U.S. patent application number 11/031421 was filed with the patent office on 2006-07-13 for intra-aneurysm devices.
Invention is credited to Thach Cao, Hahn Ho, Stephen Christopher Porter, Tri D. Tran.
Application Number | 20060155323 11/031421 |
Document ID | / |
Family ID | 36121387 |
Filed Date | 2006-07-13 |
United States Patent
Application |
20060155323 |
Kind Code |
A1 |
Porter; Stephen Christopher ;
et al. |
July 13, 2006 |
Intra-aneurysm devices
Abstract
Devices for occluding an aneurysm are provided. In particular,
the device include an upper member that sits against the dome of
the aneurysm, a lower member that sits in the neck of the aneurysm,
and a means of adjusting the overall dimensions of the device. Also
provided are methods of making and using these devices.
Inventors: |
Porter; Stephen Christopher;
(Fremont, CA) ; Tran; Tri D.; (Fremont, CA)
; Ho; Hahn; (San Jose, CA) ; Cao; Thach;
(San Jose, CA) |
Correspondence
Address: |
ROBINS & PASTERNAK
1731 EMBARCADERO ROAD
SUITE 230
PALO ALTO
CA
94303
US
|
Family ID: |
36121387 |
Appl. No.: |
11/031421 |
Filed: |
January 7, 2005 |
Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61B 17/12022 20130101;
A61B 17/12113 20130101; A61B 17/12172 20130101; A61B 2017/12063
20130101; A61B 2017/12054 20130101 |
Class at
Publication: |
606/200 |
International
Class: |
A61M 29/00 20060101
A61M029/00 |
Claims
1. A vaso-occlusive device for placement within an aneurysm having
a neck and a dome, the device comprising a lower member having a
linear configuration prior to deployment and a deployed open
configuration, wherein the deployed configuration bridges the neck
of the aneurysm; an upper member having a undeployed, linear
configuration prior and an open, deployed configuration, wherein
the deployed configuration rests against at least a portion of the
dome of the aneurysm, and a means of adjusting the overall
dimensions of the device.
2. The device of claim 1, wherein the distance between the upper
and lower members is adjustable.
3. The device of claim 1, wherein the upper and lower members are
contiguous.
4. The device of claim 1, wherein one or both of the upper member
and lower member are compressible.
5. The device of claim 1, wherein the upper and lower members are
separate, the device further comprising an adjustable central
member having a proximal end connected to the lower member and
distal end connected to the upper member.
6. The device of claim 5, wherein the central member comprises a
compressible element.
7. The device of claim 5, wherein the central member comprises an
extendable member connected to the upper member.
8. The device of claim 5, wherein the central member comprises an
expandable element.
9. The device of claim 1, wherein the upper member comprises a
plurality of axially moveable wires passing through the lumen of
the central member, each wire comprising a distal end and a
proximal end.
10. The device of claim 9, wherein the distal end of one or more of
the wires is attached to the central member.
11. The device of claim 9, wherein the distal end of one or more of
the wires is attached to the lower member.
12. The device of claim 1, wherein the lower and/or upper members
comprise a braid configuration.
13. The device of claim 1, wherein the upper and lower members are
contiguous.
14. The device of claim 1, further comprising one or more
detachment junctions.
15. The device of claim 14, wherein at least one detachment
junction comprises an electrolytically detachable end adapted to
detach by imposition of a current thereon.
16. The device of claim 14, comprising a detachment junction
positioned between the upper member and a pusher wire and one or
more detachment junctions positioned between the lower member and a
pusher tube.
17. The device of claim 1, further comprising one or more locking
mechanisms.
18. The device of claim 17, wherein the locking mechanism comprises
an expandable material.
19. The device of claim 17, wherein the locking mechanism comprises
a self-expanding element.
20. The device of claim 1, wherein the upper member comprises a
metal.
21. The device of claim 20, wherein the metal is selected from the
group consisting of nickel, titanium, platinum, gold, tungsten,
iridium and alloys or combinations thereof.
22. The device of claim 21, wherein the alloy is nitinol.
23. The device of claim 1, wherein the lower member comprises a
metal selected from the group consisting of platinum, palladium,
rhodium, gold, tungsten and alloys thereof.
24. The device of claim 23, wherein the lower member comprises
nitinol.
25. The device of claim 23, wherein the lower member comprises a
mesh or braid structure.
26. The device of claim 1, wherein the lower member comprises a
film.
27. The device of claim 26, wherein the film is selected from the
group consisting of a porous film, a polymer film and a metallic
film.
28. The device of claim 1, further comprising an additional
component.
29. The device of claim 28, wherein the additional component is
bioactive.
30. A method of occluding a body cavity comprising introducing a
vaso-occlusive device according to claim 1 into the body
cavity.
31. The method of claim 29, wherein the body cavity is an aneurysm.
Description
FIELD OF THE INVENTION
[0001] Compositions and methods for repair and treatment of
aneurysms are described. In particular, devices and systems for
placement in an aneurysm are disclosed, as are methods of making
and using these devices.
BACKGROUND
[0002] An aneurysm is a dilation of a blood vessel that poses a
risk to health from the potential for rupture, clotting, or
dissecting. Rupture of an aneurysm in the brain causes stroke, and
rupture of an aneurysm in the abdomen causes shock. Cerebral
aneurysms are usually detected in patients as the result of a
seizure or hemorrhage and can result in significant morbidity or
mortality.
