U.S. patent application number 10/690438 was filed with the patent office on 2004-05-20 for method and apparatus for attaching connective tissues to bone using a perforated suture anchoring device.
This patent application is currently assigned to Opus Medical, Inc.. Invention is credited to Tran, Minh.
Application Number | 20040098053 10/690438 |
Document ID | / |
Family ID | 29584835 |
Filed Date | 2004-05-20 |
United States Patent
Application |
20040098053 |
Kind Code |
A1 |
Tran, Minh |
May 20, 2004 |
Method and apparatus for attaching connective tissues to bone using
a perforated suture anchoring device
Abstract
A bone anchor device for attaching connective tissue to bone
comprises an anchor body, a plurality of suture retaining apertures
disposed in the anchor body, and deployable structure for securing
the anchor body in bone. A longitudinal axis is disposed along a
center of the anchor body, wherein the plurality of suture
retaining apertures are spaced axially relative to one another.
Additionally, in preferred embodiments, at least two of the
plurality of suture retaining apertures are transversely offset
from one another relative to the longitudinal axis, in staggered
relation. Preferably, the deployable structure comprises a pair of
deployable flaps. The anchor body comprises a substantially planar
surface in which the plurality of suture retaining apertures are
disposed. In its presently preferred embodiment, the anchor body
comprises opposing substantially flat surfaces, wherein the
plurality of suture retaining apertures extend through the entire
anchor body. A stem extends proximally from a proximal end of the
anchor body. At least a portion of a longitudinal slit is disposed
in the stem.
Inventors: |
Tran, Minh; (Fountain
Valley, CA) |
Correspondence
Address: |
Donald E. Stout
Stout, Uxa, Buyan & Mullins, LLP
Suite 300
4 Venture
Irvine
CA
92618
US
|
Assignee: |
Opus Medical, Inc.
San Juan Capistrano
CA
|
Family ID: |
29584835 |
Appl. No.: |
10/690438 |
Filed: |
October 21, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10690438 |
Oct 21, 2003 |
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09687185 |
Oct 13, 2000 |
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6652561 |
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Current U.S.
Class: |
606/232 |
Current CPC
Class: |
A61B 2017/042 20130101;
A61B 17/0401 20130101; A61B 2017/0422 20130101; A61B 2017/0412
20130101; A61B 2017/0459 20130101; A61B 2017/0414 20130101; A61B
2017/0409 20130101; A61B 2017/0417 20130101 |
Class at
Publication: |
606/232 |
International
Class: |
A61B 017/04 |
Claims
What is claimed is:
1. A bone anchor device for attaching connective tissue to bone,
comprising: an anchor body; a plurality of suture retaining
apertures disposed in said anchor body; and deployable structure
for securing said anchor body in bone.
2. The bone anchor device as recited in claim 1, wherein said
plurality of suture retaining apertures comprises two suture
retaining apertures.
3. The bone anchor device as recited in claim 1, wherein said
plurality of suture retaining apertures comprises three suture
retaining apertures.
4. The bone anchor device as recited in claim 1, wherein said
plurality of suture retaining apertures comprises four suture
retaining apertures.
5. The bone anchor device as recited in claim 1, and further
comprising a longitudinal axis disposed along a center of said
anchor body, wherein said plurality of suture retaining apertures
are spaced axially relative to one another.
6. The bone anchor device as recited in claim 5, wherein at least
two of said plurality of suture retaining apertures are
transversely offset from from one another relative to said
longitudinal axis.
7. The bone anchor device as recited in claim 6, wherein a first of
the at least two of said plurality of suture retaining apertures is
disposed on one side of the longitudinal axis and a second of the
at least two of said plurality of suture retaining apertures is
disposed on the other side of the longitudinal axis.
8. The bone anchor device as recited in claim 1, wherein said
deployable structure comprises a pair of deployable flaps.
9. The bone anchor device as recited in claim 1, wherein said
anchor body comprises a substantially planar surface in which said
plurality of suture retaining apertures are disposed.
10. The bone anchor device as recited in claim 9, wherein said
anchor body comprises opposing substantially flat surfaces, said
plurality of suture retaining apertures extending through said
entire anchor body.
