U.S. patent application number 12/334029 was filed with the patent office on 2009-04-16 for self-locking suture anchor.
This patent application is currently assigned to DEPUY MITEK, INC.. Invention is credited to Richard Caspari, Jeffrey Halbrecht, Dennis McDevitt.
Application Number | 20090099598 12/334029 |
Document ID | / |
Family ID | 23463884 |
Filed Date | 2009-04-16 |
United States Patent
Application |
20090099598 |
Kind Code |
A1 |
McDevitt; Dennis ; et
al. |
April 16, 2009 |
SELF-LOCKING SUTURE ANCHOR
Abstract
A tissue anchor having a length of filament held so that an
applied force greater than a threshold force will cause the
filament to move longitudinally, while an applied force less than
the threshold force will not move the filament, and methods of
attaching soft tissue to bone using such an anchor.
Inventors: |
McDevitt; Dennis; (Upton,
MA) ; Halbrecht; Jeffrey; (San Francisco, CA)
; Caspari; Richard; (Maidens, VA) |
Correspondence
Address: |
NUTTER MCCLENNEN & FISH LLP
WORLD TRADE CENTER WEST, 155 SEAPORT BOULEVARD
BOSTON
MA
02210-2604
US
|
Assignee: |
DEPUY MITEK, INC.
Raynham
MA
|
Family ID: |
23463884 |
Appl. No.: |
12/334029 |
Filed: |
December 12, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
11052557 |
Feb 7, 2005 |
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12334029 |
|
|
|
|
10629978 |
Jul 30, 2003 |
7081126 |
|
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11052557 |
|
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|
10375389 |
Feb 27, 2003 |
6660023 |
|
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10629978 |
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09371411 |
Aug 10, 1999 |
6527794 |
|
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10375389 |
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Current U.S.
Class: |
606/232 |
Current CPC
Class: |
A61B 2017/0459 20130101;
A61B 2090/037 20160201; A61F 2/0811 20130101; A61B 2017/0414
20130101; A61B 90/03 20160201; A61B 2017/00862 20130101; A61B
2017/0408 20130101; A61B 2017/0403 20130101; A61B 2017/0427
20130101; A61B 2017/045 20130101; A61B 2017/0438 20130101; A61B
2017/0458 20130101; A61B 17/0401 20130101; A61B 2017/044 20130101;
A61B 2017/0412 20130101; A61B 2017/0424 20130101; A61F 2002/0882
20130101 |
Class at
Publication: |
606/232 |
International
Class: |
A61B 17/04 20060101
A61B017/04 |
Claims
1. A method for anchoring a suture, comprising: implanting an
anchor member in bone, the anchor member having a cavity extending
therethrough with opposite open ends; moving a deployment shaft to
position insertion element in the cavity in the anchor member, the
insertion element and the anchor member engaging a suture extending
through the cavity to lock a loop of suture extending from the
cavity in a fixed position; and frangibly detaching the deployment
shaft from the insertion element.
2. The method of claim 1, wherein the suture is held between the
anchor member and the insertion element by a compression fit.
3. The method of claim 1, wherein moving the deployment shaft
comprising pulling the deployment shaft to pull the insertion
element into the cavity.
4. The method of claim 1, wherein frangibly detaching the
deployment shaft from the insertion element comprises applying
tension to a frangible portion formed between the deployment shaft
and the insertion element.
5. A method for anchoring tissue to bone, comprising: implanting an
anchor member in a bone tunnel; applying tension to a deployment
shaft attached to an insertion element to pull the insertion
element into a cavity formed in the anchor member; applying tension
to a frangible portion formed between the deployment shaft and the
insertion element to cause the frangible portion to shear to
separate the deployment shaft from the insertion element.
6. The method of claim 5, wherein the insertion element is held
within the cavity of the anchor member by an interference fit.
7. The method of claim 5, wherein the anchor member includes a
suture extending therethrough, and wherein the suture is engaged
between the anchor member and the insertion element.
8. The method of claim 7, wherein the suture extends through the
cavity, forms a loop segment, and extends back through the
cavity.
9. A method for anchoring tissue to bone, comprising: implanting an
anchor element in a bone tunnel, the anchor element having a suture
passing through a cavity in the anchor element, forming a loop
segment, and passing back through the cavity in the anchor element;
and inserting an insertion element into the cavity in the anchor
element to hold the suture therein by interference fit.
10. The method of claim 9, wherein the insertion element is
inserted into the cavity in the anchor member using a deployment
device.
11. The method of claim 10, wherein the deployment device is
attached to the insertion element during deployment, and wherein
the deployment device is frangibly sheared from the insertion
element after deployment of the insertion element into the anchor
member.
