U.S. patent application number 10/242469 was filed with the patent office on 2003-02-27 for device and method for controlling injection of liquid embolic composition.
Invention is credited to Cragg, Andrew H., Greene, George Robert, Greff, Richard J., Jones, Michael, Perl, John II, Walker, Blair D., Wallace, George.
Application Number | 20030040733 10/242469 |
Document ID | / |
Family ID | 23529190 |
Filed Date | 2003-02-27 |
United States Patent
Application |
20030040733 |
Kind Code |
A1 |
Cragg, Andrew H. ; et
al. |
February 27, 2003 |
Device and method for controlling injection of liquid embolic
composition
Abstract
A liquid embolic delivery system is provided for trapping an
injected liquid embolic composition to prevent the liquid embolic
from solidifying or otherwise passing outside of an embolization
area. The delivery system includes a catheter for delivery of a
liquid embolic composition and a containment member positioned at a
distal end of the catheter which is shaped to trap the liquid
embolic composition delivered through the lumen of the catheter.
The containment member is formed as a brush, nest, sponge, swab,
flexible sack, or other shape into and around which the liquid
embolic composition is injected. The liquid embolic composition is
trapped or meshes with the containment member during solidification
containing the liquid embolic and preventing the embolic
composition from passing into the blood stream.
Inventors: |
Cragg, Andrew H.; (Edina,
MN) ; Walker, Blair D.; (Clemente, CA) ; Perl,
John II; (Brunswick, OH) ; Jones, Michael;
(Capistrano Beach, CA) ; Greene, George Robert;
(Costa Mesa, CA) ; Wallace, George; (Coto de Caza,
CA) ; Greff, Richard J.; (St. Pete Beach,
FL) |
Correspondence
Address: |
Gerald F. Swiss
BURNS, DOANE, SWECKER & MATHIS, L.L.P.
P.O. Box 1404
Alexandria
VA
22313-1404
US
|
Family ID: |
23529190 |
Appl. No.: |
10/242469 |
Filed: |
September 13, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10242469 |
Sep 13, 2002 |
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|
09387274 |
Aug 31, 1999 |
|
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|
09387274 |
Aug 31, 1999 |
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08953149 |
Oct 17, 1997 |
|
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6146373 |
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Current U.S.
Class: |
604/508 |
Current CPC
Class: |
A61B 17/12177 20130101;
A61B 2017/12063 20130101; A61B 17/12168 20130101; A61B 2017/12059
20130101; A61M 25/00 20130101; A61B 17/12113 20130101; A61B
17/12195 20130101; A61M 25/0097 20130101; A61M 2025/0036 20130101;
A61B 17/00491 20130101; A61B 17/12172 20130101; A61B 17/12022
20130101; A61M 2025/004 20130101; A61B 2017/00893 20130101; A61B
17/12136 20130101; A61B 2017/1205 20130101; A61B 2017/00495
20130101; A61B 2017/00876 20130101; A61B 17/1219 20130101; A61M
25/0028 20130101; A61B 17/12186 20130101 |
Class at
Publication: |
604/508 |
International
Class: |
A61M 031/00 |
Claims
What is claimed is:
1. A liquid embolic delivery system comprising: a catheter having a
lumen for delivery of a liquid embolic composition to a cavity; a
containment member positioned at a distal end of the catheter, the
containment member shaped to trap the liquid embolic composition
delivered through the lumen of the catheter; and a detachment
mechanism for completely detaching the containment member from the
catheter after solidification of the liquid embolic composition to
allow separation of the catheter from a mass of solidified embolic
composition.
2. The liquid embolic delivery system according to claim 1, wherein
the containment member is a flexible sack which fills with the
liquid embolic composition.
3. The liquid embolic delivery system according to claim 2, wherein
the flexible sack is positioned over a distal outlet of the lumen
with a neck of the sack connected to the distal end of the catheter
around an opening of the catheter lumen, the detachment mechanism
detaching the flexible sack neck from the distal end of the
catheter.
4. The liquid embolic delivery system according to claim 2, wherein
the flexible sack is formed of a mesh material which allows solvent
to pass through the sack, the mesh material containing the liquid
embolic composition which has solidified.
5. The liquid embolic delivery system according to claim 2, wherein
the flexible sack is formed as a resilient balloon over the distal
end of the catheter.
6. The liquid embolic delivery system according to claim 1, wherein
the containment member is a nidus extending from the distal end of
the catheter and positioned to trap the liquid embolic composition
as the liquid embolic composition solidifies.