11. The bone anchor device as recited in claim 1, and further
comprising a stem extending proximally from a proximal end of said
anchor body.
12. The bone anchor device as recited in claim 11, and further
comprising a longitudinal slit, at least a portion of which is
disposed in said stem.
13. A bone anchor device for attaching connective tissue to bone,
comprising: an anchor body having opposing substantially flat
surfaces; deployable structure on a proximal end of said anchor
body for securing said anchor body in bone; and a suture retaining
aperture extending through said anchor body flat surfaces, said
suture retaining aperture being disposed distally of said
deployable structure.
14. A bone anchor device for attaching connective tissue to bone,
comprising: an anchor body having a distal end and a proximal end;
a stem extending proximally from the proximal end of the anchor
body; a deployable flap disposed on the proximal end of the anchor
body; and a notch on said anchor body at a location joining said
anchor body and said deployable flap, said notch being adapted to
cause said deployable flap to deploy outwardly when force is
applied to a proximal end of the deployable flap by a distally
moving actuator.
15. A bone anchor device for attaching connective tissue to bone,
comprising: an anchor body having a distal end and a proximal end;
a stem extending proximally from the proximal end of the anchor
body; a deployable flap disposed on the proximal end of the anchor
body; and a slit, at least a portion of which is disposed in said
stem.
16. A bone anchor device for attaching connective tissue to bone,
comprising: an anchor body having two opposing surfaces; a suture
retaining aperture disposed in said anchor body and extending
through both of said opposing surfaces; and a length of suturing
material extending through said suture retaining aperture, wherein
said length of suturing material is looped about said anchor body
and contacts substantial portions of both of said two opposing
surfaces.
17. The bone anchor device as recited in claim 16, wherein a first
portion of the length of suturing material is looped over a second
portion of the length of suturing material, the second portion of
which lies in contacting engagement with one of said opposing
surfaces of said anchor body.
18. The bone anchor device as recited in claim 16, and further
comprising a second suture retaining aperture disposed in said
anchor body in axially spaced relation to said suture retaining
aperture, wherein said length of suture retaining material is
looped through both of said suture retaining apertures.
19. A method for securing connective tissue to bone, comprising:
securing a first end of a length of suture to a portion of soft
tissue to be attached to a portion of bone; threading a second end
of the length of suture sequentially through a plurality of suture
retaining apertures in a body of a bone anchor device so that the
length of suture is securely fastened to said bone anchor body;
placing said bone anchor body in a blind hole disposed in said
portion of bone; and deploying structure on said bone anchor body
in an outward direction to secure said bone anchor body in said
blind hole.
20. The method as recited in claim 19, and further comprising a
step of securing a proximal end of the length of suture to said
anchor body.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to methods and apparatus
for attaching soft tissue to bone, and more particularly to anchors
and methods for securing connective tissue, such as ligaments or
tendons, to bone. The invention has particular application to
arthroscopic surgical techniques for reattaching the rotator cuff
to the humeral head, in order to repair the rotator cuff.
[0002] 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.
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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 is
able to 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 are of the
arthroscopic type, and are considered investigational in
nature.
[0008] Another significant difficulty with current arthroscopic
rotator cuff repair techniques are 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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] 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
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
[0015] The present invention solves the problems outlined above by
providing innovative bone anchor and connective techniques which
permit a suture attachment which lies beneath the cortical bone
surface. In the present state of the art, the sutures which are
passed through the tissues to be attached to bone typically are
threaded through a small eyelet incorporated into the head of the
anchor and then secured by tying knots in the sutures. Endoscopic
knot tying is an arduous and technically demanding task. Therefore,
the present invention discloses devices and methods for securing
sutures to a bone anchor without the requirement of knot tying.
[0016] In one aspect of the invention, there is provided a bone
anchor device for attaching connective tissue to bone, which
comprises an anchor body, a plurality of suture retaining apertures
disposed in the anchor body, and deployable structure for securing
the anchor body in bone. The term "plurality of suture retaining
apertures" means at least two, but three suture retaining apertures
are employed in the presently preferred embodiment.
