U.S. patent application number 11/540702 was filed with the patent office on 2007-02-01 for tissue connector apparatus and methods.
Invention is credited to Isidro Matias Gandionco, Barry Gardiner, John Nguyen, Laurent Schaller.
Application Number | 20070027461 11/540702 |
Document ID | / |
Family ID | 27733454 |
Filed Date | 2007-02-01 |
United States Patent
Application |
20070027461 |
Kind Code |
A1 |
Gardiner; Barry ; et
al. |
February 1, 2007 |
Tissue connector apparatus and methods
Abstract
A tissue connector assembly having a flexible member and a
surgical clip releasably coupled to the flexible member. A needle
may be secured to one end portion of the flexible member with the
surgical clip coupled to the other end portion of the flexible
member. A locking device may be used to couple the flexible member
to the surgical clip. A method for connecting tissues is also
disclosed. The method includes drawing tissue portions together
with a clip assembly and securing the tissue portions together with
the clip assembly.
Inventors: |
Gardiner; Barry; (Orinda,
CA) ; Schaller; Laurent; (Los Altos, CA) ;
Gandionco; Isidro Matias; (Fremont, CA) ; Nguyen;
John; (San Jose, CA) |
Correspondence
Address: |
James R. Keogh;Medtronic, Inc.
710 Medtronic Parkway
Minneapolis
MN
55432
US
|
Family ID: |
27733454 |
Appl. No.: |
11/540702 |
Filed: |
September 29, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10439973 |
May 16, 2003 |
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11540702 |
Sep 29, 2006 |
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09089884 |
Jun 3, 1998 |
6607541 |
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10439973 |
May 16, 2003 |
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Current U.S.
Class: |
606/151 |
Current CPC
Class: |
A61B 17/0644 20130101;
A61B 17/11 20130101; A61B 17/06 20130101; A61B 2017/06057 20130101;
A61B 2017/06009 20130101; A61B 17/064 20130101 |
Class at
Publication: |
606/151 |
International
Class: |
A61B 17/08 20060101
A61B017/08 |
Claims
1-38. (canceled)
39. A method for connecting a graft vessel to a target vessel in an
anastomosis comprising: inserting a tissue connector assembly
through said graft and target vessels with said graft vessel being
spaced from said target vessel and said tissue connector assembly
having a first end extending from an exterior surface of said graft
vessel and a second end extending from an exterior surface of said
target vessel; and pulling at least a portion of said tissue
connector assembly to draw said graft vessel into contact with said
target vessel.
40. The method of claim 39 further comprising inserting a second
tissue connector assembly through said graft and target vessels
prior to pulling at least a portion of said tissue connector
assembly.
41. The method of claim 39 further comprising inserting a plurality
of clips into said graft and target vessels after pulling at least
a portion of said tissue connector assembly, to sealingly engage
said vessels.
42. The method of claim 41 further comprising placing said clips
into an open configuration prior to inserting said clips into said
vessels.
43. The method of claim 42 wherein said deforming of said clips
includes attaching a restraining device to each of said clips.
44. The method of claim 39 wherein said inserting a tissue
connector assembly includes inserting said tissue connector
assembly through an end margin of said graft vessel and a side of
said target vessel.
45. The method of claim 39 wherein said inserting a tissue
connector assembly includes inserting said tissue connector
assembly through an end margin of said graft vessel and an end
margin of said target vessel.
46. The method of claim 39 wherein said inserting a tissue
connector assembly includes inserting said tissue connector
assembly through said a side of said graft vessel and a side of
said target vessel.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to instruments and methods for
connecting body tissues, or body tissue to prostheses.
BACKGROUND OF THE INVENTION
[0002] Minimally invasive surgery has allowed physicians to carry
out many surgical procedures with less pain and disability than
conventional, open surgery. In performing minimally invasive
surgery, the surgeon makes a number of small incisions through the
body wall to obtain access to the tissues requiring treatment.
Typically, a trocar, which is a pointed, piercing device, is
delivered into the body with a cannula. After the trocar pierces
the abdominal or thoracic wall, it is removed and the cannula is
left with one end in the body cavity, where the operation is to
take place, and the other end opening to the outside. A cannula has
a small inside diameter, typically 5-10 millimeters, and sometimes
up to as much as 20 millimeters. A number of such cannulas are
inserted for any given operation.
[0003] A viewing instrument, typically including a miniature video
camera or optical telescope, is inserted through one of these
cannulas and a variety of surgical instruments and refractors are
inserted through others. The image provided by the viewing device
may be displayed on a video screen or television monitor, affording
the surgeon enhanced visual control over the instruments. Because a
commonly used viewing instrument is called an "endoscope," this
type of surgery is often referred to as "endoscopic surgery." In
the abdomen, endoscopic procedures are commonly referred to as
laparoscopic surgery, and in the chest, as thoracoscopic surgery.
Abdominal procedures may take place either inside the abdominal
cavity (in the intraperitoneal space) or in a space created behind
the abdominal cavity (in the retroperitoneal space). The
retroperitoneal space is particularly useful for operations on the
aorta and spine, or abdominal wall hernia.