[0003] There are a variety of materials and devices which have been
used for treatment of aneurysms, including platinum and stainless
steel microcoils, polyvinyl alcohol sponges (Ivalone), and other
mechanical devices. For example, vaso-occlusion devices are
surgical implements or implants that are placed within the
vasculature of the human body, typically via a catheter, either to
block the flow of blood through a vessel making up that portion of
the vasculature through the formation of an embolus or to form such
an embolus within an aneurysm stemming from the vessel. One widely
used vaso-occlusive device is a helical wire coil having windings
that may be dimensioned to engage the walls of the vessels. (See,
e.g., U.S. Pat. No. 4,994,069 to Ritchart et al.). Other less stiff
helically coiled devices have been described, as well as those
involving woven braids. See, e.g., U.S. Pat. No. 6,299,627.
[0004] U.S. Pat. No. 5,354,295 and its parent, U.S. Pat. No.
5,122,136, both to Guglielmi et al., describe an electrolytically
detachable embolic device. Vaso-occlusive coils having little or no
inherent secondary shape have also been described. For instance,
co-owned U.S. Pat. Nos. 5,690,666; 5,826,587; and 6,458,119 by
Berenstein et al., describes coils having little or no shape after
introduction into the vascular space. U.S. Pat. No. 5,382,259
describes non-expanding braids covering a primary coil
structure.
[0005] However, there is a risk that known coil designs will
migrate fully or partially out of the aneurysm entrance zone and
into the feeding vessel. This risk is particularly high with wide
neck aneurysms. Generally, wide neck aneurysms are those in which
the neck (the entrance zone) has a diameter that either: (1) is at
least 80% of the largest diameter of the aneurysm; or (2) is
clinically observed to be too wide effectively to retain
vaso-occlusive coils that are deployed using the techniques
discussed above. Accordingly, devices for retaining coils within
aneurysms have been described. See, e.g., U.S. Pat. No. 6,168,622
and U.S. Patent Application Publication No. 20030195553.
[0006] Thus, there remains a need for systems and methods for
occluding an aneurysm neck would be desirable, including systems
that do not rely on coils that may migrate out of aneurysms.
SUMMARY OF THE INVENTION
[0007] Thus, this invention includes novel occlusive devices as
well as methods of using and making these devices.
[0008] In one aspect, the invention includes a vaso-occlusive
device for placement within an aneurysm having a neck and a dome,
the device comprising a lower member having a linear configuration
prior to deployment and a deployed open configuration, wherein the
deployed configuration bridges the neck of the aneurysm; an upper
member having a undeployed, linear configuration prior and an open,
deployed configuration, wherein the deployed configuration rests
against at least a portion of the dome of the aneurysm, and a means
of adjusting the overall dimensions of the device. In certain
embodiments, the distance between the upper and lower members is
adjustable. In other embodiments, the lower and/or upper member is
compressible (e.g., deformable against the wall of the
aneurysm).
[0009] In any of the devices described herein, the upper and lower
members may be contiguous or alternatively, the upper and lower
members may be separate, for example when the device further
comprises an adjustable central member having a proximal end
connected to the lower member and distal end connected to the upper
member. One or more of the upper member lower member and optional
central member may be compressible or may comprise a compressible
element. Furthermore, the optional central member may further
comprise an extendable member connected to the upper member; and/or
an expandable element.
[0010] In any of the devices described herein, the upper member may
comprise a plurality of axially moveable wires passing through the
lumen of the central member, each wire comprising a distal end and
a proximal end. In certain embodiments, the distal end of one or
more of the wires is attached to the central member and/or to the
lower member. The upper member may be compressible or deformable,
for example against the dome of an aneurysm, thereby changing the
overall dimensions of the device.
[0011] In another aspect, the invention includes any of the devices
as described herein, which device further comprises one or more
detachment junctions, each detachment junction comprising an
electrolytically detachable end adapted to detach by imposition of
a current thereon. One or more detachment junctions may be
positioned between the upper member and a pusher wire and/or
between the lower member and a pusher tube.
[0012] In another aspect, the invention includes any of the devices
as described herein, which device further comprises one or more
locking mechanisms. In certain embodiments, the locking mechanism
comprises an expandable material, for example a self-expanding
element.
[0013] In yet another aspect, the invention includes any of the
devices as described herein, wherein the upper member comprises a
metal, for example, a metal selected from the group consisting of
nickel, titanium, platinum, gold, tungsten, iridium and alloys or
combinations thereof. In certain embodiments, the upper member
comprises the alloy nitinol.
[0014] In yet another aspect, the invention includes any of the
devices as described herein, wherein the lower member comprises a
metal, for example a metal selected from the group consisting of
platinum, palladium, rhodium, gold, tungsten and alloys thereof. In
certain embodiment, the lower member comprises nitinol.
[0015] In yet another aspect, the invention includes any of the
devices as described herein, wherein the upper and/or lower member
comprises a braid or mesh configuration. In certain embodiments,
the lower member comprises a mesh or braid structure. In other
embodiments, the lower member comprises a film (e.g., a porous
film, a polymer film or a metallic film).