[0017] A longitudinal axis is disposed along a center of the anchor
body, wherein the plurality of suture retaining apertures are
spaced axially relative to one another. Additionally, in preferred
embodiments, at least two of the plurality of suture retaining
apertures are transversely offset from one another relative to the
longitudinal axis. Most preferably, a first of the at least two of
the plurality of suture retaining apertures is disposed on one side
of the longitudinal axis and a second of the at least two of the
plurality of suture retaining apertures is disposed on the other
side of the longitudinal axis. In other words, the two apertures
are in a staggered orientation along the axis, with one on one side
of the axis, and the other on the other side of the axis. The
advantage of this configuration is that, as the suturing material
is threaded through the axially spaced suture retaining apertures,
because the apertures are offset from one another transversely,
relative to the axis, the suturing material is wrapped in an
angular orientation relative to the axis. This permits the suturing
material to be wrapped over itself as it is threaded through the
suture retaining apertures, in an "over and back" fashion, as will
be described more fully hereinbelow.
[0018] In a preferred embodiment, the aforementioned deployable
structure comprises a pair of deployable flaps. The anchor body
comprises a substantially planar surface in which the plurality of
suture retaining apertures are disposed. In its presently preferred
embodiment, the anchor body comprises opposing substantially flat
surfaces, wherein the plurality of suture retaining apertures
extend through the entire anchor body. A stem extends proximally
from a proximal end of the anchor body. At least a portion of a
longitudinal slit is disposed in the stem.
[0019] In another aspect of the invention, a bone anchor device is
provided for attaching connective tissue to bone. The bone anchor
device comprises an anchor body having opposing substantially flat
surfaces, deployable structure on a proximal end of the anchor body
for securing the anchor body in bone; and a suture retaining
aperture extending through the anchor body flat surfaces. The
suture retaining aperture is disposed distally of the deployable
structure.
[0020] In yet another aspect of the invention, there is provided a
bone anchor device for attaching connective tissue to bone, which
comprises an anchor body having a distal end and a proximal end. A
stem extends proximally from the proximal end of the anchor body. A
deployable flap is disposed on the proximal end of the anchor body,
and a notch on the anchor body is disposed at a location joining
the anchor body and the deployable flap. The notch is adapted to
cause the deployable flap to deploy outwardly when force is applied
to a proximal end of the deployable flap by an actuator which moves
distally relative to the deployable flap.
[0021] In another aspect of the invention, there is provided a bone
anchor device for attaching connective tissue to bone. This
inventive device comprises an anchor body having a distal end and a
proximal end and a stem extending proximally from the proximal end
of the anchor body. A deployable flap is disposed on the proximal
end of the anchor body. The inventive device further comprises a
slit, at least a portion of which is disposed in the stem.
[0022] In still another aspect of the invention, there is provided
a bone anchor device for attaching connective tissue to bone. The
inventive device comprises an anchor body having two opposing
surfaces, and a suture retaining aperture disposed in the anchor
body and extending through both of the opposing surfaces. A length
of suturing material extends through the suture retaining aperture,
wherein the length of suturing material is looped about the anchor
body and contacts substantial portions of both of the two opposing
surfaces. Advantageously, in order to fully lock the suturing
material in place on the anchor body, a first portion of the length
of suturing material is looped over a second portion of the length
of suturing material, the second portion of which lies in
contacting engagement with one of the opposing surfaces of the
anchor body.
[0023] Preferably, a second suture retaining aperture is disposed
in the anchor body in axially spaced relation to the suture
retaining aperture, wherein the length of suture retaining material
is looped through both of the suture retaining apertures.
[0024] In yet another aspect of the invention, there is disclosed a
method for securing connective tissue to bone. This inventive
method comprises a step of securing a first end of a length of
suture to a portion of soft tissue to be attached to a portion of
bone. A second end of the length of suture is threaded sequentially
through a plurality of suture retaining apertures in a body of a
bone anchor device so that the length of suture is securely
fastened to the bone anchor body. The bone anchor body is placed in
a blind hole disposed in the aforementioned portion of bone. Then,
structure on the bone anchor body is deployed in an outward
direction to secure the bone anchor body in the blind hole.
