U.S. patent application number 12/605065 was filed with the patent office on 2010-05-13 for methods and devices for suture anchor delivery.
This patent application is currently assigned to The Foundry, LLC. Invention is credited to Mark Deem, Hanson S. Gifford, III, Darin C. Gittings, Vivek Shenoy, Doug Sutton.
Application Number | 20100121355 12/605065 |
Document ID | / |
Family ID | 42165912 |
Filed Date | 2010-05-13 |
United States Patent
Application |
20100121355 |
Kind Code |
A1 |
Gittings; Darin C. ; et
al. |
May 13, 2010 |
METHODS AND DEVICES FOR SUTURE ANCHOR DELIVERY
Abstract
A method for impacting a suture anchor into bone comprises
providing an implantable suture anchor and providing an impactor
device for impacting the suture anchor into the bone. The suture
anchor is coupled to a distal portion of the impactor device.
Positioning the suture anchor engages the anchor with the bone at
an implantation site, and powering the impactor device impacts the
suture anchor thereby implanting the suture anchor into the bone.
The frequency of impaction is less than 20 KHz. The impactor device
is then decoupled from the suture anchor, and the impactor device
may be removed from the implantation site.
Inventors: |
Gittings; Darin C.;
(Sunnyvale, CA) ; Deem; Mark; (Mountain View,
CA) ; Gifford, III; Hanson S.; (Woodside, CA)
; Sutton; Doug; (Pacifica, CA) ; Shenoy;
Vivek; (Redwood City, CA) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER, EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
The Foundry, LLC
Menlo Park
CA
|
Family ID: |
42165912 |
Appl. No.: |
12/605065 |
Filed: |
October 23, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61108420 |
Oct 24, 2008 |
|
|
|
Current U.S.
Class: |
606/148 ;
606/232 |
Current CPC
Class: |
A61B 2017/00398
20130101; A61B 2017/0414 20130101; A61B 2017/0409 20130101; A61B
17/0401 20130101; A61B 17/0642 20130101; A61B 2017/0432 20130101;
A61B 2017/00411 20130101; A61B 2017/00544 20130101; A61B 2017/00986
20130101; A61B 2017/0437 20130101; A61B 2017/00867 20130101 |
Class at
Publication: |
606/148 ;
606/232 |
International
Class: |
A61B 17/04 20060101
A61B017/04 |
Claims
1. A method for impacting a suture anchor into bone, said method
comprising: providing an implantable suture anchor; providing an
impactor device for impacting the suture anchor into the bone,
wherein the suture anchor is coupled to a distal portion of the
impactor device; positioning the suture anchor into engagement with
the bone at an implantation site; powering the impactor device to
impact the suture anchor thereby implanting the suture anchor into
the bone, wherein the frequency of impaction is less than 20 KHz;
decoupling the impactor device from the suture anchor; and removing
the impactor device from the implantation site.
2. The method in claim 1, wherein the suture anchor passes through
adjacent musculoskeletal tissues.
3. The method in claim 2, wherein the suture anchor attaches the
adjacent musculoskeletal tissues to the bone.
4. The method in claim 3, wherein the adjacent musculoskeletal
tissues comprise bony tissue.
5. The method in claim 3, wherein the adjacent musculoskeletal
tissues comprise soft tissue.
6. The method in claim 1, wherein the suture anchor attaches soft
tissue to the bone.
7. The method in claim 1, wherein the suture anchor comprises one
or more lengths of suture.
8. The method in claim 1, wherein the powering comprises
pneumatically actuating the impactor device.
9. The method in claim 1, wherein the powering comprises
electrically actuating the impactor device.
10. The method in claim 1, wherein the powering comprises
magnetically actuating the impactor device.
11. The method in claim 1, wherein the powering comprises
mechanically actuating the impactor device.
12. The method in claim 1, wherein the powering impacts the anchor
so as to linearly and rotatably drive the suture anchor into the
bone.
13. The method in claim 1, wherein the frequency of impaction is
less than 1 KHz.
14. The method in claim 1, wherein the impaction has an amplitude
of 1000 micrometers or less per impact.
15. The method in claim 1, further comprising expanding a portion
of the suture anchor radially outward so as to firmly engage the
suture anchor with the bone.