[0004] Minimally invasive surgery has virtually replaced open
surgical techniques for operations such as cholecystectomy and
anti-reflux surgery of the esophagus and stomach. This has not
occurred in either peripheral vascular surgery or cardiovascular
surgery. An important type of vascular surgery is to replace or
bypass a diseased, occluded or injured artery. Arterial replacement
or bypass grafting has been performed for many years using open
surgical techniques and a variety of prosthetic grafts. These
grafts are manufactured as fabrics (often from DACRON.RTM.
(polyester fibers) or TEFLON.RTM. (fluorocarbon fibers)) or are
prepared as autografts (from the patient's own tissues) or
heterografts (from the tissues of animals) or a combination of
tissues, semi-synthetic tissues and or alloplastic materials. A
graft can be joined to the involved artery in a number of different
positions, including end-to-end, end-to-side, and side-to-side.
This attachment between artery and graft is known as an
anastomosis. Constructing an arterial anastomosis is technically
challenging for a surgeon in open surgical procedures, and is
almost a technical impossibility using minimally invasive
techniques.
[0005] Many factors contribute to the difficulty of performing
arterial replacement or bypass grafting. See generally, Wylie,
Edwin J. et al., Manual of Vascular Surgery, (Springer-Verlag New
York), 1980. One such factor is that the tissues to be joined must
be precisely aligned with respect to each other to ensure the
integrity and patency of the anastomosis. If one of the tissues is
affixed too close to its edge, the suture can rip through the
tissue and impair both the tissue and the anastomosis. Another
factor is that, even after the tissues are properly aligned, it is
difficult and time consuming to pass the needle through the
tissues, form the knot in the suture material, and ensure that the
suture material does not become tangled. These difficulties are
exacerbated by the small size of the artery and graft. The arteries
subject to peripheral vascular and cardiovascular surgery typically
range in diameter from several millimeters to several centimeters.
A graft is typically about the same size as the artery to which it
is being attached. Another factor contributing to the difficulty of
such procedures is the limited time available to complete the
procedure. The time the surgeon has to complete an arterial
replacement or bypass graft is limited because there is no blood
flowing through the artery while the procedure is being done. If
blood flow is not promptly restored, sometimes in as little as
thirty minutes, the tissue the artery supplies may experience
significant damage, or even death (tissue necrosis). In addition,
arterial replacement or bypass grafting is made more difficult by
the need to accurately place and space many sutures to achieve a
permanent hemostatic seal. Precise placement and spacing of sutures
is also required to achieve an anastomosis with long-term
patency.
[0006] Highly trained and experienced surgeons are able to perform
arterial replacement and bypass grafting in open surgery using
conventional sutures and suturing techniques. A suture has a suture
needle that is attached or "swedged on" to a long, trailing suture
material. The needle must be precisely controlled and accurately
placed through both the graft and artery. The trailing suture
material must be held with proper tension to keep the graft and
artery together, and must be carefully manipulated to prevent the
suture material from tangling. In open surgery, these maneuvers can
usually be accomplished within the necessary time frame, thus
avoiding the subsequent tissue damage (or tissue death) that can
result from prolonged occlusion of arterial blood flow.
[0007] A parachuting technique may be used to align the graft with
the artery in an end-to-side anastomosis procedure. One or multiple
sutures are attached to the graft and artery and are used to pull
or "parachute" the graft vessel into alignment with an opening
formed in a sidewall of the artery. A drawback to this procedure is
the difficulty in preventing the suture from tangling and the time
and surgical skill required to tie individual knots when using
multiple sutures. Due to space requirements, this procedure is
generally limited to open surgery techniques.
[0008] The difficulty of suturing a graft to an artery using
minimally invasive surgical techniques has effectively prevented
the safe use of this technology in both peripheral vascular and
cardiovascular surgical procedures. When a minimally invasive
procedure is done in the abdominal cavity, the retroperitoneal
space, or chest, the space in which the operation is performed is
more limited, and the exposure to the involved organs is more
restricted, than with open surgery. Moreover, in a minimally
invasive procedure, the instruments used to assist with the
operation are passed into the surgical field through cannulas. When
manipulating instruments through cannulas, it is extremely
difficult to position tissues in their proper alignment with
respect to each other, pass a needle through the tissues, form a
knot in the suture material once the tissues are aligned, and
prevent the suture material from becoming tangled. Therefore,
although there have been isolated reports of vascular anastomoses
being formed by minimally invasive surgery, no system has been
provided for wide-spread surgical use which would allow such
procedures to be performed safely within the prescribed time
limits.
[0009] As explained above, anastomoses are commonly formed in open
surgery by suturing together the tissues to be joined. However, one
known system for applying a clip around tissues to be joined in an
anastomosis is disclosed in a brochure entitled, "VCS Clip Applier
System", published in 1995 by Auto Suture Company, a Division of
U.S. Surgical Corporation. A clip is applied by applying an
instrument about the tissue in a nonpenetrating manner, i.e., the
clip does not penetrate through the tissues, but rather is clamped
down around the tissues. As previously explained, it is imperative
in forming an anastomosis that tissues to be joined are properly
aligned with respect to each other. The disclosed VCS clip applier
has no means for positioning tissues. Before the clip can be
applied, the tissues must first be properly positioned with respect
to each other, for example by skewering the tissues with a needle
as discussed above in common suturing techniques or with forceps to
bring the tissues together. It is extremely difficult to perform
such positioning techniques in minimally invasive procedures.