[0025] 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 THE DRAWINGS
[0026] FIG. 1 is a plan view of a presently preferred embodiment of
the inventive bone anchor device;
[0027] FIG. 1A is a plan view of the inventive bone anchor device
illustrated in FIG. 1, wherein the stem of the device has been
inserted into a hollow casing;
[0028] FIG. 2 is a plan schematic view illustrating a preferred
deployment system for a bone anchoring device of the type shown in
FIGS. 1 and 1A;
[0029] FIGS. 3A-3C are plan views similar to those of FIGS. 1 and
1A, illustrating in sequence a preferred method for deploying the
bone anchor device of the present invention;
[0030] FIGS. 4A-4E are perspective views of the inventive bone
anchor device shown in FIGS. 1-3C, illustrating in sequence a
preferred method for threading the device with suturing
material;
[0031] FIGS. 5A-5I are diagrammatic plan views, in sequence,
illustrating one preferred method of using the inventive bone
anchor device in the attachment of soft tissue to bone, in this
case, the repair of a torn rotator cuff;
[0032] FIG. 6 is a perspective view of an inventive anchoring
device of the type shown in FIGS. 1-5I, illustrating one
alternative approach for locking the suture in place;
[0033] FIG. 7 is a plan view of an alternate embodiment of the
inventive bone anchor device; and
[0034] FIG. 8 is a plan view similar to that of FIG. 7,
illustrating another alternate embodiment of the inventive
device.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0035] Referring now more particularly to the drawings, there is
shown in FIG. 1 a bone anchor 10 in its undeployed state. The
distal end of the bone anchor 10 is comprised of a substantially
flat body 11 which preferably has three eyelet holes or suture
retaining apertures 12a, 12b, and 12c, and which comes to a point
13 at a distal end where it is to be inserted into the bone. Two
deployable flaps 14a, 14b are defined by two notches 16a,b which
allow for deployment of the flaps, and are disposed at a point
where the flaps 14a, 14b are attached to the flat body 11. To a
proximal end of the bone anchor is joined a relatively narrow stem
18. A slit 20 is disposed at least partially on the stem 18 and
partially on the flat body 11, although in presently preferred
embodiments, the slit 20 is disposed entirely on the stem 18, as
shown in FIG. 1. Weak links 22a, 22b are formed on either side of
the slit 2.
[0036] As shown in FIG. 1a, the proximal end of the stem 18 of the
bone anchor 10 is preferably inserted into a hollow casing 24,
which in turn has been attached to the stem 18 utilizing methods
well known in the art such as crimping, welding or the like, in
order to secure the bone anchor 10 to the casing 24. The casing 24
is intended to provide an easy means for insertion of the bone
anchor apparatus 10 into a deployment device for deploying the bone
anchor as shall be more fully described and illustrated
hereinbelow. It is to be understood, of course, that the flat form
of the bone anchor 10 and the shape of the casing 24 are used
herein for informational purposes as to possible methods of
fabrication only, and are not to be deemed limiting.
[0037] Referring now to FIG. 2 there is illustrated a deployment
device 26 which may, for example, be used to deploy the bone anchor
10. This representative deployment device 26 includes a handle 28,
a trigger 30, and a hollow barrel 32 into which the casing 24 on
the proximal end of the bone anchor 10 has been inserted for
deployment. Although many methods of deployment may be utilized, in
the deployment device 26 herein illustrated, the proximal end of
the casing 24 is coupled to the trigger mechanism 30 through the
barrel 32 of such deployment device 26. When the trigger mechanism
30 is activated, the proximal end of the casing 24 is pulled into
the hollow barrel 32 until the distal end of the hollow barrel 32
comes into contact with the flaps 14a, 14b on the bone anchor 10,
thus applying a distally-directed force thereon and thereby
deploying such flaps 14a, 14b, as shall be shown and described
below.
[0038] Referring now to FIG. 3A, the casing 24 that has been
crimped or otherwise attached to the bone anchor 10 is shown
inserted into the barrel 32 of the deployment device 26 (FIG. 2)
before deployment of the anchor flaps 14a, 14b. As seen in FIG. 3B,
the barrel 32 is driven in a distal direction (or, preferably, the
casing 24 is drawn into the barrel 32), which causes the distal end
of the barrel 32 to come into contact with flaps 14a, 14b. By
continuing to move the barrel 32 distally, relative to the flaps
14a, 14b, once the aforementioned contact has been made, force will
be applied against the base of each flap, causing each flap to bend
outwardly at its respective notch 16a, 16b as shown in FIG. 3B. The
result is that the flaps 14a, 14b are deployed outwardly from the
body of the bone anchor 10.
