U.S. patent application number 12/652565 was filed with the patent office on 2010-04-29 for flexible embolic device delivery system.
This patent application is currently assigned to BOSTON SCIENTIFIC SCIMED, INC.. Invention is credited to Kevin M. Jaeger, Maria Pizarro, Stephen C. Porter, Clifford Teoh, Michael Wallace.
Application Number | 20100106162 12/652565 |
Document ID | / |
Family ID | 33097511 |
Filed Date | 2010-04-29 |
United States Patent
Application |
20100106162 |
Kind Code |
A1 |
Jaeger; Kevin M. ; et
al. |
April 29, 2010 |
FLEXIBLE EMBOLIC DEVICE DELIVERY SYSTEM
Abstract
The present invention provides an embolic assembly delivery
apparatus having superior flexibility characteristics at its distal
end, that is, at the point of attachment of the embolic assembly to
the delivery apparatus. It also provides a method of using the
apparatus to deliver an embolic assembly to a target site in a
patient's body.
Inventors: |
Jaeger; Kevin M.;
(Pleasanton, CA) ; Porter; Stephen C.; (Oakland,
CA) ; Teoh; Clifford; (Los Altos, CA) ;
Wallace; Michael; (Fremont, CA) ; Pizarro; Maria;
(Union City, CA) |
Correspondence
Address: |
VISTA IP LAW GROUP LLP
12930 Saratoga Avenue, Suite D-2
Saratoga
CA
95070
US
|
Assignee: |
BOSTON SCIENTIFIC SCIMED,
INC.
Maple Grove
MN
|
Family ID: |
33097511 |
Appl. No.: |
12/652565 |
Filed: |
January 5, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10407295 |
Apr 3, 2003 |
7651513 |
|
|
12652565 |
|
|
|
|
Current U.S.
Class: |
606/108 ;
606/200 |
Current CPC
Class: |
A61B 2017/12063
20130101; A61B 17/12113 20130101; A61B 17/12022 20130101; A61B
2017/1205 20130101; A61B 2017/00867 20130101; A61B 17/12154
20130101; A61B 2017/00862 20130101 |
Class at
Publication: |
606/108 ;
606/200 |
International
Class: |
A61F 11/00 20060101
A61F011/00; A61F 2/01 20060101 A61F002/01 |
Claims
1. A device for releasing an embolic assembly at a target site in a
vessel of a patient, comprising: a core wire comprising a first
electrically-conductive substance that is at least partially
fixedly encased in a first non-conductive substance and has a
proximal and a distal end, its proximal end being connected to an
electrical signal generator; a flexible member having a proximal
and a distal end, its proximal end being coupled to the distal end
of the core wire; an embolic assembly having a proximal and a
distal end, its proximal end being operatively coupled to the
distal end of the flexible member; and an electrolytic detachment
site located between the proximal end of the embolic assembly and a
distal end of the first non-conductive substance, wherein the
flexible member comprises a first loop interlinked with a second
loop, the first loop having a first and a second end, both of which
are operatively coupled to the distal end of the core wire, a
distal portion of which is optionally bare, and the second loop
having a first and a second end, both of which are operatively
coupled to the proximal end of the embolic assembly.
2. The device of claim 1, wherein the first and second ends of the
first loop are operatively coupled to a bare portion of the distal
end of the core wire by a second electrically-conductive substance
that is different from the first electrically-conductive substance,
the second electrically-conductive substance having a proximal end
fixedly coupled to the distal end of the bare portion of the core
wire and a distal end that, along with the two ends of the first
loop, is fixedly encased in a second non-conductive substance,
which may be the same as, or different than, the first
non-conductive substance.
3. The device of claim 2, wherein the second
electrically-conductive substance comprises an electrically
conductive wire that is helically wound around the bare portion of
the distal end of the core wire and the ends of the first loop.