[0016] In a still further aspect, the invention includes any of the
devices as described herein, which device further comprises an
additional component, for example a bioactive component.
[0017] In yet another aspect, the invention includes a method of
occluding a body cavity comprising introducing a vaso-occlusive
device as described herein into the body cavity (e.g., an
aneurysm). These and other embodiments of the subject invention
will readily occur to those of skill in the art in light of the
disclosure herein.
BRIEF DESCRIPTION OF THE FIGURES
[0018] In order to better appreciate how the devices, methods and
other advantages and objects of the present disclosure, a more
particular description will be rendered by reference to specific
embodiments thereof, which are illustrated in the accompanying
drawings. It is to be understood that the drawings depict only
exemplary embodiments and are not to be considered limiting in
scope.
[0019] FIG. 1 depicts a side-view of an exemplary assembly as
described herein having umbrella shaped upper and lower members. A
compressible, spring-like central member connects the upper and
lower members and adjusts the distance between the upper and lower
members.
[0020] FIG. 2 depicts a side-view of an exemplary assembly as
described herein having umbrella shaped upper and lower members.
The distance between the upper and lower member can be adjusted by
extending or retracting an extendable member located on a central
member. The central member connects and extends between the upper
and lower members.
[0021] FIG. 3 depicts a side view of another exemplary assembly as
described herein having an umbrella shaped lower member from which
a central tubular member extends. The central member may be
integral to or separate from the lower member. Upper member
comprises a plurality of individual members that extend from and
loop back into the central member. Upper member elements are
extendable and retractable through the central member.
[0022] FIG. 4 depicts a side view of another exemplary assembly as
described herein having an umbrella shaped lower member from which
a central tubular member extends. The central member may be
integral to or separate from the lower member. Upper member
comprises a plurality of individual members that extend from and
the central member. Upper member elements are attached at their
distal ends to the lower member and may be extended or retracted
through the central member to change the overall dimensions of the
device.
[0023] FIG. 5, panels A and B, are side views depicting another
exemplary embodiment in which the upper and lower members comprise
a contiguous element. Panel A depicts contiguous upper and lower
members connected by a central member that includes a compressible
member. Panel B depicts contiguous upper and lower members that are
expandable and an expandable central member.
[0024] FIG. 6, panels A and B, are side views of an exemplary
locking mechanism. Panel A depicts the device in an unlocked
position in which the distance between upper and lower members can
be adjusted. Panel B depicts the locked position in which the
distance between the upper and lower members remains fixed. Also
shown is detachment junction for releasing the device once the
desired configuration is achieved.
[0025] FIG. 7, panels A and B, are side views of an exemplary
locking mechanism. Panel A depicts the device in an unlocked
position in which the distance between upper and lower members can
be adjusted. Panel B depicts the locked position in which the
distance between the upper and lower members remains fixed. Also
shown is detachment junction for releasing the device once the
desired configuration is achieved.
[0026] FIG. 8, panels A and B, are side views of an exemplary
locking mechanism. Panel A depicts the device in an unlocked
position in which the distance between upper and lower members can
be adjusted. Panel B depicts the locked position in which the
distance between the upper and lower members remains fixed. Also
shown is detachment junction for releasing the device once the
desired configuration is achieved.
[0027] FIG. 9, panels A to D, depict exemplary deployment
procedure. Panel A depicts the lower portion of the device as it is
advanced through the delivery catheter by the pusher wire. Panel B
shows expansion of the lower member after extrusion from a
constraining member (e.g., pusher catheter and/or sheath). Panel C
shows the device after it is locked in place via an expandable
material and after the pusher wire has been detached. Panel D shows
detachment of the pusher catheter and removal of the pusher and
delivery catheters. Although all panels show partial side-views
depicting lower and central members, it will be appreciated that
the devices shown will also include upper members as described
herein.
DESCRIPTION OF THE INVENTION
[0028] Occlusive (e.g., embolic) devices are described. The devices
described herein find use in vascular and neurovascular indications
and are particularly useful in treating aneurysms, for example
wide-neck, small-diameter, curved or otherwise difficult to access
vasculature, for example aneurysms, such as cerebral aneurysms.
Methods of making and using these vaso-occlusive devices also form
aspects of this invention.
[0029] All publications, patents and patent applications cited
herein, whether above or below, are hereby incorporated by
reference in their entirety.
[0030] It must be noted that, as used in this specification and the
appended claims, the singular forms "a", "an", and "the" include
plural references unless the content clearly dictates otherwise.
Thus, for example, reference to a device comprising "an extendable
member" includes devices comprising of two or more elements.
[0031] The device is a surgical implement and can be readily
deployed, removed and/or repositioned in human vasculature.
Typically, the devices include a lower member, an upper member and
a means for adjusting the overall dimensions of the device,
including, for example, a means of adjusting the distance between
the lower and upper members. The upper and lower members may be
separate or contiguous elements. In addition, one or both of the
upper and lower members may be compressible. The lower member
typically sits in the neck of the aneurysm while the upper member
sits against the walls (e.g., dome) of the aneurysm.