7. The liquid embolic delivery system according to claim 6, wherein
the nidus is formed from a wire which is delivered through the
catheter lumen and forms a coil upon exiting the distal end of the
lumen.
8. The liquid embolic delivery system according to claim 6, wherein
the nidus is in the form of a wire brush.
9. The liquid embolic delivery system according to claim 6, wherein
the nidus is in the form of a swab.
10. The liquid embolic delivery system according to claim 6,
wherein the nidus is in the form of a sponge.
11. The liquid embolic delivery system according to claim 6,
wherein the nidus is in the form of a flexible sack.
12. The liquid embolic delivery system according to claim 6,
wherein the nidus is formed from a wire which is delivered through
the catheter lumen and forms a randomly shaped nest upon exiting
the distal end of the lumen.
13. The liquid embolic delivery system according to claim 1,
wherein the detachment mechanism includes means for delivering an
electrical charge to a point between the containment member and the
catheter to detach the containment member from the catheter.
14. The liquid embolic delivery system according to claim 1,
wherein the detachment mechanism includes a chemical detachment
section between the containment member and the catheter which is
dissolved by a chemical agent.
15. A method of containing a liquid embolic composition at an
embolization site within a body comprising: delivering a liquid
embolic composition to an embolization site within a body with a
catheter; containing the liquid embolic composition during
solidification with a containment member; and detaching the
containment member from the catheter after solidification of the
liquid embolic composition to release the catheter from a mass of
solidified embolic composition.
16. The method according to claim 15, wherein the liquid embolic
composition is contained by trapping embolic composition in a nidus
during solidification.
17. The method according to claim 15, wherein the liquid embolic
composition is contained by a flexible sack and solvent dissipates
through the sack during solidification of the liquid embolic
composition.
18. The method according to claim 15, wherein the containment
member is positioned at the embolization site before delivery of
the liquid embolic composition by moving the containment member out
of a lumen of the catheter.
19. The method according to claim 15, wherein the containment
member and the catheter are delivered to the embolization site
through an introducing catheter.
Description
[0001] This application is a continuation-in-part of U.S. Ser. No.
08/953,149 filed Oct. 17, 1997, which is incorporated herein by
reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field Of The Invention
[0003] The invention relates to a device for controlling injection
of a liquid embolic composition into a patient, and more
particularly, to a device for containment and restraint of a liquid
embolic composition during and after solidification. The device for
controlling injection may be incorporated in a catheter system used
for delivery of the embolic composition in a controlled manner.
[0004] 2. State Of The Art
[0005] In many clinical situations it is desirable to selectively
occlude blood vessels for a variety of purposes, such as, the
control or prevention of bleeding, the prevention of blood supply
to tumors, treatment of arterial venous malformations (AVMs), and
the blocking of blood flow within an aneurysm. Embolization of
blood vessels has been performed by employing certain polymer
compositions, particulates, and/or selerosing material including
silicone balloons, metallic coils, PVA particles, gelatin, and the
like, to selectively block blood flow in the blood vessels.
However, these embolization procedures have certain drawbacks.
[0006] Intracranial aneurysms are abnormal blood filled dilations
of a blood vessel wall which may rupture causing significant
bleeding and damage to surrounding brain tissue or death.
Traditionally, intracranial aneurysms have been surgically clipped
to reduce the risk of rupture by placing a metal clip around the
neck of the aneurysm to cut off and prevent further blood flow to
the aneurysm. However many aneurysms cannot be treated surgically
because of either the location and configuration of the aneurysm or
because the condition of the patient does not permit cranial
surgery.
[0007] When aneurysms cannot be treated surgically or when surgery
is considered to be too risky or invasive, aneurysms may be treated
endovascularly with coils. The coils are placed in the aneurysm by
extending a catheter endovascularly to the site of the aneurysm and
passing single or often multiple metallic coils such as platinum,
stainless steel, or tungsten coils through the catheter into the
aneurysm. The coils placed within the aneurysm create a thrombus
which occludes the aneurysm and prevents further blood flow to the
aneurysm. The treatment of intracranial aneurysms with coils
isolates the aneurysm from arterial circulation, helping to guard
against rupture and further growth of the aneurysm. However, the
use of metallic coils to treat intracranial aneurysms may not be a
permanent solution because the blood clot around the coils may lyse
or dissolve due to the dynamic nature of the blood clotting
function. Once a clot formed around the coils in an aneurysm lyses,
the coil can no longer perform its function of occluding the
aneurysm. In addition, the coils may become dislodged, move from
the aneurysm, and enter the patient's blood stream causing
blockages at other locations within the vascular system. Coils can
also form a loop extending into the blood stream which generates
undesirable embolisms downstream.
