U.S. patent application number 11/143132 was filed with the patent office on 2005-12-15 for knotless suture lock apparatus and method for securing tissue.
This patent application is currently assigned to ArthroCare Corporation. Invention is credited to Foerster, Seth, Vijay, Francis.
Application Number | 20050277986 11/143132 |
Document ID | / |
Family ID | 25123956 |
Filed Date | 2005-12-15 |
United States Patent
Application |
20050277986 |
Kind Code |
A1 |
Foerster, Seth ; et
al. |
December 15, 2005 |
Knotless suture lock apparatus and method for securing tissue
Abstract
A suture-locking apparatus comprising a body member having a
proximal end, a distal end, and an axial lumen in between the
proximal and distal ends, wherein the proximal end adapted for
passing a portion of a suture into the lumen; and a plug member
movable from a first position to a second position in the lumen,
the plug member comprising a radial protrusion adapted for
compressing the suture against the body member on moving to the
second position. In a further embodiment the invention is a method
of anchoring soft tissue in a body cavity with a suture using the
present apparatus and without tying a knot.
Inventors: |
Foerster, Seth; (Irvine,
CA) ; Vijay, Francis; (Irvine, CA) |
Correspondence
Address: |
ARTHROCARE CORPORATION
680 VAQUEROS AVENUE
SUNNYVALE
CA
94085-3523
US
|
Assignee: |
ArthroCare Corporation
Austin
TX
|
Family ID: |
25123956 |
Appl. No.: |
11/143132 |
Filed: |
June 1, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11143132 |
Jun 1, 2005 |
|
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09781793 |
Feb 12, 2001 |
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Current U.S.
Class: |
606/232 |
Current CPC
Class: |
A61B 17/0401 20130101;
A61B 2017/0417 20130101; A61B 2017/045 20130101; A61F 2002/0882
20130101; A61B 2017/0414 20130101; A61F 2002/0888 20130101; A61B
2017/0409 20130101; A61B 2017/0458 20130101 |
Class at
Publication: |
606/232 |
International
Class: |
A61B 017/04 |
Claims
1. A suture-locking apparatus for anchoring a suture within a body
cavity, comprising: a body member having a proximal end, a distal
end, and an axial lumen in between said proximal and distal ends,
said proximal end adapted for passing a portion of a suture into
said lumen; and a plug member movable from a first position to a
second position in said lumen, said plug member comprising a radial
protrusion adapted for compressing said suture against said body
member on moving to said second position.
2. The suture-locking apparatus of claim 1, wherein said radial
protrusion is also adapted for stopping said plug member at said
second position.
3. The suture-locking apparatus of claim 1, wherein said radial
protrusion is adapted for compressing said suture and stopping
proximal axial movement of said plug member in said lumen.
4. The suture-locking apparatus of claim 1, wherein said body
member further comprises an aperture defined in said body member
for inserting said plug member into said lumen.
5. The suture-locking apparatus of claim 1, wherein said body
member further comprises a suture pulley member fixed with respect
to said lumen for turning around and exiting said suture through
said lumen at said proximal end.
6. The suture-locking apparatus of claim 5, wherein said body
member comprises a tubular body, and said suture pulley member
comprises a portion of said tubular body defined between said
aperture and said distal end.
7. The suture-locking apparatus of claim 1, wherein said suture is
movable in said lumen while said plug member is located at said
first position.
8. The suture-locking apparatus of claim 1, wherein said plug
member is movable from said first position to said second position
while said suture is attached to a body tissue.
9. The suture-locking apparatus of claim 1, wherein said lumen is
characterized by a larger internal wall cross-section within said
first position, and a smaller internal wall cross-section at said
second position, said larger cross-section transitioning to said
smaller cross-section at a zigzag wall section therein.
10. The suture-locking apparatus of claim 8, wherein said zigzag
wall section is adapted for limiting said movement of said plug
member at said second position.
11. The suture-locking apparatus of claim 5, wherein said suture
pulley member is deployed transversely across said lumen.
12. The suture-locking apparatus of claim 5, wherein said suture
pulley member comprises a rod member.
13. The suture-locking apparatus of claim 5, wherein said suture
pulley member comprises a bridge member defined between two
apertures in said body member.
14. The suture-locking apparatus of claim 1, wherein said body
member comprises a material selected from the group consisting of a
plastic, a polyaryletheketone and a stainless steel.
15. The suture-locking apparatus of claim 1, wherein said body
member is dimensioned for anchoring a body tissue in a body
cavity.
16. The suture-locking apparatus of claim 1, wherein said radial
protrusion comprises a step portion formed thereon between a larger
tail-section and a smaller nose-section of said plug member.
17. The suture-locking apparatus of claim 1, wherein said radial
protrusion comprises a radial ridge formed thereon between a larger
tail-section and a smaller nose-section of said plug member.
18. The suture-locking apparatus of claim 1, wherein said radial
protrusion comprises a circumferential stop formed thereon between
a larger tail-section and a smaller nose-section of said plug
member.
19. The suture-locking apparatus of claim 1, wherein said plug
member further comprises an actuator member attached thereto for
moving said plug member within said lumen.
20. The suture-locking apparatus of claim 19, wherein said actuator
includes a built-in failure-point for detaching said actuator from
said plug member upon application of a threshold tensile force on
said plug member.
21. The suture-locking apparatus of claim 19, wherein said plug
member comprises a lumen for attaching said actuator to said plug
member.
22. The suture-locking apparatus of claim 1, wherein said plug
member comprises a material selected from the group consisting of a
plastic, a polyaryletheketone and a stainless steel.
23. The suture-locking apparatus of claim 1, further comprising: a
toggle member disposed proximally and axially with said body
member, and a strut member connecting said toggle member to said
body member, wherein said toggle member when disposed at an
undeployed position projects a smaller profile transverse to said
body member, and at a deployed position projects a larger profile
transverse to said body member, said strut member adapted for
collapsing to translate said toggle member from said undeployed
position to said deployed position.
24. A knotless suture-locking apparatus for anchoring a suture
within a body cavity, comprising: a body member for fixing said
suture-locking apparatus within a body cavity, said body member
having a proximal end, a distal end, and a lumen opened at said
proximal end to receive a length of suture therein; and a
suture-locking plug member comprising a radial protrusion for
positively interfering with proximal movement of said
suture-locking plug with respect to said body member, wherein said
suture-locking plug member is movable within said lumen from a
first position that does not interfere with axial movement of said
length of suture, to a second position that interferes with axial
movement of said length of suture.
25. The suture-locking apparatus of claim 24, wherein said
suture-locking plug further includes a detachable actuation rod
member removably attached thereto and projecting out of said
proximal end of said anchor body, said actuation rod for moving
said suture-locking plug axially within said lumen.
26. The suture-locking apparatus of claim 25, wherein said
actuation rod comprises a built-in point of tensile weakness along
said actuation rod for permitting said rod to be detached from said
suture-locking plug upon application of a threshold tensile force
on said actuation rod in said proximal direction while said radial
protrusion is compressing said suture in said lumen.
27. The suture-locking apparatus of claim 24, wherein said body
member further includes a suture pulley member fixed with respect
to said lumen such that said length of suture may be passed into
said lumen from said proximal end, looped around said pulley, and
passed out of said lumen through said proximal end.
28. The suture-locking apparatus of claim 27, wherein said body
member comprises a tubular body, and said suture pulley member
comprises a portion of said tubular body between an aperture and
said distal end.
29. The suture-locking apparatus of claim 24, wherein a portion of
said suture is attached to a body tissue.
30. The suture-locking apparatus of claim 24, wherein said lumen is
characterized by a larger wall cross-section at said first
position, and a smaller wall cross-section at said second section,
said larger cross-section transitioning to said smaller
cross-section at a zigzag wall section therein.
31. The suture-locking apparatus of claim 30, wherein said zigzag
wall section is adapted for limiting the movement of said plug
member at said second position in said lumen.
32. The suture-locking apparatus of claim 27, wherein said suture
pulley member is deployed transversely across said lumen.
33. The suture-locking apparatus of claim 27, wherein said suture
pulley member comprises a rod member.
34. The suture-locking apparatus of claim 26, wherein said suture
pulley member comprises a bridge member defined between two
apertures in said body member.