[0032] Overall dimensions of the device are changed using any
suitable adjustment means. For example, in certain embodiments, the
upper and/or lower member may be moved in relation to each other
(e.g., extended, expanded, compressed, etc.) in order to change the
overall dimensions of the device. One or more adjustable elements
(e.g., a central member) may be employed to facilitate the change
the dimensions, for example an extendable central member connecting
the lower and upper members may be included.
[0033] Depicted in the Figures are exemplary embodiments of the
present invention. It will be appreciated that this is for purposes
of illustration only and that the various elements depicted can be
of other materials or shapes.
[0034] Turning to FIG. 1, device (10) constructed in accordance
with one embodiment of the present invention is shown in a
side-view of a deployed position within an aneurysm (70) of a blood
vessel (15). The aneurysm (70) is shown with an oppositely disposed
neck (75) and dome (85). As shown in the FIG. 1, upper (20) and
lower (30) members have a flared open (umbrella) configuration
after deployment that advantageously conforms to the shape of the
aneurysm (70). The diameter of the upper member (20) is larger than
the neck (75), and thus preferably completely covers the neck (75)
upon deployment. Also shown in FIG. 1 is central member (40), which
is connected at its distal end to upper member (20) and at its
proximal end to lower member (30). Central member (40) also
includes a compressible portion (50) that acts as a spring to
adjust the distance between and to transfer force from lower member
(30) to upper member (20). Central member (40) may also be
extendable.
[0035] FIG. 2 shows a side view of another variation in which the
distance between upper (20) and lower (30) members can be adjusted
using an extendable member (60) extending from the distal end of
central member (40). Extendable member (60) can be extended and
retracted from the lumen of the central member (40) to move the
upper (20) and lower (30) members closer together or farther apart.
In this variation, the upper member (20) is attached to the distal
end of the extendable member (60) and the lower member (30) is
attached to the distal end of the tubular central member (40). As
will be described further herein, movement of the extendable member
(60) can be controlled by any suitable actuator.
[0036] FIG. 3 shows a side view of another variation in which the
overall dimensions are adjusted using an extendable upper member
(20). Upper member (20) comprises a plurality of moveable elements
(e.g., wires or microcoils) that extend from an optional central
member (40). In this variation, the plurality of extendable members
that comprise upper member (20) form loops as they extend from and
back into a lumen in the central member (40). The distal ends of
the wires are shown attached to the central member (40) while the
proximal ends can be extended or retracted by an operator until the
device has the desired overall dimensions (e.g., the loop portion
abuts the dome of the aneurysm). In certain embodiments, the wires
making up the loops of the upper member may be compressed against
the upper wall of the aneurysm upon deployment and thereby change
the distance between the uppermost portion of the device and the
lower member.
[0037] FIG. 4 depicts a side view of a variation similar to that
shown in FIG. 3 in which the distal ends of the plurality of
moveable upper member elements (20) are attached to the lower
member (30) rather than the central member (40). As with the
embodiment shown in FIG. 3, the proximal ends can be extended or
retracted by an operator, thereby forcing the loop portion against
the dome of the aneurysm. Also as shown in FIG. 3, the wires may be
compressed against the upper wall of the aneurysm upon deployment,
thereby changing the overall configuration of the device.
[0038] FIG. 5, panels A and B, depict another variation in which
the upper member (20) and lower member (30) are a single structure.
Panel A is a side view of an exemplary embodiment in which upper
(20) and lower (30) members are connected by central member (40).
Central member further comprises a compressible portion (50) to
adjust distance between upper and lower members. Panel B is a side
view of an exemplary embodiment in which upper (20) and lower (30)
members comprise a plurality of wires that can expand the overall
diameter of the device. Central member (40) also comprises an
expandable member (55).
[0039] In embodiments in which the upper and lower members are
contiguous, the contiguous structure may take any number of forms,
including but not limited to, wires (FIG. SB), braided or woven
configurations, solid configurations (FIG. 5A) and the like. It
will be apparent that, as a whole, the materials making up
contiguous upper and lower member structures may vary in different
portions of the structure. For example, in braided or woven
structures, the tightness of the braid or weave may be different in
the upper portion as compared to the lower portion. Similarly,
different additional components may be used in different portions
of a contiguous upper and lower member structure.
[0040] As shown in the Figures, the overall dimensions of the
devices described herein are adjustable, thereby facilitating a
transfer of force between the lower member (in the neck) to the
upper member (the dome of the aneurysm). The dimensions can be
adjusted (and force transferred) in a variety of ways, including
but not limited to, the inclusion a moveable central member; a
moveable upper member; springs; and/or expandable elements such as
balloons. Whatever force transfers design or combinations of
designs are employed, the adjustable nature of the dimension(s) of
the devices described herein aid in ensuring that the lower member
sits in the neck the aneurysm while the upper member presses safely
against the dome of the aneurysm. Preferably, the area of contact
between the upper and the aneurysm wall is maximized so as to
distribute the force across the widest possible area and thus exert
the least amount of pressure on the aneurysm wall. Furthermore, it
is to be understood that one or more design features shown in the
Figures and described herein can be combined into one device.
