U.S. patent application number 10/391152 was filed with the patent office on 2003-11-20 for vasoocclusion coil device having a core therein.
This patent application is currently assigned to Board of Regents, University of Texas System. Invention is credited to Konya, Andras, Wallace, Sidney, Wright, Kenneth Carroll.
Application Number | 20030216772 10/391152 |
Document ID | / |
Family ID | 22296287 |
Filed Date | 2003-11-20 |
United States Patent
Application |
20030216772 |
Kind Code |
A1 |
Konya, Andras ; et
al. |
November 20, 2003 |
Vasoocclusion coil device having a core therein
Abstract
A coil-type vasoocclusion device (10) for establishing an
embolus or vascular occlusion in a human or veterinary patient is
adapted for introduction into the patient via a catheter (32). The
device (10) first includes a coil (12) having proximal and distal
coil ends (16,18) and a coil lumen (20). The device (10) also
includes a core (22) disposed in at least part of the coil lumen
(20), the core having proximal and distal core ends (24,26). Only
one core end (24 or 26) is directly affixed to a respective end (16
or 18) of the coil (12); the other core end (26 or 24) is not
directly connected to either end (16 or 18) of the coil (12). The
core (22) is preferably nitinol in a superelastic state, being in
other than its stress induced, martensitic condition. The device
(10) can include a thrombogenic material (38) connected to or
carried by the coil (12). The coil (12) is preferably adapted to
achieve a suitable secondary shape (60) when deployed from the
catheter (32). A medical device (40) combining the catheter (32), a
pusher (34), a coupling (30) and the vasoocclusion device (10) is
also disclosed. The vasoocclusion device (10) is easily
repositioned in the vascular system, thereby ensuring proper
deployment, and also enjoys a dislodging force about twice as great
as comparable coil-type devices lacking the core (22),
substantially or completely preventing migration of the device (10)
after its deployment.
Inventors: |
Konya, Andras; (Houston,
TX) ; Wallace, Sidney; (Houston, TX) ; Wright,
Kenneth Carroll; (Houston, TX) |
Correspondence
Address: |
James P. Naughton
BRINKS HOFER GILSON & LIONE
P.O. BOX 10395
CHICAGO
IL
60610
US
|
Assignee: |
Board of Regents, University of
Texas System
|
Family ID: |
22296287 |
Appl. No.: |
10/391152 |
Filed: |
March 20, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10391152 |
Mar 20, 2003 |
|
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|
09413520 |
Oct 6, 1999 |
|
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6551340 |
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60103647 |
Oct 9, 1998 |
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Current U.S.
Class: |
606/195 |
Current CPC
Class: |
A61B 17/12113 20130101;
A61B 17/12145 20130101; A61B 17/1215 20130101; A61B 2017/1205
20130101; A61B 17/12022 20130101 |
Class at
Publication: |
606/195 |
International
Class: |
A61M 029/00 |
Claims
What is claimed is:
1. A vasoocclusion device (10) for establishing an embolus or
vascular occlusion in a vessel of a human or veterinary patient,
the device (10) comprising: a coil (12) having a proximal coil end
(16), a distal coil end (18) spaced from the proximal coil end (16)
and a coil lumen (20) defined therein extending between the
proximal coil end (16) and the distal coil end (18); and a core
(22) disposed in at least part of the coil lumen (20), the core
(22) having a proximal core end (24) and a distal core end (26);
and one portion of the core (22) affixed to the coil (12) at a
selected location, whereby the core (22) provides the coil (12)
with an anchoring force in the vessel (42).
2. The device (10) as set forth in claim 1 wherein the coil lumen
(20) possesses a defined cross-section, and the core (22)
substantially fills the defined cross-section of the coil lumen
(20).
3. The device (10) as set forth in claim 1 wherein the distal core
end (26) is affixed to the distal coil end (18).
4. The device (10) as set forth in claim 3 wherein the distal core
end (26) is soldered, welded or adhered to the distal coil end
(18).
5. The device (10) as set forth in claim 1 adapted for introduction
into the patient via a catheter (32), wherein the device (10) is
detachably secured to the catheter (32).
6. The device (10) as set forth in claim 5 wherein the device (10)
further comprises a reversible coupling (30) for detachably
connecting the device (10) to the catheter (32) for introducing it
into the patient.
7. The device (10) as set forth in claim 6 adapted for introduction
into the patient via a pusher (34) contained in the catheter (32),
wherein the coupling (30) detachably connects the device (10) to
the pusher (34).
8. The device (10) as set forth in claim 1 wherein the core (22)
comprises nitinol, another shape memory material, stainless steel
or MP35N.
9. The device (10) as set forth in claim 1 wherein the core (22)
comprises nitinol in a superelastic state.
10. The device (10) as set forth in claim 1 wherein the core (22)
comprises nitinol in other than its stress induced, martensitic
condition.
11. The device (10) as set forth in claim 1 wherein the coil (12)
comprises a secondary nonlinear shape (60) when unstressed.
12. The device (10) as set forth in claim 11 wherein the secondary
shape (60) is a saddle-type (62), helical type (64), vortex-type
(66), irregular baffle-type (68) or fusiform helix-type (70)
shape.
13. The device (10) as set forth in claim 11 wherein the secondary
shape (60) is a substantially spherical secondary shape (72).
14. The device (10) as set forth in claim 13 wherein the
substantially spherical secondary shape (72) is defined by circular
loops (74) angularly spaced about an axis.
15. The device (10) as set forth in claim 13 wherein the
substantially spherical secondary shape (72) is defined by D-shaped
loops (78) angularly spaced about an axis.
16. The device (10) as set forth in claim 11 wherein the secondary
shape (60) is an oval plate (84).