35. The suture-locking apparatus of claim 24, wherein said body
member comprises a material selected from the group consisting of a
plastic, a polyaryletheketone and a stainless steel.
36. The suture-locking apparatus of claim 24, wherein said body
member is dimensioned for anchoring a body tissue in a body
cavity.
37. The suture-locking apparatus of claim 24, wherein said radial
protrusion comprises a zigzag shoulder portion formed at a
transition between a larger tail-section and a smaller nose-section
on said plug member.
38. The suture-locking apparatus of claim 24, wherein said radial
protrusion comprises a radial ridge formed between a larger
tail-section and a smaller nose-section on said plug member.
39. The suture-locking apparatus of claim 25, wherein said plug
member comprises a lumen for attaching said actuation rod to said
plug member.
40. The suture-locking apparatus of claim 24, wherein said plug
member comprises a material selected from the group consisting of a
plastic, a polyaryletheketone and a stainless steel.
41. The suture-locking apparatus of claim 24, further comprising: a
toggle member disposed proximally to and axially with said body
member; and a collapsible strut member connecting said toggle
member to said body member, wherein said toggle member while
located at an undeployed position projects a smaller profile
transverse to said body member, and at a deployed position projects
a larger profile transverse to said body member, said strut member
adapted for collapsing and translating said toggle member from said
undeployed position to said deployed position.
42. A method for repairing a torn rotator cuff comprising:
manipulating a rotator cuff tendon over a surface of a humerus;
suturing the rotator cuff tendon to obtain at least one length of
suture extending therefrom; passing said length of suture into a
bone anchor; forming a bone tunnel in the humerus; deploying said
bone anchor in said bone tunnel; and actuating a suture-locking
component of said bone anchor to lock said suture such that said
rotator cuff tendon is secured to said humerus.
43. The method of claim 42 wherein said step of actuating is
performed without tensioning or slackening said suture length.
44. The method of claim 43 wherein said suture-locking component is
a plug and said step of locking comprises compressing said suture
between said plug and a body of said anchor.
45. The method of claim 42 further comprising tensioning said
length of suture prior to actuating step.
46. The method of claim 42 wherein said suturing step comprises
forming a loop in said tendon and two free ends of suture extending
therefrom.
47. The method of claim 45 wherein said actuating step is performed
while said suture is under tension.
48. The method of claim 42 wherein said actuating step is performed
with an instrument.
49. The method of claim 48 wherein said instrument is adapted to
deploy said bone anchor.
Description
[0001] This application is a Continuation-in-part of commonly
assigned U.S. patent application Ser. No. 09/781,793, filed on Feb.
12, 2001, which is herein incorporated by reference in its
entirety.
BACKGROUND
[0002] 1. Field of the Invention
[0003] This invention relates generally to apparatus and methods
for attaching soft tissue to bone, and more particularly to a
knotless suture-locking apparatus comprising a radial protrusion on
a suture plug for securing a suture and for restricting the
movement of the plug in the apparatus such that the plug will not
be dislodged when the suture is subjected to loading after the
procedure is completed. The invention has particular application to
arthroscopic surgical techniques for anchoring the rotator cuff in
the humeral head in repairing the rotator cuff.
[0004] 2. Prior Art
[0005] It is an increasingly common problem for tendons and other
soft, connective tissues to tear or to detach from associated bone.
One such type of tear or detachment is a "rotator cuff" tear,
wherein the supraspinatus tendon separates from the humerus,
causing pain and loss of ability to elevate and externally rotate
the arm. Complete separation can occur if the shoulder is subjected
to gross trauma, but typically, the tear begins as a small lesion,
especially in older patients.
[0006] To repair a torn rotator cuff, the typical course today is
to do so surgically, through a large incision. This approach is
presently taken in almost 99% of rotator cuff repair cases. There
are two types of open surgical approaches for repair of the rotator
cuff, one known as the "classic open" and the other as the
"mini-open". The classic open approach requires a large incision
and complete detachment of the deltoid muscle from the acromion to
facilitate exposure. The cuff is debrided to ensure suture
attachment to viable tissue and to create a reasonable edge
approximation. In addition, the humeral head is abraded or notched
at the proposed soft tissue to bone reattachment point, as healing
is enhanced on a raw bone surface. A series of small diameter
holes, referred to as "transosseous tunnels", are "punched" through
the bone laterally from the abraded or notched surface to a point
on the outside surface of the greater tuberosity, commonly a
distance of 2 to 3 cm. Finally, the cuff is sutured and secured to
the bone by pulling the suture ends through the transosseous
tunnels and tying them together using the bone between two
successive tunnels as a bridge, after which the deltoid muscle must
be surgically reattached to the acromion. Because of this maneuver,
the deltoid requires postoperative protection, thus retarding
rehabilitation and possibly resulting in residual weakness.
Complete rehabilitation takes approximately 9 to 12 months.
[0007] The mini-open technique, which represents the current
growing trend and the majority of all surgical repair procedures,
differs from the classic approach by gaining access through a
smaller incision and splitting rather than detaching the deltoid.
Additionally, this procedure is typically performed in conjunction
with arthroscopic acromial decompression. Once the deltoid is
split, it is retracted to expose the rotator cuff tear. As before,
the cuff is debrided, the humeral head is abraded, and the
so-called "transosseous tunnels", are "punched" through the bone or
suture anchors are inserted. Following the suturing of the rotator
cuff to the humeral head, the split deltoid is surgically
repaired.
[0008] Although the above described surgical techniques are the
current standard of care for rotator cuff repair, they are
associated with a great deal of patient discomfort and a lengthy
recovery time, ranging from at least four months to one year or
more. It is the above described manipulation of the deltoid muscle
together with the large skin incision that causes the majority of
patient discomfort and an increased recovery time.
[0009] Less invasive arthroscopic techniques are beginning to be
developed in an effort to address the shortcomings of open surgical
repair. Working through small trocar portals that minimize
disruption of the deltoid muscle, a few surgeons have been able to
reattach the rotator cuff using various bone anchor and suture
configurations. The rotator cuff is sutured intracorporeally and an
anchor is driven into bone at a location appropriate for repair.
Rather than thread the suture through transosseous tunnels which
are difficult or impossible to create arthroscopically using
current techniques, the repair is completed by tying the cuff down
against bone using the anchor and suture. Early results of less
invasive techniques are encouraging, with a substantial reduction
in both patient recovery time and discomfort.
[0010] Unfortunately, the skill level required to facilitate an
entirely arthroscopic repair of the rotator cuff is inordinately
high. Intracorporeal suturing is clumsy and time consuming, and
only the simplest stitch patterns can be utilized. Extracorporeal
knot tying is somewhat less difficult, but the tightness of the
knots is difficult to judge, and the tension cannot later be
adjusted. Also, because of the use of bone anchors to provide a
suture fixation point in the bone, the knots that secure the soft
tissues to the anchor by necessity leave the knot bundle on top of
the soft tissues. In the case of rotator cuff repair, this means
that the knot bundle is left in the shoulder capsule where it can
be felt by the patient postoperatively when the patient exercises
the shoulder joint. So, knots tied arthroscopically are difficult
to achieve, impossible to adjust, and are located in less than
optimal areas of the shoulder. Suture tension is also impossible to
measure and adjust once the knot has been fixed. Consequently,
because of the technical difficulty of the procedure, presently
less than 1% of all rotator cuff procedures is of the arthroscopic
type, and is considered investigational in nature.
[0011] Another significant difficulty with current arthroscopic
rotator cuff repair techniques is shortcomings related to currently
available suture anchors. Suture eyelets in bone anchors available
today, which like the eye of a needle are threaded with the thread
or suture, are small in radius, and can cause the suture to fail at
the eyelet when the anchor is placed under high tensile loads.
[0012] There are various bone anchor designs available for use by
an orthopedic surgeon for attachment of soft tissues to bone. The
basic commonality between the designs is that they create an
attachment point in the bone for a suture that may then be passed
through the soft tissues and tied, thereby immobilizing the soft
tissue. This attachment point may be accomplished by different
means. Screws are known for creating such attachments, but suffer
from a number of disadvantages, including their tendency to loosen
over time, requiring a second procedure to later remove them, and
their requirement for a relatively flat attachment geometry.