[0039] As the deployment force exerted by the barrel 32 is taken
directly on the face of the flaps 14a, 14b, as noted supra, the
notches 16a, 16b close and limit the bending of the flaps 14a, 14b,
and the load on the weak links 22a, 22b on opposing sides of the
slit 20 begins to increase as a result of the imposition of a
tensile force on the proximal end of the bone anchor after the
distal end thereof has been anchored into the bone. In other words,
because the anchor body 11 is fixed in the bone, and cannot move
responsive to the applied tensile force, the reactive force applied
by the anchor body on the stem 18 causes the weak links 20a, 20b to
fracture, thereby separating the casing 24 and the broken stem 18
from the bone anchor 10, leaving the bone anchor 10 anchored into
the bone structure.
[0040] Referring to FIGS. 4a-4e, it may be seen how suture may be
attached to the bone anchor apparatus 10, in accordance with one
preferred method, prior to its deployment into the bone structure.
As illustrated in FIG. 4a, adjacent lengths of suture 34a, 34b have
two corresponding free ends 35a, 35b, respectively, which have
already been disposed through a tendon or portion of soft tissue
(not shown), and then are passed from the underside of the bone
anchor 10 in its undeployed state through the eyelet hole 12a. In
actuality, as will be explained in more detail hereinbelow, the two
suture lengths 34a, 34b represent the free ends of a length of
suture which has been looped through a portion of soft tissue in
the form of a mattress stitch. In FIG. 4b, the suture lengths 34a,
34b are then threaded from the top side of the bone anchor body 11
through the eyelet 12b to the underside of the anchor body 11, and
then back up to the top side thereof through the eyelet hole 12c.
In FIG. 4c the loose or free ends 35a, 35b of the suture lengths
34a, 34b, respectively, are passed, as illustrated, through a loop
36, which is formed by a portion of the lengths of suture 34a, 34b,
on the top side of the bone anchor between eyelet holes 12a,b.
[0041] An important feature of the present invention concerns the
placement of the suture retaining apertures or eyelet holes 12a,
12b, and 12c. As illustrated in FIG. 4a, the bone anchor 10 of the
present invention has a longitudinal axis 37 extending along its
axial center. In the illustrated preferred embodiment, each of the
suture retaining apertures 12, 12b, and 12c are axially spaced and
are offset from the longitudinal axis in a transverse direction
(meaning the direction orthogonal to the axis). This offset can be
measured by measuring the distance from the longitudinal axis 37 to
a center of the suture retaining aperture. More preferably,
successive suture retaining apertures (i.e. 12a and 12b or 12b and
12c) are offset in a "staggered" fashion, meaning they are offset
from the longitudinal axis in opposed transverse directions. The
purpose for this offset is to ensure that the suturing material, as
it is threaded through the apertures in a distal direction (FIG.
4b), and then returned in a proximal direction beneath the loop 36
(FIG. 4c), lies at an angle relative to the longitudinal axis 37.
Without this angled orientation, the suture loop lock feature of
the invention would not be as easy to achieve, nor as
effective.
[0042] In one presently preferred embodiment, as illustrated in
FIGS. 1 and 4a, an angle a between a line 38 which lies between a
center point 38b of aperture 12b and a center point 38c of aperture
12c, and the longitudinal axis 37 preferably falls within a range
of approximately 10-30 degrees, and is most preferably about 18-25
degrees. In the preferred embodiment shown, the angle .alpha. is
between 19 and 20 degrees. The inventor has found that if the angle
.alpha. is too great, improper suture locking may occur, and,
conversely, there may be an inadequate ability to adjust the suture
once it has been threaded about the anchor body.