16. The method in claim 15, wherein the suture anchor comprises a
plurality of fingers, and wherein the expanding comprises releasing
a constraint from the fingers so as to allow the fingers to
radially expand outward.
17. The method in claim 1, wherein the impactor comprises an
elongate tubular shaft and the decoupling comprises advancing the
suture anchor axially away from a distal portion thereof.
18. The method in claim 1, further comprising cooling the suture
anchor or the implantation site with a fluid.
19. A suture anchor delivery system comprising: an implantable
suture anchor having a longitudinal axis and a plurality of fingers
circumferentially disposed therearound, the fingers having a
constrained configuration and an unconstrained configuration,
wherein in the constrained configuration the fingers are
substantially parallel with the longitudinal axis, and wherein in
the unconstrained configuration, the fingers expand radially
outward; and an impactor device for impacting the suture anchor
into bone, wherein the suture anchor is releasably coupled to a
distal portion of the impactor device.
20. The system of claim 19, wherein the suture anchor comprises a
textured outer surface to allow for bone ingrowth.
21. The system of claim 19, further comprising a length of suture
coupled to the suture anchor.
22. The system of claim 19, wherein the impactor device impacts the
suture anchor at a frequency of less than 20 KHz.
23. The system of claim 19, wherein the impactor device comprises
an actuation mechanism for impacting the suture anchor that is
pneumatically actuated.
24. The system of claim 19, wherein the impactor device comprises
an actuation mechanism for impacting the suture anchor that is
electrically actuated.
25. The system of claim 19, wherein the impactor device comprises
an actuation mechanism for impacting the suture anchor that is
magnetically actuated.
26. The system of claim 19, wherein the impactor device comprises
an actuation mechanism for impacting the suture anchor that is
mechanically actuated.
27. The system of claim 19, wherein the impactor device impacts the
suture anchor so as to linearly and rotatably drive the suture
anchor into the bone.
28. The system of claim 19, wherein the impactor device impacts the
suture anchor at a frequency of less than 1 KHz.
29. The system of claim 19, wherein the impactor device impacts the
suture anchor with an impaction having an amplitude of 1000
micrometers or less per impact.
30. The system of claim 19, further comprising a cooling system for
cooling the impactor device and the suture anchor during
impaction.
31. The system of claim 30, wherein the cooling system comprises a
cooling fluid.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] The present application is a non-provisional of, and claims
the benefit of priority of U.S. Provisional Patent Application No.
61/108,420 (Attorney Docket No. 020979-003900US), filed Oct. 24,
2008, the entire contents of which are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present disclosure relates to medical devices, systems
and methods, and more specifically to methods, systems and devices
used for anchoring suture and delivery of suture anchors.
[0004] Soft tissue such as tendons, ligaments and cartilage are
generally attached to bone by small collagenous fibers which are
strong, but which nevertheless still can tear due to wear or
disease. Examples of musculoskeletal disease include a torn rotator
cuff as well as a torn labrum in the acetabular rim of a hip joint
or the glenoid rim in a shoulder joint.
[0005] Thus, treatment of musculoskeletal disease may involve
reattachment of torn ligaments, tendons or other tissue to bone.
This may require the placement of suture anchors in the humeral
head for reattachment of a torn rotator cuff, placement of suture
anchors in the acetabular or glenoid rim for reattachment of the
torn labrum, placement of tacks to attach labral tissue to the
glenoid rim, placement of screws in the vertebral bodies to attach
cervical plates for spinal fusion, placement of screws in small
joint bones for stabilizing reduced fractures, etc. A suture anchor
is a device which allows a suture to be attached to tissue such as
bone. Suture anchors may include screws or other tubular fasteners
which are inserted into the bone and anchored in place. After
insertion of the anchor, the tissue to be repaired is captured by a
suture, the suture is attached to the anchor (if not already
pre-attached), tension is adjusted, and then the suture is often
knotted so that the tissue is secured in a desired position.