17. The device (10) as set forth in claim 16 wherein the oval plate
secondary shape (84) is defined by a generally flattened array of
loops of wire (14) and defining a plurality of holes through which
other coils are deployable.
18. The device (10) as set forth in claim 1 further comprising a
thrombogenic material (38) connected to or carried by the coil
(12).
19. The device (10) as set forth in claim 18 wherein the
thrombogenic material (38) comprises Dacron, cotton, silk, wool or
polyester threads (44).
20. The device (10) as set forth in claim 1 the coil (12) comprises
a wire (14) having a wire diameter of about 0.010 in. to about
0.032 in. (about 0.25 mm to about 0.81 mm).
21. The device (10) as set forth in claim 1 wherein the core (22)
has a diameter of about 0.004 in. to about 0.015 in. (about 0.10 mm
to about 0.38 mm).
22. The device (10) as set forth in claim 1 wherein the core is of
nitinol and has a diameter of about 0.004 in. to about 0.006 in.
(about 0.10 mm to about 0.15 mm), and the coil has a diameter of
about 0.010 in. to about 0.015 in. (0.25 mm to 0.38 mm).
23. The device (10) as set forth in claim 1 wherein the core (22)
includes at least one tapered end portion (46).
24. The device (10) as set forth in claim 23 wherein the core (22)
includes two tapered end portions (46).
25. The device (10) as set forth in claim 1 wherein the core (22)
defines alternating portions of larger (48) and smaller (50)
diameters therealong having even and continuous transitions
therebetween.
26. The device (10) as set forth in claim 11 wherein the secondary
shape (36) of the coil (12) has a general outer dimension of about
3 mm to about 15 mm.
27. The device (10) as set forth in claim 11 wherein the coil (12)
is about 2 to about 40 cm long when within a catheter.
28. A vasoocclusion device (10) for establishing an embolus or
vascular occlusion in a human or veterinary patient, the device
(10) being adapted for introduction into the patient via a catheter
(32), and the catheter (32) having a pusher (34) contained therein
for deploying the device (10) from the catheter (32); the device
(10) comprising: a coil (12) having a proximal coil end (16), a
distal coil end (18) spaced from the proximal coil end (16) and a
coil lumen (20) defined therein extending between the proximal coil
end (16) and the distal coil end (18); a core (22) disposed in at
least part of the coil lumen (20), the core (22) having a proximal
core end (24) and a distal core end (26); and a thrombogenic
material (38) connected to or carried by the coil (12); wherein one
and only one of the proximal core end (24) and the distal core end
(26) is directly affixed to a respective one of the proximal coil
end (16) and the distal coil end (18), the other of the distal core
end (26) and the proximal core end (24) not being directly affixed
to either the distal coil end (18) or the proximal coil end (16);
wherein the distal core end (26) is directly affixed to the distal
coil end (18) by solder (28) or an adhesive; wherein the core (22)
comprises nitinol in a superelastic state, being in other than its
stress induced, martensitic condition; wherein the thrombogenic
material (38) comprises Dacron, cotton, silk, wool or polyester
threads (44); wherein the coil (12) comprises a wire (14) having a
diameter of about 0.010 in. to about 0.032 in. (about 0.25 mm to
about 0.81 mm); wherein the core (22) has a diameter of about 0.004
in. to about 0.015 in. (about 0.10 mm to about 0.38 mm); wherein
the coil (12) is about 2 to about 40 cm long when constrained
within a catheter; and wherein the core (22) provides the coil (12)
with an additional force assisting anchoring of the coil (12) in
the human or veterinary patient when the coil (12) and the core
(22) are deployed from the catheter (32).
29. A medical device (40) for establishing an embolus or vascular
occlusion in a vessel of a human or veterinary patient, comprising:
a coil (12) having a proximal coil end (16), a distal coil end (18)
spaced from the proximal coil end (16) and a coil lumen (20)
defined therein extending between the proximal coil end (16) and
the distal coil end (18); a core (22) disposed in at least part of
the coil lumen (20), the core (22) having a proximal core end (24)
and a distal core end (26); one portion of the core (22) affixed to
the coil (12) at a selected location, a catheter (32) dimensioned
to receive the coil (12) and the core (22) therein; and a pusher
(34) contained in the catheter (32), adapted to deploy the coil
(12) and the core (22) from the catheter (32); wherein the core
(22) provides the coil (12) with an anchoring force in the vessel
when the coil (12) and the core (22) are deployed from the catheter
(32).
30. The device (10) as set forth in claim 29 further comprising a
coupling (30) for detachably connecting the coil (12) to the pusher
(34).
31. In a coil-type vasoocclusion device for establishing an embolus
or vascular occlusion in a vessel of a human or veterinary patient,
where the device comprises (a) a coil having a proximal coil end, a
distal coil end spaced from the proximal coil end, a coil lumen
defined therein extending between the proximal coil end and the
distal coil end; and (b) a core disposed in at least part of the
coil lumen, the core having a proximal core end and a distal core
end; the improvement being characterized in that: only one section
of the coil is affixed to the coil at a selected location, wherein
the core provides the coil with an anchoring force in the
vessel.
32. The device as set forth in claim 31, wherein one of the
proximal core end and distal core end is affixed to a respective
one of the proximal coil end and the distal coil end.
33. A method of treating an aneurysm (86), comprising: placing a
first device (10) within the aneurysm (86), with the first device
(10) in its unstressed state being sufficiently large when so
placed such that it traverses a neck (88) of the aneurysm to extend
beyond the periphery of the neck (88) and defines a plurality of
holes extending through the first device permitting subsequent
deployment therethrough of additional devices within the aneurysm
(86).