[0013] Another approach is to utilize the difference in density in
the cortical bone (the tough, dense outer layer of bone) and the
cancellous bone (the less dense, airy and somewhat vascular
interior of the bone). There is a clear demarcation between the
cortical bone and cancellous bone, where the cortical bone presents
a kind of hard shell over the less dense cancellous bone. The
aspect ratio of the anchor is such that it typically has a longer
axis and a shorter axis and usually is pre-threaded with a suture.
These designs use a hole in the cortical bone through which an
anchor is inserted. The hole is drilled such that the shorter axis
of the anchor will fit through the diameter of the hole, with the
longer axis of the anchor being parallel to the axis of the drilled
hole. After deployment in to the cancellous bone, the anchor is
rotated 90.degree. so that the long axis is aligned perpendicularly
to the axis of the hole. The suture is pulled, and the anchor is
seated up against the inside surface of the cortical layer of bone.
Due to the mismatch in the dimensions of the long axis of the
anchor and the hole diameter, the anchor cannot be retracted
proximally from the hole, thus providing resistance to pull-out.
These anchors still suffer from the aforementioned problem of
eyelet design that stresses the sutures.
[0014] Still other prior art approaches have attempted to use a
"pop rivet" approach. This type of design requires a hole in the
cortical bone into which a split shaft is inserted. The split shaft
is hollow, and has a tapered plug leading into its inner lumen. The
tapered plug is extended out through the top of the shaft, and when
the plug is retracted into the inner lumen, the tapered portion
causes the split shaft to be flared outwardly, ostensibly locking
the device into the bone.
[0015] Other methods of securing soft tissue to bone are known in
the prior art, but are not presently considered to be feasible for
shoulder repair procedures, because of physicians' reluctance to
leave anything but a suture in the capsule area of the shoulder.
The reason for this is that staples, tacks, and the like could
possibly fall out and cause injury during movement. As a result of
this constraint, the attachment point often must be located at a
less than ideal position. Also, the tacks or staples require a
substantial hole in the soft tissue, and make it difficult for the
surgeon to precisely locate the soft tissue relative to the
bone.
[0016] As previously discussed, any of the anchor points for
sutures mentioned above require that a length of suture be passed
through an eyelet fashioned in the anchor and then looped through
the soft tissues and tied down to complete the securement. Much
skill is required, however, to both place the sutures in the soft
tissues, and to tie knots while working through a trocar under
endoscopic visualization.
[0017] There have been attempts to solve some of the problems that
exist in current anchor designs. One such approach is disclosed in
U.S. Pat. No. 5,324,308 to Pierce. In this patent, there is
disclosed a suture anchor that incorporates a proximal and distal
wedge component having inclined mating faces. The distal wedge
component has two suture thread holes at its base through which a
length of suture may be threaded. The assembly may be placed in a
drilled hole in the bone, and when tension is placed on the suture,
the distal wedge block is caused to ride up against the proximal
wedge block, expanding the projected area within the drilled hole,
and locking the anchor into the bone. This approach is a useful
method for creating an anchor point for the suture, but does not in
any way address the problem of tying knots in the suture to fix the
soft tissue to the bone.
[0018] The problem of placing sutures in soft tissues and tying
knots in an endoscopic environment is well known, and there have
been attempts to address the problem and to simplify the process of
suture fixation. One such approach is disclosed in U.S. Pat. No.
5,383,905 to Golds et al. The patent describes a device for
securing a suture loop about bodily tissue that includes a bead
member having a longitudinal bore and an anchor member adapted to
be slidably inserted within the bore of the bead member. The anchor
member includes at least two axial compressible sections which
define a passageway to receive two end portions of a suture loop.
The axial sections collapse radially inwardly upon insertion of the
anchor member within the bore of the bead member to securely wedge
the suture end portions received within the passageway.
[0019] Although the Golds et al. patent approach utilizes a
wedge-shaped member to lock the sutures in place, the suture legs
are passing through the bore of the bead only one time, in a
proximal to distal direction, and are locked by the collapsing of
the wedge, which creates an interference on the longitudinal bore
of the anchor member. Also, no provision is made in this design for
attachment of sutures to bone. The design is primarily suited for
locking a suture loop, such as is used for ligation or
approximation of soft tissues.
[0020] An approach that includes bone attachment is described in
U.S. Pat. No. 5,584,835 to Greenfield. In this patent, a two part
device for attaching soft tissue to bone is shown. A bone anchor
portion is screwed into a hole in the bone, and is disposed to
accept a plug that has been adapted to receive sutures. In one
embodiment, the suture plug is configured so that when it is forced
into its receptacle in the bone anchor portion, sutures that have
been passed through an eyelet in the plug are trapped by friction
between the wall of the anchor portion and the body of the plug
portion.
[0021] Although there is some merit to this approach for
eliminating the need for knots in the attachment of sutures to
bone, a problem with being able to properly set the tension in the
sutures exists. The user is required to pull on the sutures until
appropriate tension is achieved, and then to set the plug portion
into the bone anchor portion. This action increases the tension in
the sutures, and may garrot the soft tissues or increase the
tension in the sutures beyond the tensile strength of the material,
breaking the sutures. In addition, the minimal surface area
provided by this anchor design for pinching or locking the sutures
in place will abrade or damage the suture such that the suture's
ability to resist load will be greatly compromised.
[0022] A disclosure that incorporates bone attachment and
eliminates knot tying is set forth in U.S. Pat. No. 5,702,397 to
Goble et al. One embodiment, in particular, is shown in FIG. 23 of
that patent and includes a bone anchor that has a threaded body
with an inner cavity. The cavity is open to one end of the threaded
body, and joins two lumens that run out to the other end of the
threaded body. Within the cavity is disposed a gear, journaled on
an axle. A length of suture is threaded through one lumen, around
the gear, and out through the other lumen. A ball is disposed
within the cavity to ride against a tapered race and ostensibly
lock the suture in place. What is not clear from the patent
disclosure is how the force D shown as the tension in the suture
would lock the ball into the race. Although this embodiment
purports to be a self-locking anchor adapted for use in blind holes
for fixing sutures into bone, the construct shown is complicated,
and does not appear to be adequate to reliably fixate the
suture.
[0023] What is needed, therefore, is a new approach for repairing
the rotator cuff or fixing other soft tissues to bone, wherein
suture tension can be adjusted and possibly measured, the suture
anchor resides completely below the cortical bone surface, there is
no requirement for the surgeon to tie a knot to attach the suture
to the bone anchor, and wherein the procedure associated with the
new approach is better for the patient, saves time, is
uncomplicated to use, and easily taught to practitioners having
skill in the art.
SUMMARY OF THE INVENTION
[0024] In one embodiment, the invention is a suture-locking
apparatus comprising a body member having a proximal end, a distal
end, and an axial lumen in between the proximal and distal ends,
wherein the proximal end adapted for passing a portion of a suture
into the lumen; and a plug member movable from a first position to
a second position in the lumen, the plug member comprising a radial
protrusion adapted for compressing the suture against the body
member on moving to the second position.
[0025] In another embodiment, the invention is a knotless
suture-locking apparatus comprising a body member for anchoring a
suture within a body cavity, the body member having a proximal end,
a distal end, and a lumen opened at the proximal end to receive a
length of suture therein; and a suture-locking plug member
comprising a radial protrusion for positively interfering with
proximal movement of the suture-locking plug with respect to the
body member, wherein the suture-locking plug member is movable
within the lumen from a first position that does not interfere with
axial movement of the length of suture, to a second position that
interferes with axial movement of the length of suture. In one
embodiment, the protrusion is also adapted for stopping the
proximal movement of the plug in the lumen to prevent dislodging of
the plug from the lumen after the procedure is completed and when
the suture is subjected to cyclical loading.
[0026] In a further embodiment, the invention is a method of
anchoring soft tissue in a body cavity using a suture without tying
a knot, comprising the steps of suturing the soft tissue such that
at least one free end of the suture is available; providing a
suture-anchor apparatus comprising a proximal end that opens into a
lumen therein, and a pulley fixed with respect to the lumen;
passing the free end of the suture into the lumen through the open
proximal end, looping the free end around the pulley, and extending
the free end out of the lumen through the open proximal end;
embedding the suture-anchor with respect to a body cavity;
tensioning the suture by pulling on the free end; and compressing
the suture against a radial protrusion on a movable suture-locking
plug member within the lumen, thereby securing the suture without
tying a knot on the suture.