4. The device of claim 2, wherein the first electrically-conductive
substance comprises stainless steel or nitinol, the first
non-conductive substance comprises a first non-conductive polymer,
the second electrically-conductive substance comprises a
platinum-tungsten alloy, and the second non-conductive substance
comprises a second non-conductive polymer which may be the same as,
or different than, the first non-conductive polymer.
5. A device for releasing an embolic assembly at a target site in a
vessel of a patient, comprising: a core wire comprising a first
electrically-conductive substance that is at least partially
fixedly encased in a first non-conductive substance and has a
proximal and a distal end, its proximal end being connected to an
electrical signal generator; a flexible member having a proximal
and a distal end, its proximal end being coupled to the distal end
of the core wire; an embolic assembly having a proximal and a
distal end, its proximal end being operatively coupled to the
distal end of the flexible member; and an electrolytic detachment
site located between the proximal end of the embolic assembly and a
distal end of the first non-conductive substance, wherein the
flexible member comprises a second wire and a third wire, the
second wire comprising a second electrically-conductive substance
which may be the same as, or different than, the first
electrically-conductive substance, the second wire having a
proximal end forming a first helical coil segment and a distal end
forming a first loop segment, the first helical coil segment being
fixedly coupled to the distal end of the core wire, and the third
wire comprising a third electrically-conductive substance which is
different than the second electrically-conductive substance, the
third wire having a proximal end forming a second loop segment
interlinked with the first loop segment of the second wire, and a
distal end forming a second helical coil segment that is fixedly
encased in a second non-conductive substance with the proximal end
of the embolic assembly.
6. The device of claim 5, wherein the first and second conductive
substances comprise stainless steel or nitinol, the first
non-conductive substance comprises a first non-conductive polymer,
the third conductive substance comprises a platinum-titanium alloy,
and the second non-conductive substance comprises a second
non-conductive polymer which may be the same as, or different than,
the first non-conductive substance.
Description
RELATED APPLICATION DATA
[0001] This application is a continuation application of co-pending
U.S. patent application Ser. No. 10/407,295, filed Apr. 3, 2003,
the priority of which is claimed under 35 U.S.C. .sctn.120, and the
contents of which are incorporated herein by reference in their
entirety, as though set forth in full.
BACKGROUND OF THE INVENTION
[0002] The use of embolic devices to prevent rupture, or to
minimize blood loss in case of rupture, of aneurysms has become a
relatively routine medical procedure. The basic approach is to
deliver the device to the site of an aneurysm using a steerable
catheter that is inserted in a vessel at a remote location and is
then directed to a position adjacent to the aneurysm. A pusher
wire, with the embolic device attached to its distal end, is then
threaded through the catheter and beyond until the device is
situated in the aneurysm. The presently preferred embolic device is
a coil of wire, typically platinum/tungsten alloy, that when
stretched assumes a linear helical configuration and when relaxed
assumes a convoluted configuration that will fill the interior of
the aneurysm. The convoluted configuration may be completely random
or it may be controlled using shape-memory alloys. The wire
generally has a diameter of 2-6 mils while the coils are usually in
the range of 10-30 mils in diameter. The coils may be of any length
appropriate for the intended use. Depending on its size, from one
to a great many coils may used to fill a single aneurysm. Once in
place, the embolic devise initiates formation of a thrombus that is
soon complemented by a collagenous material that further lessens
the potential for rupture or for significant blood loss should the
aneurysm break.
[0003] Once a coil is in place in the aneurysm, it is detached from
the distal end of the pusher wire. Detachment can be accomplished
in numerous ways including mechanically (unscrew, remove key from
slot, separate ball and socket, etc.), electrolytically
(disintegration of junction between metals having different
standard electrode potentials) and energetically (vibrational
cohesive disruption). Electrolytic detachment is one of the
currently favored method of releasing an embolic device due it lack
of a need for complex remote manipulation of the connection and,
therefore, its speed and precision.
[0004] In virtually all electrolytically separable embolic device
delivery systems presently in use, the embolic device is attached
essentially to the end of the pusher wire, the difference in
electrode potential between the pusher wire metal and that of which
the embolic device is constructed supplying the requisite
potential. The pusher wire, however, is generally relatively stiff,
a necessary characteristic that allows it to be controllably
threaded through the catheter and beyond to position the embolic
device at the target site.