Description
TECHNICAL FIELD
[0001] This invention relates generally to medical devices, and
more particularly to embolization devices, that is, devices for
occluding a portion of the vascular system of a human or veterinary
patient.
BACKGROUND OF THE INVENTION
[0002] Embolization of vascular occlusion devices (hereinafter
generally referred to as "vasoocclusion devices") are surgical
implements or implants that are placed within the vascular system
of a patient. Vasoocclusion devices are typically used either to
block the flow of blood through a vessel by the formation of an
embolus in the vessel, or to form such an embolus within an
aneurysm stemming from the vessel. Such devices are conventionally
introduced into the vascular system of the patient by a catheter,
and can include a mechanical interlock to permit detachment of them
from a pusher extending through the catheter.
[0003] A variety of prior implantable, coil-type vasoocclusion
devices are known which include a coil having a lumen defined
therein, and some kind of safety wire disposed in and extending
through the lumen. The coils of such devices may themselves be
formed into a secondary coil shape, or any of a variety of more
complex secondary shapes adapted to the particular location at
which an embolism or occlusion is to be established. A variety of
thrombogenic materials may be attached to or carried by the coils
of such devices to promote the formation of clots (thus, in turn,
promoting the establishment of the embolism or occlusion), such as
Dacron, polyester, silk or cotton fibers, filaments or the like.
The coil itself, or the secondary coil shape, abuts or engages the
wall of the vessel in which the device is disposed, serving to
anchor the device in the vessel of interest.
[0004] For example, U.S. Pat. No. 4,994,069 to M. Ritchart et al.,
issued Feb. 19, 1991, discloses a flexible, coiled wire for use in
small vessel occlusion. The wire has a stretched, linear condition
in which it can be advanced through a catheter lumen to a selected
vessel, and a relaxed, convoluted condition produced by a
combination of helical windings of the wire and irregularities of
the helical winding (referred to as a "memory"). The patent does
not appear to suggest that the wire can itself be a conventional
shape memory material, such as nitinol alloy.
[0005] Numerous similar devices have been disclosed. U.S. Pat. No.
5,749,891 issued May 12, 1998 and U.S. Pat. No. 5,582,619 to issued
on Dec. 10, 1996, both to C. G. M. Ken et al., are directed to
implantable vasoocclusion devices comprising a helically wound coil
which is itself wound into a secondary shape. The devices can
include an inner, stretch-resisting member positioned in the lumen
of the coil. Possible materials for the wire making up either the
coil or the inner member include stainless steel and nitinol. The
device shown in FIG. 4 of the '891 patent can include multiple
layers of coils, the inner member being a wire which prevents
stretching of the coil during movement of it.
[0006] The '619 patent also discloses a coil having a wire
positioned therein to similarly prevent stretching.
[0007] U.S. Pat. No. 5,645,558 issued Jul. 8, 1997 to J. A. Horton,
in FIG. 4 discloses a vasoocclusion device having a helical coil
with a safety wire positioned therein for structural support.
Alternatively, the internal wire may be preformed into an
ultimately desired shape (for example, a sphere) and fed through
the coiled strand, the coiled strand then assuming the shape of the
safety wire.
[0008] Finally, FIG. 4 of U.S. Pat. No. 5,522,822 issued Jun. 4,
1996 to J. J. Phelps et al., discloses a vasoocclusion device which
comprises a helical coil having an internal wire attached to end
caps at both ends of the coil. The wire may be made of a shape
memory material such as nitinol, while the coil is typically made
of a radiopaque material such as tungsten, platinum, gold or
silver.
[0009] The coil-type vasoocclusion devices in the last four of
these patents can all be generally characterized in that the
proximal and distal ends of the safety wire are affixed or directly
secured to the respective proximal and distal ends of the coil
itself. Each of these devices is of course subject to its own
advantages and drawbacks during use. In general, however, and
without ascribing this drawback to any of the devices disclosed in
these particular patents, commercially available vasoocclusion
coils do not anchor well in the target vessel and/or do not attain
a shape which effectively occludes blood flow when deposited in the
target vessel. This is because the only thing by which such
commercially available coils apply an anchoring force against the
wall of the target vessel, is the abutment force provided by the
resilient return of the coils themselves to a desired shape.
[0010] It would be highly advantageous to have a coil-type
vasoocclusion device in which the assistive force provided by the
core to anchor the device at the location of interest, could be
adjusted or selected to provide an optimal total anchoring force
for the device. It would also be highly advantageous to have a
coil-type vasoocclusion device which maximizes the assistive force
provided by the core to anchor the device at the location of
interest. It would further be highly advantageous to have a
coil-type vasoocclusion device which could more readily be removed
or repositioned than could prior coil-type vasoocclusion
devices.
SUMMARY OF THE INVENTION
[0011] The foregoing problems are solved and a technical advance is
achieved in an illustrative vasoocclusion device. More
particularly, the device of the present invention is directed to a
rapidly and reliably deployable and repositionable, self-anchoring,
mechanical vascular occluder whose shape and anchoring force are
predetermined by an included core having a shape memory. The device
of the present invention is a coil-type vasoocclusion device having
a coil with a coil lumen defined therein, the core being disposed
in part or most of the coil lumen. The core can be composed of a
nitinol or other shape memory material, preferably in a
superelastic state, or can be composed of stainless steel, MP35N or
the like. (If nitinol material is used, the nitinol need not be in
its stress induced, martensite condition, however, and preferably
is not in such a condition.) The core is "springy" and provides an
additional, anchoring assistive force, which supplements the
anchoring force provided by the coil itself and which can improve
the effectiveness of the coil in several applications. The present
invention can be further characterized in that, unlike comparable
coil-type devices, the nitinol or other shape memory material core
is not affixed coil at both of its ends. Instead, only one portion
of the core is affixed the coil preferably one end of the core
affixed at or near one end of the coil, while the remainder of the
core is not affixed to the coil.