[0006] Delivery of a suture anchor to a treatment site can be time
consuming and challenging to undertake in the tight space
encountered during endoscopic surgery and sometimes even in
conventional open surgery. In most surgical procedures, a pilot
hole is drilled at the implantation site prior to screwing in the
device. In other cases a self-tapping device tip is used to screw
in the device without a pilot hole. Alternatively, ultrasonic
energy has been proposed in embedding bone anchors in bony tissue
without pre-drilling a pilot hole. These methods of implanting a
device in bone tissue, while commonly used in surgery today, are
not optimal. Pre-drilling a pilot hole prior to placing the device
requires the surgeon to exchange tools through the cannula and to
locate the pilot hole after introducing the implant in the
arthroscopic field. Self-tapping devices are limited to use at
sites with the appropriate thickness of cortical bone. Ultrasonic
energy based devices are susceptible to large energy losses with
minor changes in device configuration, and rely on ultrasonic
energy sources which can be expensive. It would therefore be
desirable to provide a suture anchor system that provides easy
access to the treatment site and that can easily and accurately
deliver a suture anchor to a desired location.
[0007] In a particular application, treating musculoskeletal
disease in a hip joint can be especially challenging. The hip joint
is a deep joint surrounded by a blanket of ligaments and tendons
that cover the joint, forming a sealed capsule. The capsule is very
tight thereby making it difficult to advance surgical instruments
past the capsule into the joint space. Also, because the hip joint
is a deep joint, delivery of surgical instruments far into the
joint space while still allowing control of the working portions of
the instrument from outside the body can be challenging.
Additionally, the working space in the joint itself is very small
and thus there is little room for repairing the joint, such as when
reattaching a torn labrum to the acetabular rim. Thus, the suture
anchor tool must be small enough to fit in the limited space.
Moreover, when treating a torn labrum, the suture anchor must be
small enough to be inserted into the healthy rim of bone with
adequate purchase, and the anchor also must be short enough so that
it does not protrude through the bone into the articular surface of
the joint (e.g. the acetabulum). Thus, the anchor delivery
instrument must also be able to hold and deliver suture anchors
having a small diameter and small length.
[0008] Therefore, it would be desirable to provide improved suture
anchors and suture anchor delivery instruments that overcome some
of the aforementioned challenges. Such suture anchors and delivery
instruments are preferably suited to arthroscopic procedures, and
in particular labral repair in the hip. At least some of these
objectives will be met by the disclosure described below.
[0009] 2. Description of the Background Art
[0010] Patents disclosing suture anchoring devices and related
technologies include U.S. Pat. Nos. 7,566,339; 7,390,329;
7,309,337; 7,144,415; 7,083,638; 6,986,781; 6,855,157; 6,770,076;
6,767,037; 6,656,183; 6,652,561; 6,066,160; 6,045,574; 5,810,848;
5,728,136; 5,702,397; 5,683,419; 5,647,874; 5,630,824; 5,601,557;
5,584,835; 5,569,306; 5,520,700; 5,486,197; 5,464,427; 5,417,691;
and 5,383,905. Patent publications disclosing such devices include
U.S. Patent Publication Nos. 2009/0069845; 2008/0188854; and
2008/0054814.
BRIEF SUMMARY OF THE INVENTION
[0011] The current invention comprises surgical devices and methods
to treat various soft tissue and joint diseases, and more
specifically relates to suture anchors and suture anchor delivery
instruments used in the treatment of bone, cartilage, muscle,
ligament, tendon and other musculoskeletal structures.
[0012] In a first aspect of the present invention, a method for
impacting a suture anchor into bone comprises providing an
implantable suture anchor, and providing an impactor device for
impacting the suture anchor into the bone. The suture anchor is
coupled to a distal portion of the impactor device. Positioning the
suture anchor engages the suture anchor with the bone at an
implantation site, and powering the impactor device impacts the
suture anchor thereby implanting the suture anchor into the bone.
The frequency of impaction is less than 20 KHz. The impactor device
is decoupled from the suture anchor and then the impactor device is
removed from the implantation site.
[0013] The suture anchor may pass through adjacent musculoskeletal
tissues and may attach the adjacent musculoskeletal tissues to the
bone. The adjacent musculoskeletal tissues may comprise bony
tissues or soft tissues. The suture anchor may include one or more
lengths of suture. Powering of the impactor device may comprise
pneumatically, electrically, mechanically, or magnetically
actuating the impactor device. The impactor device may impact the
anchor when powered so as to linearly, rotationally, or linearly
and rotationally drive the suture anchor into the bone. The
frequency of impaction may be less than 1 KHz. The impaction may
have an amplitude of 1,000 micrometers or less per impact.