12. The method of claim 10, wherein the deployment device is pulled
to pull the insertion element into the cavity in the anchor member.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 11/052,557 filed on Feb. 7, 2005 and entitled
"Self-Locking Suture Anchor," which is a continuation of U.S.
patent application Ser. No. 10/629,978 (now U.S. Pat. No.
7,081,126), filed on Jul. 30, 2003 and entitled "Self-Locking
Suture Anchor," which is a continuation of U.S. patent application
Ser. No. 10/375,389 (now U.S. Pat. No. 6,660,023), filed on Feb.
27, 2003 and entitled "Self-Locking Suture Anchor," which is a
continuation of U.S. patent application Ser. No. 09/371,411 (now
U.S. Pat. No. 6,527,794), filed on Aug. 10, 1999 and entitled
"Self-Locking Suture Anchor." These references are hereby
incorporated by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] This invention relates to surgical fasteners, e.g., anchors
that secure sutures to bone, a meniscus, or other tissue. It
further relates to a suture anchor that attaches a suture to tissue
without the use of knots, and to methods of securing tissue using
one or more anchors and a length of suture.
[0003] Many surgical procedures require the attachment of soft
tissue, e.g., ligament or tendon grafts, to bone. This is typically
accomplished by anchoring a suture in bone, for example with a
screw, pin, or other bone anchoring device, and looping the suture
around or stitching the suture to the soft tissue. When this
process is completed, the surgeon generally must knot the suture to
secure the tissue. This knotting process can be difficult and
tedious, particularly during laparoscopic or endoscopic procedures,
where the surgeon must remotely manipulate the suture using tools
inserted through an endoscopic tube. Further, as many as six knots
are often required to secure one suture. These knots may "stand
proud" above the tissue and interfere with movement and
healing.
[0004] One advance which has been proposed is the anchor apparatus
disclosed by Goble, et al., in U.S. Pat. No. 5,702,397. That
apparatus comprises an anchor body through which a suture passes,
and which contains a clamping mechanism such as a spherical element
within the anchor body. When the suture is pulled in a proximal
direction, the clamp is urged into contact with the anchor body,
thereby holding the suture in place. When the suture is pulled in a
distal direction, the clamp disengages, and the suture can move
freely through the anchor body. At least one end of the suture is
stitched and/or knotted to soft tissue.
[0005] Several knotless suture anchor assemblies have recently been
proposed by Thal in U.S. Pat. Nos. 5,569,306; 5,658,313; 5,665,112;
and 5,683,419. These describe suture anchors which secure a
filament having a small loop at one end. In some embodiments,
another length of suture ends in a small block, which is passed
through the loop to secure the tissue. While these structures can
be secured without knots, the block used to secure the suture may
itself stand proud above the tissue, causing discomfort and
interfering with healing. In other embodiments, the anchor itself
is passed through the small loop, creating a larger loop which is
used to hold tissue.
[0006] U.S. Pat. No. 5,709,708, also by Thal, describes a suture
anchor utilizing a continuous loop of suture material, which
secures the tissue in a similar manner. As in the other Thal
knotless anchors, the tension of the suture is dependent on the
length of specially provided suture, which cannot be adjusted.
Thus, these anchors cannot be used in surgical operations in which
it is necessary to tighten a loop of suture to secure soft
tissue.
[0007] The tying of suture knots presents difficulties in other
surgical procedures, as well. For example, tears occur commonly in
the menisci of athletes. The simplest method of repairing such a
tear is to stitch it closed by passing a length of suture through
the tissue and tying. However, the needles used in such surgery are
very difficult to manipulate during endoscopic surgery, and the
knots used to secure the suture may interfere with healing as
described above. These difficulties are particularly severe in the
restricted space of the joint capsule of the knee, a common
location for such injuries. Other devices such as darts and clamps
have also been proposed for this purpose; see for example U.S. Pat.
Nos. 5,154,189; 5,269,783; and 5,702,462. Like suture knots, these
devices may cause considerable discomfort during healing of the
tear. Further, if made of non-bioabsorbable materials, a second
surgery must be performed to remove the devices from the meniscus
after healing.
[0008] A need thus exists for an improved technique and apparatus
for securing tissues without the use of knots. A further need
exists for such techniques and apparatus which also permit the
position of the suture to be readily adjusted. A still further need
exists for such apparatus which is small enough to avoid
discomfort, which is amenable to fabrication from bioabsorbable
materials, and which can be used either in bone or in soft
tissue.
SUMMARY OF THE INVENTION
[0009] The above needs are among those met by the invention, which
provides an anchoring device that can be embedded in bone or soft
tissue, that permits suture length and/or tension to be readily
adjusted, and that can be secured without the use of knots.