[0012] Such an arrangement of fixing the core to the coil may
advantageously allow an adjustment of the assistive anchoring force
provided by the core to a coil of a given length, by selection of
the length of the core. Such an arrangement may also maximize the
assistive anchoring force provided by the core, since such force
would not be diminished by any twisting of the core during
manipulation or positioning of the coil. Further, such an
arrangement may facilitate removal or repositioning of the device,
since elongation of the coil when subjected to a longitudinal
removing force may lessen the anchoring force supplied by the coil
itself, making engagement with the introducing or removal apparatus
easier.
[0013] In a first aspect, then, the present invention is directed
to a vasoocclusion device for establishing an embolus or vascular
occlusion in a human or veterinary patient, the device comprising:
a coil having a proximal coil end, a distal coil end spaced from
the proximal coil end and a coil lumen defined therein extending
between the proximal coil end and the distal coil end; and a core
disposed in at least part of the coil lumen, the core having a
proximal core end and a distal core end; and wherein one portion of
the core is affixed to the coil at a selected location, whereby the
core provides the coil with an anchoring force in a vessel of the
human or veterinary patient.
[0014] Preferably, the coil lumen possesses a defined
cross-section, and the core can but need not substantially fill the
defined cross-section of the coil lumen. Also preferably, the
distal core end is directly affixed to the distal coil end in any
convenient manner, for example, by solder, welding or adhesive.
[0015] The diameter of the core is selected so as to provide a
desired assist to the expansile or anchoring force of the coil.
Such force can be adjusted over a relatively wide range. The core
can extend through the entire lumen of the coil, or can instead
extend in only part of the lumen, for example, from either the
proximal or distal end of the coil. This leaves the remaining part
of the coil highly flexible, or "floppy."
[0016] In certain embodiments, the core has a changing diameter. In
one, the core tapers toward its free end, that is, an end which is
not affixed to the respective coil end; by using a tapered nitinol
wire, the assistive forces of the coil can be even more precisely
adjusted along the coil. In another, both end-portions of the core
are tapered; as a result, the coil's expansive force will be the
greatest at its mid-portion, while the coil strength will be evenly
reduced toward the ends. Consequently, it is the mid-portion of the
coil that will mostly anchor the device within the vasculature
while the moderately reinforced end-portions allow for better
coverage of the center space of the vessel resulting in quicker
occlusion.
[0017] In a further embodiment, the core is formed from a nitinol
wire whose diameter alternates between a larger and a smaller
caliber, and the transition between the larger and smaller caliber
segments is even and continuous without step formation. This
technical solution makes it possible to use relatively great
assistive forces to anchor the device, but simultaneously preserves
the pliability or flexibility of the coil to a certain degree,
facilitating both the proper arrangement of coil turns within the
vasculature and pushability of the coil through the delivery
catheter.
[0018] The vasoocclusion device is preferably adapted for
introduction into the patient via a catheter, the device being
detachably secured to the catheter. More particularly, the device
is preferably adapted for introduction via a pusher contained in
the catheter, and the device further comprises a reversible
coupling for detachably connecting the device to the pusher.
[0019] As indicated, the core preferably comprises nitinol, another
shape memory material, stainless steel or MP35N. The nitinol is
preferably in a superelastic state, but is in a condition other
than its stress induced, martensitic condition.
[0020] The coil of the vasoocclusion device can comprise any
convenient non-linear secondary shape upon its deployment in the
patient. The secondary shape can be a saddle-type, helical type,
vortex-type, irregular baffle-type, fusiform helix-type or oval
plate shape. It may also be spherical, derived from circular or
D-shaped or semicircular shapes of the helical turns. The
vasoocclusion device preferably further comprises a thrombogenic
material connected to or carried by the coil, such as Dacron, silk,
cotton, wool or polyester threads.
[0021] In a second aspect, the present invention is directed to a
specific combination of the features mentioned above. More
particularly, it is directed to a vasoocclusion device for
establishing an embolus or vascular occlusion in a human or
veterinary patient, the device being adapted for introduction into
the patient via a catheter, and the catheter having a pusher
contained therein for deploying the device from the catheter; the
device comprising: a coil having a proximal coil end, a distal coil
end spaced from the proximal coil end and a coil lumen defined
therein extending between the proximal coil end and the distal coil
end; a core disposed in at least part of the coil lumen, the core
having a proximal core end and a distal core end; and a
thrombogenic material connected to or carried by the coil; wherein
the distal core end is affixed to the distal coil end by solder,
welding, or an adhesive; wherein the core comprises nitinol in a
superelastic state, being in other than its stress induced,
martensitic condition;
[0022] wherein the thrombogenic material comprises Dacron, cotton
or polyester threads; wherein the coil (12) comprises a wire (14)
having a diameter of about 0.010 in. to about 0.032 in. (about 0.25
mm to about 0.81 mm); wherein the core (22) has a diameter of about
0.004 in. to about 0.015 in. (about 0.10 mm to about 0.38 mm);
wherein the coil (12) is about 2 to about 40 cm long when
constrained within a catheter; and wherein the core provides the
coil with an additional force assisting anchoring of the coil in
the human or veterinary patient when the coil and the core are
deployed from the catheter.
