (e.g., based on
fundus size, neck width, etc.). For example, if an aneurysm is
expected to take one month to thrombose and the device 110 is
expected to persist through thrombosis but not long thereafter, PGA
may be selected. The polymer(s) used in the device 110 may be
selected based on the amount of time an aneurysm may take to
obliterate (e.g., based on fundus size, neck width, etc.). For
example, if an aneurysm is expected to take one year to obliterate
and the device 110 is expected to persist through obliteration, PLA
may be selected. Other polymers or combinations of polymers can be
selected based on the particular aneurysm to be treated and the
desired action and/or persistence of the device 110 with respect to
the aneurysm. Other selection criteria are also possible. Different
combinations of polymers with different rates of bioabsorption can
allow for selection of a desired rate of bioabsorption for the
device 110. For example, a device 110 with a combination of PGA and
PLA filaments 114 may have a rate of bioabsorption in between the
rate of bioabsorption of a device 110 comprising only filaments 114
comprising PGA and the rate of bioabsorption of a device 110
comprising only filaments 114 comprising PLA. In some embodiments,
the coupling of the filaments 114 may also comprise a bioabsorbable
polymer. For example, the filaments 114 may be coupled at the
proximal end 112 of the device 110 by intertwining the
bioabsorbable filaments 114 or the filaments 114 may be coupled at
the proximal end 112 of the device 110 using a separate
bioabsorbable component.
[0063] As described herein, certain embodiments comprising
bioabsorbable filaments (e.g., the filaments 114) can be
advantageous in conjunction with permanent placement of the device
(e.g., the device 110). In certain embodiments in which the
coupling of the proximal end 112 of the device 110 comprises a
bioabsorbable polymer, the coupling may absorb over time, releasing
the filaments 114. Once released, the filaments 114 may extend
towards and may flatten against the wall of the afferent vessel.
This capability may advantageously clear the interior section of
the afferent vessel, restoring normal blood flow therein (e.g., in
embodiments in which the coupled proximal end may have altered
blood flow). In some embodiments, this capability may clear the
interior section of the afferent vessel before bioabsorption of the
filament 114 is complete. In certain such embodiments, the coupling
may comprise a material that bioabsorbs faster than the filaments
(e.g., the coupling comprising PGA and the filaments comprising
PLA).
[0064] The device 110 comprises a plurality of perforations or
cells 116 between the filaments 114. In certain embodiments, a
percentage of the outer surface of the device 110 covered by the
filaments 114 is between about 25% and about 40%. In certain
embodiments, a percentage of the outer surface of the device 110
covered by the cells 116 is between about 60% and about 75%. Other
porosities are also possible. In some embodiments, porosity
distally increases between the second end 112 and an approximate
midpoint and distally decreases between the approximate midpoint
and the first end 111.
[0065] In some embodiments, the device 110 further comprises a
radiopaque marker 118 proximate to the first end 111 and/or a
radiopaque marker 119 proximate to the second end 112. In certain
embodiments, the radiopaque marker 118 may extend at least
partially into the aneurysm 20 when the device 110 is positioned at
the junction of a bifurcation. In some embodiments, the radiopaque
markers 118, 119 may comprise a sleeve situated or wrapped around
the filaments 114, thereby coupling the filaments 114. The
radiopaque markers 118, 119 may aid in positioning the device 110
at the junction of a bifurcation.
[0066] In some embodiments, the device 110 further comprises a
covering (e.g., comprising a porous or non-porous polymer)
proximate to the first end 111. In some embodiments, the covering
improves the scaffolding properties of the device 110 by reducing
the porosity at the first end 111, thereby further inhibiting the
herniation or prolapse of embolic material from the aneurysm 20. In
certain embodiments, the covering may be attached to the device 110
by sewing the covering from a pre-formed thin film. In certain
embodiments, the covering may be mechanically attached (e.g.,
wrapped around, looped through, etc.) the filaments 114. In certain
embodiments, the covering may be deposited (e.g., via physical
vapor deposition, chemical vapor deposition, etc.) on the filaments
114. Other portions of the device 110 may also comprise a
covering.