[0010] Therefore, there is currently a need for other tissue
connecting systems.
SUMMARY OF THE INVENTION
[0011] The present invention involves apparatus and methods for
connecting material, at least one of which is tissue. The invention
may, for example, be used to secure one vessel to another, such as
in a vascular anastomosis.
[0012] According to one aspect of the invention, a tissue connector
assembly is provided and comprises a flexible member and a surgical
clip which may be releasably coupled to the flexible member. With
this construction, a needle may be coupled to the flexible member,
which may be in the form of a suture, to facilitate, for example,
parachuting suture tissue connecting procedures. The surgical clip
may eliminate the need for tying sutures, which requires
significant skill, space, and time.
[0013] According to another aspect of the invention a tissue
connector assembly comprises a needle, a flexible member coupled to
the needle, and a locking device coupled to the flexible member.
The locking device is adapted for receiving a surgical fastener.
Thus, a surgical fastener may be selected based on a desired
procedure and coupled to the locking device to facilitate, for
example, parachuting suture tissue connecting procedures as
discussed above.
[0014] According to another aspect of the invention, a method for
connecting tissues includes drawing portions of tissue together
with a clip assembly and securing the tissue portions together with
the clip assembly.
[0015] According to another aspect of the invention, multiple
portions of material are drawn together with a tissue connector
assembly having a clip in an open position. At least one of the
portions of material is tissue. The clip is closed to secure the
material portions therein. The materials may be drawn together by
pulling the tissue connector assembly with at least a portion of
the clip positioned in the materials. A needle may be used to
insert the tissue connector assembly into the material. A portion
of the tissue connector assembly may be manipulated to
simultaneously actuate closure of the clip and release the needle
from the clip.
[0016] According to another aspect of the invention, a tissue
connector assembly is inserted through graft and target vessels
with the graft vessel being spaced from the target vessel. The
tissue connector assembly has a first end extending from an
exterior surface of the graft vessel and a second end extending
from an exterior surface of the target vessel. At least one end of
the tissue connector assembly is pulled to draw the graft vessel
into contact with the target vessel.
[0017] According to another aspect of the invention, a tissue
connector assembly is inserted through the graft and target vessels
with the graft vessel being spaced from the target vessel and the
tissue connector assembly having a first end extending from an
exterior surface of the graft vessel and a second end extending
from an exterior surface of the target vessel. At least a portion
of the tissue connector assembly is pulled to draw the graft vessel
into contact with the target vessel.
[0018] The above is a brief description of some deficiencies in the
prior art and advantages of the present invention. Other features,
advantages, and embodiments of the invention will be apparent to
those skilled in the art from the following description,
accompanying drawings, and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a perspective of a tissue connector assembly of
the present invention;
[0020] FIG. 2A shows two tissue connector assemblies of FIG. 1 in a
first step for connecting a graft vessel to a target vessel;
[0021] FIG. 2B shows a second step for connecting the graft vessel
to the target vessel;
[0022] FIG. 2C shows a third step for connecting the graft vessel
to the target vessel;
[0023] FIG. 2D shows the graft vessel connected to the target
vessel;
[0024] FIG. 2E is a front view of the connected graft and target
vessels of FIG. 2D, with portions broken away to show detail;
[0025] FIG. 2F is an enlarged view of the tissue connection shown
in FIG. 2E;
[0026] FIG. 2G shows an alternate method for connecting the graft
vessel to the target vessel with the tissue connector assembly of
FIG. 1;
[0027] FIG. 3A is an enlarged view of a fastener of the tissue
connector assembly of FIG. 1 shown in a closed position;
[0028] FIG. 3B is a side view of the fastener of FIG. 3A;
[0029] FIG. 3C is an enlarged view of the fastener in an open
position;
[0030] FIG. 3D is an enlarged view of an alternate configuration of
the fastener shown in a closed position;
[0031] FIG. 3E is an enlarged view of an alternate configuration of
the fastener shown in a closed position;
[0032] FIG. 3F is a side view of the fastener of FIG. 3E;
[0033] FIG. 3G is an enlarged view of an alternate configuration of
the fastener shown in a closed position;
[0034] FIG. 4A is a cross-sectional view of a restraining device of
the tissue connector assembly of FIG. 1 in a locked position;
[0035] FIG. 4B is a cross-sectional view of the restraining device
of FIG. 4A taken in the plane including line 4B-4B;
[0036] FIG. 4C is a cross-sectional view of the restraining device
of FIG. 4A in an unlocked position;
[0037] FIG. 5 is an alternate embodiment of the restraining device
of FIG. 4A; and
[0038] FIG. 6 is a front view of a second embodiment of a tissue
connector assembly of the present invention shown in an open
position.