[0027] Advantageously, with the present device, since the suture is
locked between the plug and the body member, the device can be used
in procedures to connect and anchor a tissue in a bone without the
need to tie a knot on the suture. Further, with the present device,
since the suture is compressed between the plug and the body member
at the radial protrusion on the plug, a surgeon can apply
compressive and frictional forces on the suture by pulling on the
plug to hold the suture in place without slippage. Additionally,
since the radial protrusion on the plug is adapted to stop the
proximal movement of the plug, and since the applied tension on the
suture is in the proximal direction, the plug will not dislodge out
of the lumen due to cyclical loading tensioning the suture after
the procedure is completed. Further, since the plug is in a
compressed state when the suture is under tension, the plug and the
body member can be made of relatively soft materials such as
plastic that are will withstand the compressive forces. This is in
contrast to the need to use a stronger material if the plug was
being tensioned. Additionally, since the radial protrusion on the
plug combines two the functions of compressing the suture and
stopping the movement of the plug in the lumen, the overall
dimension of the lock in one embodiment can be reduced depending on
the material used.
[0028] In accordance with a further aspect, the present invention
comprises a knotless suture anchor apparatus for anchoring a length
of suture with respect to a body cavity comprises an anchor body
having an anchoring structure for fixing the anchor body within a
body cavity, and a suture-locking plug. The anchor body has
proximal and distal ends, and a lumen opening at the proximal end.
A suture pulley fixed with respect to the anchor body is provided
such that a length of suture may be introduced into the lumen from
the proximal end, looped around pulley, and passed out of lumen
through the proximal end. The suture-locking plug is movable within
the lumen from a first position to a second position. Desirably,
the suture-locking plug and lumen cooperate such that the
suture-locking plug does not interfere with axial movement of the
length of suture in the first position and interferes with axial
movement of the length of suture in the second position, preferably
by compressing the length of suture against the anchor body.
[0029] In a preferred embodiment, the anchor body is generally
tubular and the lumen opens at the distal end as well as at the
proximal end. The distal end of the anchor body may be
discontinuous at one side thereof wherein a slot extends in a
proximal direction from the discontinuity to a slot end. The
suture-locking plug includes a proximal section that fits within
the lumen and a distal stop extending radially outward into the
slot that interferes with the anchor body at the end of the slot
and limits proximal movement of the plug with respect thereto. An
actuation rod may be removably attached to the proximal end of the
suture-locking plug and project out of the proximal end of the
anchor body so as to be usable to displace the locking plug within
the lumen. Desirably, the actuation rod includes a point of tensile
weakness permitting the rod to be detached from the locking
plug.
[0030] The suture pulley may be formed in a sidewall of lumen. For
example, where the anchor body is tubular, the suture pulley is
desirably disposed at a distal end of the tubular body. In a
preferred embodiment, the lumen opens at the distal end of the
tubular body and a pulley comprises a rod at the open distal end
transverse to the lumen axis. The rod may rotate with respect to
the anchor body, or may be fixed. Instead of a rod, the pulley may
comprise a bridge formed between two spaced apertures at the distal
end of the tubular body.
[0031] In another aspect, the present invention is a knotless
suture anchor apparatus for anchoring a length of suture with
respect thereto includes an anchor body and a suture-locking plug.
The anchor body has proximal and distal ends and a lumen open at
the proximal end. A suture pulley fixed with expect to the anchor
body permits a length of suture to be introduced into the lumen
from the proximal end, looped around the pulley, and passed out of
lumen through the proximal end. The suture-locking plug is movable
within the lumen from a first position which does not interfere
with axial movement of the length of suture to a second position
that compresses the length of suture against the anchor body and
interferes with axial movement of the length of suture.
[0032] In accordance with a further aspect, the present invention
is a knotless suture anchor apparatus for anchoring a length of
suture with respect to a body cavity comprises an anchor body
having an anchoring structure for fixing the anchor body within a
body cavity. The anchor body has proximal and distal ends, and a
lumen opening at both the proximal and distal ends, the lumen
having a diameter that permits a length of suture to be passed
therethrough. A suture-locking plug comprises a shaft axially
displaceable within the lumen from a first position, which does not
interfere with axial movement of the length of suture to a second
position that interferes with axial movement of the length of
suture. A stop is provided that positively interferes with proximal
movement of the suture-locking plug with respect to the anchor
body.
[0033] The present invention also provides for a method of securing
soft tissue with respect to a body cavity without knots. The method
includes passing a length of suture through soft tissue so that a
loop of suture material is embedded in the soft tissue resulting in
two free ends. An anchor body having an open proximal end and a
lumen is provided, wherein a pulley is fixed with respect to the
anchor body. The two free ends of length of suture are passed into
lumen of the anchor body through the open proximal end and looped
around pulley. The two free ends are extended out of lumen through
the open proximal end. The anchor body is fixed with respect to a
body cavity, and the loop of suture material is tightened by
pulling one or both of the two free ends of the length of suture.
Finally, the two free ends of the length of suture are fastened
with respect to the anchor body without knots.
[0034] In the described method, the soft tissue may be a tendon and
the body cavity may be formed in bone. In a particular preferred
operation, the tendon is the rotator cuff tendon, and the bone is
the humerus. The step of fixing the anchor body with respect to the
body cavity may include forming a body cavity, passing the anchor
body therein, and radially extending anchoring structure on the
anchor body. In a preferred embodiment, the anchoring structure is
provided on a proximal end of the anchor body and interferes with
the cortical layer of the bone to prevent proximal removal of the
anchor body from the cavity. The method may include providing a
suture-locking plug movable within the lumen from a first position
which does not interfere with axial movement of the two free ends
of the length of suture to a second position that compresses the
two free ends of the length of suture against the lumen and
interferes with axial movement thereof. The proximal actuation rod
that extends out of the lumen from the proximal end of the anchor
body may be coupled to the suture-locking plug, wherein the method
includes displacing the actuation rod in the proximal direction
with respect to the anchor body, and desirably severing the
actuation rod from the suture-locking plug after the step of
fastening.
[0035] It is to be understood that the above-described invention is
particularly suited to locking sutures that have been passed
through soft tissues and are to be anchored to bone. The creation
of an anchor point within the bone is outside the scope of this
invention, although many alternative methods of anchoring suture to
bone are contemplated. For example, some currently preferred
methods are discussed in U.S. patent application Ser. No.
09/616,802, entitled Method & Apparatus for Attaching
Connective Tissues to Bone Using a Suture Anchoring Device, filed
on Jul. 14, 2000, now U.S. Pat. No. 6,582,453. The referenced
application is commonly assigned with the present application, and
is incorporated by reference in its entirety herein. Other prior
art anchors, such as screws, moly bolts, and pop rivets may be
adapted for use with the present invention as well.
[0036] The invention, together with additional features and
advantages thereof, may best be understood by reference to the
following description taken in conjunction with the accompanying
illustrative drawing.
BRIEF DESCRIPTION OF DRAWINGS
[0037] FIG. 1A is a partial sectional view through the left
shoulder of a human as seen from the front showing the use of a
minimally invasive soft tissue to bone attachment system of the
present invention.
[0038] FIG. 1B is an enlarged sectional view taken within the
circle denoted 1B in FIG. 1A.
[0039] FIGS. 2A-2D are enlarged sectional views of the use of the
soft tissue to bone attachment system of FIG. 1A to reattach a
rotator cuff tendon.
[0040] FIGS. 3A-3C are partial longitudinal sectional views through
a distal end of an exemplary soft tissue to bone attachment system
of the present invention.
[0041] FIG. 4A is a perspective view of a combined suture-locking
portion and bone anchor structure of the soft tissue to bone
attachment system of the present invention, showing a locking plug
disengaged from an anchor body.
[0042] FIG. 4B is a partial longitudinal sectional view of the
combined suture-locking portion and bone anchor structure taken
along line 4B-4B of FIG. 4A.
