US20200178955A1 - System and method for attaching soft tissue to bone - Google Patents

Abstract

Methods and devices for securing soft tissue to a rigid material such as bone are disclosed herein. A bone anchor is described that comprises a base and a top such that suture material may be compressed between surfaces on the base and top to secure the suture to the anchor. Also described is an inserter that can be used to insert the bone anchor into bone and move the anchor top relative to the anchor base to clamp suture material there between. Also described is a soft-tissue and bone piercing anchor and associated inserter. Methods are described that allow use of the bone anchors to provide multiple lengths of suture material to compress a large area of soft tissue against bone.

Description

RELATED APPLICATIONS
• This application is a continuation of U.S. application Ser. No. 14/725,348, filed May 29, 2015, which is a continuation of U.S. application Ser. No. 14/019,162, filed Sep. 5, 2013, now U.S. Pat. No. 9,044,226, which is a continuation of U.S. application Ser. No. 12/549,105, filed Aug. 27, 2009, now U.S. Pat. No. 8,529,601, which is a divisional of U.S. patent application Ser. No. 11/143,007, filed Jun. 1, 2005, now U.S. Pat. No. 7,585,311, which claims the benefit of U.S. Provisional Application Nos. 60/576,477, filed Jun. 2, 2004, 60/610,924, filed Sep. 17, 2004, and 60/634,174, filed Dec. 7, 2004, each of which is herein incorporated by reference in their entirety.
BACKGROUNDField of the Invention
• The present invention relates to medical devices and procedures. More particularly, the present invention relates to devices and methods for securing soft tissue to a rigid material such as bone.
Description of the Related Art
• There are several medical procedures where a surgeon needs to attach soft tissue such as tendons or other soft connective tissue to bone. One common example is a torn rotator cuff, where the supraspinatus tendon has separated from the humerus causing pain and loss of ability to elevate and externally rotate the arm. To repair a torn rotator cuff, typically a surgical procedure is used to suture the torn tendon to the bone using a variety of methods. Some procedures utilize large incisions and involve complete detachment of the deltoid muscle from the acromion. Small diameter holes are made in the bone for passing suture material through the bone to secure the tendon. Such large incision procedures are traumatic, causing prolonged pain and recovery time. Other procedures make small incisions and use arthroscopic techniques to attach sutures using either small diameter holes or a bone anchor. However, it is difficult to manipulate sutures within the surgical site using arthroscopic techniques. In addition, when knot tying is used to secure the suture to a bone anchor, it is difficult to properly adjust the tension of the suture while tightening the knot. Similarly, when the suture is attached to a bone anchor prior to insertion of the anchor into the bone, it is difficult to judge the appropriate point of attachment so that the suture will be properly tensioned upon insertion of the bone anchor into the bone. Thus, there is a need for methods and devices that allow easy arthroscopic attachment of a suture to a bone anchor after the anchor is inserted into the bone without the use of knot tying.
SUMMARY
• The present invention is particularly suited for use in arthroscopic procedures, including but not limited to rotator cuff surgery. More broadly, it can be used in any procedure in which it is desired to fix a suture to a solid object without tying of knots, including not only arthroscopic procedures, but also open surgery, and can be used for such diverse purposes as bladder neck suspension, tendon and ligament affixation or repair, prosthetic attachment, and rotator cuff repair.
• In one embodiment, the invention includes an anchor for securing a suture to bone, including an anchor base adapted to be securely fixed into the bone and a suture securing mechanism coupled to the anchor base and positioned proximally relative to the anchor base, the mechanism adapted to receive and secure a suture moved laterally into the mechanism.
• In another embodiment, the invention includes an anchor for securing a suture to bone, including an anchor base adapted to be securely fixed into the bone, a first surface coupled to the anchor base and positioned proximally relative to the anchor base, and a second surface coupled to the anchor base and positioned proximally relative to the anchor base, wherein the first and second surfaces are adapted to be relatively positioned in at least two configurations, one of the configurations such that a gap is present between the first and second surfaces so that the suture can be positioned between the first and second surfaces by moving the suture laterally into the gap, and the other of the configurations such that the first and second surfaces are in close proximity so that the suture can be securely clamped between the first and second surfaces.
• In another embodiment, the invention includes a method of attaching soft tissue to bone, including passing a length of suture over the soft tissue, inserting an anchor into the bone, and securing the length of suture to the anchor after the inserting without passing an end of the length of suture through any aperture in the anchor and without tying any knots.
• In another embodiment, the invention includes a method of attaching soft tissue to bone, including inserting a first anchor through the soft tissue, wherein the first anchor comprises a length of suture fixedly secured to the first anchor prior to insertion, inserting the first anchor into the bone, passing the length of suture over the soft tissue, and fixedly securing, after the passing, the length of suture to a second anchor.
• In another embodiment, the invention includes a method of attaching soft tissue to bone, the soft tissue comprising a first surface adjacent to the bone's surface and a second surface opposite the first surface, the method including inserting a first portion of a length of suture into the second surface of the soft tissue, passing a second portion of the length of suture over the second surface of the soft tissue, inserting a first anchor with no suture coupled thereto into the bone, and fixedly securing the length of suture to the inserted first anchor, with the proviso that no part of the first portion of the length of suture is passed out of the second surface of the soft tissue.
• In another embodiment, the invention includes a method of attaching soft tissue to bone, including inserting a first anchor with a length of suture pre-coupled thereto through the soft tissue, inserting the first anchor into the bone, inserting a second anchor with no suture coupled thereto into bone, passing the length of suture over the soft tissue, and fixedly securing the length of suture to the inserted second anchor.
• In another embodiment, the invention includes a method of attaching soft tissue to bone, the method including inserting a first, second, and third anchor into the bone, fixedly securing a first length of suture over the soft tissue to the first and second anchors, and fixedly securing a second length of suture over the soft tissue to the first and third anchors.