[0008] Another drawback associated with the use of coils to occlude
an aneurysm is that the coils are known to compact over time
leaving cavities for subsequent aneurysm growth. In addition, if a
subsequent surgical clipping procedure is warranted, it can be
difficult to place the clip over the coil mass.
[0009] Other procedures for treating aneurysms include occluding
the aneurysm with a silicone balloon or filling the aneurysm with
particulate material.
[0010] Aneurysms having large necks are not easily treated by
either surgical clipping or by coils because the aneurysm neck may
have a shape which cannot be completely clipped surgically and the
coils may tend to become dislodged from the aneurysm when the neck
is particularly large.
[0011] One minimally invasive procedure for treating intracranial
aneurysms which addresses the problems with the surgical clipping
and coil techniques involves the endovascular injection of a liquid
embolic composition which solidifies in the aneurysm to occlude the
aneurysm. Typically, liquid embolic compositions include a water
insoluble, biocompatible, non-biodegradable polymer, dissolved in a
biocompatible solvent. Once the liquid embolic composition is
injected into the aneurysm, the biocompatible solvent dissipates
into the blood and the polymer solidifies to occlude the blood flow
through the aneurysm. These liquid embolic compositions preferably
include a radiopaque material which allows the physician to view
the embolization procedure by fluoroscopy.
[0012] Prior to delivery of the liquid embolic composition to the
aneurysm, the aneurysm and delivery device are preferably
positioned so that the liquid embolic composition will be delivered
by gravity into the aneurysm and will solidify and remain in the
aneurysm. This means that the patient position is often manipulated
to position the aneurysm with the aneurysm neck pointing up. As the
embolic composition is delivered to the aneurysm, the solvent
dissipates from the polymer material and is removed in the blood
stream causing the polymer material within the aneurysm to
solidify.
[0013] Depending on the rate at which the liquid embolic material
is injected into the blood vessel and the amount of blood flow
present, the polymer may remain in liquid form for a period of time
while the solvent dissipates into the blood stream. In addition,
the solvent concentration at the point of injection metal increase
to a point where small strings of unsolidified polymer material may
separate from the polymer mass and be carried away in the blood
stream where the polymer can occlude an undesired vascular
location.
[0014] Accordingly, it would be desirable to provide a device or
method for controlling the solidification of the polymer material
during injection so that an aneurysm which is in a non-gravity
dependent position can be filled without causing the liquid embolic
composition to pass out of the aneurysm into the blood stream. It
would also be desirable to prevent polymer strings from being
carried away in the blood stream.
SUMMARY OF THE INVENTION
[0015] The present invention relates to a containment member for
trapping an injected liquid embolic composition to prevent the
liquid embolic from solidifying outside of an embolization
area.
[0016] In accordance with one aspect of the present invention, a
liquid embolic delivery system includes a catheter having a lumen
for delivery of a liquid embolic composition to a cavity, a
containment member positioned at a distal end of the catheter, and
a detachment mechanism for completely detaching the containment
member from the catheter after solidification of the liquid embolic
composition to allow separation of the catheter from a mass of
solidified embolic composition. The containment member is shaped to
trap the liquid embolic composition delivered through the lumen of
the catheter.