[0043] FIG. 4C is an end elevational view of the combined
suture-locking portion and bone anchor structure taken along line
4C-4C of FIG. 4B.
[0044] FIG. 5 is a perspective view of an anchor body of the
combined suture-locking portion and bone anchor structure of FIG.
6A.
[0045] FIG. 6 is a top plan view of the combined suture-locking
portion and bone anchor structure without the locking plug and an
attached actuation rod.
[0046] FIG. 7A is a perspective view of an exemplary suture-locking
portion of the soft tissue to bone attachment system of the present
invention showing a locking plug disengaged from an anchor
body.
[0047] FIG. 7B is a partial longitudinal sectional view of the
suture-locking portion taken along line 7B-7B of FIG. 7A.
[0048] FIG. 7C is an end elevational view of the suture-locking
portion taken along line 7C-7C of FIG. 7A.
[0049] FIG. 8A is a perspective view of the exemplary
suture-locking portion of the soft tissue to bone attachment system
of the present invention showing the locking plug engaged with the
anchor body.
[0050] FIG. 8B is a partial longitudinal sectional view taken along
line 8B-8B of FIG. 8A.
[0051] FIG. 8C is an end elevational view taken along line 8C-8C of
FIG. 8A illustrating the locking plug clamping a length of suture
against an inner lumen of the anchor body.
[0052] FIG. 9A is a side elevational view of the deployed anchor
structure relative to the anchor body and locking plug therein.
[0053] FIG. 9B is an end elevational view of FIG. 9B.
[0054] FIG. 10 is a partial sectional view through the left humeral
head of a human as seen from the front showing the use of an
alternative minimally invasive soft tissue to bone attachment
system of the present invention.
[0055] FIG. 11A is a perspective view of a combined suture-locking
portion and bone anchor structure of the present invention, showing
an alternative suture pulley structure.
[0056] FIG. 11B is a cross-sectional view taken along lines 11B-11B
of FIG. 11A.
[0057] FIGS. 12A and 12B are cross-sectional views of an embodiment
illustrating a lumen wherein a plug is useable for compressing and
locking the suture, and wherein the plug will not dislodge when the
suture is subjected to cyclical loading.
[0058] FIGS. 13A and 13B are perspective views of the plug located
in the lumen at first and second positions in the lumen.
[0059] FIG. 14 is a cross-section view of an embodiment of the plug
member.
[0060] FIG. 15 is a perspective view of an embodiment of the plug
member.
DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS
[0061] The present invention provides an improved knotless suture
anchor apparatus for anchoring a length of suture with respect to a
body cavity. In the exemplary embodiment described herein, the
apparatus is used to anchor a length of suture to a bone structure,
specifically the humeral bone of the human shoulder. The length of
suture is desirably looped through soft tissue, such as a rotator
cuff tendon, to approximate and fix the soft tissue with respect to
the body cavity (e.g., bone structure). It should be understood,
however, that the suture anchor apparatus may be utilized to secure
a length of suture to body cavities other than in a bone structure,
and may even be used to anchor the suture outside of a body cavity,
merely to a predetermined location within the body. In this regard,
the preferred apparatus includes an anchor body member within which
the length of suture may be anchored without knots. If the anchor
body is to be implanted within the body cavity, structure on its
exterior may also be provided for securing the anchor body therein.
In a preferred embodiment, the anchor body is positioned within a
pre-formed cylindrical cavity within a bone structure and a bone
anchor deployed, from the exterior of the anchor body, to hold it
within the cavity.
[0062] As mentioned, the present invention is particularly
well-suited for repairing rotator cuff injuries by re-attaching the
rotator cuff tendon to the outside of the humeral head. The
invention permits minimally invasive surgeries on such injuries and
greatly facilitates rapid and secure fixation of the rotator cuff
tendon to the humeral head. It should be understood that the same
principles described herein apply to the repair of other injuries
in which soft tissue is to be re-attached to a bone structure.
[0063] FIGS. 1A-1BA and 2A-2D are cross-sectional views through the
left shoulder of a human as viewed from the front and illustrate
the use of an exemplary suture anchor system 20 for repairing a
rotator cuff tendon injury. The rotator cuff tendon 22 is shown in
its natural positioned overlying the bulbous humeral head 24 of the
humerus bone 26. In rotator cuff injuries, the tendon 22 partially
or completely separates from its attachment point to the humeral
head 24, which point of attachment is typically located along an
angled shelf, the greater tuberosity 28. In minimally invasive
surgeries to repair the rotator cuff injury, the surgeon threads
one or more sutures through the rotator cuff tendon 22 and anchors
them to the greater tuberosity 28. The suture-anchor system 20 of
the present invention facilitates this latter step of anchoring the
sutures to the greater tuberosity 28.
[0064] With reference first to FIG. 1A, a generally tubular trocar
30 provides a conduit through the soft tissue of the shoulder for
the suture anchor system 20 of the present invention. Typically,
the surgeon makes an incision or stab wound through the outer
dermal layers of sufficient size to permit passage of the trocar 30
through skin and the deltoid muscle into proximity with the humeral
head 24. Various trocars and techniques for creating the approach
passageway are known and may be utilized with the present
invention. In addition, more than one incision and conduit may be
necessary to perform the several suturing and anchoring steps.
[0065] After establishing one or more direct conduits to the
humeral head 24, the surgeon passes a length of suture through the
soft tissue of the rotator cuff tendon 22 so that a loop 32 of
suture material is embedded therein, as seen in FIG. 1B. The two
free ends 34a, 34b of the length of suture are withdrawn from the
patient and coupled to the suture anchor system 20. The specifics
of this coupling and subsequent manipulation of the two free ends
of the suture will be described more fully below. For the purpose
of explaining the exemplary method of use, it is sufficient to
understand that the two free ends 34a, 34b pass into a lumen at the
distal end of the suture anchor system 20 and extend through the
lumen in a proximal direction to a proximal end of the system to
enable fixation or pulling of the suture ends. As seen in FIG. 1B,
the two free ends 34a, 34b are shown projecting from a proximal end
of the system. The system 20 further includes a plurality of
concentrically disposed cannulas or tubes as shown that perform the
knotless suture anchoring operation. The interrelationship and
functioning of these tubes will also be more fully explained
below.
[0066] The exemplary system 20 as illustrated is particularly
suitable for anchoring a suture to a body cavity, specifically the
humeral head 24 as shown. When anchoring sutures to such a bone
structure, a conventional technique is to first form a blind hole
or cavity 40 through the cortical layer 42 and into the soft
cancellous matter 44, as seen in FIGS. 1A-1B and 2A-2D. The surgeon
then positions a suture anchor 46 within the cavity 40 and deploys
it such that it cannot be removed from the cavity.
[0067] The suture anchor 46 performs two functions: anchoring
itself within the body cavity and anchoring the sutures therein. In
the illustrated embodiment, the former function is accomplished
using an expandable anchoring structure 48 located on the proximal
end of the suture anchor 46. The anchoring structure 48 functions
like a toggle bolt used in ceiling fixtures, and specifically
expands to a larger dimension in the cavity 40 beyond the hard
cortical bone 42. In this manner, the suture anchor 46 is prevented
from being removed from the cavity 40 once the anchoring structure
48 is deployed. The present invention illustrates a particular
anchoring structure 48, although any similar expedient will work.
For example, a different toggle-like anchoring structure may be
used such as shown in co-pending application Ser. No. 09/616,802,
filed Jul. 14, 2000, the disclosure of which is hereby expressly
incorporated by reference. Alternatively, an anchoring structure
that expands into contact with the cancellous matter 44 may be
used. In short, the present invention is not considered to be
limited by the particular anchoring structure.
[0068] The second function of the suture anchor 46 is the anchoring
or fixation of the suture with respect to the suture anchor itself,
without the use of knots. Desirably, the particular manner of
anchoring the suture with respect to the suture anchor 46 permits
easy adjustment of the length of suture between the suture anchor
and the loop 32 formed in the soft tissue. This adjustment allows
the surgeon to establish the proper tension in the length of suture
for effective repair of the soft tissue; reattachment of the
rotator cuff tendon 22 in the illustrated embodiment. In this
regard, FIG. 2D shows the fully deployed suture anchor 46 after the
free ends 34a, 34b have been placed in tension and locked within
the suture anchor. Although not shown, the remaining steps in the
procedure involve withdrawing the concentric tubes from the
surgical site and severing the free ends 34a, 34b close to the
suture anchor 46.