[0039] Corresponding reference characters indicate corresponding
parts throughout the several views of the drawings.
DESCRIPTION OF THE INVENTION
[0040] Referring now to the drawings, and first to FIG. 1, a tissue
connector assembly constructed according to the principles of the
present invention is shown and generally indicated with reference
numeral 10. The tissue connector assembly 10 may be used to
manipulate and align tissues, or tissue and prosthesis with respect
to each other and thereafter connect the tissues or tissue and
prosthesis together (FIGS. 2A-2G). As used herein, the term graft
includes any of the following: homografts, xenografts, allografts,
alloplastic materials, and combinations of the foregoing. The
tissue connector assembly 10 may be used in vascular surgery to
replace or bypass a diseased, occluded, or injured artery by
connecting a graft vessel 12 to a coronary artery 14 or vein in an
anastomosis, for example. The tissue connector assembly 10 may be
used in open surgical procedures or in minimally invasive or
endoscopic procedures for attaching tissue located in the chest,
abdominal cavity, or retroperitoneal space. These examples,
however, are provided for illustration and are not meant to be
limiting.
[0041] In the embodiment shown in FIG. 1, the tissue connector
assembly 10 generally comprises a penetrating member 16, flexible
member 18, and fastener or surgical clip 20 (FIG. 1). A restraining
device, generally indicated at 24 and comprising a spring (or coil)
26 and a locking device (coupling member) generally indicated at
28, is connected to the fastener 20 for holding the fastener in a
deformed configuration as further described below. Although a
particular fastener and accompanying restraining device is shown in
FIG. 1, it should be understood that any suitable fastener can be
used, including but not limited to the alternate fastener
configurations described below. For example, the fastener or
surgical clip may be a plastically deformable clip or may comprise
two or more parts, at least one of which is movable relative to the
other part, such as with a hinged clip.
[0042] The penetrating member or needle 16 has a sharp pointed tip
30 at its distal end for penetrating tissue. The needle 16 may be
bent as shown in FIG. 1, for example. The diameter of at least a
portion of the needle 16 is preferably greater than the diameter of
the flexible member 18 so that the flexible member can easily be
pulled through an opening formed in the tissue by the needle. The
distal end of the needle 16 is preferably rigid to facilitate
penetration of tissue. The remaining length of the needle 16 may be
rigid or flexible to facilitate movement of the needle through the
tissue as further described below. The tip 30 of the needle 16 may
be conical, tapered, or grounded to attain a three or four facet
tip, for example. The needle 16 may be made from stainless steel or
any other suitable material, such as a polymeric material. It is to
be understood that the needle 16 may have a shape or radius of
curvature other than the one shown, without departing from the
scope of the invention. The needle 16 may also be integrally formed
with the flexible member 18 (e.g., both needle and flexible member
formed of the same material.)
[0043] The flexible member 18 may be in the form of a suture formed
from conventional filament material, metal alloy such as nitinol,
polymeric material, or any other suitable material. The material
may be non-stretchable or stretchable, solid or hollow, and have
various cross-sectional diameters. The suture may have a
cross-sectional diameter of 0.003 inch, for example. The diameter
and length of the suture will vary depending on the specific
application. The suture may be attached to the needle 16 by
crimping or swaging the needle onto the suture, gluing the suture
to the needle, or any other suitable attachment method. The
flexible member 18 may have cross-sectional shapes other than the
one shown herein.
[0044] One embodiment of a fastener comprises a deformable wire 34
made of a shape memory alloy. A nickel titanium (nitinol) based
alloy may be used, for example. The nitinol may include additional
elements which affect the yield strength of the material or the
temperature at which particular pseudoelastic or shape
transformation characteristics occur. The transformation
temperature may be defined as the temperature at which a shape
memory alloy finishes transforming from martensite to austenite
upon heating (i.e., A.sub.f temperature). The shape memory alloy
preferably exhibits pseudoelastic (superelastic) behavior when
deformed at a temperature slightly above its transformation
temperature. At least a portion of the shape memory alloy is
converted from its austenitic phase to its martensitic phase when
the wire 34 is in its deformed configuration. As the stress is
removed, the material undergoes a martensitic to austenitic
conversion and springs back to its original undeformed
configuration. When the wire 34 is positioned within the tissue in
its undeformed configuration, a residual stress is present to
maintain the tissue tightly together (FIG. 2E). In order for the
pseudoelastic wire 34 to retain sufficient compression force in its
undeformed configuration, the wire should not be stressed past its
yield point in its deformed configuration to allow complete
recovery of the wire to its undeformed configuration. The shape
memory alloy is preferably selected with a transformation
temperature suitable for use with a stopped heart condition where
cold cardioplegia has been injected for temporary paralysis of the
heart tissue (e.g., temperatures as low as 8-10 degrees
Celsius).
[0045] It is to be understood that the shape memory alloy may also
be heat activated, or a combination of heat activation and
pseudoelastic properties may be used, as is well known by those
skilled in the art.