[0067] FIG. 12 illustrates an example embodiment of treating an
aneurysm 20 using the device 110. The junction at the bifurcation
60, including the treated aneurysm 20, illustrated in FIG. 12 may
be the result of performing a method similar to the method
described with respect to FIGS. 9A-9C, the result of performing a
method similar to the method described with respect to FIGS.
10A-10C, combinations thereof, and the like.
[0068] As described above, the term "bifurcation" described herein
is not limited to the particular vasculature illustrated in FIGS.
6A-7C, 9A-10C, and 12, for example having efferent vessels at
substantially different angles, having efferent vessels that are
substantially different sizes, and/or having a different quantity
of efferent vessels and/or the aneurysm of the bifurcation may be
offset with respect to the junction (e.g., having a neck
substantially open to one efferent vessel), tilted with respect to
a plane created by the vessels (e.g., into or out of the page),
etc.
[0069] FIG. 13 illustrates still another example embodiment of a
generally spherical vascular remodeling device 130. It will be
appreciated that the device 130 may be more compliant than the
vasculature in which it is deployed such that it may be somewhat
misshapen (e.g., non-spherical) after being deployed, and that the
phrase "generally spherical" describes the shape of the device 130
when in an expanded (e.g., fully expanded) state. Additionally, the
phrase "generally spherical" distinguishes the device 130, which is
generally uniform in each dimension in an expanded state, from
tubular stents having a small radial dimension and a large
longitudinal dimension in an expanded state. In some embodiments of
a generally spherical device, an outer periphery of the device has
a shape that deviates by between about 10% and about 25% from an
outer periphery of a mathematically perfect sphere. In some
embodiments, the device 130 has a length and a width that are
within less than about 33% of each other (e.g., having a length of
6 mm and a width of 8 mm, having a length of 6 mm and a width of 8
mm). Embodiments in which the width is greater than the length may
be advantageous due to a difference in porosity at a midpoint and
an end proximate to an aneurysm. Embodiments in which the length is
greater than the width may be advantageous for positioning a
portion of the device 130 in a portion of the aneurysm 20 (e.g., to
aid in embolization).
[0070] The device 130 comprises a first or distal end 131 and a
second or proximal end 132 substantially opposite the first end
131. The device 130 further comprises a plurality of filaments 134
extending between the first end 131 and the second end 132. In the
device 130 illustrated in FIG. 13, the first end 131 extends
outwardly and the second end 132 extends outwardly to form a
generally spherical shape similar to a twisted sphere (e.g., after
rotating one or both ends 81, 82 of the device 80 illustrated in
FIG. 8 with respect to each other). In certain embodiments, the
filaments 134 are coupled at the first end 131 and/or the second
end 132 (e.g., by adhering, welding, soldering, combinations
thereof, and the like). In contrast to the filaments 84 of the
device 80 illustrated in FIG. 8, which in some embodiments are
straight enough to form a plane, the filaments 134 of the device
130 are longitudinally angled at or adjacent to at least the second
end 132. In the embodiment illustrated in FIG. 13, the device 130
comprises a lead or tail 133, which may be used for releasing
and/or retracting the device 130 after deployment, as described
herein. In some embodiments, deployment and/or retraction of the
device 130 uses less force than retraction of, for example, the
devices 50, 80, 110. In certain embodiments, the device 130
comprises a cut metallic sphere, a single filament, etc.