[0069] FIGS. 3A-3C are different partial longitudinal sectional
views taken through the exemplary suture anchor system 20 of the
present invention. The suture anchor 46 is seen in cross-section
disposed in a close-fitting relationship within a delivery tube 50.
The delivery tube 50, in turn, may be arranged to slide within a
larger tube 52, sometimes known as an introducer tube, that
includes a valve (not shown) on a proximal end to prevent fluid
leakage therefrom. Alternatively, such a fluid leakage valve may be
provided on the proximal end of the trocar 30 seen in FIGS.
1A-1B.
[0070] The suture anchor 46 is defined by a generally tubular
anchor body 54 and an inner deployment tube 56 fits closely within
a proximal end and is fastened therein. The exemplary suture anchor
46 is shown and described in greater detail below with respect to
FIGS. 4-5. The deployment tube 56 can also be seen on the right
side in FIG. 3A projecting from the series of concentric tubes,
with the free ends 34a, 34b of the length of suture projecting
therefrom. A die tube 58 sized intermediate the delivery tube 50
and the deployment tube 56 is arranged for longitudinal
displacement over the deployment tube 56. In the illustrated state
of the system 20, the suture anchor 46 is undeployed within the
delivery tube 50 and the die tube 58 is positioned just proximal to
the expandable anchoring structure 48. A further component of the
suture anchor system 20 is a suture-locking plug 62 having an
actuation rod 64 removably attached to a proximal end thereof and
extending proximally within the deployment tube 56.
[0071] FIGS. 3A-3C all show the suture loop 32 extending
transversely from within the concentric tubes of the suture anchor
system 20. In this regard, the delivery tube 50 is provided with an
axial slot 51, the deployment tube 56 is provided with an axial
slot 57, and the die tube 58 has an axial slot 59. The free ends
34a, 34b of the length of suture pass through these aligned axial
slots 51, 57, 59 to the interior of the deployment tube 56 that
opens into the lumen 66 of the tubular body 54. The aligned axial
slots 51, 57, 59 permit passage of the free ends 34a, 34b into the
system 20 from a location midway along the concentric tubes, as
indicated in FIGS. 1-2.
[0072] The various described components of the suture anchor system
20 are relatively axially movable to deploy the suture anchor 46.
Various means are known to relatively displace concentric tubes a
predetermined distance and/or with a predetermined displacement
force. For example, the concentric tubes may extend out of the
trocar 30 to an actuation device in the form of concentric syringe
bodies/finger tabs. Alternatively, the concentric tubes may be
attached to relatively movable parts in a gun-type handle, and
actuated by triggers or other such levers. It is to be understood
therefore that the present invention is not limited by the
particular actuation device on its proximal end, and no further
description in this regard will be provided.
[0073] A more complete understanding of the exemplary suture anchor
46 will be helpful prior to a detailed description of the structure
and function of the concentric tubes to deploy the system. In this
regard, FIGS. 4-6 illustrate one embodiment of a suture anchor 46
isolated from the remainder of the system and having the
aforementioned tubular anchor body 54 and deployable anchoring
structure 48. The anchor body 54 defines a lumen 66 therewithin.
FIGS. 4A and 4B also illustrate the suture-locking plug 62 and
attached actuation rod 64.
[0074] The anchor body 54 has the anchoring structure 48 on its
proximal end and a suture pulley 70 disposed in proximity to its
distal end. The aforementioned suture loop 32 is schematically
illustrated out of the soft tissue for clarity, and it should be
understood that this suture loop 32 is embedded in the soft tissue
in actual use of the system. The free ends 34a, 34b of the length
of suture pass through an angled toggle ring 72 of the anchoring
structure 48 and into an open proximal end 74 of the lumen 66
formed within the tubular anchor body 54. The angled toggle ring 72
attaches to the proximal end 74 via a pair of plastically
deformable struts 76. Both the toggle ring 72 and struts 76 are
initially formed as a projection of the tubular anchor body 54.
After continuing in the distal direction through the lumen of the
anchor body 54, the free ends 34a, 34b wrap around the suture
pulley 70 and traverse the lumen in the proximal direction to
emerge from the angled toggle ring 72 as shown.
[0075] As best seen in FIG. 4B, the actuation rod 64 extends into
an open distal mouth 76 of the anchor body 54 and through the lumen
66 and angled toggle ring 72. The actuation rod 64 and four strands
of the length of suture thus share the space within the lumen 66.
Because of the relatively smaller size of the actuation rod 64 with
respect to the lumen 66, the length of suture may slide axially
within lumen without interference. It can therefore be seen that
because the suture loop 32 is embedded in soft tissue, pulling on
the free ends 34, 34b of the length of suture places the suture
loop in tension.
[0076] Prior to a more exhaustive description of the function of
the locking plug 62 to perform the second function of the suture
anchor 46 (i.e., anchoring the length of suture with respect to the
suture body 54), use of the concentric tubes to deploy the
anchoring structure 48 will be explained. With reference again to
FIGS. 3A-3C, the deployment tube 56 can be seen attached within the
lumen 66 of the anchor body 54 using a tab 80. Of course, other
means for attaching the deployment tube 56 within the lumen of a
body 54 may be provided, but a small tab 80 bent inwardly from the
anchor body 54 and welded or otherwise secured to the deployment
tube 56 is a suitable expedient. The tab 80 is desirably provided
at only one location around the circumferential junction between
the deployment tube 56 and lumen 66 to facilitate severing of this
connection, although more than one attachment may be provided. The
tab 80 thus secures the deployment tube 56 within the anchor body
54 of the suture anchor 46, while both the die tube 58 and
actuation rod 64 can freely slide with respect to the anchor body
54.
[0077] After positioning the delivery tube 50 in proximity with the
preformed body cavity 40 as seen in FIGS. 1A and 1B, the surgeon
advances the deployment tube 56 having the suture anchor 46
attached thereto into the cavity. The suture-locking plug 62 and
die tube 58 advance along with the deployment tube 56, and the
resulting configuration is seen in FIG. 1B.
[0078] Using a depth measurement, or visualization technique, the
surgeon insures that the suture anchor 46, and in particular the
anchoring structure 48, has been inserted past the hard outer layer
of cortical bone 42. The anchoring structure is then expanded as
seen in FIG. 2A. To accomplish this, the die tube 58 contacts the
angled toggle ring 72 and forces it into an orientation that is
generally perpendicular with respect to the axis of the suture
anchor 46. With reference to FIGS. 3A-3C, the die tube 58 is
desirably held stationary while the deployment tube 56 having the
suture anchor 46 attached thereto is pulled in a proximal
direction. Again, the relative movement of these tubes can be
accomplished using a handle or other device exterior to the
patient's body. Pulling on the deployment tube 56 forces one side
of the angled toggle ring 72 against the generally circular distal
mouth of the deployment tube 56 which deforms the struts 76 as the
toggle ring 72 moves into a perpendicular orientation.
[0079] After the anchoring structure 48 is deployed, further
pulling on the deployment tube 56 detaches it from the suture
anchor 46. Specifically, the aforementioned welded tab 80 severs at
a predetermined pulling force. The die tube 58 remains in place in
its fixed position, and provides a reaction force against the
suture anchor 46. The deployment tube 56 is then pulled free and
retracted out of the way, as indicated in FIG. 2B. At this stage,
the suture anchor 46 is secured with respect to the body cavity,
but the length of suture passing therethrough remains free to be
axially displaced.
[0080] Now with specific reference to FIGS. 3A-3C, the path of the
length of suture through the suture anchor system 20 will be
described. The suture loop 32 is seen projecting upward from the
system, but it again should be noted that this loop is embedded in
soft tissue in use of the system. The two free ends 34a, 34b extend
through an axial slot 51 in the delivery tube 50, and through the
axial slot 51 in the deployment tube 56 into lumen 66 of the suture
can 46. As best seen in FIG. 3C, the free ends pass through the
lumen 66 and around the aforementioned pulley 70. The free ends
then travel in a proximal direction through the lumen 66 and
through the lumen of the deployment tube 56 to emerge from proximal
end of the system. Because the suture loop 32 is embedded in soft
tissue, pulling on both of the free ends 34a, 34b, or pulling on
one end while holding one fixed, will create tension in the length
of suture. The pulley 70 provides relatively little resistance to
sliding of the length of suture therearound, and thus this
tensioning can be accomplished relatively easily.