[0041] Although the devices described herein are capable of
retaining finer vaso-occlusive devices (e.g., coils, liquid
embolics, etc.) within the aneurysm, they are also capable of
functioning as vaso-occlusive devices by themselves. As can be
appreciated by one of ordinary skill in the art, the force-transfer
effect achieved by including one or more adjustment means (e.g.,
moveable elements) serves to anchor the device in the aneurysm and
reinforce the lower member so that it is able to remain stably
situated across the aneurysm neck while diverting the flow of blood
from within the aneurysm.
[0042] As will be apparent, the devices described herein may
conform to a range of shapes and sizes of aneurysms since the
dimensions are adjustable. Furthermore, following the teachings
described herein, the devices can be sized to fit aneurysms ranging
in size from millimeters in diameter to centimeters in diameter. In
this way, the operator can select a device of a generally suitable
size for the particular indication and adjust it to fit securely by
conforming the upper member to the dome of the aneurysm.
[0043] As noted above, the lower member and upper members may
assume a variety of structures, for example, umbrella, dome,
balloon, teardrop or cone shape. The deployed configuration of the
lower member is preferably such that it sits in and covers the neck
of the aneurysm. Similarly, the deployed configuration of the upper
member is such that it sits safely against the dome of the aneurysm
(e.g., back inner wall). Generally, the overall structure of the
upper member is typically more variable than that of the lower
member and includes, but is not limited to, configuration such as
umbrella shapes, strings or wires formed into loops, etc. One or
both of the lower and upper members may also include thin-film,
braided, mesh like or basket type structures. Furthermore, the
upper and lower members may be a single element, for example
expandable structures, for example as shown in FIG. 5.
[0044] Upper and lower members can be constructed from a wide
variety of materials, including, but not limited to, metals, metal
alloys, polymers or combinations thereof. See, e.g., U.S. Pat. Nos.
6,585,754 and 6,280,457 for a description of various polymers.
Non-limiting examples of suitable metals include, Platinum Group
metals, especially platinum, rhodium, palladium, rhenium, as well
as tungsten, gold, silver, tantalum, stainless steel and alloys of
these metals. Preferably, the lower member comprises a material
that maintains its shape despite being subjected to high stress,
for example, "super-elastic alloys" such as nickel/titanium alloys
(48-58 atomic % nickel and optionally containing modest amounts of
iron); copper/zinc alloys (38-42 weight % zinc); copper/zinc alloys
containing 1-10 weight % of beryllium, silicon, tin, aluminum, or
gallium; or nickel/aluminum alloys (36-38 atomic % aluminum).
Particularly preferred are the alloys described in U.S. Pat. Nos.
3,174,851; 3,351,463; and 3,753,700. Especially preferred is the
titanium/nickel alloy known as "nitinol."
[0045] Shape memory alloys comprise a unique class of metal alloys
that, once trained, are configured to "remember" a pre-selected
shape, i.e., deployed shape, and can return to the pre-selected
shape even if subsequently reshaped. To be trained to "remember" a
first pre-selected shape, the shape memory alloy is molded and
heated at or above a training, or austenite, temperature to place
the shape memory alloy in an austenite phase. In the austenite
phase, the shape memory alloy is formed in the first pre-selected
shape and then, once formed, is permitted to cool to a martensite
finish temperature, whereupon the shape memory alloy enters a
martensite phase. The martensite finish temperature can be any
temperature that is less than the training temperature. Upon
entering the martensite phase, the shape memory alloy has been
trained to "remember" the first pre-selected shape. While in the
martensite phase, the alloy is in a soft state and is formed into a
second pre-selected shape, e.g., an undeployed shape. The shape
memory alloy in the martensite phase is configured to maintain the
second pre-selected shape and, if subsequently reheated to an
activation temperature, automatically returns to the first
pre-selected shape. The activation temperature can comprise any
temperature that is greater than the martensite finish temperature
and generally approximately equals the training temperature. Once
the first pre-selected shape has been recovered, the shape memory
alloy is configured to maintain the first pre-selected shape
irrespective of temperature. Generally, as can be appreciated by
one of ordinary skill in the art, the training, martensite
finishing, and activation temperatures for a shape memory alloy are
adjustable, depending on the composition. For example, a slight
extra amount of Nickel added to a NiTi alloy composition can change
the training temperature from approximately 0.degree. C. to
100.degree. C. The lower member may also comprise a shape memory
polymer such as those described in International Publication WO
03/51444.
[0046] In certain embodiments, the upper and/or lower members of
the devices described herein may also be moveable. For instance, as
shown in FIG. 3 and FIG. 4, the upper member may comprise a
plurality of elements that can be extended or retracted (typically
through the central member) to change the overall dimensions of the
device and ensure that the upper member sits against the dome of
the aneurysm and the lower member sits in the neck.
[0047] As noted above, the upper and lower members may be attached
directly to each other at one or more locations as shown in FIG. 4
or may be attached via the central member or other additional
element as shown in FIGS. 1-3. Alternatively, the upper and lower
members may be contiguous, forming a single member as shown in FIG.
5.
[0048] When present, the central member may be made of a wide
variety of materials and may assume many shapes. The central member
may be a tubular or coiled structure, including a lumen
therethrough, or may be a wire (e.g., a wire or other structure
that serves as both central member and guide/pusher wire). The
central member may comprise expandable elements, for example as
shown in FIG. 5B.