[0071] In certain embodiments, the device 130 is configured to be
positioned at a junction of a bifurcation (e.g., a neurovascular
bifurcation) comprising at least one afferent vessel, efferent
vessels, and an aneurysm having a fundus and a neck. For example,
in some embodiments, the device 130 is suitably dimensioned to fit
in a junction of a bifurcation (e.g., having a diameter between
about 2 mm and about 12 mm, having a diameter between about 6 mm
and about 8 mm, having a diameter less than about 12 mm, having a
diameter greater than about 2 mm). For another example, in some
embodiments, the device 130 is less rigid than a junction of a
bifurcation (e.g., due to the number of filaments 134, the material
of the filaments 134, the thickness of the filaments 134, the
spacing of the filaments 134, the shape of the filaments 134,
combinations thereof, and the like). In certain embodiments, the
device 130 is configured to act as a scaffolding to inhibit or
prevent herniation or prolapse of objects (e.g., embolization
coils, thrombi, etc.) out of a neck of an aneurysm. For example, in
some embodiments, the filaments 134 are dense enough at the neck of
the aneurysm that objects cannot pass. In certain embodiments, the
device 130 is configured to permit perfusion of fluid (e.g., blood)
to efferent vessels of a bifurcation. For example, in some
embodiments, the device 130 is substantially devoid of a covering,
mesh, or other material between the filaments 134, thereby allowing
fluid to flow substantially unimpeded.
[0072] In some embodiments, at least one of the filaments 134
comprises a self-expanding and/or a shape-memory material (e.g.,
comprising Nitinol, CoCr alloy, etc.), thereby causing the device
130 to be self-expanding under certain conditions (e.g., not
restrained by a catheter). In some embodiments, at least one of the
filaments 134 comprises a different material than others of the
filaments 134 (e.g., some filaments 134 comprising Nitinol and some
filaments 134 comprising Nitinol and platinum). In some
embodiments, at least one of the filaments 134 comprises a
radiopaque material (e.g., platinum). In certain such embodiments,
an even number of filaments 84 (e.g., two, four, etc.) comprises a
radiopaque material (e.g., platinum). In some embodiments, at least
one of the filaments 84 comprises a radiopaque material (e.g.,
platinum) at least partially wrapped (e.g., coiled) around a
self-expanding material (e.g., Nitinol). In some embodiments, at
least one of the filaments 84 comprises a self-expanding material
with a radiopaque core (e.g., Nitinol with a platinum core) or a
radiopaque coating (e.g., Nitinol coated with platinum, tantalum,
etc. by physical vapor deposition, chemical vapor deposition,
plating, etc.). It will be appreciated that the amount and type of
radiopaque material used may depend, inter alia, on price, desired
level of radiopacity, mechanical properties of the radiopaque
material, and corrosion properties of the radiopaque material. In
certain embodiments, the filaments 134 have a substantially
circular or ovoid cross section (e.g., embodiments, in which the
filaments 84 comprise separate wires). In some embodiments, the
filaments 134 have a substantially rectangular or flat cross
section (e.g., embodiments, in which the filaments 84 comprise
uncut portions of a metallic tube). Other shapes of filaments 134
and combinations of shapes of filaments 134 are also possible. In
certain embodiments, the plurality of filaments 84 comprises
between about six and about twelve filaments 134. In certain
embodiments, the plurality of filaments 134 comprises at least
about six filaments 134, at least about eight filaments 134, or at
least about twelve filaments 134. Other numbers of filaments 134
are also possible.