[0005] While the current devices work well, certain advantages
might accrue if the distal end of the device were somewhat more
flexible than the pusher wire itself. For instance, without
limitation, some operators might find that such a device provides a
softer feel as the embolic device is positioned and released. This
invention provides such a flexible device.
SUMMARY OF THE INVENTION
[0006] Thus, in one aspect, the present invention, a device for
releasing an embolic assembly at a target site in a vessel of a
patient, comprising:
[0007] a core wire comprising a first electrically-conductive
substance that is at least partially fixedly encased in a first
non-conductive substance and has a proximal and a distal end, its
proximal end being connected to an electrical signal generator;
[0008] a flexible member having a proximal and a distal end, its
proximal end being coupled to the distal end of the core wire;
[0009] an embolic assembly having a proximal and a distal end, its
proximal end being operatively coupled to the distal end of the
flexible member; and,
[0010] an electrolytic detachment site located between the proximal
end of the embolic assembly and a distal end of the first
non-conductive substance.
[0011] In an aspect of this invention the flexible member comprises
a second wire comprising a second electrically-conductive
substance, which may be the same as, or different than, the first
electrically-conductive substance, the second wire having a helical
coil segment and, distal to the helical coil segment, a straight
segment; wherein the helical coil segment is fixedly coupled to the
distal end of the core wire and is also fixedly encased in the
first non-conductive substance and at least a portion of the
straight segment is bare, the bare portion being coupled to a
proximal end of a third electrically-conductive substance, which is
different from the second electrically-conductive substance, the
third electrically conductive substance having a distal end that is
operatively coupled to the embolic assembly.
[0012] In an aspect of this invention, the third
electrically-conductive substance is, along with the proximal end
of the embolic assembly, encased in a non-conductive substance that
may be the same as, or different than, the first non-conductive
substance.
[0013] In an aspect of this invention, the third
electrically-conductive substance comprises an electrically
conductive wire that is fixedly helically wound around the bare
portion of the straight segment of the second wire.
[0014] In an aspect of this invention, the helically wound segment
of the second wire comprises a first and a second helically wound
portion, the portions being independently open- or closed-pitched,
the first portion being at least partially fixedly encased in the
first non-conductive substance and being coupled to the distal end
of the core wire, the second portion optionally being partially
encased in the first non-conductive substance, the second portion
being distal to the first portion and coupled to the third
electrically-conductive substance.
[0015] In an aspect of this invention, the first and second
portions of the helically-wound segment are both closed
pitched.
[0016] In an aspect of this invention, the first and second
portions of the helically-wound segment are both open-pitched.
[0017] In an aspect of this invention, the first portion of the
helically wound segment is open-pitched and the second portion is
closed-pitched.
[0018] In an aspect of this invention, the second portion of the
helically-wound segment is at least partially surface-coated with a
second non-conductive substance, which may be the same as, or
different from, the first non-conductive substance.
[0019] In an aspect of this invention, the core wire comprises
stainless steel or nitinol; the first non-conductive substance
comprises a first non-conductive polymer; the second wire
independently comprises stainless steel or nitinol and the third
electrically-conductive substance comprises a platinum-tungsten
alloy.
[0020] In an aspect of this invention, the core wire comprises
stainless steel or nitinol; the first non-conductive substance
comprises a first non-conductive polymer; the second wire
independently comprises stainless steel or nitinol; the third
electrically-conductive substance comprises a platinum-tungsten
alloy and the second non-conductive substance comprises a second
non-conductive polymer, which may be the same as, or different
from, the first non-conductive polymer.
[0021] In an aspect of this invention, the flexible member
comprises a first loop having a first and a second end, both of
which are operatively coupled to the distal end of the core wire, a
distal portion of which is optionally bare and a second loop having
a first and a second end, both of which are operatively coupled to
the proximal end of the embolic assembly, wherein the first and
second loops are interlinked.