[0017] In accordance with an additional aspect of the present
invention, a method of containing a liquid embolic composition at
an embolization site within a body includes the steps of delivering
a liquid embolic composition to an embolization site within a body
with a catheter, containing the liquid embolic composition during
solidification with a containment member, and detaching the
containment member from the catheter after solidification of the
liquid embolic composition to release the catheter from a mass of
solidified embolic composition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The invention will now be described in greater detail with
reference to the preferred embodiments illustrated in the
accompanying drawings, in which like elements bear like reference
numerals, and wherein:
[0019] FIG. 1 is a side cross sectional view of a first embodiment
of a liquid embolic delivery system with a multifilament brush in a
retracted position;
[0020] FIG. 2 is a side cross sectional view of the delivery system
of FIG. 1 with the multifilament brush in the extended
position;
[0021] FIG. 3 is a side cross sectional view of a delivery system
according to a second embodiment prior to formation of a nest;
[0022] FIG. 4 is a side cross sectional view of the delivery system
of FIG. 3 with a nest formed;
[0023] FIG. 5 is a side cross sectional view of a delivery system
according to a third embodiment with a sponge in a retracted
position;
[0024] FIG. 6 is a side cross sectional view of the delivery system
of FIG. 5 with the sponge in the extended position;
[0025] FIG. 7 is a side cross sectional view of a delivery system
according to a fourth embodiment with a swab in a retracted
position;
[0026] FIG. 8 is a side cross sectional view of the delivery system
of FIG. 7 with the swab in the extended position;
[0027] FIG. 9 is a side cross sectional view of a delivery system
according to a fifth embodiment with a magnetic member in a
retracted position;
[0028] FIG. 10 is a side cross sectional view of the delivery
system of FIG. 9 with the magnetic member in the extended
position;
[0029] FIG. 11 is a side cross sectional view of an aneurysm being
treated by the delivery system of FIGS. 3 and 4;
[0030] FIG. 12 is a side cross sectional view of an aneurysm with a
mass of liquid embolic material filling the aneurysm;
[0031] FIG. 13 is a side cross sectional view of an aneurysm after
the delivery system has been detached from the mass of liquid
embolic material;
[0032] FIG. 14 is a side cross sectional view of a delivery system
according to a sixth embodiment including a flexible sack in a
retracted position;
[0033] FIG. 15 is a side cross sectional view of the delivery
system of FIG. 14 with the flexible sack in the extended
position;
[0034] FIG. 16 is a side cross sectional view of the delivery
system of FIG. 14 in which liquid embolic composition has
solidified within the flexible sack;
[0035] FIG. 17 is a side cross sectional view of an aneurysm with
an aneurysm neck flow disruption system;
[0036] FIG. 18 is a side cross sectional view of an aneurysm with
an alternative embodiment of an aneurysm neck flow disruption
system;
[0037] FIG. 19 is a cross sectional view taken along line A-A of
FIG. 18; and
[0038] FIG. 20 is a cross sectional view taken along line B-B of
FIG. 18.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] The liquid embolic delivery system includes a catheter
having a lumen through which liquid embolic composition is
delivered to an embolization site within the body. A containment
member, such a nidus or a flexible sack is positioned at the distal
end of the catheter and, the liquid embolic composition is injected
into the containment member. The liquid embolic composition is
trapped or meshes with the containment member during solidification
containing the liquid embolic and preventing the liquid embolic
composition from passing into the blood stream. The preferred
embodiments of the containment member for use with the delivery
system will be discussed below with respect to the various
figures.
[0040] Prior to discussing the present invention in further detail,
the following terms are defined:
[0041] The term "liquid embolic composition" refers to a fluid
composition that is injected at an embolization site and solidifies
to fully or partially occlude the embolization site.
[0042] The term "embolizing" or "embolization" refers to a process
wherein a fluid composition is injected into a blood vessel or
tissue which, in the case of, for example, aneurysms fills or plugs
the aneurysm sack and/or encourages clot formation so that blood
flow into the aneurysm and pressure in the aneurysm ceases, and in
the case of arterial venous malformations (AVMs) and arterial
venous fistula (AVFs) forms a plug or clot to control/reroute blood
flow to permit proper tissue perfusion. Embolization may be used
for preventing or controlling bleeding due to lesions (e.g., organ
bleeding, gastrointestinal bleeding, vascular bleeding, as well as
bleeding associated with an aneurysm). In addition, embolization
can be used to ablate diseased tissue (e.g., tumors, etc.) by
cutting off the blood supply.
[0043] The liquid embolic composition for use in the present
invention may be any biocompatible composition which solidifies
within the body, for example a biocompatible polymer combined with
a suitable biocompatible solvent such as ethanol, dimethylsulfoxide
(DMSO), ethyl lactate, acetone, and the like. Examples of
embolizing compositions are described in U.S. Pat. No. 5,667,767,
which issued Sep. 16, 1997. U.S. Pat. No. 5,580,568, which issued
Dec. 3, 1996, and U.S. Patent Application Ser. No. 08/688,050 each
of which are incorporated herein by reference in their
entirety.
[0044] According to one preferred embodiment of the invention in
which the solvent used is DMSO, the delivery system elements which
may come into contact with the solvent are DMSO compatible.