[0014] The method may further comprise expanding a portion of the
suture anchor radially outward so as to firmly engage the suture
anchor with the bone. The suture anchor may comprise a plurality of
fingers, and expanding a portion of the suture anchor may comprise
releasing a constraint from the fingers so as to allow the fingers
to radially expand outward. The impactor device may comprise an
elongate tubular shaft and the step of decoupling may comprise
advancing the suture anchor axially away from a distal portion of
the shaft. The method may also comprise cooling the suture anchor
or the implantation site with a fluid.
[0015] In another aspect of the present invention, a suture anchor
delivery system comprises an implantable suture anchor having a
longitudinal axis and a plurality of fingers circumferentially
disposed therearound. The fingers have a constrained configuration
and an unconstrained configuration. In the constrained
configuration the fingers are substantially parallel with the
longitudinal axis, and in the unconstrained configuration, the
fingers expand radially outward. The system also includes an
impactor device for impacting the suture anchor into bone. The
suture anchor is releasably coupled to a distal portion of the
impactor device.
[0016] In a further aspect, the invention provides a suture anchor
formed of shape memory material and having an unbiased
configuration adapted to securely fix the anchor in bone or other
tissue. The suture anchor is deformable into a configuration
adapted for delivery into the bone or tissue, from which it may be
released so that it returns toward its unbiased configuration
thereby anchoring the anchor in the bone or tissue. In various
embodiments, the anchor may have in its unbiased configuration a
plurality of resilient fingers that extend radially outward, a
curved shape formed around a transverse axis, two or more wings
that flare outwardly in the proximal direction, or two or more
longitudinal divisions defining a plurality of axial elements that
bow or deflect outwardly. Other structures are disclosed
herein.
[0017] In another aspect, the invention provides a suture anchor
having a tapered tip adapted for being driven into bone, with or
without a pre-drilled hole, a shaft extending proximally from the
tip, and a means for attaching a suture to the shaft. The tip, the
shaft, or both are cross-shaped in cross section.
[0018] The suture anchor may comprise a textured outer surface to
allow for bone ingrowth. The suture anchor may also comprise a
length of suture coupled thereto. The impactor device may impact
the suture anchor at a frequency of less than 20 KHz, or at a
frequency of less than 1 KHz. the impactor device may comprise an
actuation mechanism for impacting the suture anchor that is
pneumatically, electrically, magnetically, or mechanically
actuated. The impactor device may impact the suture anchor and
drive the anchor into the bone or other tissue in a linear,
rotational, or linear and rotational manner. The impactor device
may impact the suture anchor with an impaction having an amplitude
of 1,000 micrometers or less per impact. The system may further
comprise a cooling system for cooling the impactor device and
suture anchor during impaction. The cooling system may comprise a
cooling fluid.
[0019] These and other embodiments are described in further detail
in the following description related to the appended drawing
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a sectional view of an anchor loaded in the distal
end of an anchor driver and placed through a cannula.
[0021] FIG. 2 is a sectional view of a flat anchor loaded into the
distal end of an anchor driver with a stabilization sleeve.
[0022] FIG. 3 is a sectional view of a round anchor loaded into the
distal end of an anchor driver with a tubular profile.
[0023] FIG. 4 is a sectional view of the body of a pneumatic
powered impactor.
[0024] FIG. 5 is a sectional view of the body of a
electromechanically powered impactor.
[0025] FIG. 6 is a sectional view of the body of an impactor with a
rotary mechanism.
[0026] FIG. 7 is an example of an anchor.
[0027] FIGS. 8A-8D are examples of anchors.
[0028] FIGS. 9A-9B are examples of anchor in a constrained and
deployed configuration.
[0029] FIGS. 10A-10B are examples of a device for sutureless
attachment of tissue to bone in a constrained and deployed
configuration.
[0030] FIGS. 11A-11B are examples of a curved anchor in a
constrained and deployed configuration.