[0022] In an aspect of this invention, the first and second ends of
the first loop are operatively coupled to a bare portion of the
distal end of the core wire by a second electrically-conductive
substance that is different from the first electrically-conductive
substance, the second electrically-conductive substance having a
proximal end fixedly coupled to the distal end of the bare portion
of the core wire and a distal end that, along with the two ends of
the first loop, is fixedly encased in a second non-conductive
substance, which may be the same as, or different than, the first
non-conductive substance.
[0023] In an aspect of this invention, the second
electrically-conductive substance comprises an electrically
conductive wire that is helically wound around the bare portion of
the distal end of the core wire and the ends of the first loop.
[0024] In an aspect of this invention, the first
electrically-conductive substance comprises stainless steel or
nitinol; the first non-conductive substance comprises a first
non-conductive polymer; the second electrically-conductive
substance comprises a platinum-tungsten alloy and the second
non-conductive substance comprises a second non-conductive polymer,
which may be the same as, or different than, the first
non-conductive polymer.
[0025] In an aspect of this invention the flexible member comprises
a second wire comprising a second electrically-conductive
substance, which may be the same as, or different than, the first
electrically-conductive substance, and having a proximal and an
distal end, the second wire further having, at its proximal end, a
first helical coil segment and, at its distal end, a first loop
segment, the helical coil segment being fixedly coupled to the
distal end of the core wire and a third wire comprising a third
conductive substance, which is different than the second conductive
substance, and having a proximal and a distal end, the third wire
further having a second loop segment at its proximal end, wherein
the first and second loop segments are interlinked and the distal
end of the second helical segment and the proximal end of the
embolic assembly are fixedly encased in a second non-conductive
substance.
[0026] In an aspect of this invention, the first and second
conductive substances comprise stainless steel or nitinol; the
first non-conductive substance comprises a first non-conductive
polymer; the third conductive substance comprises a
platinum-titanium alloy and the second non-conductive substance
comprises a second non-conductive polymer, which may be the same
as, or different than, the first non-conductive substance.
[0027] In an aspect of this invention, the above device(s) further
comprises a stretch resistant member having a first and a second
end, the first end being fixedly coupled to the distal end of the
core wire and the second end being fixedly coupled to the flexible
member.
[0028] In an aspect of this invention, the above device(s) further
comprise a non-conductive bushing at a distal end of the first
non-conductive substance, the bushing having a lumen through which
the distal end of the core wire, or the distal end of a flexible
member, passes.
[0029] An aspect of this invention is a method for releasing an
embolic assembly at a target site in a patient's body,
comprising:
[0030] providing a delivery member capable of positioning a core
wire in close proximity to a target site, the delivery member
comprising a first elongate tube having a proximal end,
[0031] a distal end and an axial lumen; providing a core wire
slidably disposed within the axial lumen, the wire comprising a
first electrically-conductive substance that is at least partially
fixedly encased in a first non-conductive substance and has a
proximal and a distal end, its proximal end being connected to an
electrical signal generator;
[0032] providing a flexible member having a proximal and a distal
end, its proximal end being coupled to the distal end of the core
wire;
[0033] providing an embolic assembly having a proximal and a distal
end, its proximal end being operatively coupled to the distal end
of the flexible member; and,
[0034] providing an electrolytic detachment site located between
the proximal end of the embolic assembly and a distal end of the
first conductive substance;
[0035] moving the delivery member to a position in close proximity
to the target site;
[0036] sliding the core wire through the lumen of the delivery
member until the embolic assembly is at or in the target site;
and,
[0037] sending an electrical signal to the electrolytic detachment
site which results in release of the embolic assembly.