[0081] In one embodiment, the pulley 70 comprises a pin oriented
transversely to the axis of the suture anchor 46 and located along
a sidewall thereof. As seen best in FIG. 4A, the pin may span an
axial slot 100 in a sidewall of the anchor body 54 so that the free
ends 34a, 34b of length of suture can pass out through the slot and
around the pin. Alternatively, two axially spaced holes with
chamfered or rounded edges may be formed in the sidewall of the
anchor body 54 through which the free ends 34a, 34b can be
threaded. Of course, numerous structures are contemplated that
provide the function of the illustrated pin-type pulley 70.
Moreover, instead of being a fixed structure, the pulley 70 can be
arranged to swivel or otherwise move to facilitate sliding motion
of the free ends 34a, 34b therearound. In a specific example, the
pin-type pulley 70 can be formed separately from the anchor body 54
and inserted within a pair of facing holes in the edges of the slot
100. In this manner, the pin-type pulley 70 rotates within the
holes, thus reducing friction between the free ends 34a, 34b and
the pulley.
[0082] The step of tensioning the length of suture is seen in FIG.
2C, wherein the suture-locking plug 62 remains in its initial
position spaced from the anchor body 54. Adjustment of the length
of the suture between the suture anchor 46 and the loop 32 is very
important to ensure proper fixation of the rotator cuff tendon 22
with respect to the humeral head 24. If the suture is pulled too
tightly, the rotator cuff tendon 22 may be unduly stressed, and the
loop 32 may even pulled free from the tendon. On the other hand, if
the suture is too loose, the goal of reattaching the tendon 22 in
its proper location will be compromised.
[0083] Once the surgeon has established proper tension on the
suture, the suture is anchored with suspect to the anchor body 54.
Displacing the suture-locking plug 62 in a proximal direction so
that it is forced into the lumen 66 does this. The plug 62 includes
a generally cylindrical shaft 102 with a bullet-shaped proximal
nose 104 to help prevent its catching on the distal mouth 78 of the
anchor body 54. Proximal displacement of the actuation rod 64 from
outside the body causes proximal movement of the attached plug
62.
[0084] FIGS. 7-8 show the anchor body 54 without the aforementioned
anchoring structure 48 for clarity. These views illustrate the
movement of the suture-locking plug 62 into the lumen 66, and
consequent locking of the length of suture therein. The diameter of
the cylindrical shaft 102 of the plug 62 is sized to be slightly
smaller than the inner diameter of the lumen 66. As seen in FIGS.
8B and 8C, the diameter of the cylindrical shaft 102 is such that
it compresses the four strands of the length of suture against the
lumen 66. The locking plug 62 is dimensioned to compress or "crush"
the length of suture in the lumen 66 and interfere with its axial
movement therethrough. The amount of compression may be measured by
the amount of pull force on the suture necessary to move it once
the plug is in position. Desirably, the pull force is in a range
that would exceed the USP (United States Pharmacopeia) Standard
knot pull strength (USP 24) of the suture used. In the specific
case of #2 braided polyester suture, this knot pull strength is
approximately 3.5 Kgf. In practice, however, the knot pull strength
of commercially available #2 braided polyester sutures approaches
14 Kgf.
[0085] Proximal displacement of the locking plug 62 within the
anchor body 54 is desirably limited by a positive stop. In the
illustrated embodiment, a stop flange 110 projects outwardly from
the cylindrical shaft 102 at its distal end. The stop flange 110
slides within an axial slot 112 at the distal end of the anchor
body 54 that terminates at a slot end 114. Although not shown in
the figures, proximal movement of the locking plug 62 is ultimately
restricted by contact between the stop flange 110 and the slot end
114. Of course, other configurations that provide a positive stop
to proximal movement of the locking plug 62 are contemplated. For
example, rather than dimensioning the locking plug 62 to be larger
than the lumen 66 of the anchor body 54 (as exhibited by the stop
flange 110), a stop surface may project inwardly from the lumen 66
to interfere with movement of the plug 62.
[0086] One advantage provided by the present invention is the
ability to tighten a suture loop embedded within soft tissue to a
predetermined tension, and then locked to the suture within a
suture anchor without even slightly altering that tension. As best
seen in FIG. 8B, the locking plug 62 is shown partly inserted
within the tubular body 54 during the step of being pulled proximal
by the actuation rod 64 as indicated by the movement arrows 116.
The free ends 34a, 34b of the length of suture extend around the
pulley 70, having previously been tensioned to a predetermined
amount. Proximal movement of the locking plug 62 acts on all four
strands of the length of suture within the lumen of the tubular
body 54, and thus imparts equal frictional forces to all of the
strands tending to urge them in a proximal direction. Because the
four strands loop around the pulley 70, with two coming and two
going, these frictional forces cancel out such that the free ends
34a, 34b do not migrate within the tubular body 54. Because the
pulley 70 and tubular body 54 remain fixed with respect to the
suture loop 32 (which is embedded within the soft tissue), the
predetermined tension within the loop remains constant during the
suture-locking step.
[0087] In a further example, as seen in FIGS. 9A and 9B,
deformation of the angled toggle ring 72 forces it into an oval
shape at the proximal end 74 of the anchor body 54. This oval shape
may have a minor dimension that is smaller than the diameter of the
cylindrical shaft 102, or more typically the struts 76 may be bent
into the path of the shaft 102, thus presenting interference and a
positive stop to the shaft movement. Alternatively, the actuation
rod 64 may be bent back upon the exterior surface of the locking
plug 62 to form the stop surface.
[0088] Once the suture-locking plug 62 has been positively stopped,
the actuation rod 64 may be detached therefrom. As seen in the
figures, the actuation rod 64 extends within a through bore in the
cylindrical shaft 102 and includes a frangible point 120 in that
bore. The segment of the actuation rod distal from this frangible
point 120 is secured within the bore in a conventional manner, such
as with crimping indicated at 122 in FIG. 7A. The die tube 58 may
be used as a reaction force against the anchor body 54 while the
actuation rod 64 is pulled the proximal direction causing the
frangible point 120 to sever. The final configuration is seen in
FIG. 2D.
[0089] As mentioned above, the exemplary structure for locking
sutures relative to a body cavity may be utilized in a variety of
anatomical environments. For instance, FIG. 10 shows an alternative
surgical technique for using a combined suture anchor 46' and
anchoring structure 48' to repair a rotator cuff tendon 22. In this
embodiment, rather than forming a blind cavity within the humeral
head 24, the surgeon forms a cavity 130 that transects the greater
tuberosity 28 and opens through the cortical layer 42 at both ends.
After embedding the loop 32 of suture material within the rotator
cuff tendon 22, the free ends 34a, 34b are inserted into and
threaded through the cavity 130. The ends 34a, 34b are then passed
through the lumen formed within the combined suture anchor 46' and
anchoring structure 48', which combination is then inserted as
shown into the cavity 130. The free ends 34a, 34b of suture are
then tightened to the prescribed level and secured within the
suture anchor 46'. It should be noted that the combined suture
anchor 46' and anchoring structure 48' may be configured somewhat
differently to permit the aforementioned tightening step, though
the suture locking steps are preferably accomplished in the same
manner as described above; namely, with a suture-locking plug
compressing the length of suture within the suture anchor 46'.
Furthermore, the anchoring structure 48' contacts the exterior of
the cortical bone rather than the interior as described above.
[0090] FIG. 11 illustrates an alternative suture anchor 140 of the
present invention having a body cavity anchoring structure 142 on a
proximal end. A length of suture is shown having a loop 144 and a
pair of free ends 146a, 146b passing through the anchoring
structure 142 and through a lumen 148 of a generally tubular body
150 of the suture anchor 140. In a distal portion of the tubular
body 150, the free ends 146a, 146b pass out of the lumen 148
through a first aperture 152a and re-enter the lumen through a
second aperture 152b located distally from the first aperture. As
illustrated, the lumen 148 in the region of the apertures 152a,
152b is only partly defined by a semi-cylindrical extension of the
tubular body 150, but other arrangements having a more complete
lumen at this location are within the scope of the present
invention.