[0046] The cross-sectional diameter of the wire 34 and length of
the wire will vary depending on the specific application. The
diameter d of the wire 34 may be, for example, between 0.001 and
0.015 inch. For coronary bypass applications, the diameter is
preferably between 0.001 and 0.008 inch with a diameter D of the
loop being between 0.0125 and 0.0875 inch (FIG. 3A). As shown in
FIG. 3A, the wire 34 has a circular cross-sectional shape. The
diameter D of the loop of the fastener 20 in its closed position is
preferably sized to prevent movement between adjacent tissues. It
is to be understood, however, that the wire may have other
cross-sectional shapes such as rectangular, or may be formed from
multiple strands without departing from the scope of the
invention.
[0047] The proximal end of the wire 34 may include a stop 36 having
a cross-sectional area greater than the cross-sectional area of the
wire and coil 26 to prevent the wire and coil from passing through
the tissue. The stop 36 may be attached to the end of the wire 34
by welding, gluing or other suitable attachment means or may be
formed integrally with the wire by deforming the end of the wire.
The stop 36 may also be eliminated to facilitate pulling the
fastener completely through the tissue, if, for example, the entire
fastener needs to be removed from the vessel during the insertion
procedure. The distal end of the wire 34 includes an enlarged
portion 38 for engagement with the restraining device 24 as further
described below (FIG. 4A). The enlarged portion 38 may be formed by
deforming the end of the wire 34 by swaging or arc welding, or
attaching by welding, swaging, or other suitable means an enlarged
portion to the end of the wire.
[0048] The wire 34 has an undeformed or closed configuration
(position, state) (FIG. 3A) for keeping or connecting tissue
together, and a deformed or open configuration (position, state)
(FIG. 3C) for insertion of the wire into tissue. As discussed
above, the wire 34 is in its closed configuration when in a relaxed
state. The wire 34 is preferably not deformed past its yield point
in its open position. Accordingly, it may have a U-shaped
configuration in its open position to facilitate insertion of the
wire through the tissue. It is to be understood that U-shaped
configuration may be alternatively substituted by an equivalent
structure such as C-shaped, V-shaped, J-shaped, and other similarly
shaped configurations. The wire 34 is moved from its closed
position to its open position by a restraining device, as further
described below. When in its closed position, the wire 34 forms a
loop with the ends of the wire in a generally side-by-side or
overlapping orientation (FIG. 3B).
[0049] The wire 34 may be formed in the above described shape by
first wrapping the wire onto a mandrel and heat treating the wire
at approximately 400-500 degrees Celsius for approximately 5 to 30
minutes. The wire 34 is then air quenched at room temperature. The
mandrel may have a constant diameter or may be conical in
shape.
[0050] An alternate configuration of the surgical clip 20 in its
closed position is shown in FIG. 3D, and generally indicated at 40.
The fastener 40 forms a spiral configuration in its closed position
for trapping the tissue within a loop formed by the spiral. In its
open position, the fastener 40 is configured to form less than a
full 360 degree turn.
[0051] Another alternate configuration of the surgical clip 20 is
shown in FIGS. 3E and 3F in its closed position, and is generally
indicated at 41. The fastener 41 is formed in a spiral about a
central longitudinal axis A. As shown in FIG. 3F, the fastener 41
has a generally conical shape along the longitudinal axis A, with a
decreasing diameter as the radius of curvature of the fastener 41
decreases. The fastener 41 has an inner end portion 45 and an outer
end portion 47, with the enlarged portion 38 of the wire being
disposed at the outer end portion for engagement with the
restraining device 24.
[0052] A modification of the fastener 41 is shown in FIG. 3G, and
generally indicated at 43. The fastener 43 is similar to the
fastener 41 described above, except that the enlarged portion 38,
which is adapted for engaging a restraining device or releasable
locking mechanism, is positioned at the inner end portion 45 of the
fastener. Placement of the restraining device 24 at the inner end
portion 45 of the fastener 43 increases the compression force of
the wire in its undeformed position on the tissue and decreases the
surface area of the fastener exposed to blood flow.
[0053] It is to be understood that the fastener 20, 40, 41, 43 may
have undeformed or deformed configurations different than those
shown herein without departing from the scope of the invention. In
addition, a locking clip (not shown) may also be attached to
connect the ends of the fastener 20, 40, 41, 43 when the fastener
is in its closed position to prevent possible opening of the
fastener over time. The locking clip may also be integrally formed
with one end of the fastener.
[0054] As shown in FIG. 3C, the wire 34 is surrounded by the spring
or coil 26 which, along with the locking device 28, restrains the
wire in its deformed configuration. The coil 26 comprises a helical
wire forming a plurality of loops which define a longitudinal
opening 44 for receiving the shape memory alloy wire 34. The coil
26 may be formed from a platinum alloy wire having a
cross-sectional diameter of approximately 0.0005-0.005 inch, for
example. The helical wire may have other cross-sectional shapes and
be formed of different materials. The coil 26 is preferably sized
so that when in its free (uncompressed state) it extends the length
of the wire 34 with one end adjacent the stop 36 at the proximal
end of the wire and the other end adjacent the enlarged portion 38
at the distal end of the wire. It is to be understood that the coil
may not extend the full length of the wire. For example, a flange
or similar device may be provided on an intermediate portion of the
wire 34 to limit movement of the coil along the length of the
wire.