[0073] In certain embodiments, at least some of the filaments 134
comprise a polymer. In some embodiments, at least some of the
filaments 134 comprise a polymer that is bioabsorbable. In certain
embodiments, at least some of the filaments 134 comprise
polyglycolic acid (PGA), polylactic acid (PLA),
poly(lactic-co-glycolic acid) (PLGA), poly-epsilon-caprolactone
(PCL), naturally-derived bioabsorbable polymers (NDB), or
combinations thereof (e.g., a first group of the filaments 134
comprising PGA and a second group of the filaments 134 comprising
PLA, PLGA, PCL, and/or NDB, a first group of the filaments 134
comprising PLA and a second group of the filaments 134 comprising
PGA, PLGA, PCL, and/or NDB, a first group of the filaments 134
comprising PLGA and a second group of the filaments 134 comprising
PLA, PGA, PCL, and/or NDB, a first group of the filaments 134
comprising PCL and a second group of the filaments 134 comprising
PGA, PLA, PLGA, and/or NDB, a first group of the filaments 134
comprising NDB and a second group of the filaments 134 comprising
PGA, PLA, PLGA, and/or PCL, etc.). Other polymers are also
possible. PGA, PLA, PLGA, PCL, and NDB are all bioabsorbable;
however they have different rates of bioabsorption. The
bioabsorption rates of a single polymer can also vary based on, for
example, blood characteristics, blood flow, filament 134
dimensions, etc. PLA has the longest bioabsorption rate. In some
embodiments, the bioabsorption rate of PLA is at least about ten
months. In some embodiments, the bioabsorption rate of PLA is at
least about one year. In some embodiments, the bioabsorption rate
of PLA is at least about fourteen months. In some embodiments, the
bioabsorption rate of PLA is between about 10 months and about 14
months (e.g., about one year). In some embodiments, the
bioabsorption rate of PGA is between about 1 week and about 3
weeks. In some embodiments, the bioabsorption rate of PGA is
between about 2 weeks and about 4 weeks. The bioabsorption rates of
PLGA, PCL, and NDB are generally between the bioabsorption rates of
PLA and PGA, and may depend on parameters such as, for example,
molecular weight (e.g., generally the higher the molecular weight,
the longer the bioabsorption rate), structure (e.g., depending on
the arrangement of repeating units), etc. of the polymer. In some
embodiments, PLGA, PCL, and NDB may have a bioabsorption rate
between about 4 weeks and about 1 year. The bioabsorption rate
generally refers to the time lose about 50% of strength. The
polymer(s) used in the device 130 may be selected based on the
amount of time an aneurysm may take to thrombose (e.g., based on
fundus size, neck width, etc.). For example, if an aneurysm is
expected to take one month to thrombose and the device 130 is
expected to persist through thrombosis but not long thereafter, PGA
may be selected. The polymer(s) used in the device 130 may be
selected based on the amount of time an aneurysm may take to
obliterate (e.g., based on fundus size, neck width, etc.). For
example, if an aneurysm is expected to take one year to obliterate
and the device 130 is expected to persist through obliteration, PLA
may be selected. Other polymers or combinations of polymers can be
selected based on the particular aneurysm to be treated and the
desired action and/or persistence of the device 130 with respect to
the aneurysm. Other selection criteria are also possible. Different
combinations of polymers with different rates of bioabsorption can
allow for selection of a desired rate of bioabsorption for the
device 130. For example, a device 130 with a combination of PGA and
PLA filaments 134 may have a rate of bioabsorption in between the
rate of bioabsorption of a device 130 comprising only filaments 134
comprising PGA and the rate of bioabsorption of a device 130
comprising only filaments 134 comprising PLA. In some embodiments,
the coupling of the filaments 134 may also comprise a bioabsorbable
polymer. For example, the filaments 134 may be coupled at the
proximal end 132 of the device 130 by intertwining the
bioabsorbable filaments 134 or the filaments 134 may be coupled at
the proximal end 132 of the device 130 using a separate
bioabsorbable component.
[0074] As described herein, certain embodiments comprising
bioabsorbable filaments (e.g., the filaments 134) can be
advantageous in conjunction with permanent placement of the device
(e.g., the device 130). In certain embodiments in which the
coupling of the proximal end 132 of the device 130 comprises a
bioabsorbable polymer, the coupling may absorb over time, releasing
the filaments 134. Once released, the filaments 134 may extend
towards and may flatten against the wall of the afferent vessel.
This capability may advantageously clear the interior section of
the afferent vessel, restoring normal blood flow therein (e.g., in
embodiments in which the coupled proximal end may have altered
blood flow). In some embodiments, this capability may clear the
interior section of the afferent vessel before bioabsorption of the
filament 134 is complete. In certain such embodiments, the coupling
may comprise a material that bioabsorbs faster than the filaments
(e.g., the coupling comprising PGA and the filaments comprising
PLA).