[0023] In a third aspect, the present invention is directed to the
combination of the coil and core device with the catheter and
pusher for deploying the device in the patient. Thus, in its third
aspect, the present invention is directed to a medical device for
establishing an embolus or vascular occlusion in a human or
veterinary patient, comprising: a coil having a proximal coil end,
a distal coil end spaced from the proximal coil end and a coil
lumen defined therein extending between the proximal coil end and
the distal coil end; and a core disposed in at least part of the
coil lumen, the core having a proximal core end and distal core
end; wherein one portion of the core is affixed to the coil at a
selected location; a catheter dimensioned to receive the coil and
the core therein; and a pusher contained in the catheter, adapted
to deploy the coil and the core from the catheter; wherein the core
provides the coil with an additional force assisting anchoring of
the coil in the human or veterinary patient when the coil and the
core are deployed from the catheter. This third aspect of the
present invention preferably further comprises a coupling for
detachably connecting the coil to the pusher.
[0024] In a fourth and final aspect, the present invention is
directed to an improvement in a coil-type vasoocclusion device for
establishing an embolus or vascular occlusion in a vessel of a
human or veterinary patient, the device comprising: (a) a coil
having a proximal coil end, a distal coil end spaced from the
proximal coil end, a coil lumen defined therein extending between
the proximal coil end and the distal coil end; and (b) a core
disposed in at least part of the coil lumen, the core having a
proximal core end and a distal core end; the improvement being
characterized in that one and only one of the proximal core end and
the distal core end is affixed to the coil proximate to a
respective one of the proximal coil end and the distal coil end,
the other of the distal core end and the proximal core end not
being affixed to either the distal coil end or the proximal coil
end; and wherein the core provides the coil with an anchoring force
in the vessel.
[0025] As indicated above, the vasoocclusion device of the present
invention may possess significant advantages over prior coil-type
vasoocclusion devices. It may be possible to adjust the assistive
anchoring force provided by the core to a coil of a given length,
by selection of the length of the core. Since one end of the core
is free and not affixed to an end of the coil, the assistive
anchoring force provided by the coil may be maximized, and not
diminished by any twisting of the core during manipulation or
positioning of the coil. Finally, such an arrangement may
facilitate removal or repositioning of the device, since elongation
of the coil when subjected to a longitudinal removing force may
lessen the anchoring force supplied by the coil itself, making
engagement with the introducing or removal apparatus easier. Of
course, in contrast to comparable stainless steel coils lacking the
nitinol or other core, the vasoocclusion device possesses
significantly enhanced self-anchoring capability, which is expected
to result in the substantial reduction or elimination of migration
of the installed coil. Further, however, the vasoocclusion device
is rapidly and readily repositionable after deployment in a
patient. Advantageously, the vasoocclusion device can often be
deployed into a patient through the same catheter as is used for
comparably-sized stainless steel coils.
BRIEF DESCRIPTION OF THE DRAWING
[0026] A better understanding of the present invention will now be
had upon reference to the following detailed description, when read
in conjunction with the accompanying drawing, wherein like
reference characters refer to like parts throughout the several
views, and in which:
[0027] FIG. 1 is a partial longitudinal section view of a first
embodiment vasoocclusion device of the present invention;
[0028] FIG. 2 is a side view of the device of FIG. 1;
[0029] FIG. 3 is a partial cross-sectional view of the device of
FIGS. 1 and 2;
[0030] FIG. 4 is a partially sectioned side view of another
embodiment of vasoocclusion device of the present invention showing
thrombogenic material;
[0031] FIGS. 5 and 6 are partial longitudinal cross-section views
of the device showing other embodiments of cores;
[0032] FIG. 7 is an elevation view of another embodiment of core of
the present invention;
[0033] FIG. 8 is a partial cross-sectional view of the device of
FIGS. 1 to 3 during use depicting a secondary coil shape;
[0034] FIG. 9 is a partial cross-sectional view, similar to FIG. 8,
of another embodiment of secondary coil shape;
[0035] FIGS. 10 through 13 are isometric views of other embodiments
of secondary shapes of vasoocclusion devices of the present
invention;
[0036] FIGS. 14 to 19 are additional embodiments of the device of
the present invention associated with a spherical secondary coil
shape as seen in FIGS. 18 and 19 formed from circular (FIG. 15) or
D-shaped (FIG. 16) helical coil turns;
[0037] FIG. 20 is a partial cross-sectional view of another
embodiment of the present invention during use in treating an
aneurysm; and
[0038] FIG. 21 is a partial cross-sectional view taken along line
21-21 of FIG. 20.
DETAILED DESCRIPTION
[0039] With reference first to FIGS. 1 and 2, a first embodiment of
a coil-type vasoocclusion device 10 as set forth in the present
invention is thereshown, useful for establishing an embolus or
vascular occlusion in a human or veterinary patient. The
vasoocclusion device 10 of the present invention first comprises a
coil 12 composed of a wire 14 of stainless steel or another
suitable medical grade material. The individual loops of wire 14
preferably lie closely together in forming the coil 12. The coil 12
has a proximal coil end 16 and a distal coil end 18 spaced from the
proximal coil end 16. The coil 12 also has a coil lumen 20 defined
therein, extending between the proximal coil end 16 and the distal
coil end 18. This is, of course, the simplest conformation of the
coil 12; more complex shapes for the coil 12 itself can be employed
as appears appropriate for the particular use to which the device
10 is to be put.
[0040] The vasoocclusion device 10 next comprises a core 22
disposed in at least part of the coil lumen 20. The core 22 need
not extend the entire length of the coil lumen 20. To the contrary,
it may facilitate some uses of the device 10 to allow part of the
coil 12 to remain "floppy," that is, unsupported by the core 22.
The core has a proximal core end 24 and a distal core end 26 spaced
from the proximal core end 24. Preferably, the distal core end 26
is located adjacent to the distal coil end 18. It is a
characterizing feature of the invention, however, that unlike the
prior art devices mentioned above, the core 22 is affixed to the
coil at one selected location, such as one and only one of the
proximal and distal coil ends 24,26 is affixable or affixed to or
near a respective one of the proximal and distal coil ends 16, 18.