[0055] When the coil 26 is in its free state (with the wire in its
undeformed configuration), loops of the coil are generally spaced
from one another and do not exert any significant force on the wire
34 (FIG. 3A). When the coil 26 is compressed (with the wire 34 in
its deformed configuration), loops of the coil on the inner portion
46 of the coil are squeezed together with a tight pitch so that the
loops are contiguous with one another while loops on the outer
portion 48 of the coil are spaced from one another (FIG. 3C). This
is due to the compressed inner arc length of the coil 26 and the
expanded outer arc length of the coil. The compression of the loops
on the inner portion 46 of the coil 26 exerts a force on the inner
side of the wire 34 which forces the wire to spread open (i.e.,
tends to straighten the wire from its closed configuration to its
open configuration). The end of the coil 26 adjacent the stop 36 is
held in a fixed position relative to the wire 34. The opposite end
of the coil 26 is free to move along the wire 34 and is held in
place when the coil is in its compressed position by the locking
device 28.
[0056] The locking device 28 of the embodiment shown in FIGS. 1 and
4A-4C comprises a flexible tubular member 50 having a distal end
portion 52 coupled to the flexible member 18 and a proximal end
portion 54 releasably attached to the wire. The locking device 28
couples the flexible member 18 and needle 16 to the clip 20. In
addition to releasably coupling the flexible member 18 and needle
16 to the clip 20, the locking device compresses the coil 26 to
bias the clip 20 in its open configuration. The distal end 52 of
the tubular member 50 is attached to the flexible member 18 with a
tapered portion or transition sleeve 56 extending from the tubular
member to the suture to facilitate insertion of the locking device
28 through tissue. The tapered portion 56 is preferably
sufficiently curved to facilitate movement of the tissue connector
assembly 10 through connecting tissue in an anastomosis, for
example. The tapered portion 56 may be formed from a metal alloy
such as stainless steel or a suitable polymeric material and may be
solid or in the form of a sleeve. Generally, portion 56 gradually
diminishes in diameter to provide a smooth, non-stepped transition
between the relatively small diameter of flexible member 18 to the
larger diameter of locking device 28. The flexible member 18 may be
swaged into the tapered portion 56, or a heat shrink plastic
covering may hold the flexible member in place. The locking device
28 may also be curved.
[0057] The tubular member 50 is movable between a locked position
(FIG. 4A) for holding the coil 26 in its compressed position and
the wire 34 in its deformed position, and an unlocked position
(FIG. 4C) for inserting or releasing the wire and coil. Three slots
58 are formed in the tubular member 50 extending from the proximal
end 54 of the member and along at least a portion of the member
(FIGS. 4B and 4C). The slots 58 are provided to allow the proximal
end 54 of the tubular member 50 to open for insertion and removal
of the wire 34 when the tubular member is in its unlocked position
(FIG. 4C). It is to be understood that the number of slots 58 and
configuration of the slots may vary, or the tubular member 50 may
be formed to allow expansion of the proximal end 54 without the use
of slots.
[0058] The proximal end 54 of the tubular member 50 includes a bore
62 having a diameter slightly greater than the outer diameter d of
the wire 34, but smaller than the diameter of the enlarged portion
58 at the distal end of the wire and the outer diameter of the coil
26. The bore 62 extends into a cavity 64 sized for receiving the
enlarged portion 38 of the wire 34. Member 50 may be described as
having an annular flange 61 for releasably securing the enlarged
portion 38. As shown in FIG. 4C, upon application of an inwardly
directed radial squeezing force on the tubular member 50 the
proximal end 54 of the tubular member is opened to allow for
insertion or removal of the wire 34. When the force is released
(FIG. 4A), the tubular member 50 moves back to its locked position
and securely holds the wire 34 in place and compresses the coil 26.
A disc 51 may be inserted into the tubular member 50 to act as a
fulcrum and cause the proximal end 54 of the tubular member to
open. Alternatively, the disc 51 may be integrally formed with the
tubular member 50. As shown in FIG. 4A, the length l of the bore 62
or flange 61 determines the amount of compression of the coil,
which in turn determines the amount of deformation of the wire 34.
The greater the length l of the bore 62, the greater the
compression of the coil 26 and the more straightening the wire 34
will undergo. The compression of the coil 26 is preferably limited
so that the wire 34 is not stressed beyond its yield point. This
allows the wire 34 to revert back to its original undeformed
configuration and apply sufficient pressure to hold the connected
tissue together.
[0059] It is to be understood that locking devices other than those
described above may be used without departing from the scope of the
invention. For example, a locking device (not shown) may comprise a
tubular member having an opening formed in a sidewall thereof for
receiving an end portion of the wire. The end of the wire may be
bent so that it is biased to fit within the opening in the sidewall
of the tubular member. An instrument, such as a needle holder may
then be used to push the wire away from the opening in the tubular
member and release the wire from the tubular member. Various other
types of locking devices including a spring detent or bayonet type
of device may also be used.