[0038] In an aspect of this invention, in the above method, the
flexible member comprises a second wire comprising a second
electrically-conductive substance, which may be the same as, or
different than, the first electrically-conductive substance, the
second wire having a helical coil segment and, distal to the
helical coil segment, a straight segment wherein the helical coil
segment is fixedly coupled to the distal end of the core wire and
is also fixedly encased in the first non-conductive substance and
at least a portion of the straight segment is bare, the bare
portion being coupled to a proximal end of a third
electrically-conductive substance, which is different from the
second electrically-conductive substance, the third electrically
conductive substance having a distal end that is operatively
coupled to the embolic assembly.
[0039] In an aspect of this invention, in the above method, the
third electrically-conductive substance comprises an electrically
conductive wire that is fixedly helically wound around the bare
portion of the straight segment of the second wire.
[0040] In an aspect of this invention, in the above method, the
helically wound segment of the second wire comprises a first and a
second helically wound portion, the portions being independently
open- or closed-pitched, the first portion being at least partially
fixedly encased in the first non-conductive substance and being
coupled to the distal end of the core wire, the second portion
optionally being partially encased in the first non-conductive
substance, the second portion being distal to the first portion and
coupled to the third electrically-conductive substance.
[0041] In an aspect of this invention, in the above method, the
first and second portions of the helically wound segment are both
closed-pitched.
[0042] In an aspect of this invention, in the above method, the
first and second portions of the helically wound segment are both
open-pitched.
[0043] In an aspect of this invention, in the above method, the
first portion of the helically would segment is open-pitched and
the second portion is closed-pitched.
[0044] In an aspect of this invention, in the above method, the
second portion of the helically-wound segment is at least partially
surface-coated with a second non-conductive substance, which may be
the same as, or different from the first non-conductive
substance.
[0045] In an aspect of this invention, in the above method, the
flexible member comprises a first loop having a first and a second
end, both of which are fixedly coupled to the distal end of the
core wire, a distal portion of which is optionally bare and a
second loop having a first and a second end both of which are
operatively coupled to the proximal end of the embolic assembly
wherein the first and second loops are interlinked.
[0046] In an aspect of this invention, in the above method, the
first and second ends of the first loop are operatively coupled to
a bare portion of the distal end of the core wire by a second
electrically-conductive substance that is different from the first
electrically-conductive substance, the second
electrically-conductive substance having a proximal end fixedly
coupled to the bare portion of the distal end of the core wire and
a distal end that, along with the two ends of the first loop, is
fixedly encased in a second non-conductive substance, which may be
the same as, or different than, the first non-conductive
substance.
[0047] In an aspect of this invention, in the above method, the
flexible member comprises a second wire comprising a second
electrically-conductive substance, which may be the same as, or
different than, the first electrically-conductive substance, and
having a proximal and an distal end, the second wire further
having, at its proximal end, a first helical coil segment and, at
its distal end, a first loop segment, the helical coil segment
being fixedly coupled to the distal end of the core wire and a
third wire comprising a third conductive substance, which is
different than the second conductive substance, and having a
proximal and a distal end, the third wire further having a second
loop segment at its proximal end wherein the first and second loop
segments are interlinked and the distal end of the second helical
segment and the proximal end of the embolic assembly are fixedly
encased in a second non-conductive substance.
[0048] In an aspect of this invention, the above method further
comprises a stretch resistant member having a first and a second
end, the first end being fixedly coupled to the distal end of the
core wire and the second end being fixedly coupled to the flexible
member.
[0049] In an aspect of this invention, the above method further
comprises a non-conductive bushing coupled to a distal end of the
first non-conductive substance and having a lumen through which the
distal end of the core wire, or the distal end of the flexible
member, passes.
[0050] In an aspect of this invention, the target site is selected
from the group consisting of an aneurysm, an arteriovenous
malformation, a fistula, a blood vessel or any other body
lumen.
DETAILED DESCRIPTION OF THE INVENTION
Brief Description of the Drawings
[0051] The figures and description of each of them below are
intended solely to aid in the understanding of the invention
herein. They are not intended, nor should they be construed, to
limit the scope of this invention in any manner whatsoever. For
example, where a helical coil is being represented, out of
necessity only a certain number of actual turns can be shown. The
number of turns shown, however, is not to be construed as limiting
the scope of this invention in any manner whatsoever; more or less
turns are possible and are within the scope of this invention.