Examples of DMSO compatible catheter materials include polyolefins,
such as polyethylene or polypropylene; fluoropolymers, such as PTFE
and ETFE, and silicones.
[0045] The liquid embolic delivery system as shown in FIGS. 1 and 2
includes an elongated flexible catheter 10 and a containment brush
12 disposed within the catheter. The catheter 10 may be an over the
wire catheter, a flow directed catheter, or any other type of
catheter capable of delivering the liquid embolic composition to
the embolization site. The brush 12 includes an elongated flexible
shaft 14 which extends through the lumen of the catheter 10 for
manipulation of the brush from the proximal end of the catheter
which extends outside the patient's body. The brush 12 includes a
plurality of filaments 16 extending substantially radially from a
distal end of the shaft 14.
[0046] In use, the catheter 10 is delivered to an embolization site
with the brush 12 in the retracted position, shown in FIG. 1, in
which the brush is positioned fully or substantially within the
lumen. The shaft 14 is then moved distally within the catheter 10
to extend the brush 12 from the distal end of the catheter. The
brush 12 is positioned such that the liquid embolic composition
exiting the lumen of the catheter 10 will become trapped by the
brush. Preferably, the brush is positioned about 0 to 5 mm, more
preferably about 1 to 4 mm from the distal end of the catheter with
the exact position depending on the particular embolization site
and procedure being performed.
[0047] Once the brush 12 has been positioned the liquid embolic
composition is then injected through the catheter 10 either through
the same lumen in which the shaft 14 of the brush 12 extends or
through a second parallel lumen of the catheter. As the liquid
embolic composition is delivered down the catheter the liquid which
exits the distal end of the catheter is injected into the filaments
16 of the brush 12. The solvent begins to dissipate from the liquid
embolic composition and the polymer material precipitates and
meshes with the bristles of the brush. Subsequent injections of
liquid embolic material increase the mass of solidified embolic
material surrounding the brush at the embolization site. Injection
of the liquid embolic composition continues until the embolization
site is completely embolized. The brush 12 acts to contain and trap
the precipitating material and prevent the effects of gravity and
blood flow from causing the polymer material to be carried away
from the embolization site.
[0048] After the liquid embolic composition has been delivered
through the catheter 10 and has formed a solid mass around the
brush 12, the mass is detached from the catheter and the brush
shaft 14 by a detachment mechanism, such as a mechanical,
electrical, or chemical detachment system as discussed below.
[0049] Although the brush 12 has been described as attached to an
elongated flexible shaft 14 which extends through the lumen of the
catheter 10, the brush may also be connected by a mounting member,
such as a short shaft, directly to the distal end of the catheter.
When the brush 12 is connected directly to the end of the catheter
10 the catheter and brush may be introduced together as a single
unit through a separate introducing catheter of a larger diameter
than the catheter 10. After delivery of liquid embolic composition
the brush 12 may be detached from the catheter 10 or the entire
distal end of the catheter may be detachable.
[0050] The filaments 16 of the brush 12 are preferably flexible
members formed of a material such as nylon, polyethylene,
polypropylene, polyester, PTFE, Dacron, and the like. The filaments
are preferably soft, flexible, absorbent, biocompatible, and DMSO
compatible. The filament size may vary depending on the
application, however, one example of a suitable filament has a
diameter of about 75 to about 500 microns, preferably about 150 to
about 250 microns, and a length depending on an inner diameter of
the vascular site of about 1 to about 30 mm, preferably about 2 to
about 10 mm.
[0051] FIGS. 3 and 4 illustrate an alternative embodiment of the
liquid embolic delivery system in which a wire 20 is delivered
through the lumen of a catheter 22 when the wire 20 exits the
distal end of the catheter 22 the wire forms into a nest
configuration at the embolization site. The wire 20 is preformed
with a curvature which creates the nest 24 when the wire is
delivered out of the distal end of the catheter 22. The shape of
the nest 24 generally conforms to the shape of the embolization
site, for example, when treating an aneurysm the nest 24 will
conform to the shape of the aneurysm. The liquid embolic
composition is subsequently delivered through the catheter lumen
and is trapped by and precipitates on the wire nest 24. As in the
embodiment described above, after embolization is complete, the
solidified mass of embolic material and the wire nest 24 are
detached from the catheter.