[0049] In certain embodiments, the central member (or an element
attached thereto or extending therefrom) is moveable. For instance,
as shown in FIG. 2, the central member can have an axially moveable
extendable member passing through and extending from the lumen of
the central member. The upper member is attached to the extendable
member and by extending or retracting the extendable member, the
overall dimension of the device can be changed and bolster the
upper member. As noted above, various adjustment means may be used
in conjunction with the central member to change the dimensions of
the device and thereby transfer force between the upper and lower
members including, but not limited to, compressible elements (e.g.,
elements having characteristics of a spring as depicted in FIG. 1
and FIG. 5A) and/or an expandable element such as a braid, woven
structure or balloon-like structure (FIG. 5B).
[0050] It will be apparent that the devices described herein can be
made in a wide range of sizes in order to fit any size aneurysm. As
described above, the operator (surgeon) will typically image the
aneurysm and determine the approximate dimensions, for example from
dome to neck. The appropriate size device can then be selected and
positioned within the aneurysm as described herein.
[0051] In certain embodiments, the device is secured in the desired
dimensions by employing one or more locking mechanisms are
generally included. A variety of locking mechanisms can be used, as
shown in FIGS. 6, 7 and 8. For convenience, exemplary locking
mechanisms are depicted as positioned on extendable members (60),
which is shown passing through the lumen of central element (40).
However, it will be apparent that the extendable member (60) shown
in the Figures could also be the upper member (20). Also shown in
FIGS. 6, 7 and 8 are lower member (30), pusher (80), detachment
junctions (25, 26), delivery catheter (or sheath) (17), and
stabilizer catheter (or "pusher tube") (35). Delivery catheter (17)
and pusher tube (35) are coaxial.
[0052] In the variation shown in FIG. 6, an expandable material is
used to lock the device in the desired dimensions (e.g., maintain
the upper and lower members at the desired distance from each
other). FIG. 6, panel A, depicts lower member (30) and extendable
member (60) passing through central member (40). At the proximal
end of extendable member (60) is detachment junction (25).
Extendable member (60) further comprises expandable material (65)
that may be expanded upon exposure to one or more selected stimuli.
Non-limiting examples of suitable stimuli include exposure to
liquid, air (e.g., balloon), change in temperature, electromagnetic
radiation and the like. Panel B shows expandable material (65) in
its expanded configuration, which locks the device in the desired
overall configuration, both by fitting the expandable material (65)
into the grooves of the lumen of central member (40) and by
providing a stop (90) that is larger than the lumen of the central
member (40) and does not allow the extendable member (60) to be
moved.
[0053] FIG. 7 shows an embodiment in which the device is locked
into place by interlocking grooves. In particular, extendable
member (60) includes grooves (65) that interlock with the lumen of
central member (40). As long as the extendable member is attached
to the pusher (80), the extendable member (60) can be moved through
the lumen of the central member (40). Once the desired
configuration (distance between upper and lower members) is
achieved (FIG. 6B), the extendable member (60) is detached from the
pusher (80) at the detachment junction (25). Once detached, the
overall dimensions of the device remain constant due to the
interlocking mechanism.
[0054] FIG. 8 shows another exemplary locking mechanism that
includes an expanding flange-like mechanism (95). Panel A, shows
the device as the operator pushes the extendable member (60)
through the central member (40) in order to place the upper member
against the dome of the aneurysm. Panel B shows the device as
locked into place with the expandable flange (95) in its expanded
position.
[0055] Also as shown in FIGS. 6-9, the device may also include one
or more detachment junctions (25, 26), for example so that the
upper member can be extended to the proper size for the aneurysm
and the portion(s) of the upper member that are not needed detached
from the pusher wire and removed from the vessel. In certain
embodiments, the lower member may be detachably joined to a pusher
tube (35). The pusher tube is preferably detached (via detachment
junctions (26)) and removed after deployment. Any of the devices
described herein may further comprise one or more additional
detachment junctions, which is(are) severable by the same or
different mechanisms. The detachment junction may be connected to a
pusher element, such as a pusher wire or a tubular structure such
as a stabilizer catheter ("pusher tube").
[0056] The detachment junction can be positioned anywhere on the
device, for example at one or both ends of the device. In certain
embodiments, the detachment junction(s) is(are) positioned where
the extendable member or upper member is attached to an actuator or
locking member. In other embodiments, the detachment junction(s)
is(are) positioned at the junction between a pusher tube and the
lower member or the central member. In still other embodiments, for
example as shown in FIG. 9, panels A-D, detachment junction (25) is
positioned the junction of the device and actuator while additional
detachment junctions (26) are positioned at the junctions of the
pusher tube (35) and upper member (30).
[0057] In certain embodiments, the severable junction(s) are, an
electrolytically detachable assembly adapted to detach by
imposition of a current; a mechanically detachable assembly adapted
to detach by movement or pressure; a thermally detachable assembly
adapted to detach by localized delivery of heat to the junction; a
radiation detachable assembly adapted to detach by delivery of
electromagnetic radiation to the junction or combinations
thereof.