[0060] An alternate embodiment of the restraining device is shown
in FIG. 5, and generally indicated with reference numeral 70. The
restraining device 70 is used with a tubular (hollow) shape memory
alloy wire 72 and comprises an elongated member (or mandrel) 74
sized for insertion into the wire or tube. The mandrel 74 is
preferably formed from a material which is stiffer than the
material of the wire 72 so that upon insertion of the mandrel into
the wire, the wire is deformed into its open position. The
restraining device 70 includes a stop 76 located at the proximal
end of the wire 72. The stop operates to prevent the fastener from
being pulled through the tissue, and limits axial movement of the
mandrel 74 in the proximal direction (to the right as viewed in
FIG. 5). The distal end of the mandrel 74 is attached to the suture
18 and includes a tapered portion 78. The tapered portion 78 may be
a sleeve or may be solid and may be formed from any suitable metal
or polymeric material, for example. It is to be understood that
other types of restraining devices may be used without departing
from the scope of the invention.
[0061] Another tissue connector assembly is shown in FIG. 6 and
generally indicated with reference numeral 100. The tissue
connector assembly 100 is the same as the first embodiment 10
except that a needle 102 is attached directly to a locking device
104 with the suture 18 of the first embodiment being eliminated.
The tissue connector assembly 100 includes the needle 102, a
restraining device 108, and a fastener 110. FIG. 6 shows the tissue
connector assembly 100 with the fastener in its open (deformed)
configuration. The fastener 110 may be the same as the fasteners
20, 40, 41, 43 described above and shown in FIGS. 3A-3G for the
tissue connector assembly of the first embodiment, for example.
[0062] The restraining device 108 comprises a coil 112 and the
locking device 104. The locking device 104 is similar to the
locking device 28 shown in FIGS. 4A-4C, except that the distal end
is configured for attachment directly to the needle 102. The needle
102 may be integrally formed with the locking device 104 or may be
swaged, welded, threadably attached, or attached by any other
suitable means to the locking device. The restraining device 70
shown in FIG. 5 may also be used with this embodiment 100 of the
tissue connector assembly.
[0063] As noted above, the tissue connector assemblies 10, 100 have
many uses. They may be especially useful for minimally invasive
surgical procedures including creating an anastomosis between a
vascular graft 12 and an artery 14 (FIGS. 2A-2G). The anastomosis
may be used to replace or bypass a diseased, occluded or injured
artery. A coronary bypass graft procedure requires that a source of
arterial blood flow be prepared for subsequent bypass connection to
a diseased artery. An arterial graft may be used to provide a
source of blood flow, or a free graft may be used and connected at
the proximal end to a source of blood flow. Preferably, the source
of blood flow is one of any number of existing arteries which may
be dissected in preparation for the bypass graft procedure. In many
instances it is preferred to use the left internal mammary artery
(LIMA) or the right internal mammary artery (RIMA), for example.
Other vessels which may be used include the saphenous vein,
gastroepiploic artery in the abdomen, radial artery, and other
arteries harvested from the patient's body as well as synthetic
graft materials, such as DACRON.RTM. (polyester fibers) or
GORETEX.RTM. (expanded polytetrafluoroethylene). If a free graft
vessel is used, the upstream end of the dissected vessel, which is
the arterial blood source, will be secured to the aorta to provide
the desired bypass blood flow, as is well known by those skilled in
the art. The downstream end of the graft vessel is trimmed for
attachment to an artery, such as the left anterior descending
coronary (LAD). It is to be understood that the anastomosis may be
formed in other vessels or tissue.
[0064] FIGS. 2A-2F show an exemplary use of the tissue connector
assemblies 10, 100 for connecting a graft vessel 12 to an artery 14
(target vessel). In this example, two tissue connector assemblies
10 are used to make connections at generally opposite sides of the
graft vessel and tissue connector assemblies 100 are used to make
connections between those made with assemblies 10 (FIG. 6). The
procedure may be accomplished with a beating heart procedure with
the use of a heart stabilizer to keep the heart stable, for
example. The procedure may also be performed endoscopically.
[0065] The patient is first prepped for standard cardiac surgery.
After exposure and control of the artery 14, occlusion and
reperfusion may be performed as required. After the arteriotomy of
the snared graft vessel 12 has been made to the appropriate length,
a tissue connector assembly 10 is attached to the free end of the
graft vessel along an edge margin of the vessel. In order to attach
the connector assembly 10, the surgeon grasps the needle 16 with a
needle holder (e.g., surgical pliers, forceps, or any other
suitable instrument) and inserts the needle 16 into the tissue of
the graft vessel 12 in a direction from the exterior of the vessel
to the interior of the vessel. The surgeon then releases the needle
16 and grasps a forward end of the needle which is now located
inside the graft vessel 12 and pulls the needle and a portion of
the suture 18 through the vessel. The needle 16 is passed through
an opening 120 formed in the sidewall of the artery 14 and inserted
into the tissue of the artery in a direction from the interior of
the artery to the exterior of the artery. The surgeon then grasps
the needle 16 located outside the artery 14 and pulls the needle
and a portion of the suture 18 through the arterial wall. A second
tissue connector assembly 10 may be inserted at a location
generally 180 degrees from the location of the first tissue
connector in a conventional "heel and toe" arrangement.