[0052] The wire 20 may be preformed to cause the nest 24 to take on
a particular predetermined shape. Examples of nest shapes include
the randomly curving wire shape shown in FIG. 4 and a coil or
spiral shape. The wire 20 may be formed of a biocompatible
material, such as, stainless steel, platinum, Nitinol, gold,
tungsten, and the like. In addition, it may be desirable to form
the wire 20 from a shape memory material, such as Nitinol.
[0053] Another alternative embodiment of the invention including a
sponge like member 30 and a catheter 32 is illustrated in FIGS. 5
and 6. As shown in FIG. 5, the sponge 30 is compressed within the
lumen of the catheter 32 during delivery of the catheter to the
embolization site. Once the distal tip of the catheter 32 is
located at or near the embolization site, the sponge 30 is deployed
from the catheter by a plunger or rod 34 which extends through the
catheter lumen 32 and connects to the sponge 30. Once the sponge 30
has been deployed from the catheter 32 the sponge expands to the
configuration shown in FIG. 6. The expanded sponge 30 includes a
plurality of large holes 36 and smaller pores into which the liquid
embolic composition is injected.
[0054] As in the embodiment of FIGS. 1 and 2, the sponge 30 of
FIGS. 5 and 6 may be fixed to the end of the catheter 32 instead of
to the plunger 34 and the entire catheter and sponge system may be
delivered to the embolization site through an introducing catheter.
The liquid embolic composition may then be delivered by the
catheter 32 to an exterior or an interior of the sponge. Once an
embolic mass has formed around the sponge 30 by injection of the
liquid embolic composition through the catheter lumen, the embolic
mass is detached from the catheter 32 and remains within the
embolization site after the catheter has been removed. The
detachment of the solidified embolic mass from the catheter 32 and
the rod 34 is performed by mechanical, electrical, or chemical
detachment as will be described further below.
[0055] The sponge member 30 according to the embodiment of FIGS. 5
and 6 is formed of a biocompatible, open cell, compressible
material having a high porosity, such as polyethylene sponge,
polypropylene sponge, polyurethane sponge , PVA, fluoropolymer, and
the like. The size and shape of the sponge 30 will be modified to
properly fit within the particular embolization site. The sponge
material is preferably a biocompatible, DMSO compatible, non-toxic,
soft, hydrophillic material which fully fills the aneurysm. An
expansion ratio of the sponge is preferably about 5:1 to 20:1, more
preferably about 10:1
[0056] FIGS. 7 and 8 relate to a further alternative embodiment of
the invention in which the containment member for trapping the
liquid embolic composition is a swab shaped member 40 of a
filamentous material. The swab shaped member 40 may be compressed
within and deployed from the lumen of a catheter 42 by a pusher or
rod 44 or can be permanently affixed to the distal end of the
catheter and inserted through an introducing catheter. The liquid
embolic composition which is delivered through the catheter 42 is
trapped in and around the swab shaped member 40. Additional embolic
composition solidifies in shells around the core provided by the
swab shaped member 40. Appropriate materials for the swab shaped
member 40 include biocompatible materials, such as polyester, PTFE,
silk, Dacron, polyethylene, nylon, fluoropolymer, cotton, and the
like. The shape and size of the swab 40 may be modified to
correspond with a particular shape and size of an embolization
site.
[0057] A further embodiment of the liquid embolic delivery system,
as shown in FIGS. 9 and 10, includes a node 50, such as an
electrically charged member or a magnet, which attracts the liquid
embolic composition delivered through the lumen of a catheter 52.
The node 50 can be fixed on the end of the catheter 52 or
preferably is movable from a retracted position, shown in FIG. 9,
to an extended position, shown in FIG. 10, by a rod 54 extending
through the catheter lumen. The polymer preferably includes
magnetic particles which are attracted to the node. The node 50 is
positioned generally in a center of an embolization site and the
liquid embolic agent solidifies in shells around the node.
[0058] FIGS. 11-13 illustrate a method of treating an aneurysm with
the liquid embolic delivery system having the wire nest 54 which
has been described above with respect to FIGS. 3 and 4. As shown in
FIG. 11, the catheter 22 is positioned at or near a neck 60 of an
aneurysm 62 and the wire 20 is passed through the lumen of the
catheter 22 to form a wire nest 24 within the aneurysm. The liquid
embolic material is then injected through the lumen of the catheter
22 and is trapped by the wire nest 24 during solidification.
Injection of the liquid embolic material continues until the
aneurysm 62 is completely or substantially filled with an embolic
mass 64 as illustrated in FIG. 12. The catheter is then detached
from the solidified mass 64 of liquid embolic material within the
aneurysm by chemical, mechanical, or electrical detachment means.