The other of the distal and proximal core ends 26,24 is not
affixable or affixed to an end 16, 18 of the coil 12, and in
particular, to the distal coil end 18. The distal core end 26 can
be affixed to the distal coil end 18 by a drop of solder, or/by
welding, or by a suitable adhesive or the like.
[0041] With particular reference now to FIG. 3, the vasoocclusion
device 10 is preferably adapted for introduction into, for example,
a vessel 42 of the human or veterinary patient via a catheter 32,
as a medical device assembly 40. The specific nature of the
catheter 22 itself is pertinent to the use of the device 10 only
insofar as the material of the catheter 32 must be selected to
allow the free movement of the coil 12 within the catheter 32.
Otherwise, any of a variety of catheter configurations are expected
to be useful for the catheter 32, such as the well known "hockey
stick" style catheter. For example, when the coil 12 includes a
thrombogenic material in the manner described below, the catheter
32 should be made of a material which does not develop frictional
binding with the thrombogenic material. A catheter 32 composed of
polytetrafluoroethylene (PTFE), for example, may be necessary when
some thrombogenic materials are used on the coil 12.
[0042] In any event, the vasoocclusion device 10 is preferably
secured to the catheter 32 in a detachable manner. More preferably,
the device 10 comprises a reversible coupling 30 for detachably
connecting the device 10 to the catheter 32 for introducing the
device 10 into the patient. Even more preferably, the device 10 is
further adapted for introduction into the patient via a pusher wire
or pusher 34 contained within the catheter 32. The coupling 30 then
detachably connects the device 10 to a complementary coupling 30'
of the pusher 34. A variety of couplings for this purpose are
known, and the selection of any particular one should be made in
dependence upon the construction of the catheter 32, the coil 12
and the target location for deployment of the device 10. The
coupling 30,30' shown in FIG. 2 is a conventional interdigitating
connection.
[0043] Deployment of the device 10 from the catheter 32 is
remarkably straightforward. The device 10 is engaged with the
pusher 34 via the coupling 30 and withdrawn into the catheter 32 in
a straight condition. The catheter 32 is then introduced into the
patient and advanced until its distal end is adjacent the target
location for deployment of the device 10. The pusher 34 is then
advanced to deploy the device 10, and the coupling 30 actuated to
detach the device 10 from the pusher 34. Retrieval of the device
10, for either removal from the patient or repositioning in the
patient, is carried out by reversing these steps.
[0044] As indicated above, it is preferred for some uses of the
device 10 that a thrombogenic material 38 be connected to or
carried by the coil 12. The thrombogenic material 38 can be any
material conventionally used for this purpose, for example, Dacron,
silk, cotton, wool or polyester. Other suitable materials are of
course known. The thrombogenic material 38 can be configured as
threads, either looped or meshed, or braided as in FIG. 4. Those
skilled in the art will be well aware of other configurations for
the thrombogenic material. In FIG. 4, a braided fibrous mesh 44 of
threads of thrombogenic material 38 extends around and along coil
12.
[0045] The core 22 provides the coil 12 with an additional force
which assists anchoring of the coil 12 in the human or veterinary
patient. The amount of such additional force is selected by
choosing the composition, diameter and length of the core 22. For
example, the core 22 can substantially fill the cross-sectional
area of the coil lumen 20, if desired. However, the device 10 can
work quite well with a core 22 of smaller diameter.
[0046] The core 22 can be composed of any of several materials
which provide an additional force to assist the anchoring of the
coil 12. Preferably, however, the core 22 comprises nitinol,
another shape memory material, stainless steel or MP35N superalloy
(SPS Corporation, Jenkintown, Pa.). More preferably, the core 22
comprises nitinol in its superelastic state. However, it is also
preferred that the nitinol not be in its stress induced,
martensitic condition.
[0047] In other embodiments, the core 22 has a changing diameter.
In a preferred embodiment, seen in FIG. 5, it tapers toward its
free end, that is, which is not affixed to the respective coil end,
defining a tapered end portion 46. By using a tapered nitinol wire,
the assistive forces of the coil can be even more precisely
adjusted along the coil. In another embodiment (FIG. 6), both
end-portions 46 of the core 22 are tapered. As a result, the coil's
expansive force will be the greatest at its cylindrical
mid-portion, while the coil strength will be evenly reduced toward
the ends. Consequently, it is the mid-portion of the coil 22 that
will mostly anchor the device within the vasculature while the
moderately reinforced end-portions allow for better coverage of the
center space of the vessel resulting in quicker occlusion.
[0048] It can be seen, with reference to FIGS. 5 and 6, that either
distal end 26 of core 22 or distal coil end 18 for example can
include means for affixing (such as an amount of adhesive) for
affixing the distal core end to the distal coil end, so that the
device can be shipped prior to assembly of the core within the coil
lumen. Also, a detachable interlocking dip (not shown) may be
utilized to affix a portion of the core to the coil.
[0049] FIG. 7 illustrates a further embodiment, wherein the core 22
is formed from a nitinol wire whose diameter alternates between a
larger and a smaller caliber. The transition between the larger 48
and smaller 50 caliber segments is even and continuous without step
formation. This technical solution makes it possible to use
relatively great assistive forces to anchor the device, but
simultaneously, by weakening the core at several sites, the
pliability/flexibility of the coil can be preserved to a certain
degree. This will facilitate both the proper arrangement of coil
turns within the vasculature and pushability of the coil through
the delivery catheter.
[0050] With reference now to FIGS. 8 through 13, it is preferred
that the coil 12 comprise a non-linear secondary shape 60 when
deployed in the patient, for example, in a vessel 42 (see FIG. 13)
The non-linear secondary shape 60 is supported by the core 22 (FIG.