• In another embodiment, the invention includes an anchor for securing a suture to bone, the anchor including an anchor base adapted to be securely fixed into the bone, the anchor base comprising a first proximal surface and an anchor top, the anchor top comprising a distal member coupled to the anchor base and a first proximal member comprising a first distal surface, wherein the anchor top is adapted to couple to the anchor base in at least two configurations, one of the configurations such that the first distal surface is above the bone's surface when the anchor base is securely fixed into the bone, such that a suture can be freely passed between the first proximal and first distal surfaces above the bone's surface, and the other of the configurations such that the first distal surface is in close proximity to the first proximal surface, such that a suture can be securely clamped between the first proximal and first distal surfaces.
• In another embodiment, the invention includes an anchor for securing a suture to bone, the anchor including a substantially hollow cylinder comprising an open end and comprising a portion of its walls cut in such a manner so as to allow the cylinder to deform under stress and form lateral protrusions, a substantially pointed tip coupled to the cylinder opposite the open end, wherein the pointed tip is adapted to pierce the bone, and a suture receiver coupled to the pointed tip and positioned within the substantially hollow cylinder so that a suture may be attached to the suture receiver and extend through the cylinder and out of the open end.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 depicts attaching soft tissue to bone using a single bone anchor and a stitch.
• FIG. 2 depicts attaching soft tissue to bone using a two bone anchors with a suture stretched there between.
• FIGS. 3A-3C depict various geometries of bone anchors and suture patterns for attaching soft tissue to bone.
• FIGS. 4A-4D depicts the base of a two-part suture anchor that can be inserted into bone.
• FIGS. 5A-5C depicts the top of a two-part suture anchor.
• FIGS. 6A and 6B depict the suture anchor top ofFIGS. 5A-5C inserted into the suture anchor bottom ofFIGS. 4A-4D.
• FIGS. 7A and 7B depict a suture anchor inserter.
• FIG. 8 depicts components on a suture anchor inserter for attaching to bone and manipulating a suture anchor.
• FIGS. 9A-9E depicts manipulation of a suture anchor using a suture anchor inserter to insert the suture anchor into bone and attach suture material to the suture anchor.
• FIGS. 10A and 10B depict a piercing bone anchor in an un-deployed (FIG. 10A) and deployed (FIG. 10B) state.
• FIG. 11 depicts a piercing bone anchor tip.
• FIG. 12 depicts an anchor inserter for inserting a piercing bone anchor.
• FIG. 13 depicts the interface between a piercing bone anchor and an anchor inserter.
• FIG. 14 is a cut-away view of a bone anchor inserter.
• FIG. 15 depicts a safety switch mechanism for a bone anchor inserter.
• FIGS. 16A-16F depict a method for attaching soft-tissue to bone using a piercing bone anchor and a suture capturing anchor.
DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS
• In various embodiments, soft tissue may be attached to bone utilizing one or more bone anchors with suture attached thereto. As used herein, “suture” refers to any flexible structure that can be stretched between two or more anchors and includes, without limitation, traditional suture material, single or multiple stranded threads, or a mesh structure. In some embodiments, suture is passed over the top of the soft tissue so that the suture can press the soft tissue against the bone. In one embodiment, a length of suture is attached to a single bone anchor. One non-limiting example, depicted inFIG. 1, includes stitching thesuture10 to thesoft tissue12, such as by an incline mattress stitch, and then securing thesuture10 to thesingle bone anchor14 that is inserted into thebone16. However, in other embodiments, a length of suture is attached to multiple bone anchors. The use of multiple bone anchors increases the footprint over which the suture material presses the soft tissue against bone. One non-limiting example, depicted inFIG. 2, includes two bone anchors. Oneanchor20 is positioned in a medial location underneath thesoft tissue12 and asecond anchor22 is positioned lateral to thesoft tissue12. Thesuture10 is attached to both anchors.
• In one embodiment, thesuture10 is attached to thelateral bone anchor22 only after themedial bone anchor20 is inserted and thesuture10 is passed over thesoft tissue12. In one embodiment, thesuture10 is attached to themedial bone anchor20 prior to insertion of themedial bone anchor20. Thus, in this embodiment, the surgeon does not need to pass the suture through thesoft tissue12 from beneath thesoft tissue12. In one embodiment, the procedure involves inserting themedial bone anchor20 withsuture10 pre-attached through thesoft tissue12. Themedial bone anchor20 may then be moved laterally relative to thebone16 in order to pull thesoft tissue12 laterally relative to thebone16. After appropriate positioning of thesoft tissue12, themedial bone anchor20 may then be inserted into thebone16. Thelateral bone anchor22 may then be inserted into thebone16. Thesuture12 may then be passed over thesoft tissue12 and attached to thelateral bone anchor22. In some embodiments, alateral bone anchor22 is provided to whichsuture12 can be attached without tying any knots or without passing thesuture12 through any aperture in thelateral bone anchor22.
• In some embodiments, multiple anchors and multiple suture lengths may used to provide a wider area of pressure of the soft tissue against bone. For example, as depicted inFIG. 3A, three anchors are used with two lengths ofsuture26 and28. Alternatively, amesh structure29 may be stretched between the three anchors. In another example, as depicted inFIG. 3B, four anchors are used with two lengths of suture. In still another example, as depicted inFIG. 3C, four anchors are used with four lengths of suture. In some embodiments, the individual suture lengths may be part of a larger continuous suture. For example, inFIG. 3A, thesuture lengths26 and28 may be part of a larger length of suture such that thelengths26 and28 are joined atmedial bone anchor20. Those of skill in the art will appreciate that there are any number of anchor and suture geometries that can be used.
• In some embodiments, the medial bone anchors20 are designed so that they can be easily pierced through thesoft tissue12 andbone16. In some embodiments, the lateral bone anchors22 are designed so that they can easily capture suture material after insertion of the bone anchors22. Together, these design features provide a suturing system and method that provides an increased footprint of suture pressure against thesoft tissue12 and ease of implementation for a surgeon. For example, in some embodiments, the entire procedure may be done arthroscopically, with the surgeon needing only to insert themedial bone anchor20 with suture optionally pre-attached through a first port, insert thelateral anchor22 through a second port, pass the suture over thesoft tissue12 by capturing it from within the second port, and securing the suture to thelateral anchor22. Accordingly, described below are certain embodiments of anchors adapted to capture suture material and anchors adapted to easily pierce through soft tissue and bone.