[0058] Furthermore, one or more actuators may be included so that
an operator can manipulate the shape or position of the device. For
example, the moveable members may be attached, either directly or
through another element such as a pusher wire, to an actuator. In
certain embodiments, the pusher wire both advances the device into
the aneurysm and acts as the actuator to adjust the overall
dimensions. As noted above, a pusher wire can serve as guide wire
and, optionally actuator. For example, the extendable element (60)
of FIG. 2 can be the pusher wire that is attached to the upper
member (20) and extendable through the central member (40).
Similarly, the pusher wire can be attached to the central member to
actuate expansion of one or more components. (FIG. 5B). FIGS. 6-9
show pusher wire (80) that also actuates movement of the device.
Additionally, actuators may include one or more handles, dials or
the like with which the operator (e.g., surgeon placing the device)
controls movement of the device, adjusts the dimensions (e.g., by
changing the distance between the upper and lower members and/or
expanding a balloon or basket shaped structure) once in the
aneurysm and/or locks the device into a desired configuration.
[0059] The devices described herein may also comprise additional
components, such as co-solvents, plasticizers, coalescing solvents,
bioactive agents, antimicrobial agents, antithrombogenic agents,
antibiotics, pigments, radiopacifiers and/or ion conductors which
may be coated using any suitable method or may be incorporated into
the element(s) during production. See, e.g., co-owned U.S. patent
application Ser. No. 10/745,911, U.S. Pat. No. 6,585,754 and WO
02/051460, incorporated by reference in their entireties
herein.
[0060] As noted elsewhere, the location of the device is preferably
visible using fluoroscopy. A highly preferred method is to ensure
that at least some of the elements making up the device are
provided with significant radio-visibility via the placement of a
radio-opaque covering on these elements. A metallic coating of a
metal having comparatively more visibility, during fluoroscopic
use, than stainless steel is preferred. Such metals are well known
but include gold and members of the Platinum Group described
above.
[0061] As noted above, one of more of the elements may also be
secured to each other at one or more locations. For example, to the
extent that various elements are thermoplastic, they may be melted
or fused to other elements of the devices. Alternatively, they may
be glued or otherwise fastened. Furthermore, the various elements
may be secured to each other in one or more locations.
[0062] Methods of Use
[0063] The devices described herein are often introduced into a
selected site using the procedure outlined below. This procedure
may be used in treating a variety of maladies. For instance in the
treatment of an aneurysm, the aneurysm itself will be filled
(partially or fully) with the devices described herein.
[0064] Generally, devices as described above are delivered to an
aneurysm via a delivery catheter. It will be apparent that the
device is preferably delivered in an undeployed shape, e.g., a
tubular shape and that, following deployment, the device assumes a
different three-dimensional configuration. The device may be
self-configuring (e.g., self-expanding) upon deployment, may
require actuation by one or more stimuli and/or may be partially
self-configuring and partially shaped by application of one or more
stimuli.
[0065] Self-configuring materials include shape memory alloys and
polymers, described above. Thus, the super-elastic characteristics
of these materials allow the device to be deployed in a compressed
configuration and upon deployment, to assume its three-dimensional
configuration. It is to be understood that the three-dimensional
configuration assumed by self-configuring devices may also be
shaped further (e.g., changing the distance between lower and upper
members) using one or more stimuli described below.
[0066] In other embodiments, the device assumes a deployed
configuration upon the application of one or more appropriate
stimuli. For example, the device may be configured so as to achieve
its deployed shape when exposed to body temperature (e.g.,
temperature of the aneurysm). This can be readily achieved by
adjusting the training and activation temperatures to be at, or
just below, the temperature of the aneurysm (e.g., approximately
37.degree. C.). The martensite temperature is adjusted to be at a
lower temperature. With these temperatures set, the device is
heated to, or above the training temperature (austentite phase) and
shaped into its desired deployed shape, as described above. Then,
the temperature is lowered to, or below, the martensite finish
temperature and shaped into its desired undeployed shape.
Subsequently, the device is then placed inside the catheter for
delivery. The catheter can be constructed of a material that
insulates the device from the outside environment and maintains the
temperature of the device below the activation temperature. Thus,
when the catheter is inserted into the lumen of the blood vessel,
the device does not expand into its deployed shape within the
catheter.
[0067] Other stimuli that can be used to change the configuration
of the device upon deployment include application of
electromagnetic radiation (light), electricity, mechanical
pressure, etc. In certain embodiments, the device self-expands and,
subsequently, one or more stimuli are also applied to achieve the
desired configuration and/or to lock the device in the desired
configuration.
[0068] Conventional catheter insertion and navigational techniques
involving guidewires or flow-directed devices may be used to access
the site with a catheter. The mechanism will be such as to be
capable of being advanced entirely through the catheter to place
vaso-occlusive device at the target site but yet with a sufficient
portion of the distal end of the delivery mechanism protruding from
the distal end of the catheter to enable detachment of the
implantable vaso-occlusive device. In certain embodiments, the
device (e.g., lower member) is attached to the distal end of a
retractable sheath (also referred to as a pusher tube). The device
may be extended and retracted from the pusher tube (by the
actuator) and delivery catheter until the desired configuration is
achieved, at which point, the pusher tube is detached from the
device and withdrawn along with the delivery catheter. FIG. 9.