[0075] The device 130 comprises a plurality of perforations or
cells 136 between the filaments 134. In certain embodiments, a
percentage of the outer surface of the device 130 covered by the
filaments 134 is between about 25% and about 40%. In certain
embodiments, a percentage of the outer surface of the device 130
covered by the cells 136 is between about 60% and about 75%. Other
porosities are also possible. In some embodiments, porosity
distally increases between the second end 132 and an approximate
midpoint and distally decreases between the approximate midpoint
and the first end 131.
[0076] In some embodiments, the device 130 further comprises a
radiopaque marker 138 proximate to the first end 131 and/or a
radiopaque marker 139 proximate to the second end 132. In certain
embodiments, the radiopaque marker 138 may extend at least
partially into the aneurysm 20 when the device 130 is positioned at
the junction of a bifurcation. In some embodiments, the radiopaque
markers 138, 139 may comprise a sleeve situated or wrapped around
the filaments 134, thereby coupling the filaments 134. The
radiopaque markers 138, 139 may aid in positioning the device 130
at the junction of a bifurcation.
[0077] In some embodiments, the device 130 further comprises a
covering (e.g., comprising a porous or non-porous polymer)
proximate to the first end 131. In some embodiments, the covering
improves the scaffolding properties of the device 130 by reducing
the porosity at the first end 131, thereby further inhibiting the
herniation or prolapse of embolic material from the aneurysm 20. In
certain embodiments, the covering may be attached to the device 130
by sewing the covering from a pre-formed thin film. In certain
embodiments, the covering may be mechanically attached (e.g.,
wrapped around, looped through, etc.) the filaments 134. In certain
embodiments, the covering may be deposited (e.g., via physical
vapor deposition, chemical vapor deposition, etc.) on the filaments
134. Other portions of the device 130 may also comprise a
covering.
[0078] The device 130 may be positioned and retracted as described,
for example, by performing a method similar to the method described
with respect to FIGS. 9A-9C, by performing a method similar to the
method described with respect to FIGS. 10A-10C, combinations
thereof, and the like. As described above, the device 130 may be
particularly advantageous for embodiments in which retraction and
redeployment of the device 130 is likely.
[0079] FIG. 14 illustrates an example embodiment of a generally
spherical vascular remodeling device 140 (e.g., having a football
shape similar to the device 80) at a stage of an example
manufacturing process comprising cutting and shaping a metallic
tube (e.g., a laser cut hypotube). In some embodiments, the
starting tube has a diameter between about 0.5 mm and about 3 mm or
between about 1 mm and about 2 mm (e.g., about 1 mm, about 1.5 mm,
about 2 mm, etc.). Other diameters are also possible. The device
has a first or distal end 141 and a second or proximal end 142
substantially opposite the first end 141. A laser may cut out
portions 146 of the tube, leaving a plurality of filaments 144
extending between the first end 141 and the second end 142. In the
embodiment illustrated in FIG. 14, the filaments 144 are coupled at
the first end 141 and the second end 142 (e.g., due to being
integrally formed with the metallic tube and not cut away from each
other). In some embodiments, a lead or tail, which may be used for
releasing and/or retracting the device 140 after deployment, as
described herein, may be attached to the device 140 (e.g., by
adhering, soldering, welding, etc.). In certain embodiments, a tail
143 may be integral with the device 140 by being defined by the cut
tube.
[0080] In some embodiments, the device 140 further comprises a
radiopaque marker 148 proximate to the first end 141 and/or a
radiopaque marker 149 proximate to the second end 142. In certain
embodiments, the radiopaque marker 148 may extend at least
partially into the aneurysm 20 when the device 140 is positioned at
the junction of a bifurcation. In some embodiments, the radiopaque
markers 148, 149 may be integral with the device by being defined
by the cut tube. The radiopaque markers 148, 149 may aid in
positioning the device 140 at the junction of a bifurcation.