[0010] In one aspect of the invention, a suture anchor suitable to
be embedded in bone has a cavity which holds a filament (e.g., a
suture) by interference fit. The anchor holds the suture tightly
enough to resist "operational" forces to which the suture is
subjected subsequent to deployment, e.g., during movement of the
bones and/or soft tissues to which the suture is attached. However,
the interference fit is weak enough to allow the suture to be
pulled longitudinally through the cavity by a stronger force.
[0011] In use, such an anchor can be placed with some slack in the
suture. The suture can then be tightened by pulling on one of its
ends (with the larger force). It is an advantage of the invention
that the tightening of the suture can be reversed, simply by
pulling on a loop formed by the suture or by pulling on its
opposite end. The suture does not loosen in normal use, however,
since the forces required to move during deployment are greater
than those exerted by the bones and/or tissues to which it is
attached.
[0012] In a related aspect, the anchor may hold the suture at two
points, forming a loop. The loop can be disposed around tissue and,
then, tightened by pulling one end of the suture, thereby securing
the tissue. Again, if the loop is drawn too tight, it can be
loosened by pulling firmly.
[0013] The invention also provides methods for attaching soft
tissue to bone. In these methods, an anchor of the type described
above can be emplaced in bone. The soft tissue is secured by
stitching or by catching a portion of the tissue in a loop of
suture, which is subsequently tightened. The suture can be
tightened or loosened as necessary during deployment, and need not
be knotted.
[0014] These and other aspects of the invention are evident in the
drawings and in the description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The invention is best understood with reference to the
drawings, in which:
[0016] FIGS. 1 and 2 are illustrations of suture anchors according
to the invention, adapted to be embedded in bone;
[0017] FIG. 3 is an illustration of a suture anchor according to
the invention before deployment; and
[0018] FIGS. 4A-4C illustrate a deployment process for the anchors
shown in FIGS. 1 and 2.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0019] FIG. 1a shows a cutaway view of a suture anchor according to
the invention. The anchor comprises an anchoring element 10, which
is adapted to be embedded in a bone tunnel or in soft tissue, and
comprises an axial channel 12. In the embodiment shown, element 10
comprises a series of ridges 14 on its outer surface, which aid in
securing the element, for example, in a bone tunnel. It will be
understood that the ridges 14 are not a necessary element of the
anchor, and may be omitted if desired. The anchor 10 further
comprises an insertion stem 16. When the anchor is in the deployed
position shown in FIG. 1a, the insertion stem 16 is held within the
axial channel 12, e.g., by interference fit. In preferred
embodiments, the insertion stem 16 is slightly larger than the
axial channel 12, so that the stem 16 forces the anchoring element
10 to expand when it is inserted therein, thereby securing the
anchor firmly in the bone tunnel.
[0020] The anchor further comprises a filament 18, e.g., a suture,
disposed between the anchoring element 10 and the insertion stem
16. In the preferred embodiment shown in FIGS. 1a and 1b, the
insertion element comprises a suture channel 20. This channel
guides the suture 18, and holds it in compression against the
anchoring element 10. The configuration of anchoring element 10,
insertion stem 16, and suture 18 can be seen clearly in FIG. 1b,
which shows a cross-sectional view of the anchor at the point
indicated by the arrows of FIG. 1a. The mild compression of the
suture 18 in the channel 20 provides a frictional resistance to
prevent movement of the suture when tension is applied to one of
its free ends 22. This frictional resistance is overcome when a
tension greater than the threshold tension is applied to a free end
of the suture. The suture 18 may then slide longitudinally through
the channel 20, allowing the length of the free ends 22 to be
adjusted.
[0021] It will be understood that the configuration of suture 18 in
FIG. 1 represents only one of many possible embodiments of the
invention. In particular, it will often be preferable to pass the
suture between the insertion stem 16 and the anchoring element 10
multiple times, for example, in order to form a loop segment. In
other embodiments of the invention, the compression of the suture
may be stronger, so that the threshold tension which would be
necessary to move the suture is close to or exceeds the breaking
strength of the suture. In such embodiments, the length of the free
ends is no longer adjustable once the compression on the suture is
applied.
[0022] In one such embodiment, the suture (or other filament) may
be formed with a small loop at one end, which is used to secure the
suture to the anchor. This embodiment is illustrated in FIGS. 2a
and 2b; the former depicting a cross-section of the anchor along
the axis of symmetry; and the latter depicting a transverse
section. The head of suture 18 comprises a small loop 28; e.g.,
disposed at the distal end of the anchor. The suture passes between
the insertion stem 16 and the anchoring element 10, forms a loop
segment 26, and passes back between the insertion stem and the
anchoring element. The suture then passes through head loop 28,
back up between the insertion stem 16 and the anchoring element 10,
and ends in free end 22. The loop segment 26 can be tightened by
pulling free end 22, and loosened by pulling the loop segment 26
itself. Because of the mechanical advantage afforded by looping of
the suture, the force required to loosen the suture by pulling on
loop 26 is twice the force required to tighten the suture by
pulling on free end 22. In the embodiment shown, the suture passes
through two channels 23, 25 in the anchor 16; one of these channels
25 could be eliminated so that the suture would pass around the
head of the anchor.