[0069] For use in peripheral or neural surgeries, the delivery
mechanism will normally be about 100-200 cm in length, more
normally 130-180 cm in length. The diameter of the delivery
mechanism is usually in the range of 0.25 to about 2.0 mm. Briefly,
occlusive devices (and/or additional components) described herein
are typically loaded into a carrier for introduction into a
delivery catheter and introduced to the chosen site using the
procedure outlined below. This procedure may be used in treating a
variety of maladies. For instance, in treatment of an aneurysm, the
aneurysm itself may be filled with a device as described herein
which cause formation of an emboli and, at some later time, is at
least partially replaced by neovascularized collagenous material
formed around the implanted vaso-occlusive devices.
[0070] A selected site is reached through the vascular system using
a collection of specifically chosen catheters and/or guide wires.
It is clear that should the site be in a remote site, e.g., in the
brain, methods of reaching this site are somewhat limited. One
widely accepted procedure is found in U.S. Pat. No. 4,994,069 to
Ritchart, et al. It utilizes a fine endovascular catheter such as
is found in U.S. Pat. No. 4,739,768, to Engelson. First of all, a
large catheter is introduced through an entry site in the
vasculature. Typically, this would be through a femoral artery in
the groin. Other entry sites sometimes chosen are found in the neck
and are in general well known by physicians who practice this type
of medicine. Once the introducer is in place, a guiding catheter is
then used to provide a safe passageway from the entry site to a
region near the site to be treated. For instance, in treating a
site in the human brain, a guiding catheter would be chosen which
would extend from the entry site at the femoral artery, up through
the large arteries extending to the heart, around the heart through
the aortic arch, and downstream through one of the arteries
extending from the upper side of the aorta. A guidewire and
neurovascular catheter such as that described in the Engelson
patent are then placed through the guiding catheter. Once the
distal end of the catheter is positioned at the site, often by
locating its distal end through the use of radiopaque marker
material and fluoroscopy, the catheter is cleared. For instance, if
a guidewire has been used to position the catheter, it is withdrawn
from the catheter and then the assembly, for example including the
vaso-occlusive device at the distal end, is advanced through the
catheter.
[0071] In certain embodiments, the delivery catheter comprises a
retractable sheath (or pusher tube) at its distal end that
surrounds the device to be delivered. Typically, the retractable
distal sheath includes a pull back means operatively connected to
the distal sheath. The catheter may be constructed and arranged
such that distal end of the sheath does not extend past the distal
end catheter. Alternatively, the distal end of the sheath may
extend beyond the distal end of the delivery catheter, for example
so that is extrudes the device directly into the target site. In
certain preferred embodiments, the devices described herein are
detachably linked to the distal end of a retractable sheath. FIGS.
6-9. Non-limiting examples of suitable delivery catheters will be
known to those of skill in the art in view of the teachings herein.
See, also, U.S. Pat. Nos. 6,425,914; 5,772,669; and 6,391,050.
[0072] Once the selected site has been reached, the vaso-occlusive
device is extruded, for example by retracting the sheath
surrounding and mounted to the device. Preferably, the
vaso-occlusive device is loaded onto the pusher wire and/or tube
via a mechanically or electrolytically cleavable junction (e.g., a
GDC-type junction that can be severed by application of heat,
electrolysis, electrodynamic activation or other means).
Additionally, the vaso-occlusive device can be designed to include
multiple detachment points, as described in co-owned U.S. Pat. No.
6,623,493 and 6,533,801 and International Patent publication WO
02/45596. Once detached the devices are held in place by gravity,
shape, size, volume, magnetic field or combinations thereof.
[0073] After deployment and prior to detachment from the pusher
wire and/or pusher tube, it may be preferable to lock the device in
the desired configuration. This can be accomplished in any number
of ways, for example, using locking elements as shown in FIGS. 6-8.
As can be seen in the exemplary embodiments depicted in these
Figures, the inclusion of one or more locking mechanisms helps
ensure the overall configuration of the device and, accordingly,
the efficient transfer of force between the upper and lower members
and the surfaces of the aneurysm they contact. Detachment from the
pusher wire and/or pusher tube can then be accomplished as
described above.
[0074] An exemplary deployment scheme is shown in FIG. 9. FIG. 9A
shows a side-view of the lower and central members of an exemplary
device as described herein as it is advanced through the delivery
catheter (17) by the pusher wire (80). Lower member (30) is
constrained in linear position by delivery catheter (17) and by
pusher catheter sheath (35). Extendable member (60) further
comprises an expandable member (65). Central member (40) is
depicted with inward-facing grooves. FIG. 9B depicts how lower
member (30) assumes an expanded, three-dimensional configuration
upon extrusion from pusher catheter sheath (35) and delivery
catheter (17). FIG. 9C depicts the device in a locked position
after expansion of expandable member (65). In addition, pusher wire
is shown as detached from extendable member (60) via detachment
junction (25). FIG. 9D shows the withdrawal of the delivery
catheter (17) and pusher catheter (35), leaving the device in place
where desired. Pusher catheter (35) is detached from lower member
(30) via detachment junctions (26).
[0075] Modifications of the procedure and vaso-occlusive devices
described above, and the methods of using them in keeping with this
invention will be apparent to those having skill in this mechanical
and surgical art. These variations are intended to be within the
scope of the claims that follow.
* * * * *