[0081] The cut tube can then be expanded into a generally spherical
shape through shape setting using a heat treatment process. The
shape setting process may include several steps comprising of
successively increasing diameters of generally spherical shapes
using appropriate tooling to stretch and confine the cut tube into
a new shape while heat treating it. At the end of the each heat
treatment step, the cut tube assumes the shape in which it was
confined during the heat treatment process. This process is then
repeated to form a slightly larger size and a shape closer to the
end product. The final shape (e.g., a football shape similar to the
device 80) and size may obtained by several such steps. Other
devices described herein (e.g., the devices 50, 110, 130) may also
be formed using cut a metallic tube that is reshaped after being
cut, although it will be appreciated that the pattern of the
initial cut may be different, such that details about possible
materials, dimensions, porosities, deployment methods, possibly
coverings, etc. are not provided.
[0082] The disclosures of U.S. Provisional Patent App. No.
61/082,579, filed Jul. 22, 2008, and U.S. patent application Ser.
No. 12/506,945, filed Jul. 21, 2009, may be relevant to certain of
the generally spherical vascular remodeling devices described
herein, and the disclosure each of those applications is
incorporated herein by reference in its entirety.
[0083] Certain devices described herein may be advantageously used
to treat aneurysms having a neck ratio (a ratio of fundus width to
neck width) greater than about 2 to 1 and/or a neck width greater
than about 4 mm. In treatment of such aneurysms, embolization coils
may be prone to herniating into parent vessels because the size
and/or shape of the aneurysm is not conducive to maintaining the
coils in their inserted locus. In certain such embodiments,
embolization coils are inserted in the fundus of the aneurysm after
positioning a generally spherical device so that the embolization
coils do not have an opportunity to herniate. It will be
appreciated that certain devices described herein may also be used
to treat aneurysms having a neck ratio less than about 2 to 1
and/or a neck width less than about 4 mm. In certain such
embodiments, embolization coils are inserted in the fundus of the
aneurysm before positioning a generally spherical device.
[0084] Certain devices described herein may advantageously be a
single generally spherical device placed at a junction of a
bifurcation rather than a plurality of tubular bifurcations.
Certain such devices can span a neck of an aneurysm as well as
arterial ostia. Positioning such devices may be less complicated,
thereby reducing risks associated with, for example, than ensuring
that a tubular device is properly anchored in an afferent vessel
and in an efferent vessel.
[0085] In some embodiments in which embolic material was previously
inserted in an aneurysm but has herniated, certain devices
described herein may be used as a "rescue device" to push the
herniated material back into the aneurysm and to act as a
scaffolding to inhibit or prevent further herniation or prolapse of
the embolic material. In certain such embodiments, deployment of
such devices may advantageously avoid traversal of the junction
comprising the herniated material by wires or a catheter (e.g.,
there is no need to traverse wires or a catheter past the junction
into an efferent vessel for positioning of the device as is
generally needed to position tubular devices such as the devices
42, 44 illustrated in FIGS. 4B and 4C), which may cause the
herniated material to become tangled and/or dislodged and which may
cause rupture of the aneurysm.
[0086] Although this invention has been disclosed in the context of
certain embodiments and examples, it will be understood by those
skilled in the art that the invention extends beyond the
specifically disclosed embodiments to other alternative embodiments
and/or uses of the invention and obvious modifications and
equivalents thereof. In addition, while several variations of the
embodiments of the invention have been shown and described in
detail, other modifications, which are within the scope of this
invention, will be readily apparent to those of skill in the art
based upon this disclosure. It is also contemplated that various
combinations or sub-combinations of the specific features and
aspects of the embodiments may be made and still fall within the
scope of the invention. It should be understood that various
features and aspects of the disclosed embodiments can be combined
with, or substituted for, one another in order to form varying
modes of the embodiments of the disclosed invention. Thus, it is
intended that the scope of the invention herein disclosed should
not be limited by the particular embodiments described above.
* * * * *