For example, the mass 64 of embolic composition may be detached by
holding the catheter 22 stationary while pulling the wire 20
proximally within the catheter lumen to break the wire at a
location where the wire enters the liquid embolic mass. The
catheter 22 and the wire 20 are then removed from the embolization
site leaving the liquid embolic mass 64 and the wire nest 24
embedded within the mass in the aneurysm. The wire 20 which has
been broken as described above may also be used as a pusher to
separate the embolic mass 64 from the catheter 22. This method of
treating an aneurysm may also be used for other embolization
treatments.
[0059] The liquid embolic delivery system according to the present
invention may be configured so that injection of liquid embolic
composition forms as consecutive shells over a beginning kernel as
the embolic mass increases in size. Alternatively, the liquid
embolic may be injected from a center of the containment member so
that an outer skin is created first and additional embolic is added
inside the mass causing the outer skin to expand.
[0060] FIGS. 14-16 illustrate a liquid embolic delivery system
including a flexible sack 70 affixed to a distal end of a catheter
72. The edges 78 of the flexible sack 70 are affixed in a known
manner to an exterior of the catheter distal tip such that the
flexible sack surrounds the catheter outlet. The catheter 72 having
the flexible sack 70 affixed to the distal end are delivered to an
embolization site through an introducer catheter 76 having a
somewhat larger diameter than the catheter 72. Once the flexible
sack 70 is placed within the embolization site such as within an
aneurysm, a liquid embolic composition is injected through the
catheter lumen.
[0061] The flexible sack 70 is formed of a membrane or woven
material which is substantially impermeable to the precipitate of
the liquid embolic composition while being permeable to the solvent
to allow the solvent to dissipate from the liquid embolic material
injected into the flexible sack. Examples of biocompatible
materials which may be used to form the flexible sack 70 include
polyester, PTFE, urethane, Dacron, nylon, polyethylene,
fluoropolymers, silicone, and the like. According to one
embodiment, the flexible sack is a mesh bag having a structure
which allows the diameter of the bag to increase as the embolic
composition is injected. The mesh material may be non-elastic or
may be elastic acting like a balloon. The mesh allows the solvent
to dissipate out of the bag while the structure of the bag prevents
fingers or strands of embolic material from passing out of the
embolization area. The flexible sack 70 is detachable from the
distal end of the catheter 72 once the embolization is complete so
that the catheter can be removed from the embolization site.
[0062] The method of detachment of any one of the containment
members described above from the catheter of the present invention
may be either mechanical, electrical, or chemical. One example of a
mechanical method of detachment involves forcibly detaching the
mass of embolic material and the containment member from the distal
tip of the catheter such as by use of a plunger member extending
through the lumen of the catheter. Alternatively, an outer catheter
sleeve may be used to strip a mass from a distal tip of the
catheter. Mechanical detachment can also be performed by various
interlocking, pushing, twisting, and locking motions.
[0063] Electrical detachment may be performed by providing a
weakened section at a junction between the containment member and
the catheter which is easily vaporized by application an electric
current. For example, a 9V electric power source may apply a
current of about 0.3 mA for detachment. One example of an
electrical detachment mechanism is described in U.S. Pat. No.
5,928,226, which is incorporated herein by reference.
[0064] Finally, with a chemical detachment mechanism, a dissolvable
detachment section is included in the delivery system between the
catheter and the containment member or at the distal end of the
catheter. The dissolvable detachment section is dissolved,
softened, swollen, degraded, or otherwise changed by the injection
of a biocompatible chemical through the catheter. Some examples of
chemical detachment systems include dissolvable detachment
sections, such as a polymer section which is dissolved by DMSO, a
nylon section which is dissolved by a fluorinated hydrocarbon, or
sections which are dissolved by saline or any of the other
biocompatible solvents discussed above.
[0065] FIGS. 17-20 illustrate a liquid embolic delivery system
which disturbs the blood flow into and out of the aneurysm to
improve control over injection of the liquid embolic composition.
The disturbance of blood flow into and out of the aneurysm through
the aneurysm neck creates a low turbulence or "peaceful" fluid
environment within the aneurysm which allows improved filling of
the aneurysm with the embolic material.