Suture Capturing Anchor
• One embodiment is a bone anchor that allows easy capturing and securing of a suture after the bone anchor is inserted into the bone. In one embodiment, the bone anchor includes a suture securing mechanism positioned on the proximal end of the bone anchor (i.e., the end nearest the surface of the bone and the surgeon). In one embodiment, the suture securing mechanism allows a suture to be moved laterally into the mechanism. By “laterally,” it is meant that the suture can be moved into the mechanism by moving the suture in a direction that is generally perpendicular to the axis of the suture. In other words, the suture can be moved into the mechanism without threading an end of the suture into the mechanism. In one embodiment, the suture can be fixedly secured within the mechanism without tying any knots. By “fixedly secured,” it is meant that the suture within the securing mechanism cannot be easily moved relative to the bone anchor.
• One embodiment is a bone anchor that allows easy attachment of suture material by clamping the suture material between two surfaces on the bone anchor. The bone anchor may be configured such that the bone anchor is inserted into the bone without the suture material attached. The two surfaces of the suture securing mechanism may be spaced apart so as to form a gap between the surfaces. The suture material may be passed between the two surfaces and tensioned as desired followed by clamping of the two surfaces together, thereby clamping the suture material there between.
• In one embodiment, the bone anchor consists of two parts: an anchor base and an anchor top. The anchor base may be designed to be inserted into a hole in the bone with a proximal surface facing up. The anchor top may be coupled to the anchor base via a distal member. A proximal member on the anchor top may have a distal surface facing down toward the proximal surface on the anchor base. The coupling of the anchor top to the anchor base may be such that the anchor top can move relative to the anchor base such that it can be positioned in one configuration where there is space between the proximal surface on the anchor base and the distal surface on the proximal member of the anchor top. In another configuration, the proximal member of the anchor top may be position such that there is very little space, if any, between the proximal surface on the anchor base and the distal surface on the proximal member of the anchor top. Thus, in the first configuration, suture material may be easily passed between the two surfaces and tensioned as desired. In the second configuration, the suture material may be clamped between the two surfaces such that the suture is secured to the bone anchor.
• One embodiment of ananchor base100 is depicted inFIGS. 4A through 4D.FIG. 4A is a perspective view showing theside101 andbottom102 of theanchor base100. Thebottom102 of theanchor base100 may advantageously be tapered to facilitate insertion of theanchor base100 into bone. In some embodiments, a hole is predrilled into the bone to facilitate insertion of theanchor base100. In other embodiments, theanchor base100 is forced directly into the bone, thereby creating the hole. Thesides101 of theanchor base100 comprisethreads104 so that theanchor base100 may be inserted into bone using a screwing action. In some embodiments, theanchor base100 may be tapped to start thethreads104 into the bone followed by screwing theanchor base100 into the bone. When the hole in the bone is pre-drilled, the hole is advantageously drilled with a diameter smaller than the diameter ofthreads104 so that the threads engage the bone through the sides of the hole. It will be appreciated that means other than threads may be used to secure theanchor base100 to bone. For example, angled protrusions may be used that provide greater resistance to removal of theanchor base100 than to insertion. The protrusions may be static or deployable once the anchor is inserted.
• The top ofanchor base100 preferably includes astructure106 for facilitating the driving or screwing of the base100 into the bone. In the illustrated embodiment, this comprises ahex nut structure106 that facilitates engagement with a hex nut driver for screwing theanchor base100 into the bone. It will be appreciated that other structures known in the art for engaging tools used for screwing action may be used instead ofhex nut structure106, and that this structure can be indented into or extending out from the top of theanchor base100, or can alternatively be formed on the sides of theanchor base100.
• With reference toFIG. 4B, which is a perspective view of the top and side ofanchor base100, the top (proximal end) comprises ahole108 in the center for receiving the anchor top, which is described below. The top ofanchor base100 also contains a suture gripping structure such as acircular groove110 that may be concentric withhole108. Because ofgroove110, the proximal surface ofanchor base100 is not flat and comprisestop surfaces112 and114,bottom surface116, andside surfaces118 and120. In some embodiments, some or all of these surfaces may be textured such as with a scallop shape or grooves so as to inhibit movement of suture material pressed against the surfaces. Although a grooved surface is illustrated, it will be appreciated that other shapes for the proximal surface ofanchor base100 are also contemplated, including multiple concentric grooves, a series of protruding ridges, a “vee” shaped channel, or any other suitable structure that permits a suture to be securely locked against the top or proximal end of theanchor base100.
• Hole108 inanchor base100 is an opening into a central (“axial”) bore into theanchor base100. The sides of the central bore preferably include structures for gripping something inserted into the central bore, such asratchet structures122.FIG. 4C show acentral ratchet bushing126 that fits within the central bore and contains theratchet structures122. In the embodiment ofFIG. 4C, theratchet structures122 are constructed by cutting U shaped cuts intobushing126. The U shaped cuts then define tabs that make up theratchet structures122. It will be appreciated that other shapes and methods for making ratchet structures may be used. The purpose ofratchet bushing126 is to receive the anchor top and secure it to theanchor base100. It will be appreciated that other methods of securing the anchor top to theanchor base100 may be used, such as a frictional fit or threading. Furthermore, the anchor top may be coupled to theanchor base100 using means other thanhole108 andbushing126. For example, the anchor top may be coupled via structures at the perimeter rather than the center or by a hinge.