3) and serves as an anchor for keeping the device 10 in position in
the vessel 42, that is, for preventing unintended migration of the
device 10 once it has been deployed in the vessel 42. A variety of
secondary shapes for anchoring other coil-type devices are well
known. The secondary shape 60 of the device 10 may comprise a
saddle-type shape 62 (FIG. 8), a helical-type shape 64 (FIG. 9), a
vortex-type shape 66 (FIG. 10), an irregular baffle-type shape 68
(FIGS. 11 and 12) or a fusiform helix-type shape 70 (FIG. 13).
[0051] With reference again to FIG. 3, one caveat should be noted
with regard to the secondary shape 60, associated with the recovery
or recapture of the device 10 by the catheter 32, and in
particular, with engagement of the pusher 34 with the coupling 30
on the device 10. Recovery or recapture may be facilitated if the
proximal or tail portion 36 of the coil 12 (extending distally from
the proximal coil end 16) is kept straight, without any curve in
it. This is particularly important if the proximal coil end 16
contains the proximal end 26 of the core, and even more important
if the proximal core end 26 is affixed to the proximal coil end 16.
Ideally, however, a short portion of the coil adjacent to the
proximal coil end 16 is made without core reinforcement.
Maintaining a straight proximal coil end portion 36 is also
important for allowing the coil 12 to be readily pushed within the
catheter 32 by the pusher 34, particularly when a relatively large
diameter core 22 is employed. A non-reinforced coil (like a
traditional spring coil) even with a curve usually does not
interfere with the pushability of the coil through the delivery
catheter.
[0052] In a further possible embodiment, a complex, substantially
spherical secondary shape 72 is created from a series of helical
turns (FIG. 14) spaced angularly about an axis. The shape of these
turns may be, for example, circular (round) 74 as in FIG. 15, or
D-shaped 78 as in FIG. 16. FIG. 14 shows a series of helical turns
74 initially aligned longitudinally. To make the complex,
substantially spherical secondary shape 72, the two end-turns 76 of
the helix should be held and then approached to each other to first
form a semicircle from the helix (FIG. 17). By continuing to
approach the end-turns 76 to one another until the circle is
completed, a complex, substantially spherical secondary shape 72 is
created (FIG. 18 and FIG. 19). By doing so, the central portion of
each turn forms a vertical segment in the center of the device.
This vertical segment is more prominent (and actually vertical) if
the turns are D-shaped 78 as in FIG. 16. The central, vertical
portions 80 of the D-shaped turns 78 can move beside and/or toward
each other if the outer convex portions 82 of the D-shaped turns 78
are pressed together from outward. This is the case, when the
above-described complex spherical secondary shape 72 is deployed in
a vessel. Depending upon the relationship between the diameters of
the occluder and the vessel, the complex coil will be constrained
to a certain degree by the vessel wall, similar to the arrangement
shown in FIG. 3. As a result, the regular shape of the design will
be distorted to a certain extent, and simultaneously the device
will be effectively anchored.
[0053] The features of the substantially spherical secondary shape
72 depicted in FIGS. 14 to 19 which are advantageous in particular
are:
[0054] a) the described arrangement of the coil can produce a
better coverage of the vascular space resulting in a quicker
occlusion;
[0055] b) the self-anchoring capability of the occluder will be
ideal, as the coil will press against the vessel wall at several
points;
[0056] c) being substantially spherically shaped, the occluder does
not require any particular orientation within the vasculature to
achieve the best possible occlusion effect, so the occlusive
capacity of the design is very similar whatever its orientation
within the given space; and
[0057] d) because of its spherical shape, the given cross-section
of the vessel to be occluded will be evenly covered resulting in
fast occlusion and minimal chance for recanalization; (the
traditional helical coils are basically aligned along the
circumference of the vessel leaving the center of the vessel
unoccupied;) the ideal spherical shape can be approached better if
the coil turns are formed with a D-shape as seen in FIG. 17.
[0058] An additional embodiment of a secondary shape for device 10
is illustrated in FIGS. 20 and 21 especially suitable for treatment
of wide neck aneurysms. FIG. 20 (lateral) and FIG. 21
(antero-posterior view) depict a wide neck aneurysm 86 in a vessel
42. The wide aneurysm neck 88 poses a significant problem to
embolotherapy, since it is not able to prevent protrusion of coil
turns deployed within the sac of the aneurysm. Apprehensive of
causing inadvertent thrombosis in the parent vessel, the
interventional radiologist often has to leave the neck unoccupied
by the coil. The incomplete occlusion may result in further
expansion and, possibly, consequent rupture and/or recurrence of
the aneurysm.
[0059] In the protective embodiment of device 10 of the present
invention shown in FIGS. 20 and 21, a series of helical turns of
the reinforced coil of device 10 are arranged in a generally
flattened array so that they can form a virtual flat, oval plate 84
(like a platter), with a general size greater than the aneurysm
neck. Even more preferably, the oval plate 84 is bent
circumferentially providing the plate with some depth and making it
concave (seen from inside) or convex (seen from outside). The
reinforced coil is preferably deployed within the aneurysmal sac
around the rim or periphery of the aneurysmal neck 88 with its
convexity facing the parent vessel 42. As a result, the coil abuts
the aneurysm wall adjacent to the neck 88 at several points about
its periphery ensuring good fixation of the device. In this special
protective embodiment and the associated method, this type of coil
is used to cover the wide neck 56 forming a relatively loose mesh.