DETAILED DESCRIPTION OF THE INVENTION
[0031] The devices and methods disclosed herein address at least
some of the limitations of current methods of implanting devices
into bony tissue. The method involves driving the device into bony
tissue by impaction whereby, an impactor drives the implant into
bone at frequencies between 10 and 20 KHz, preferably between 20
and 1000 Hz, most preferably between 30 and 500 Hz; and at
amplitudes of 100 to 1000.mu., preferably 200-750.mu., most
preferably 300-500.mu.. The implantable device may be loaded into
the distal end of the impactor such that the distal end of the
impactor and the attached device may be introduced into an
arthroscopic field through a cannula.
[0032] FIG. 1, shows a sectional view of implant 103 loaded into an
impactor 102 and introduced through a cannula 103. Implant 101 is
located at the distal end of impactor assembly 102. The assembly
102 is introduced down the bore of cannula 103 and placed in the
proximity of bony structure 104. Having been placed at the surface
of bony structure 104 the impactor 102 is energized and the implant
101 is driven into the bone. Channel 105 extends transversely
through the implant 103 and allows a suture to be secured thereto.
During the impaction period, contact between the tip of the device
and the bony tissue is maintained manually by the surgeon.
[0033] In one exemplary embodiment the implant is impacted into the
bone by application of force onto the proximal surface of the
implant. Referring to FIG. 2, implant 201 is impacted by impactor
member 202. This allows the implant 201 to be constructed with
substantially consistent cross sections. Sleeve 203 can move
relative to the implant 201 and impactor member 202 while remaining
concentric and serves to stabilize and guide the implant 201 while
the implant 201 is being impacted into the bone.
[0034] In another embodiment the implant is configured with a
stepped shoulder region 303 along the length of the body suitable
for applying impaction force. FIG. 3 shows a cross sectional view
of anchor 301 which has a round cross section and interfaces with
the distal end of the impactor 302. The distal end of the impactor
302 is generally round and hollow. The distal end of the impactor
302 which interfaces with the anchor device 301 could be of varying
length to enable introduction through cannulas used to access joint
spaces in the shoulder, knee, hip etc. The impactor 302 may also be
loaded with multiple devices.
[0035] At the frequencies utilized during deployment of anchors,
the amount of energy loss by heat dissipation is low. However, the
distal end of the impactor may optionally be designed to circulate
cold fluid to regulate the temperature of the impactor tip and the
implant. Other forms of cooling well know in the art may also be
used in conjuction with the impactor.
[0036] The frequency and amplitude of the impactor may be adjusted
to optimize the implantation process depending on the size of the
implant, the design of the implant, as well as the properties of
bone at the implant site, etc.
[0037] In another embodiment, the impactor is powered by compressed
gas which is commonly available in operating rooms. FIG. 4 shows a
cutaway view of one embodiment of a pneumatic driver used for
placing devices in bony tissue. Shuttle element 401 is cycled back
and forth based on air pressure by selectively pressurizing and
releasing pressure in chamber 402 through the cyclic motion of
shuttle 401 relative to ports 403 and 404. As the shuttle moves
port 403 is selectively covered or uncovered causing the shuttle to
reverse direction based on the action of spring 405 which rebounds
shuttle 401 back into the depressurized chamber 402. At one end of
the shuttle travel, the shuttle impacts active element 406 which is
in contact with the proximal end of the device 407 thereby
transmitting the energy from the shuttle 401 to the device 407 with
each cycle. At the end of the cycle, the spring 408 returns the
active element 406 back to its original position. Those skilled in
the art will appreciate that the system shown in FIG. 4 is an
exemplary system and the same effect could be accomplished with a
variety of pressured driving mechanisms.
[0038] In another embodiment, the impactor could be designed to
operate using a mechanical shuttle mechanism driven by an
electromagnetic field. FIG. 5 shows a sectional view of an
instrument used for driving devices into bony tissue. Shuttle
element 501 may be composed of any ferromagnetic material and is
cycled back and forth based on the magnetic field created by a coil
502 which is connected to a signal generator capable of generating
alternating current. At one end of the shuttle travel, the shuttle
impacts active element 503 which is in contact with the proximal
end of the device 504 thereby transmitting the energy from the
shuttle to the device with each cycle. Those skilled in the art
will appreciate this system shown in FIG. 5 is an exemplary system
and the same effect could be accomplished with a variety of
electromechanical driving mechanisms.