• FIG. 4D depicts a cross section through the center ofanchor base100. This view illustratescentral bore130 andgroove110. Theproximal surfaces112,114,116,118, and120 are also apparent. Central bore130 preferably does not extend all the way through theanchor base100. Instead, asmaller bore132 is present at thedistal end102 of theanchor base100.Smaller bore132 is used to receive a wire connected to an anchor inserter. It will be appreciated that other structures thanbore132 may be used for attaching the wire and that other means than a wire may be used to secure the anchor to the anchor inserter.
• FIGS. 5A through 5C illustrate one embodiment of ananchor top200.FIG. 5A provides a perspective view of the side and top of theanchor top200 andFIG. 5B provides a perspective view of the side and bottom of theanchor top200. Anchor top200 has two members, adistal member202 and aproximal member204. Thedistal member202 comprises an elongated shaft, the longitudinal direction of which shall be considered to run along the axis of thedistal member202. A series of grooves or other mating or locking surfaces orstructures206 exist along a portion of the outside surface of the shaft. Thedistal member202 is designed to be inserted into thecentral bore130 of theanchor base100. Theratchet structures122 in theanchor base100 engagegrooves206 to couple theanchor top200 to theanchor base100. Theratchet structures122 are oriented such that thedistal member202 can be easily moved in the distal direction incentral bore130 with theratchet structures122 snapping into thegrooves206 as thedistal member202 is moved downward. However, when theratchet structures122 are snapped intogrooves206, proximal movement ofdistal member202 is inhibited. Thus, theanchor top200 may be ratcheted down intoanchor base100. Because theratchet structures122 exist along substantially the entire surface of the central bore130 (seeFIG. 4C), theanchor top200 may be coupled to theanchor base100 in several positions. In other words, in one embodiment theanchor top200 need not be ratcheted into theanchor base100 as far as it will go for it to be secured to theanchor base100.
• Theproximal member204 ofanchor top200 is generally cylindrical in shape with a diameter larger thandistal member202. Ahole208 may advantageously be provided in the center ofproximal member204. With reference toFIG. 5B, the bottom ofdistal member202 also contains ahole210.Holes208 and210 open into a central bore through theanchor top200. This central bore allows the wire referred to above to extend through theanchor top200 to be secured to bore132 in theanchor bottom100, thus allowing theanchor bottom100 to be attached to an anchor inserter while still allowinganchor top200 to be ratchet intoanchor bottom100.FIG. 5B also illustrates thatproximal member204 contains agroove212 in its distal surface. Thus, the distal surface ofproximal member204 is not flat and comprises distally facingsurfaces214 and216 andside facing surfaces218 and220. In some embodiments, some or all of these surfaces may be textured such as with a scallop shape or grooves so as to inhibit movement of suture material pressed against the surfaces. In some embodiments, texturing in the distal surfaces ofproximal member204 match texturing in the proximal surfaces ofanchor base100. It will be appreciated that the illustrated embodiments represent only one possibility; thus, other shapes for the distal surface ofproximal member204 may also be used.FIG. 5C depicts a cross section through the center ofanchor top200. In this figure, thecentral bore226 is depicted as aresurfaces214,216,218, and220 andgrooves206.
• FIGS. 6A and 6B depict cross sections showing how theanchor top200 may be coupled to anchor base100 to form thecomplete anchor300. InFIG. 6A, theanchor top200 is coupled to anchor base100 with theproximal member204 separated from theanchor base100. Theanchor top200 is secured to anchor base100 bydistal member202 extending intocentral bore130 of theanchor base100. Thedistal member202 is secured by ratchet structures (not shown) engaginggrooves206 indistal member202. Central bore226 inanchor top200 andcentral bore130 inanchor base100 allow a wire to extend into the top of theanchor300 and be secured to bore132. Alternatively, the wire may be secured at other locations withincentral bore130. Thus the wire, which can be coupled to an anchor inserter, can hold theentire anchor assembly300 and still allowanchor top200 to move relative to anchorbase100 and the wire.
• FIG. 6B depicts theanchor assembly300 with thedistal member202 of anchor top200 ratcheted all the way intocentral bore130 inanchor base100. In this configuration, it can be seen thatproximal surfaces112,114,116,118, and120 of theanchor base100 anddistal surfaces214,216,218, and220 of theproximal member204 ofanchor top200form passageways302 and304. The size ofpassageways302 and304 are advantageously such that when a suture passes through them, it will be compressed so that it is securely attached to theanchor300.
• Another embodiment of the present invention is an inserter designed to insert and manipulate an anchor such as described inFIGS. 1-3. Onesuch inserter400 is depicted inFIGS. 7A and 7B.Inserter400 comprises ahandle402 and anouter tube404. As depicted inFIG. 7A, thehandle402 comprises acover403.FIG. 7B depicts theinserter400 withcover403 removed. Not depicted inFIGS. 7A and 7B are an inner tube disposed insideouter tube404 and a wire disposed within the inner tube. As will be described in more detail below, the inner and outer tubes may be used to manipulate ananchor300 such as that described inFIGS. 4-6. The wire may be used to couple theinserter400 to theanchor300 as described above.Inserter400 also comprises anouter tube manipulator406 and awire manipulator408.Outer tube manipulator406 comprisesrelease button410.Outer tube manipulator406 is securely attached toouter tube404.Outer tube manipulator406 may move longitudinally relative to handle402 and the inner tube whenrelease button410 is pressed. Thus, whenouter tube manipulator406 is moved,outer tube404 also moves.
• Wire manipulator408 compriseswire grabber410 to which the wire is attached. The wire extends fromwire grabber410, throughhandle402, and then through the inner tube. In one embodiment,wire manipulator408 also comprises arelease button412. Whenrelease button412 is pressed, thewire manipulator408 may be pressed into thehandle402 to contact and thus provide additional tension on the wire. When in use, the additional tension causes theanchor base100 to mover relative toinserter400. When enough tension is provided to the wire bywire manipulator408, the wire may break free from theanchor300 at its attachment point inbore132 or at some other predetermined location along the wire. It will be appreciated that any suitable breakable attachment means may be used for securing the wire to theanchor300. For example, the wire may be frictionally secured intobore132 or it may welded to theanchor base100 using a weld that is weaker than the wire itself or a portion of the wire where breaking is desired may be weakened. In one embodiment, the wire is notched so as to create a weaker region in the wire that will break upon application of suitable force.