[0066] As shown on FIG. 17, a delivery system 100 is placed at an
embolization site such as an aneurysm 90 having an aneurysm neck
92. The delivery system has two lumens including an inner lumen 102
for delivery of the liquid embolic composition and an outer lumen
104 for injection of a fluid such as saline which is used to
disrupt blood flow at the aneurysm neck 92. The delivery system 100
may be formed from an inner catheter 106 and an outer catheter 108
concentrically surrounding the inner catheter and having a
plurality of side ports 110 which can be positioned at the aneurysm
neck 92. A distal end of the outer catheter 108 forms a fluid tight
seal with an exterior of the inner catheter 106. This distal end of
the outer catheter 108 may be permanently bonded to the inner
catheter or may be slideable over the inner catheter with or
without a valve member. The inner and outer catheters 106, 108 may
be provided with radiopaque markers 112 for visualization of the
position of the inner and outer catheters. Alternatively, a
radiopaque marker may be sandwiched between the two tubes at a fuse
joint at the distal end of the outer catheter 108.
[0067] The side holes 110 are preferably spaced around the outer
catheter 108 and are positioned within an area of a relatively
short axial length. In use, the delivery system 100 is guided to an
aneurysm over a guidewire using the inner catheter lumen 102 as a
guidewire lumen. The tip of the inner lumen is located within the
dome of the aneurysm and the side holes 110 are positioned near the
aneurysm neck 92. The guidewire is then removed and the disruption
fluid is then injected through the outer catheter 108 and exits the
side holes 110 of the delivery device. The disruption fluid can be
any biocompatible fluid such as saline, contrast medium, or
mixtures thereof. The flow of the disruption fluid is visualized
and adjusted so that optimum disruption of blood flow at the
aneurysm neck occurs. The liquid embolic material is then injected
through the lumen 102 of the center catheter 106 until the aneurysm
90 has been filled and the embolic composition is solidified.
[0068] According to one embodiment of the present invention, the
inner catheter 106 is slideable with respect to the outer catheter
108 to allow adjustment of the distance between the distal tip
where the liquid embolic composition is injected and the disruption
side holes 110. The ability to adjust the delivery device 100 in
this manner is useful because aneurysm vary in size. A valve at the
distal end of the outer catheter 108 can allow the outer catheter
to slide easily over the inner catheter in an axial direction
without the leakage of fluid.
[0069] FIGS. 18-20 illustrate an alternative embodiment of a
delivery system 120 which allows a pattern of the disruption flow
to be controlled. Because the necks 92 of many aneurysms 90 have
non-circular or elliptical cross sections, it may be desirable to
vary the flow rate of the aneurysm neck disrupting fluid out of
different side holes around the circumference of the delivery
system. In other words, it may be desirable to increase the
disruption fluid flow at side holes which are oriented in a
direction of a major axis of the elliptical neck while decreasing
the flow at side holes which are oriented in the direction of the
minor axis of the elliptical neck.
[0070] FIG. 18 illustrates an aneurysm 90 having an elliptical
aneurysm neck 92 and a delivery system 120 for delivery of liquid
embolic composition and disruption fluid to the aneurysm. The
delivery system 120 includes an elongated catheter 122 with a
central lumen 124 and a plurality of surrounding lumens 126. The
surrounding lumens 126 are spaced around the central lumen 124 and
each include a side port 128 for delivery of the disruption fluid.
FIG. 19 shows a cross section of the catheter 122 taken along line
A-A illustrating the central lumen 124 and a plurality of
surrounding lumens 126.
[0071] At a proximal end of the catheter 122 a fluid connection 130
is provided for connection of the central lumen to a source of the
liquid embolic composition. A fluid connection 132 is also provided
for connection of the plurality of surrounding lumens 126 to a
source of disruption fluid. A manifold 134 and a plurality of
valves are provided for controlling delivery of the disruption to
the different surrounding lumens 126 at relatively variable
velocities. The manifold 134 and valves provide a flow regulating
means for delivery of the fluid which allows the fluid delivered
from the different side ports 128 at the aneurysm neck 92 to be
carefully controlled as illustrated in FIG. 20.
[0072] According to a further embodiment of the liquid delivery
having aneurysm neck disruption side flow, one or more rows of side
holes may be provided. These rows of side holes may be positioned
just inside and just outside the aneurysm neck to further disrupt
the blood flow through the neck.
[0073] While the invention has been described in detail with
reference to the preferred embodiments thereof, it will be apparent
to one skilled in the art that various changes and modifications
can be made and equivalents employed, without departing from the
present invention.
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