Also, the pitch of the helical coils is not limited to that shown
in the figures. The pitch can be varied to impart any desired
degree of flexibility to the segments of the device containing the
coils.
[0052] FIG. 1 is a schematic depiction of an embodiment of this
invention wherein flexibility is introduced between the distal end
of pusher wire 10 and embolic member 120 by helically wound wire
100.
[0053] FIG. 2 is a schematic depiction of an embodiment of this
invention wherein flexibility is introduced between distal end of
pusher wire 10 and embolic member 480 by a helically wound wire
comprised of two portions, 420 and 430, which are independently
open or closed-pitched. In FIG. 2A, the proximal portion 520 is
open-pitched and the distal portion 530 is closed-pitched.
[0054] FIG. 3 is a schematic depiction of the embodiment shown in
FIG. 2 wherein both the proximal portion 520 and the distal portion
530 of the helically wound segment are open-pitched.
[0055] FIG. 4 is a schematic depiction of a further embodiment of
this invention wherein flexibility is conferred on the distal end
of the device by virtue of interlinked loops 60 and 95.
[0056] FIG. 5 is a schematic depiction of a still further
embodiment of this invention wherein the flexibility-conferring
features of the device in FIGS. 1 and 4 are combined; that is, the
device in FIG. 5 comprises both a helically wound segment 100 and
interlinked loops, 300 and 310.
DISCUSSION
[0057] FIG. 1 schematically depicts an embodiment of the present
invention. The distal end of pusher (or core, the terms are used
interchangeably herein) wire 10 is coupled to the proximal end of
helical coil 100 by weld junction 110. Helical coil 100 may be open
or closed pitch and the pitch itself can be varied to establish a
desired degree of softness or pliability in region of the device.
Pusher wire 10 is encased in non-conducting substance 20. Weld
junction 110 and helical coil 100 are also encased in
non-conductive substance 20. Weld junction 110 and helical coil 100
are also encased in non-conductive substance 20. Typically the
non-conducting substance will encase wire 10 from near its proximal
end (enough being left bare to connect to a power supply) to its
distal end and then encase helical coil 100 to near its distal end,
where a portion is left bare to provide detachment site 30 where
electrolytic disintegration of the wire can occur resulting in
separation of embolic member 120. Non-conducting substance 20 can
be any suitable insulating material such as
poly(tetrafluoroethylene) (Teflon..RTM..), poly(paraxylene)
(Parylene..RTM..), poly(ethylene terephthalate) (PET),
poly(cyanoacrylates) and the like. PET is presently preferred.
Pusher wire 10 may be made of any material that has sufficient
resilience/flexibility to permit accurate movement and placement of
its distal end at a target site in a patient's body by manipulation
of the wire at its proximal end, which may be many centimeters
away. While this includes material such as carbon fiber and
polymers, it is presently preferred that pusher wire 10 be
stainless steel or nitinol. Helical coil 100 likewise can be made
of any conductive substance with the appropriate mechanical
characteristics. It is presently preferred that helical coil 100 be
of the same material as pusher wire 10. Non-conductive bushing 50
may optionally be included at the distal end of insulating layer 20
to provide additional isolation of electrolytic detachment site 30
from helical coil 100. Detachment site 30 is coupled to embolic
assembly 120 by another conductive substance that has a different
standard electrode potential (E.sup.0) than that of detachment site
30. In FIG. 1, the conductive substance is shown as a wire
helically-wound around detachment site 30. This, however, is not to
be construed as the only way to connect embolic assembly 120 and
the delivery device. Any manner of connection such as wire winding,
spot welds, pressure clips, etc. that permit close contact of the
first conductive substance of detachment site 30 and the second
conductive substance will suffice. As shown in FIG. 1, helical coil
70 is wound around the distal end of electrolytic detachment site
30 and partially encased in a mass of non-conductive substance 80.