• Thetip414 ofouter tube404 is depicted in more detail along withinner tube420,wire422, andanchor300 inFIG. 8. The end ofouter tube404 may comprise a hexnut driver structure424 for receiving thehex nut structure106 ofanchor base100. Of course, any other suitable engagement structure can be provided on theinserter400 and theanchor base100 in order to facilitate placement of theanchor base100.Wire422 extends out ofinner tube420 and into the central bore in theanchor top200 to attach to anchor base100 as described above. In some advantageous embodiments, the wire length and tension is adjusted such that theproximal member204 ofanchor top200 buts against theend426 ofinner tube420.
• FIGS. 9A through 9E depict howinserter400 andanchor300 may be used to insert theanchor300 into bone and attach a suture to it.FIG. 9A depicts the configuration for inserting theanchor300 into bone.Outer tube404 and outer tube manipulator406 (seeFIGS. 7A and 7B) are positioned relative toinner tube420 and handle402 (seeFIGS. 7 and 8) so that theouter tube404 engageshex nut structure106 in theanchor base100. It is advantageous in this configuration for theanchor top200 to be in a position relative to theanchor base100 such as depicted inFIG. 6A. In the configuration ofFIG. 9A, a surgeon may then screw theanchor base100 into bone by twistinghandle402 of inserter400 (seeFIGS. 7A and 7B).
• After theanchor base100 is inserted into the bone, theouter tube404 may be slid backward relative to theinner tube420 and handle402 to expose theanchor top200 such as inFIG. 9B. One or more lengths ofsuture600 may then be placed in the space between thedistal surface602 of theproximal member204 ofanchor top200 and theproximal surface604 of theanchor base100 by moving the suture laterally into the space as depicted inFIG. 9C. Thesuture600 may be manually tensioned as desired. In some embodiments, tensioning of thesuture600 is aided by pulling thesuture600 against thedistal member202 of theanchor top200.
• After appropriate tensioning ofsuture600,wire manipulator408 may be pressed to tension the wire, causing thehandle402 of theinserter400 and theinner tube420 to be pulled down towards theanchor base100 so thatinner tube420 ratchets theanchor top200 down into theanchor bottom100 as depicted inFIG. 9D. As theanchor top200 is pushed axially down,suture600 will be clamped between thedistal surface602 of theproximal member204 ofanchor top200 and theproximal surface604 of the anchor base100 (see alsoFIG. 9C). The clamping will force the suture to be compressed within thepassageways302 and304 depicted inFIG. 6B and thus be secured to anchor300. The fit between theanchor top200 and theanchor base100 in the clamping region is such that thesuture600 is firmly gripped, but is not cut, when it is clamped in place. Appropriate edges that may contact the suture are preferably beveled or rounded to avoid damage to the suture. Afteranchor top200 is ratcheted sufficiently intoanchor base100, wire manipulator408 (seeFIGS. 7A and 7B) ininserter400 may be compressed further to further tension wire422 (seeFIG. 8) such thatwire422 breaks free from its attachment to anchorbase100, thus leaving theanchor300 free frominserter400 withsuture600 securely attached as depicted inFIG. 9E.
• Although a particular inserter device for inserting and manipulatinganchor300 has been described, it should be understood that other inserter designs may be used for manipulating the parts ofanchor300 described above to insert the anchor into bone and secure suture material to the anchor. For example, it may be possible to use separate tools for inserting the anchor and securing the suture material. In addition, in alternative embodiments, theanchor base100 may be connected to theanchor top200 throughout the procedure, or the anchor base may be separately inserted into the bone, and the anchor top can be attached thereafter by axially sliding the distal end of theanchor top200 into thehole108 in theanchor base100.
• It will be appreciated by those of skill in the art that theanchor300 andinserter400 provide a system for easy attachment of a suture to bone. Theanchor300 may be inserted into bone with minimal disruption of surrounding tissue. Only an access route having the diameter of theouter tube404 and theanchor base100 is required. Furthermore, the suture can be securely attached to theanchor300 and tensioned as desired without having to insert additional instrumentation into the site or without performing any cumbersome attachment maneuvers such as knot tying. It should also be appreciated that the general principle illustrated by this system of inserting an anchor into bone without having suture material pre-attached and then attaching suture to the anchor without tying any knots may be implemented using any appropriate system other than the specific embodiments depicted inFIGS. 4-9.
Tissue and Bone Piercing Anchor
• One embodiment is a bone anchor adapted for piercing through the soft tissue and into underlying bone. In one embodiment, the suture material may be pre-attached to the piercing bone anchor so that after implantation, a suture passes from the bone anchor through to the top of the soft tissue for easy passing over the soft tissue. In one embodiment, the piercing bone anchor has two configurations, a first configuration having a small diameter for easy piercing through soft tissue and bone and a second deployed configuration where structures such as protrusions are deployed to prevent the bone anchor from being easily removed from the bone.
• In one embodiment, the anchor includes a substantially hollow cylinder having a portion of its walls cut in such a manner so as to allow the cylinder to deform under axial stress and form lateral protrusions. The lateral protrusions may thus prevent the anchor from being easily removed from the bone after deployment. In one embodiment, the anchor comprises a pointed tip coupled to the hollow cylinder for piercing the soft tissue and bone. In one embodiment, suture is pre-attached to the pointed tip inside of the hollow cylinder. In other embodiments, suture is pre-attached at other locations on the piercing anchor, such as at the proximal end of the hollow cylinder.
• One embodiment of a deployable piercing anchor is depicted inFIGS. 10A and 10B. InFIG. 10A, the anchor is depicted in a pre-deployed state. The anchor includes a substantiallyhollow cylinder650 with a plurality ofcuts652 in the side of thecylinder650. Thecylinder650 is open on oneend654. On the other end, apointed tip656 is disposed, allowing the anchor to pierce through soft tissue and bone. InFIG. 10B, the anchor is depicted in a deployed state. Stress is applied in an axial direction such that thecylinder650 collapses alongcuts652 so as to form twolateral wings660. Thelateral wings660 prevent the anchor from being removed from the bone.Hinges662 connect one end of each wing to either the top or the bottom parts of anchor body. These hinges deform and fold, in the plane tangent to the anchor body at that point when the anchor is deployed. A strip ofmaterial664 connects the top and bottom wing on each side of the anchor body, and serves as a hinge between the two as well as aiding in alignment of the wings during deformation. The tips of the wings adjacent to the connectingstrip664 utilize rollingedges666, which ensure uniform alignment and smooth transition during deformation. Those of skill in the art will appreciate that any number of geometries of cuts in thecylinder650 may be utilized to create a deformable structure that will produce lateral protrusions upon exposure to stress.