[0091] With reference to FIG. 11B, the apertures 152a, 152b are
shown to be rounded to reduce abrasion on the suture free ends
146a, 146b. In addition, the bridge portion 154 of the tubular body
150 that separates the apertures 152a, 152b defines a pulley
structure, much like the pulley 70 (FIG. 8B) described above in the
earlier embodiment. That is, the suture free ends 146a, 146b can
easily slide with respect to the bridge portion 154, especially
because of the rounded corners, to permit tightening of the suture
loop 144 prior to locking the length of suture within the tubular
body 150. The length of suture may be locked within the tubular
body 150 using a locking plug as described above.
[0092] In another embodiment illustrated in FIGS. 12-15, the
present suture-locking apparatus (700) comprises a body member
(702) having a proximal end (704), a distal end (706), and an axial
lumen (708) formed in between the proximal and distal ends. In one
embodiment, the proximal end is adapted for passing a portion of a
suture (710) into the lumen. The apparatus in this embodiment
includes a plug member (712) that can be moved from a first
position as illustrated in FIG. 12A where the plug member does not
interfere with movement of the suture in the lumen, to a second
position as illustrated in FIG. 12B where the plug member
interferes with movement of the suture in the lumen by compressing
it against the wall of the lumen. In this embodiment, the plug
member is provided with a radial protrusion (714, 724) adapted for
compressing and thus locking the suture in the lumen at the second
position. In one embodiment, the radial protrusion is in the form
of a circumferential step feature (714) on the plug member as
illustrated in FIG. 14; in another embodiment the radial protrusion
is a circumferential stop ridge (724) formed on the plug member as
illustrated in FIG. 15. In alternative embodiments not shown, the
location and or shape of the protrusion on the plug can be varied
within the scope of the invention to compress the suture and
restrict the length of travel of the plug in the lumen.
[0093] As will be appreciated by one ordinarily skilled in the art,
the radial protrusion of the plug in its various embodiments
preferably performs at least two functions, namely: positively
stopping the axial movement of the plug within the lumen in the
proximal direction; and compressing and locking the suture against
the wall in the lumen, thereby securing the suture in the lumen
without the need to tie the suture with a knot.
[0094] In positively stopping the movement of the plug in the
lumen, the radial protrusion in cooperation with a matching feature
in the wall of the lumen as illustrated in FIGS. 12A and 12B,
provides an added security against ripping or pulling-out of the
plug through the lumen by an application of a tension on the
suture. Thus in one embodiment as shown in FIGS. 12A and 12B, the
lumen is characterized by a larger internal wall cross-section
(718) within a first position, and a smaller internal wall
cross-section at the second position (720), the larger
cross-section transitioning to the smaller cross-section at a
zigzag wall section (722) therein. In this embodiment the zigzag
path in the wall of the lumen cooperates with the radial protrusion
on the plug to compress the suture and stop the plug from axially
advancing in the proximal direction.
[0095] In compressing and locking the suture against the wall in
the lumen as illustrated in FIGS. 12A and 12B, the radial
protrusion in this embodiment establishes a zigzag path and thus a
zigzag interface between the plug and the lumen wall such that the
surfaces are parallel and perpendicular to the direction of tension
on the suture. This configuration of the interface and the suture
therein provides for a significant increase in the frictional force
and thus an increased locking efficiency on the suture.
[0096] In one embodiment the plug as illustrated in FIGS. 12-15 is
shaped in the form of a bullet with a nose (728) and tail (726)
sections that are sized slightly smaller than the inner diameter of
the lumen (708). As is illustrated for example in FIG. 12B, at the
second position, the diameter of the distal section of the tail is
such that the plug can be urged against the zigzag portion of the
lumen wall to compresses the suture while simultaneously
interfering with the axial movement of the plug in the proximal
direction. The amount of compression may be measured by the amount
of tension on the suture necessary to move it once the plug is in
position. Desirably, the tension is in a range that would exceed
the USP (United States Pharmacopeia) Standard knot pull strength
(USP 24) of the suture used. In the specific case of #2 braided
polyester suture, this knot pull strength is approximately 3.5 Kgf.
In practice, however, the knot pull strength of commercially
available #2 braided polyester sutures approaches 14 Kgf.
[0097] In one embodiment the plug is provided with an actuation
member (730) for use in inserting the plug into the lumen and for
axially moving the plug in the lumen from the first position to the
second position as illustrated in FIGS. 12A, 12B, 13A and 13B.
Another feature provided on the present embodiment is an aperture
(716) through the body portion that opens into the lumen at the
distal end plug. In various embodiments, the dimensions of the
aperture are sized to pass the plug into the lumen.
[0098] In one embodiment a suture pulley member (716) fixed with
respect to the lumen is provided for reversing the path of the
suture in the lumen at the distal end such that the suture can exit
the lumen at the proximal end. In an embodiment wherein the body
member is in the form of a tubular body as illustrated in FIG. 11B,
the suture pulley member comprises a portion of the tubular body
defined between the aperture and the distal end. In another
embodiment the pulley member comprises a rod member. In another
embodiment the suture pulley member comprises a bridge member
defined between two apertures in said body member. In the various
embodiments the pulley member is deployed transversely across said
lumen as illustrated in FIGS. 13A and 13B.
[0099] In another embodiment as illustrated for example in FIGS.
12A and 12B the suture-locking apparatus comprises a toggle member
(736) disposed proximally and axially with the body member (702).
Connecting the toggle member to the body member is at least one
strut member (738). In an undeployed position the toggle member
projects a smaller profile transverse to the body member, and at a
deployed position projects a larger profile transverse to the body
member. In one embodiment the strut member is adapted so as to
collapse and translate the toggle member from the undeployed
position to the deployed position.
[0100] In various embodiments the components of the present suture
lock can be made from a material suitable for implant in the body.
Examples of such materials include plastics, a polyaryletheketone
and stainless steel.
[0101] In a further embodiment the present suture anchor can be
used to anchor soft tissue in a body cavity using a suture without
tying a knot, in a method that includes the steps of: (i) suturing
the soft tissue such that at least one free end of the suture is
available; (ii) passing the free end of the suture into the lumen
through the open proximal end, looping the free end around the
pulley, and extending the free end out of the lumen through the
open proximal end; (iii) embedding the suture-anchor with respect
to a body cavity; (iv) tensioning the suture by pulling on the free
end; and (v) compressing the suture against a radial protrusion on
a movable suture-locking plug member within the lumen, thereby
securing the suture without tying a knot on the suture.
[0102] In this procedure, the soft tissue may be a tendon and the
body cavity may be formed in bone. In a particular preferred
procedure, the tendon is the rotator cuff tendon, and the bone is
the humerus. The step of fixing the anchor body with respect to the
body cavity may include forming a body cavity, passing the anchor
body therein, and radially extending anchoring structure on the
anchor body. In a preferred embodiment, the anchoring structure is
provided on a proximal end of the anchor body and interferes with
the cortical layer of the bone to prevent proximal removal of the
anchor body from the cavity. The method may include providing a
suture-locking plug movable within the lumen from a first position
which does not interfere with axial movement of the two free ends
of the length of suture to a second position that compresses the
two free ends of the length of suture against the lumen and
interferes with axial movement. The proximal actuation rod that
extends out of the lumen from the proximal end of the anchor body
may be coupled to the suture-locking plug, wherein the method
includes displacing the actuation rod in the proximal direction
with respect to the anchor body, and desirably severing the
actuation rod from the suture-locking plug after the step of
fastening.
[0103] Accordingly, although an exemplary embodiment of the
invention has been shown and described, it is to be understood that
all the terms used herein are descriptive rather than limiting, and
that many changes, modifications, and substitutions may be made by
one having ordinary skill in the art without departing from the
spirit and scope of the invention. In particular, it is noted that
the procedures, while oriented toward the arthroscopic repair of
the rotator cuff, are applicable to the repair of any body location
wherein it is desired to attach or reattach soft tissue to bone,
particularly using an arthroscopic procedure.
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