Non-conductive substance 80 can be any insulating substance,
fusable polymers being particularly useful with PET being presently
preferred. The proximal end of embolic assembly 120 is also encased
in non-conductive substance 80. Upon delivery of an electrical
signal to separation locus 30, the conductive substance with the
lower E.sup.0 will erode away resulting in release of embolic
member 120. As shown, connector 70 is a conducting metal that has a
different E.sup.0 than the metal of which detachment site 30 is
comprised. While any two metals that have the required E.sup.0
difference may be used, it is presently preferred that separation
locus 30 be stainless steel or nitinol and connector 70 be a
platinum/tungsten alloy.
[0058] Yet another embodiment of the present invention is
schematically depicted in FIG. 2. Pusher wire 10 is coupled to
helically-wound segment 410 of wire 400. Segment 420 of wire 400 is
open-pitched helically wound. Pusher wire 10, segment 410 and
segment 420 of wire 400 are encased in non-conductive substance 20.
As in the above embodiments, a non-conductive bushing 50 may be
attached to the distal end of non-conductive substance 20 to
further isolate open-pitched segment 420 of wire 400 from
closed-pitched segment 430 of wire 400. Segment 430 is optionally
coated with a non-conductive substance, which may be the same
substance used to encase pusher wire 10 and segment 420 or it may
be a different non-conducting substance. It should be noted that,
as used herein, the term "encased" refers to the complete
surrounding of an element of this invention such that the
individual features of the element are not readily apparent from
the outside of the encasing substance. Thus, the helically-wound
nature of a wire encased in a substance would not be apparent to
the casual observer. To the contrary, when the term
"surface-coated" is used, it means that the element so-coated
retained its appearance; i.e., a surface coated helically-wound
wire appears to the casual observer as a helically wound wire. A
typical example of "surface-coated" would be a common insulated
electrical wire available for purchase at a hardware store. Pliable
non-conductive materials such as those disclose above with regard
to the first embodiment of this invention are presently preferred.
The distal end of segment 430 is bare and comprises detachment site
440. The proximal end of helical coil 450 is tightly wrapped around
the distal portion of separation locus 440 to bind the two
together. As above, helical coil 450 and separation locus 440 are
made of metals or alloys having different values of E.sup.o. While
coil 450 and locus 440 can be made of any metals or alloys that
exhibit the required difference in E.sup.o, it is presently
preferred that detachment site 440 be stainless steel or nitinol
and helical coil 450 be a platinum/titanium alloy. The distal end
of coil 450 is embedded in a fusible, non-conductive polymeric mass
470. The proximal end of embolic assembly 480 is also embedded in
polymeric mass 470. Optional stretch-resistant member 460 may be
attached at one end to the distal end of pusher wire 10 and at the
other end to detachment site 440 and threaded through the lumen
described by the coiled segments of wire 400. Member 460 provides
stretch resistance to wire 400 in the helical regions. Member 460
may be made of any resilient, non-stretchable material. In general,
polymeric materials having the requisite characteristics are most
often used. Presently, polypropylene suture material is preferred.
It is emphasize that FIG. 2 represents a version of this embodiment
of the invention. that is, while segment 420 is shown as
open-pitched and segment 430 as closed-pitched, it is entirely
possible, and it is within the scope of this invention, that this
be reversed, i.e., that segment 420 be closed-pitched and segment
430 be open-pitched. Likewise, both segments can be closed-pitched
or open pitched, this latter configuration being shown
schematically in FIG. 3. Furthermore, while FIG. 2 shows the point
of separation of segments 420 and 430 as coincidentally being the
distal end of non-conductive substance 20 or, optionally, the
distal end of non-conductive bushing 50, such is not necessarily
the case. That is, the distal end of non-conductive substance 20
(or bushing 50) may be anywhere along the length of segment 420 or
segment 430. In addition, as is noted above, segment 430 and
detachment site 440 are shown being coupled to embolic assembly 480
by helically-wound wire 450 and non-conductive substance 450. There
are, however, many ways that this connection can be made give and
such will become apparent to those skilled in the art based on the
disclosures herein. All such configuration are within the scope of
this invention.