• In some embodiments, structures may be positioned within thecylinder650 for attaching sutures and engaging with an anchor inserter. In one embodiment, such structures are coupled to theanchor tip656 within thecylinder650.FIG. 11 depicts one such embodiment. Attached to thetip656 is astructure670 through which there is anaperture672. Thestructure670 may be adapted to engage the inner surface ofcylinder650 for attaching thetip656 to thecylinder650. The attachment mechanism may be by forced fit, frictional fit, threads, welding, adhesive, or any other suitable means. Suture material may be threaded through theaperture672 in order to attach the suture to the anchor. The suture material may be secured to thetip656 by tying the suture aroundstructure670, tying a knot in the end of the suture that prevents it from being pulled through theaperture672, clamping the suture between thestructure670 and the inside of thecylinder650, adhering the suture to structure670 by welding or adhesive, or any other suitable means. In one embodiment, the suture material is attached to the anchor attip656 prior to use of the anchor.
• An anchorinserter attachment structure674 may also be coupled to thetip656. Thisstructure674 may couple to an anchor inserter through a wire or any other suitable means. The attachment between the anchor inserter and the anchor at this point may be used to apply axial stress to the anchor for deploying the anchor as described above. The attachment at this point may also serve to keep the anchor attached to the inserter prior to deployment.
• One embodiment of an anchor inserter suitable for use with the above-described anchor is depicted inFIG. 12. The anchor inserter comprises agrasping handle700 to which is attached anouter sleeve702 which is fixed relative to thehandle700. The piercinganchor704 is disposed at the end of thesleeve702. Adeployment lever706 may be pressed by a user to deploy and detach theanchor704 as described below. Asafety switch708 may be provided to prevent theanchor704 from being deployed prematurely. Aspool710 may be provided at the proximal end of thehandle700 for holding excess suture. Alid712 may be provided for gaining access to the inner components of the inserter.
• FIG. 13 depicts theanchor704 coupled to the inserter. As described above, theanchor704 comprises ahollow cylinder650 with cuts in the sides and apointed tip656. Furthermore, as depicted inFIG. 11, asuture receiving aperture672 and aninserter attachment structure674 are attached to thepointed tip656 within thecylinder650. Theouter sleeve702 of the inserter may fit over theopen end654 of thecylinder650 or be flush with theopen end654. Theouter sleeve702 may thus hold the top part of theanchor704 steady during insertion. In an alternative embodiment, theouter sleeve702 may fit over the length of thecylinder650 to prevent thecylinder650 from deforming while it is being inserted into bone. In this alternative embodiment, theouter sleeve702 may be retracted prior to deployment of the anchor. Aninner tube720 may be positioned within theouter sleeve702 and thehollow cylinder650 and contact the top surface of the anchor tip656 (seeFIG. 11). Theinner tube720 provides structural reinforcement of theanchor704 and pushes against the tip of theanchor704 while it is being driven into bone or tissue. Theinner tube720 may be fixed relative to thehandle712 andouter sleeve702 during insertion, however, during deployment of theanchor704, theinner tube720 may be released by switchingsafety switch708 so that theinner tube720 can move axially relative to theouter sleeve702 while theanchor cylinder650 collapses. A wire may be positioned inside of theinner tube720 running from within thehandle712 through theinner tube720 to theanchor704 and attached to the anchorinserter attachment structure674. During deployment, thelever704 may be pressed to pull the wire axially towards thehandle700. The axially movement of the wire forces theanchor704 to press againstouter sleeve702 and stresses thecylinder650, causing it to deform and deploy. During collapse of thecylinder650, theinner tube720 will also move in an axial direction toward thehandle700. Upon further stress on the wire, the wire may break free from the anchorinserter attachment structure674, releasing the inserter from theanchor704. Suture material may run from the inside ofhandle700 through theinner tube720 to attach to theanchor704 through aperture672 (seeFIG. 11). Upon detachment of the anchor inserter from theanchor704, the inserter may be withdrawn, leaving the inserted and deployed anchor with suture coming out of theopen end654 of thecylinder650. The suture will still be coupled to the inserter through theinner tube720, handle700, and aroundspool710. Those of skill in the art will appreciate other inserters and mechanisms that may be used to insert and deploy the piercing anchors described herein. For example, rather then axially stressing theanchor704 by pulling thetip656 in an proximal direction, thecylinder650 may be pushed in a distal direction to deform thecylinder650.
• FIG. 14 is a cut-away view of thehandle700, showing the inner workings of the anchor inserter. The suture material attached to a piercing anchor at the tip of the inserter may pass through the central bore of theinner tube720 and through abore750 in thehandle700. The suture material may then pass through ahole752 in the end of thehandle700 and be wrapped around thespool710, which may be integral with thehandle700. The wire attached to the anchorinserter attachment structure674 in the anchor may also pass through the central bore of theinner tube720 and may then proceed around apulley754 and attach securely to thehandle700 atpoint756. Thepulley754 may be attached to thelever706. When thelever706 is pressed down, thepulley754 will move toward the back end of thehandle700, causing the wire attached to the anchor to retract. Because of the use ofpulley754, the wire will retract twice the distance as thepulley754 moves.
• Thesafety switch708 may be used to prevent thelever706 from being pressed and prevent theinner tube720 from moving unless thesafety switch708 is in the correct position. The safety mechanism operates via adrum760 disposed within thehandle700 to which thesafety switch708 is attached. Moving thesafety switch708 rotates thedrum760 within thehandle700.FIG. 15 shows thedrum760 andsafety switch708 mechanism in more detail. Theinner tube720 passes through a central bore in thedrum760. On the other side of thedrum760, theinner tube720 is attached to astopper762. Thestopper762 has a through-hole764 to permit passage of the deployment wire and suture. Thestopper762 may be positioned within acavity766 in the end of thedrum760. A second similarly shaped cavity may be disposed within thehandle700. Thestopper762 and attachedinner tube720 may only be allowed to move axially relative to thehandle700 when thesafety switch708 and drum760 is rotated so that thecavity766 in thedrum760 is aligned with the matching cavity in thehandle700. When the cavities are aligned, thestopper762 is allowed to move from thecavity766 to the cavity in thehandle700, thus allowing theinner tube720 to move axially and the anchor to be deployed.