[0043] Additionally, as shown in FIG. 1, in the presently preferred
embodiment, the distance x between a centerline 38d running between
center points 38a and 38c of apertures 12a and 12c and a centerline
38e running through center point 38b of aperture 12b is
approximately 0.035 inches. A distance y from the axis 37 to the
centerline 38d is 0.0175 inches in the same preferred embodiment,
which, of course, means that the aperture 12b is equally offset
0.0175 inches from the axis 37 in the opposing transverse
direction. Of course, these specific distances are merely
exemplary, and are not required for successful implementation of
the inventive concept. For example, they may be scaled to
differently sized instruments. It is also possible to implement the
invention without utilizing suture retaining apertures which are
equally spaced from the longitudinal axis 37, or which are offset
from the axis 37 at all. Such an embodiment is shown, for example,
in FIG. 7, which will be discussed hereinbelow.
[0044] In FIGS. 4d and 4e, the free ends 35a, 35b of the suture
lengths 34a, 34b, respectively, are drawn snugly by creating a
tension as represented by the letter T in the direction of the
arrow 39 in order to eliminate any slack at the fixation point of
the suture lengths 34a, 34b to the bone anchor 10 as well as to
create tension in the suture lengths 34a, 34b that is disposed, in
turn, through the tendon or soft tissue to be attached to bone by
the bound ends 40a, 40b, respectively, of the suture lengths 34a,
34b. It is to be understood that it is the combination of the
tension in the suture lengths 34a, 34b and the passing of the
suture lengths 34a, 34b beneath the loop 36 that defines the
inventive locking aspect of the invention. It may be seen that as
the tension in the suture lengths 34a, 34b is increased on the free
ends 35a, 35b, respectively, the suture lengths 34a, 34b are drawn
through the eyelets 12a, 12b, 12c and through the loop 36, creating
greater and greater tension on the bound legs 40a, 40b, which by
direct contact through the suture loop 36, locks the free suture
lengths 34a, 34b against the flat body 11 of the bone anchor
10.
[0045] It is to be understood, of course, that while we have been
talking about a preferred case of two free lengths 34a, 34b of
suture which extend from two bound ends 40a, 40b thereof, wherein
the bound ends are actually the two opposing ends of a loop of
suture extending through a portion of soft tissue in the form of a
mattress stitch, this invention is equally well adapted to the use
of a single length of suture, or a plurality of lengths of suture
greater than two, if desired.
[0046] Referring now to FIGS. 5a-5i, it can be seen more
particularly how the inventive apparatus may be utilized, in one
preferred procedure, as a bone anchor for the attachment of soft
tissues to bone. It should be noted, in this respect, that those
elements which are common to elements shown in FIGS. 1-4e are
designated by common reference numerals. Now, in FIG. 5a there is
shown a cross-sectional view of a human shoulder on the left side
of the body as seen from the front of the body and which
illustrates a rotator cuff tendon 46 which is disposed across a
humeral head 48. It is to be understood that, in this illustration,
the rotator cuff tendon is detached from the humeral head 48 at the
interface 50 between the two. This is the problem which is to be
corrected by the inventive procedure. The humeral head 48 is
comprised of an outer surface of cortical bone 52 and inner
cancellous bone 54. To allow for arthroscopic access, a trocar 56
has been inserted into the shoulder in proximity to the area where
the rotator cuff tendon 46 is to be reattached to the humeral head
48, and a hole 58 has been made, preferably by drilling or
punching, in the desired location through the cortical bone 52 and
into the cancellous bone 54. This illustration is intended only to
provide a simple structural overview of the physiological elements
involved in a typical situation where it is to be desired that soft
tissue such as a rotator cuff tendon 46 be reattached to a humeral
head 48. However, it should be clear that the inventive procedure
may be used in other areas of the body where soft tissue is to be
reattached to bone.
[0047] Alternate rotator cuff repair procedures are also discussed
in co-pending U.S. patent application Ser. No. 09/475,495, filed on
Dec. 30, 1999, and entitled Method and Apparatus for Attaching
Connective Tissues to Bone Using a Knotless Suture Anchoring
Device, which is herein expressly incorporated by reference.