[0059] FIG. 4 depicts yet another embodiment of this invention in
which increased flexibility is introduced into the device by means
of interlinking loops 60 and 95. Again, pusher wire 10 is encased
in non-conductive substance 20, with enough of wire 10 being left
exposed at its proximal end to attach to a power supply. In
addition, a portion of its distal end is also left bare to provide
detachment site 30. Non-conductive substance can be any of those
discussed above with regard to the other embodiments of this
invention. And again, a non-conductive bushing 50 may optionally be
included to provide additional separation of the encased portion of
pusher wire 10 from detachment site 30. Electrolytic separation of
embolic member 120 is accomplished by virtue of connecting entity
70, which comprises a metal having a different E.sup.o than that of
pusher wire 10. Upon delivery of an electrical signal to detachment
site 30, the metal with the lower E.sup.o will erode away resulting
in release of embolic member 120. As shown, embolic member 120 is
attached pusher wire 10 by a mass of non-conducting substance 80,
which may be the same as, or different than, the non-conducting
substance that is used to encase pusher wire 10. While any
combination of metals for core wire 10 and connector 70 that have
the requisite difference in E.sup.o may be used, typically core
wire 10 is stainless steel or nitinol and connector 70 is a
platinum/zirconium alloy.
[0060] Eyelet loop 60 can be made of any non-conductive material.
Presently preferred are those that can form a fiber or fiber-like
structure. PET is a presently preferred substance with the desired
characteristics. Embolic assembly member 40 has a distal helically
wound coil region 90 and an eyelet loop 95, which is interlinked
with eyelet loop 60. As above, the embodiments shown in FIG. 4 are
exemplary only and other configurations are possible without
exceeding the scope of this invention. For example, region 90 of
embolic assembly 40 need not necessarily be a helically-wound wire
but may simply be, for example without limitation, a straight
segment of wire or even a flat piece of metal.
[0061] FIG. 5 is a schematic representation of yet another
embodiment of this invention that combines the elements of the two
embodiments above. Thus, the distal end of pusher wire 10 is
coupled to the proximal end of helical coil 100 by weld junction
110. Helical coil 100 may be open or closed pitch, and the pitch
itself may be varied, to establish a desired degree of softness or
pliability. Pusher wire 10, weld junction 110 and helical coil 100
are encased in non-conductive substance 20. Non-conductive
substance 20 can be any of the materials mentioned above with
regard to the first and second described embodiments of this
invention or any other material that meets the requirements of the
disclosures herein. Likewise, non-conductive bushing 50 may
optionally be included at the distal end of insulating layer 20 to
provide additional isolation of eyelet loop 300, whereat
electrolytic separation of embolic assembly 120 will occur. Coil 70
and eyelet loop 310 are made of an electrically-conductive
substance, preferably a metal or alloy that has a different E.sup.0
from the substance, also preferably a metal, of which eyelet loop
300 is made. While any combination of metals or alloys that has the
required difference in E.sup.0 may be used, it is presently
preferred that eyelet loop 300 be stainless steel and that eyelet
loop 310 be a platinum/titanium alloy. Helical coil 70 is embedded
in a mass of non-conductive substance 80. Also embedded in
substance 80 is the proximal end of embolic assembly 120. Substance
80 can be any non-conductive material that can be melted or fused
to encase the distal end of coil 70 and the proximal end of
assembly 120. A polymeric material, in particular PET, is presently
preferred.
CONCLUSION
[0062] The specific embodiments of the device set forth herein for
improving the flexibility of the distal end of an embolic device
delivery apparatus are provided for the purpose of illustration
only and are not intended, nor should they be construed, to limit
the invention herein in any manner whatsoever. Many alterations and
modifications of the device herein will become apparent to those
skilled in the art based on the disclosures herein; all such
alterations and modifications are within the scope of this
invention.
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