• Additionally, thedrum760 comprises agroove768. A spring-loaded sliding pin770 (seeFIG. 14) may be coupled to thelever706. Thelever706 can only be moved when thedrum760 and switch708 are rotated so thatgroove768 is aligned with thepin770. Thus, both thestopper764 and thepin770 prevent the anchor from being deployed unless theswitch708 is in the correct position.
• Those of skill in the art will appreciate other mechanisms that could be used for deploying a deployable anchor and providing safety mechanisms to prevent premature deployment.
Example Using a Piercing Anchor and a Suture Capturing Anchor
• The above-described anchors may be used in a surgical procedure for attaching soft tissue to bone. One example of such a procedure is depicted inFIGS. 16A through 16F. InFIG. 16A, the piercinganchor800 attached to ananchor inserter802 as described above is pierced throughsoft tissue804 that has become detached fromunderlying bone806. InFIG. 16B, theanchor inserter802 is moved laterally relative to thebone806 so as to stretch thesoft tissue804 laterally relative to thebone806. Once thesoft tissue804 has been stretched to the desired position, theanchor800 is inserted into thebone806 and theanchor800 is deployed as described above and theinserter802 is detached from theanchor800, leaving asuture808 attached to theanchor800 and extending through thesoft tissue804. Theanchor800 may be inserted intobone806 by tapping on theinserter802 with a hammer or by any other suitable means of applying axial force.FIG. 16C depicts the deployedanchor800 with attachedsuture808. Thesuture808 will extend into theinserter802.
• Next, as depicted inFIG. 16D, asuture capturing anchor810 is inserted into thebone806 using theinserter812 as described above. InFIG. 16E, theinserter812 is then retracted to expose the suture capturing mechanism. Thesuture808 is then passed over thesoft tissue804 and laterally moved into the suture capturing mechanism and tensioned. Finally, as depicted inFIG. 16F, the suture capturing mechanism is deployed to capture thesuture808, theanchor inserter812 is detached from theanchor810, and thesuture808 is cut to detach it from thesuture inserter802. The result is a length ofsuture808 between the bone anchors808 and810 that presses thesoft tissue804 against thebone806. Multiple anchors and sutures may be used to produce geometries such as depicted inFIGS. 2 and 3 and variations thereof.
• It will be appreciated that there are numerous stitches, suture threading patterns, and anchor patterns that may be used to secure soft tissue to bone by the methods and devices described herein. These variations as well as variations in the design of the above described anchor devices and inserter devices are within the scope of the present disclosure.
Methods of Attaching Soft Tissue to Bone
• Various embodiments include methods for attaching soft tissue to bone. In some embodiments, the methods include using the bone anchors described above. In one embodiment, a bone anchor is inserted into the bone and then a length of suture is passed over the soft tissue and secured to the anchor after inserting the anchor without tying any knots or without passing the suture through an aperture in the anchor. In some embodiments, the suture is secured to the anchor by laterally moving it into a securing mechanism. In one embodiment, securing the suture to the anchor includes clamping the suture between at least two surfaces on the anchor. In one embodiment, the anchor is not inserted further into the bone after securing the suture to it.
• In another embodiment, a first anchor with a suture pre-attached is inserted through the soft tissue and into the bone. The suture may then be passed over the soft tissue and fixedly secured to a second bone anchor. In one embodiment, the first anchor is inserted by directly piercing the soft tissue and the bone. In one embodiment, lateral protrusion may be deployed on the first anchor to prevent the first anchor from being removed. In one embodiment, the suture may be coupled to the second bone anchor prior to insertion and then fixedly secured after insertion. In this context, “coupled” means that the suture is attached to the bone anchor but not fixedly secured, such that the suture can move to some extent relative to the bone anchor. In an alternative embodiment, the suture is not coupled to the second bone anchor during its insertion.
• In another embodiment, a first portion of suture is inserted into the proximal surface of the soft tissue. A second portion of the suture (e.g., the portion proximal to the inserted portion) is then passed over the proximal surface of the soft tissue and fixedly secured to a bone anchor. In one embodiment, the procedure may be performed without passing the first portion of the suture back out of the proximal surface of the soft tissue. In one embodiment, this result is accomplished by the first portion of the suture being attached to an anchor that is inserted through the soft tissue and into bone.
• One embodiment includes inserting a first anchor with a pre-coupled suture through soft tissue and into bone. The suture may then be passed over the soft tissue and fixedly secured to a second anchor. In one embodiment, the pre-coupled suture is fixedly secured to the first anchor prior to insertion. In an alternative embodiment, the pre-coupled suture can move relative to the first anchor prior to insertion and is fixedly secured after insertion.
• In another embodiment, multiple lengths of suture are attached to multiple anchors. In one embodiment at least three anchors are inserted into bone. A first length of suture may be secured between a first and second anchor and a second length of suture may be secured between the first and a third anchor. In one embodiment, the first anchor is positioned beneath the soft tissue and the second and third anchors are positioned laterally to the soft tissue. In an alternative embodiment, the first anchor is positioned laterally to the soft tissue and the second and third anchors are positioned beneath the soft tissue. In some embodiments, the lengths of suture are fixedly secured to the anchor(s) positioned beneath the soft tissue prior to insertion of those anchor(s). In one embodiment, the different lengths of suture may be tensioned separately.
• In various embodiments, prior to fixedly securing suture to a bone anchor, it can be tensioned. In one embodiment, tensioning is accomplished by manually pulling on the suture such as by a surgeon grasping the suture using an appropriate instrument and then pulling. In one embodiment, the suture may be pressed against the bone anchor to provide leverage for pulling. For example, the suture may be wrapped partly around a proximal portion of the anchor prior to pulling.
• Although the invention has been described with reference to embodiments and examples, it should be understood that numerous and various modifications can be made without departing from the spirit of the invention. Accordingly, the invention is limited only by the following claims.