[0048] Referring still to FIG. 5a it can be seen that a length of
suture 34 has been passed through the tendon 46 with the loose or
free ends of the suture passing through the trocar and out of the
shoulder. This step of suturing the tendon 46 is beyond the scope
of the present application, but any known technique may be
utilized. The present invention is particularly suited, however, to
the use of a suturing instrument, as described in co-pending U.S.
patent application Ser. No. 09/668,055, entitled Linear Suturing
Apparatus & Methods, filed on Sep. 21, 2000, which is commonly
assigned with the present application and is herein expressly
incorporated by reference. This type of suturing instrument will
produce a "mattress stitch" through the tendon 46, which is a
preferred stitch for most practitioners. The free ends of the
suture 34 have been threaded through the bone anchor 10 as
previously described in connection with FIGS. 4a-c, above, and the
proximal end of the bone anchor 10 has been inserted into the
barrel 32 of the deployment device 26 as also previously described
in connection with FIG. 2, above.
[0049] FIG. 5b illustrates in enlarged detail how the bone anchor
10 is inserted through the trocar 56 by means of the barrel 32 of
the deployment device 26 and into the hole 58 which has been made
in the humeral head 48.
[0050] In FIG. 5c a further enlarged view of the same general
illustration is provided, detailing the distal end of the
instrument and the procedural site. It can be seen in this view
that each free leg 34a, 34b of the suture 34 has been drawn tight
against the bone anchor 10 by applying continual tension to the
free ends 35a, 35b (not shown--they extend proximally out through
the barrel 32) of the suture 34 as the bone anchor is inserted
through the trocar 56 and into the hole 58 in the humeral head
48.
[0051] The bone anchor of FIG. 5c is still in its undeployed state.
In FIG. 5d the bone anchor device has been deployed by activating
the trigger mechanism of the deployment device 26 as illustrated in
FIG. 2 and described above. Activation of such triggering mechanism
causes the casing 24 which is attached to the proximal end of the
bone anchor 10 to be pulled proximally into the barrel 32 of the
deployment device. As the bone anchor is pulled into the barrel 32
the flaps 14a, 14b of the bone anchor impact against the end of the
barrel 32, deploying such flaps outward from the bone anchor 10 in
proximity to the interface of the cortical bone 52 and the
cancellous bone 54. The flaps 14a, 14b bear against the inside of
the cortical bone 52, thereby preventing the bone anchor from being
retracted proximally out of the hole 58 in the cortical bone 52.
Any rotational moment is also resisted by the flaps 14a, 14b, and
more specifically by the edges 15a, 15b of the flaps 14a, 14b.
[0052] In FIG. 5e the barrel 32 of the deployment device has been
removed from the trocar 56 by withdrawing it proximally through
such trocar. As previously described in connection with FIGS. 3a
through 3c, the tension imposed on the casing which is attached to
the bone anchor stem as illustrated in FIG. 1a, causes the weak
links 22a, 22b to break, thereby separating the casing 24 from the
bone anchor 10 and allowing the casing to be removed and discarded,
and leaving the bone anchor 10 permanently disposed within the
cancellous bone of the shoulder.
[0053] In FIG. 5f additional tension has been applied to the
proximal end of the suture 34, and, in comparing the position of
the rotator cuff 46 as illustrated in FIGS. 5e and 5f, it may be
seen that the rotator cuff 46 has been pulled down against the
cortical bone 52 by the manual action of creating tension on the
loose legs of the suture 34. This tightening of the suture 34 and
the subsequent approximation of the rotator cuff 46 to the bone 52
is made irreversible by the frictional force between the suture 34
passing through the suture loop 36. In order to absolutely assure
that the suture 34 may not loosen, the suture 34 is then preferably
threaded between two tabs 59a, 59b which have been formed at the
proximal end of the bone anchor 10 as a result of the breaking of
the weak links 22a,b. Then, as shown in FIG. 5g, the ends of the
tabs 59a, 59b may be pinched together tightly against the suture 34
in order to secure the loose ends of the suture 34 to the proximal
end of the bone anchor 10 and to prevent any potential loosening or
unraveling of the suture 34. The suture 34 may then be cut, as
illustrated in FIG. 5g, at the outer edge of the cortical bone 52
and the excess suture removed to complete the inventive
procedure.
[0054] Alternative methods for preventing loosening or unraveling
of the suture 34 from the bone anchor 10 are illustrated in FIG.