[0039] In another embodiment, the impactor could be designed to
operate using mechanical means whereby rotary motion is converted
to linear motion. FIG. 6 shows a sectional view of an instrument
used for driving devices into bony tissue. Cable driven cam 601 is
designed with a circular ramp 602 that interfaces with mating ramp
603 that is part of shuttle 605 that does not rotate due to pin 604
and slot in 603. Rotation of ramp 602 causes mating ramp 603 to
move in a reciprocating fashion which is transmitted to the active
element 606 which in turn imparts its energy to implant 608.
Shuttle 605 returns to its original position once ramps 602 and 603
have disengaged via the force applied by spring 607. This allows
active element 606 to return due to the force applied by spring
608. Those skilled in the art will appreciate this system shown in
FIG. 6 is an exemplary system and the same effect could be
accomplished with a variety of mechanisms that convert rotational
motion into reciprocating motion.
[0040] In all the embodiments described above, by altering the
pressure, current, rotational speed etc., the frequency and
amplitude of the impactor can be varied to enable the surgeon to
select settings that are appropriate for various tissue properties
(e.g.; cortical bone, cancellous bone, etc.)
[0041] In addition to the embodiments described above, the impactor
may have linear and rotational motion combined to create a
reciprocating twisting motion. By creating a reciprocating twisting
motion, devices may be driven in more securely into bony tissue,
thereby increasing the stability of the implanted device. The
amount of twisting motion may be varied based on the specific
design and dimensions of the device. FIG. 7 illustrates an
exemplary embodiment of a suture anchor device 702 having a pointed
distal tip 706 and a main shaft 704. Both the main shaft 704 and
the distal tip 706 have a twisted, helical-like configuration so
that the anchor will rotate as it is being driven into the bone by
an impactor having a reciprocating twisting motion.
[0042] The impaction method has advantages that are not limited to
a particular device design. For example, the implant may be
cylindrical, flat, or a have a variety of other cross sections.
Additionally the cross section may change along the length of the
implant. FIGS. 8A-8D show a variety of anchor devices that may be
useful in this application. The implant may be threaded or plain.
FIG. 8A shows an anchor with a tip 801 which has a triangular
pointed tip while the shank 802 has a substantially round cross
section. Shank 802 has a hole 803 that passes through the shank
allowing for attachment of a suture. FIG. 8B shows an anchor 810
having a rectangular cross section 812 resulting in a generally
flat configuration. FIG. 8C shows an anchor 816 with a cross
section generally described as a hollow tube and a suture S coupled
thereto. In the embodiment shown in FIG. 8C, wings or fingers 804
and 805 are active elements that deploy once the implant is
released from the delivery instrument. For example wings or fingers
804, 805 may be fabricated from a superelastic material like
Nitinol, spring temper stainless steel, a resilient polymer, or the
wings may be fabricated from a shape memory alloy, such that once
the anchor 816 is advanced from the delivery instrument and the
wings 804, 805 become unconstrained, they spring open, radially
outward. The wings help secure the anchor 816 into bone or other
tissue. In alternative embodiments, the wings 804, 805 may be
deformed into the flared radially outward position to help secure
the anchor into the bone. For example, a plunger may be advanced
into the center of the anchor thereby causing the wings 804, 805 to
flare outward. FIG. 8D shows an anchor 814 with a tip 814A and a
shank 814B having a generally X-shaped or cross-shaped cross
section that may inserted into bone using the techniques described
herein. In the embodiment shown, both the tip and the shank of
anchor 814 have a cross-shape cross-section, although in other
embodiments just the tip or just the shank may have a cross-shape.
shank 814B has a transverse hole through which a suture may be
threaded. Other means of attachment of the suture to the shank may
also be used.