Claims (11)

What is claimed is:

1. A suture anchor, comprising:

an outer anchor member comprising an outer side portion, a proximal end comprising a hole, and a central bore, wherein the hole opens into the central bore;

angled protrusions on the outer side portion configured to provide greater resistance to removal of the outer anchor member than to insertion; and

a bushing disposed within the central bore, wherein the bushing comprises a side portion having a plurality of ratchet structures.

2. The anchor ofclaim 1, wherein the outer anchor member is tapered at its distal end.

3. The anchor ofclaim 1, wherein the ratchet structures comprise U shaped cuts in the bushing to define tabs on the side portion of the bushing.

4. The anchor ofclaim 1, wherein the outer anchor member comprises a second bore at the distal end of the outer anchor member having a smaller diameter than the central bore.

5. The anchor ofclaim 1, wherein the anchor comprises a plurality of grooves into which the ratchet structures are configured to engage.

6. The anchor ofclaim 1, wherein the anchor is configured to be driven directly into bone.

7. The anchor ofclaim 1, comprising a suture securing mechanism.

8. A suture anchor-inserter assembly, comprising the suture anchor ofclaim 1 coupled to an inserter, the inserter comprising an outer tube, an inner member, and a handle.

9. The assembly ofclaim 8, wherein the outer tube and inner member are movable longitudinally relative to each other.

10. The assembly ofclaim 8, wherein the distal tip of the outer tube comprises an anchor engagement structure engaging the proximal end of the outer anchor member.

11. The assembly ofclaim 8, comprising suture coupled to the suture anchor.

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