Through the plurality of holes of this mesh other, additional coils
will then subsequently be deployed to fill the aneurysmal sac as
much as possible; consequently, this type of coil is preferably not
provided with any type of thrombogenic material. The goal of the
protective coil having the special "oval plate" secondary shape 58
is to prevent coil protrusion and to promote complete embolization
of the aneurysmal sac.
[0060] The specific dimensions of the coil 12 and core 22 of FIGS.
1 to 21 should be selected in light of the particular occlusive
function to be performed by the device 10 at the target location in
the patient. By way of example, the coil 12 can typically have an
overall length of about 2 cm to about 40 cm, such a length being
when constrained in an elongated shape within the catheter, or
being considered before the establishment of any secondary shape 60
for the coil 12. Each loop of wire 14 of coil 12 can typically have
an outside diameter of about 0.010 in. to about 0.032 in. (about
0.25 mm to about 0.81 mm), while the core 22 can typically have a
diameter of about 0.004 in. to about 0.015 in. (about 0.10 mm to
about 0.38 mm). The loops of wire 14 may be manufactured by
utilizing fine wire having a diameter of 0.003 in. to about 0.005
in. (about 0.076 mm to about 0.126 mm). The secondary shape 60 of
coil 12 may have a diameter of about 3 mm to about 15 mm. Where a
nitinol core is used having a diameter of about 0.004 in. to about
0.006 in. (about 0.10 mm to about 0.15 mm), the coil may have a
diameter of about 0.010 in. to about 0.015 in. (0.25 mm to 0.38
mm). These dimensions are, of course, merely examples. The specific
dimensions of any particular embodiment of the vasoocclusion device
10 will depend upon the particular occlusion to be established.
[0061] As indicated previously, the present invention is also
directed to a medical device 40 (see FIG. 3) for establishing an
embolus or vascular occlusion in a human or veterinary patient. The
medical device 40 comprises the coil 12, the core 22, the catheter
32 and the pusher 34 described above, and preferably also includes
the coupling 30 described above.
[0062] The vasoocclusion device 10 of the present invention is
expected to find utility in the performance of a wide range of
procedures. For example, the improved anchoring enjoyed by the
device 10 may allow it to be used in non-tapering territories of
the vascular system. It is believed that coil-type devices have not
previously been used in non-tapering territories because of the
high likelihood of migration of the coil-type devices. The device
10 of the present invention may also find use in treating
arterio-venous malformations and fistulas, in lesions of both the
extremities and the lungs.
[0063] Another possible use of the device 10 of the present
invention might be the occlusion of patent ductus arteriosus (PDA).
Failure of prior devices to achieve successful closure of PDAs
(especially those of larger diameter) is relatively frequent,
because the interventional radiologist seeks to avoid complete
occlusion through fear of causing inadvertent coil embolization.
The device 10 may be useful with larger diameter lesions than has
been possible with prior coils, while simultaneously improving
safety of this type of vessel occlusion, due to the greater
self-anchoring it enjoys. Except for very short lesions, the device
10 should have an advantage over several prior vascular occluders
in that the device 10 is considerably smaller than those occluders
and requires a smaller sized delivery system.
[0064] Yet another potential use of the device 10 is the safe
exclusion of chronic pseudoaneurysms from the circulatory system.
The device 10 might be easier to use than conventional coil(s) in
combination with the spider-type devices presently employed for
that purpose, avoiding known complications associated with such
devices.
[0065] Vasoocclusion device 10 may also achieve a significant role
in the non-surgical management of patients with
systemic-to-pulmonary collateral vessels and shunts; in the
embolization treatment of coronary artery fistulas; and in
embolization treatments on the venous side, for example, in the
treatment of varicoceles or aberrant vessels.
[0066] The vasoocclusion device 10 of the present invention
possesses significantly enhanced self-anchoring capability over
that of comparable stainless steel coils lacking the disclosed
nitinol core. Dislodgment force tests carried out on devices
deployed into the branches of the superior mesenteric artery (SMA)
in pigs, disposed in the abdominal aorta and the inferior vena cava
of pigs or positioned within a plastic tube indicate that the
device 10 requires a dislodgment force of about twice the force
required to dislodge comparable stainless steel coils lacking the
disclosed core.
[0067] It should be clear that the present invention provides a
coil-type vasoocclusion device 10 which may possess significant
advantages over prior devices for that purpose. It may be possible
to adjust the assistive anchoring force provided by the core of the
device to a coil of a given length, by selection of the length of
the core. Changing the diameter of the core is another way to find
the optimal anchoring forces of the device. Since one end of the
core is free and not affixed to an end of the coil, the assistive
anchoring force provided by the coil may be maximized, and not
diminished by any twisting of the core during manipulation or
positioning of the coil. Finally, such an arrangement may
facilitate removal or repositioning of the device, since elongation
of the coil when subjected to a longitudinal removing force may
lessen the anchoring force supplied by the coil itself, making
engagement with the introducing or removal apparatus easier.
[0068] The details of the construction or composition of the
various elements of the vasoocclusion device 10 not otherwise
disclosed are not believed to be critical to the achievement of the
advantages of the present invention, so long as the elements
possess the strength or mechanical properties needed for them to
perform as disclosed. The selection of any such details of
construction are believed to be well within the ability of one of
even rudimentary skills in this area, in view of the present
disclosure.
INDUSTRIAL APPLICABILITY
[0069] The present invention is useful for establishing an embolus
or occlusion in the vascular system, and therefore finds
applicability in human and veterinary medicine.
[0070] It is to be understood, however, that the above-described
device is merely an illustrative embodiment of the principles of
this invention, and that other devices and methods for using them
may be devised by those skilled in the art, without departing from
the spirit and scope of the invention. It is also to be understood
that the invention is directed to embodiments both comprising and
consisting of the disclosed parts.
* * * * *