[0043] Additionally, the implant and driver could be designed such
that a loaded implant constrained by the driver is placed at the
implantation site. Following placement, the implant recovers to a
pre-determined shape that enhances the anchoring of the implant in
the bony tissue. FIG. 9A shows a cylindrically shaped tubular
expandable anchor 906 in its loaded (constrained) condition. The
anchor comprises a plurality of axially oriented slits 905 that
form a plurality of axially oriented elements 901. Element 901 is
an active element that can be constrained to the profile of the non
active portion of the implant 902. Element 901 is replicated in a
circular pattern around the periphery of the implant 906. Conically
shaped nosecone 903 is distal to the end of the driver instrument
(not illustrated) while the shank is composed of active elements
and non active portions 901 and 902 respectively. The anchor 906 is
constrained in the delivery instrument. FIG. 9B shows the same
anchor 906 in its deployed configuration after being released and
unconstrained from the delivery instrument (not illustrated).
Elements 901 are self-expanding and thus have moved to an expanded
position to lock the anchor into the bony tissue. The elements 901
may be fabricated from self-expanding materials such as
superelastic nitinol, shape memory alloys, spring temper metals,
resilient polymers, or other resilient materials. Expansion element
901 causes a shortening of the overall anchor 906 length. In the
case where there is a preloaded suture or soft tissue fixation
element attached to 901, this shortening of the anchoring element
can be used as a tensioning means for the soft tissue fixation
element. Tensioning the soft tissue fixation would provide improved
coaptation of the soft tissue to the bone, and improve the repair.
The degree of foreshortening can be programmed into the device by
modifying one or a combination of the diameter of the distal
driving (pointed) element of 901, the length of the shaft of 901,
the diameter of the shaft of 901, and the specific design of the
cutouts 905 of 901.
[0044] Change in the implant after implantation could be based on
the expansion of the body of the anchor as shown in FIG. 9B or by
deployment of a fixation member from the body of the anchor as
shown in FIG. 8C. A combination of the expansion of the body of the
anchor and deployment of members from the body could also be used.
Expansion of the anchor could include mechanical means of expanding
the anchor from a first configuration to a second configuration
based on the malleability of the material or could be achieved
through the use of self-expanding or shape memory materials.
Deployment of fixation members may be achieved through various
means including shape memory and mechanical means. The implants may
include one or more sutures. The body of the implant may have holes
to allow for bony in-growth into or across the implant. The surface
of the implant may be textured or porous to allow for bone
in-growth to enhance long term anchoring of the implant. The
implant may be hollow to allow for bony in-growth within the
implant. An advantage of using a hollow implant is the entrapment
of the bone particles from the implantation site within the implant
during impaction.
[0045] An additional embodiment of the current invention is an
anchor configured to provide for fixation of tissue directly to the
bone adjacent to the anchor location. FIG. 10A shows the anchor in
a constrained configuration for delivery. Active elements 1001 are
constrained in this undeployed state in the distal end of the
driver (not illustrated) while nosecone 1002 may be exposed beyond
the distal end of the driver. FIG. 10B shows the same anchor after
it has been placed in bony tissue and the anchor has been deployed
from the delivery instrument so that it is unconstrained. Active
elements 1001 include a plurality of fingers that are axially
aligned with the longitudinal axis of the anchor when constrained,
and expand radially outward when unconstrained. The elements spread
out and allow for the capture of tissue between the fingers and the
bone or other tissue into which the anchor is disposed. Nosecone
1002 is affixed into bony tissue. By varying different parameters
of element 1001 which may include but are not limited to the
thickness, material, heat treating, and radius of curvature of the
deployed device, it will be possible to change the force of
apposition between the two tissues to be fixed. This design also
provides a degree of self-adjustment, allowing different tissue
thicknesses to be attached to underlying bone by a single device
without requiring a suture. By having a radius of curvature which
changes along the length of the active elements 1001 rather than a
constant radius of curvature, the device can be programmed to
provide approximately the same force of apposition for a range of
tissue thicknesses to the underlying bone with the same device
design. This allows a surgeon to use a single cartridge-loaded
device to place a number of anchors without device exchange.
[0046] Element 1001 may be made from a resorbable material such as
PLLA, collagen, highly crosslinked hyaluronic acid or the like.