5h, wherein the tabs 59a, 59b are shown as having been twisted
together around the loose ends of the suture 34 (as opposed to
being merely pinched together, as shown in FIG. 5g), and in FIG.
5i, wherein a knot 54 is illustrated as having been tied in the
suture at the proximal end of the bone anchor 10 (in which case the
tabs 59a, 59b are not required). In FIG. 6, another alternative
approach is illustrated, wherein an alternative bone anchor 60 has
only two apertures 62a, 62b, as opposed to the three suture
retaining apertures illustrated in connection with the earlier
embodiments. In this embodiment, a length of suture 64 (which
preferably comprises two free legs 64a, 64b) is threaded from the
top side of the bone anchor 60 down through the eyelet hole 62a,
then up through the eyelet hole 62b, and is passed under a loop 66
between the eyelet hole 62a and the body of the bone anchor 60. At
the proximal end of the bone anchor 60 are two tabs 67a, 67b that
define a slot 68. Free suture ends 69a, 69b are threaded into the
slot 68, which by nature of the shape of the tabs 67 is tapered. As
the suture ends 69a, 69b are pulled down into the slot 68 they are
wedged and held by frictional force to prevent the sutures from
loosening as discussed above.
[0055] Additional alternative embodiments of the present invention
may be seen by referring to FIGS. 7-8. FIG. 7 illustrates an
alternative bone anchor 70 of the same general shape as that shown
in prior embodiments, having two axially spaced eyelet holes 72a,
72b and with the addition of two troughs 74a, 74b forming a waist
near the middle section of the bone anchor 70. It will be noted
that in this waisted embodiment, the two eyelet holes (or suture
retaining apertures) 72a, 72b are axially aligned, meaning that
they are both centered on the longitudinal axis 77 of the anchor
70, as opposed to the prior illustrated embodiments, wherein the
axially spaced apertures are offset from the longitudinal axis, in
staggered fashion. This difference is possible because of the
waisted configuration of the anchor body 78, which permits the
wrapped suture lengths to achieve the same angled suture
orientations as in the prior embodiments.
[0056] In this embodiment, a length of suture 76, comprising free
legs 76a, 76b, is threaded from the rear side of the bone anchor 70
through the eyelet hole 72a, then weaved about the anchor body 78
through the trough 74b from the front side of the bone anchor 70
and back to the rear side of the anchor body 78. The suture 76 is
then threaded through the eyelet hole 72b to the front side of the
bone anchor 70 and passed through a loop 79 created between the
eyelet hole 72a and the trough 74b. In all respects, the deployment
of the bone anchor is essentially the same as with those anchors
described above, and it should be clear that the tension in the
suture 76 as it passes through the loop 78 creates a binding force
similar to that previously described with the 3 hole anchor.
[0057] In FIG. 8, an alternative embodiment illustrated as a bone
anchor 80 is virtually the same in shape, description and
deployment to the preferred embodiment herein described with the
exception that there are four eyelet holes 82a, 82b, 82c, and 82d
instead of three such eyelet holes. The purpose for discussing this
embodiment is to emphasize the general principle that, though three
suture retaining apertures are preferred, any number of such
apertures may be employed, if desired, within the scope of the
present invention. In this figure, a length of suture 84,
preferably comprising free legs 84a, 84b, as discussed supra, is
threaded from front to rear through eyelet hole 82a, from rear to
front through eyelet hole 82b, from front to rear again through
eyelet hole 82c, and, finally, threaded from rear to front through
eyelet hole 82d. It is then passed through the loop 86 created
between eyelet holes 82b and 82c and tension applied as fully
described in connection with the preferred embodiment, supra.
Again, it is the tension in the suture 84 that creates the binding
force in the loop 86.
[0058] It is to be understood that the figures of the bone and
anchors seen above are purely illustrative in nature, and are not
intended to perfectly reproduce the physiologic and anatomic nature
of the humeral head as expected to be seen in the human species,
nor to limit the application of the inventive embodiments to repair
of the rotator cuff. The invention is applicable to many different
types of procedures involving, in particular, the attachment of
connective or soft tissue to bone.
[0059] 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.
* * * * *