[0023] FIGS. 3a and 3b illustrate a different embodiment of the
anchor, in which the suture is secured by a small knot 27 rather
than a loop. FIG. 3a is a plan view of the anchor, and FIG. 3b is a
longitudinal cross-section.
[0024] FIGS. 4a-4c illustrate a deployment process for the anchors
shown in FIGS. 1 and 2. Only a portion of the suture is shown in
FIGS. 4a-4c; preferably, the suture will be looped in the fashion
shown in FIG. 2 or FIG. 3. FIG. 4a shows an anchor placed in bone
tunnel 32, connected to deployment apparatus 34. FIG. 4b
illustrates the insertion element 16 being pulled into the axial
channel 12 of anchoring element 10. Tension is applied to the stem
of insertion element 16 (in the direction shown by arrow A) by the
colleted stem-pulling portion of the deployment device 34, while
the anchoring element 10 is held substantially immobile within bone
hole by the anchor-holding portion of that device. These forces act
to move the insertion element 16 in the direction of arrow A such
that larger diametered portion of insertion element is pulled into
the axial channel 12 of anchoring element 10. As a result, the wall
of the anchoring element 10 expands outwardly and into the walls of
the bone hole 32. As shown in FIG. 4c, the insertion stem is pulled
proximally through the axial bore 12, until further motion is
retained by abutment of flange 36 with the distal end of anchoring
element 10. At this point, the deployment device continues to exert
tension on the stem 16, causing frangible portion 38 to shear. This
facilitates removal of the excess portion of the stem 16 and,
likewise, disengages the deployment device 34. The suture 18 can be
adjusted by pulling firmly on free end 22.
[0025] The suture anchors of the invention can be provided in a
variety of sizes and materials, depending on the intended
application. For example, a typical anchor intended to be embedded
in the shoulder blade, for use in repair of the rotator cuff of an
adult, might have a length in the range of 8-15 mm and a diameter
in the range of 3-6 mm. Such an anchor might be capable, for
example, of holding a #2 suture with a threshold force in the range
of 25-35 lbs. (As it is used herein, the term "threshold force"
describes a pulling force above which a filament moves
longitudinally through an anchor, and below which the filament
substantially does not move through the anchor). It is generally
desirable for the anchor to consist of biocompatible material,
e.g., implant grade high density polyethylene, low density
polyethylene (PE 6010 and PE 2030), polypropylene (13R9A and 23M2:
all made by Rexene, Dallas, Tex.) or surgical implant grade steel.
In some embodiments, the anchor may comprise a bioabsorbable
material, e.g., poly-1-lactide or a lactide-glycolide
composition.
[0026] In an exemplary embodiment of the methods of the invention,
the anchor illustrated in FIGS. 3a and 3b can be used to repair a
torn rotator cuff by reattachment of the rotator cuff to the
scapula. An anchor such as that illustrated in FIG. 3a, which holds
a loop of suture by interference fit, is embedded in a tunnel
drilled, for example, in the scapula. The loop of suture and the
free end of the suture extend out from the scapula at the proximal
end of the anchor.
[0027] When the anchor is disposed in the bone tunnel, a portion of
the torn rotator cuff is passed through the suture loop. The loop
is then tightened by pulling with a force greater than the
threshold force on the free end of the suture. This tightens the
loop, drawing the tissue against the anchor and securing it to the
bone without knotting the suture. The free end of the suture may
then be trimmed, if desired.
[0028] The invention may be used with various anchor designs,
depending on the nature of the surgical repair. In particular,
designs similar to those described in copending U.S. application
Ser. No. 08/813,914, e.g., at FIG. 5 and in the accompanying text,
and in copending U.S. application Ser. No. 08/814,149, and in the
accompanying text, both of which are incorporated herein by
reference, may be adapted to hold a suture in accordance with the
teachings herein.
[0029] Other embodiments of the invention will be apparent to those
skilled in the art from a consideration of the specification or
practice of the invention disclosed herein. For example, while the
invention has been described primarily in the contexts of securing
soft tissue to bone and of repairing tears in soft tissue, it may
also be used to secure or repair cartilage, ligaments, or other
tissues. It is intended that the specification and examples be
considered as exemplary only, with the true scope and spirit of the
invention being indicated by the following claims.
* * * * *