[0066] Once the tissue connector assemblies 10 are inserted, the
graft vessel 12 is positioned above and aligned with the opening
120 in the sidewall of the artery 14 (FIG. 2A). A section of each
suture 18 is located between the graft vessel 12 and artery 14. The
fasteners 20 and needles 16 are pulled generally away from the
artery 14 to reduce the length of the suture 18 (eliminate slack of
the suture) between the vessel 12 and artery and "parachute" the
vessel onto the artery (FIG. 2B). The needles 16 are then pulled
away from the artery 14 until each fastener 20 is positioned within
the graft vessel 12 and artery with one end of each fastener 20
extending from the vessel and the opposite end of each fastener
extending from the artery (FIG. 2C). The edges of the graft vessel
12 and artery 14 are positioned adjacent one another to form a
continuous interior and exterior surface along the mating portions
of the vessel and artery. As shown in FIG. 2F, the tissue is
compressed within the fastener 20.
[0067] A surgical instrument (e.g., needle holder) is used to
radially squeeze each locking device 28 to release the locking
device from the fastener 20. Upon removal of the locking device 28,
the coil 26 moves to its free uncompressed state which allows the
wire 34 to return to its original undeformed closed position (FIG.
2D). As the wires 34 move to their closed position the adjacent
tissues of the graft vessel 12 and artery 14 which were previously
pulled together during the parachuting of the graft vessel onto the
artery, are squeezed together to securely engage the graft vessel
and artery (FIGS. 2E and 2F). It should be noted that as the
locking device 28 is squeezed two steps are accomplished. The
fastener 20 is released from the locking device 28, thus allowing
the coil 26 to uncompress and the wire 34 to move to its closed
configuration, and the needle 16 is released from the fastener.
Thus, in this embodiment, the locking device 28 provides for
simultaneous actuating closure of the fastener 20 and release of
the needle 16 from the fastener.
[0068] The tissue connector assemblies 100 are subsequently
inserted at circumferentially spaced locations around the periphery
of the graft vessel to sealingly fasten the graft vessel 12 to the
artery 14. The needle 102 of the fastener 100 is inserted into the
graft vessel 12 from the exterior surface of the graft vessel and
pushed through the graft vessel and artery 14 tissue. The needle
holder is then used to pull the needle 102 through the arterial
wall. An instrument (same needle holder or other suitable
instrument) is used to apply a squeezing force to the locking
device 104 to release the wire and coil 112 from the needle 102.
This allows the coil 112 to move to its uncompressed configuration
and the wire to move to its closed position. It should be noted
that the tissue connector assemblies 10 may remain in their open
position while the tissue connector assemblies 100 are inserted
into the tissue and moved to their closed position. The locking
devices 28 of the tissue connector assemblies 10 may subsequently
be removed from the fasteners 20 to allow the fasteners to move to
their closed position. The number and combination of tissue
connectors assemblies 10, 100 required to sealingly secure the
connecting tissues together may vary. For example, only tissue
connector assemblies 10 may be used to complete the entire
anastomosis.
[0069] Although the coil 26 is shown remaining on the wire (FIG.
2D), it is to be understood that the coil 26 may also be removed
from the wire 34, leaving only the wire in the connected
tissue.
[0070] As an alternative to inserting tissue connector assemblies
10 at "heel and toe" locations described above, a number of tissue
connectors 10 may be inserted generally around the location of the
heel. The graft vessel may then be pulled towards the artery to
determine whether the opening formed in the sidewall of the artery
is large enough before completing the anastomosis.
[0071] The graft vessel 12 may also be parachuted onto the artery
14 in the method shown in FIG. 2G. The needle is inserted into the
graft vessel 12 and artery 14 as described above and the suture 18
is pulled through the vessel so that the fastener 20 is positioned
within the vessel and artery. The needles 16 are then pulled away
from the artery 14 to "parachute" the graft vessel 12 onto the
artery. The anastomosis may then be completed as described
above.
[0072] Although the suturing procedure has been described for an
end-to-side anastomosis, it should be appreciated that the
procedure is applicable to an end-to-end and side-to-side
anastomosis, connecting various tissue structures including single
and multiple tissue structures, and puncture sites, and connecting
tissue to a prosthetic graft or valve, for example.
[0073] It will be observed from the foregoing that the tissue
connector assemblies of the present invention have numerous
advantages. Importantly, the assemblies are easier and faster to
apply than conventional sutures which require tying multiple knots.
The assemblies also may be used in minimally invasive procedures
including endoscopic procedures.
[0074] All references cited above are incorporated herein by
reference.
[0075] The above is a detailed description of a particular
embodiment of the invention. It is recognized that departures from
the disclosed embodiment may be made within the scope of the
invention and that obvious modifications will occur to a person
skilled in the art. The full scope of the invention is set out in
the claims that follow and their equivalents. Accordingly, the
claims and specification should not be construed to unduly narrow
the full scope of protection to which the invention is
entitled.
* * * * *