While some of these materials may be processed and formed to
self-deploy as described above, many require secondary steps after
placement to deform them into a fixation shape. As an example, when
element 1001 is made from PLLA, a secondary step may include
application of heat to element 1001 to plastically deform it into
the desired final configuration. Once the heat source is removed,
the PLLA or other plastically deformable material remains in its
final shape and position. In other embodiments, the elements 1001
may be fabricated from self-expanding material like nitinol, spring
temper metals, or resilient polymers. The elements may also be made
from shape memory materials including metal alloys like nitinol or
shape memory polymers.
[0047] Additionally, elements 1001 and 1002 may be two separate
elements, with element 1001 being placed on top of the tissue to be
fixed, and 1002 being driven down through element 1001 and into the
underlying bone, fixing element 1001 and tissue to be fixed. In
this embodiment, element 1001 may be slotted as shown, or it may be
configured more like a washer or grommet shape.
[0048] In another embodiment both the portion of the anchor located
in bony tissue and the anchor portion in the adjacent tissue may be
configured with both elements being active.
[0049] In yet another embodiment, an anchor 1102 may be constructed
with a generally curved profile as shown in FIG. 11A. FIG. 11B
shows the anchor 1102 once it is loaded into a delivery system 1103
which constrains it to a generally straight profile within a
constraining sleeve 1101 that is part of the driver. As the anchor
1102 is deployed from the constraining sleeve 1101 into the bone,
it advances along a curved profile into the implantation site.
[0050] The implants described in this invention could be made from
metals like stainless steel, titanium, nitinol, etc., as well as
resorbable and non-resorbable polymers like PLLA, PEEK etc.
Implants may also be composites of two or more materials.
[0051] The method, devices and implants described above could be
used in a variety of applications including any application that
requires an implant to be anchored into bony tissue. For example,
placement of bone anchors in the humeral head for reattachment of a
torn rotator cuff, placement of bone anchors in the acetabular or
glenoid rim for reattachment of the torn labrum, placement of tacks
to attach labral tissue to the glenoid rim, placement of screws in
the vertebral bodies to attach cervical plates for spinal fusion,
placement of screws in small joint bones for stabilizing reduced
fractures, for treating stress urinary incontinence with a
bone-anchored pubovaginal sling, placement of plates in
cranio-facial reconstruction, fixation of fractures, etc.
[0052] While the device and implants are designed to be used
preferably in arthroscopic or minimally invasive procedures, they
could also be utilized in open or mini-open surgical
procedures.
[0053] The implants in this invention may be loaded into a delivery
device (e.g. a tube) which can be attached to the distal end of the
impactor. The loaded delivery device may be designed to be
introduced through a standard arthroscopic cannula and may contain
one or more implants, thereby enabling the implantation of multiple
implants without removing the delivery tool from the arthroscopic
field. The delivery device may have features like a slit to enable
manipulation of sutures attached to the implant. Alternatively, the
sutures may pass through the body of the delivery device and be
accessible through the proximal end of the cannula.
EXAMPLE 1
[0054] An impactor device was fabricated similar to the device
shown in FIG. 4. Air pressure was used to cycle a metal shuttle
that impacts the active member at the distal end of the impactor. A
cylindrical anchor (proximal diameter=1.5 mm, body diameter=2 mm)
with a conical distal tip (length of anchor=6 mm), was loaded into
the distal tip of the impactor. A #2 braided polyester suture was
attached to the anchor via a hole through the minor diameter of the
anchor. The distal tip of the active member had an OD of 2 mm and
ID of 1.5 mm, and a slit to allow for egress of the suture. The
impactor anchor assembly was connected to 90 psi compressed air.
The distal end of the assembly was placed in contact with fresh
cadaveric bovine cortical and cancellous bone. An air supply valve
was opened and the anchors were driven into the bony tissue with
ease. The pullout strength of the anchors were assessed
subjectively and indicated good fixation of the anchors. The
anchors were then carved out of the bony tissue and the surrounding
tissue was examined for gross damage. There was no sign of thermal
necrosis or other damage at the implantation site.
[0055] While the above detailed description and figures are a
complete description of the preferred embodiments of the invention,
various alternatives, modifications, and equivalents may be used.
The various features of the embodiments disclosed herein may be
combined or substituted with one another. Therefore, the above
description should not be taken as limiting in scope of the
invention which is defined by the appended claims.
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