Abstract:
An inserter for simultaneously creating a bone tunnel and delivering an all-suture anchor. The inserter is capable of inserting into the bone tunnel a soft, non-rigid suture anchor by forming a bone tunnel (to serve as an anchor receiving area) and simultaneously, in one motion, delivering the soft suture anchor to the anchor receiving area. The soft suture anchor is made entirely of non-rigid materials including, but not limited to, filaments of soft, malleable materials such as those commonly used to make sutures. The inserter is able to not only carry or deliver the all-suture anchor into a bony substrate, but is able to do so without having to preform a hole in the bone.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to all-suture anchors made entirely of suture material and inserters for inserting such anchors into tissue at a surgical site. More particularly, this invention relates to devices for percutaneously inserting or driving all-suture anchors into a surgical site. 
     2. Description of the Prior Art 
     Anchors are commonly employed during surgical procedures to provide a reliable attachment location for sutures in or against a substrate, those attached sutures then being used to capture and retain other objects, such as soft tissue or bone. The substrate may be bony tissue or soft tissue such as ligaments, tendons, etc. In the case of bony tissue, suture anchors are generally inserted into and retained in a pre-formed hole in the bone, so that suture extends from the anchor out of the hole. In the case of soft tissue, suture anchors generally are placed on a side of the soft tissue such that suture extends through a hole in the tissue to extend beyond the soft tissue on a side opposite the anchor. 
     Soft suture anchors have recently been developed from filaments of suture material which are retained within pre-formed bone holes by being deformable to increase their diameter to a size greater than that of the bone hole, to thereby reside within the cancellous bone and under the bone cortex. One such suture anchor is disclosed in U.S. Patent Publication 2012/0290004, published Nov. 15, 2012, assigned to the assignee hereof and incorporated by reference herein. Since soft anchors are commonly made entirely of suture materials, they are sometimes called “all-suture” anchors. 
     The necessity for a pre-formed hole when using all-suture anchors in bone requires extra instrumentation and extra steps in the process of implanting soft suture anchors. The extra steps involve making a pilot hole in the bone with either a drill, a broach or a punch and then removing the instrument. The hole thus created is an anchor receiving area, but once this space is created the instrument must be removed to allow the all-suture anchor to be inserted by an inserter and then deployed. While so-called “self-punching” inserters, drivers or applicators have been known to be used with some suture anchors which are hard enough to withstand the stresses of insertion without pre-drilling, there remains a need for a self-punching inserter for soft, all-suture anchors. 
     Accordingly, it is an object of this invention to produce a self-punching inserter suitable for inserting all-suture anchors into bone. 
     It is another object of this invention to produce a self-punching inserter capable of percutaneously driving an all-suture anchor into place at a surgical site. 
     SUMMARY OF THE INVENTION 
     These and other objects of the present invention are achieved by a soft anchor inserter system as described herein which enables the creation of the anchor receiving area in a bony substrate and the delivery of an all-suture anchor into that space, both in a single step. 
     In one aspect, the invention is an all-suture anchor inserter for inserting an all-suture anchor into a bone substrate without first, separately, forming a hole to receive the anchor. The inserter comprises a passage forming portion for being pushed into the substrate to therein create an anchor receiving area and an all-suture anchor carrying portion immediately adjacent the passage forming portion for delivering said all-suture anchor into the anchor receiving area. 
     In another aspect, the invention is an all-suture anchor inserter comprising an elongated shaft having an axis, a proximal end and a distal end, the distal end comprising a pair of longitudinally aligned and distally extending tines situated on opposite sides of the axis. Each of the tines comprises a distally facing planar tip surface and a tapered, radially outward, distally and laterally facing surface proximal to the planar tip surface. Each tine further comprises a flat radially inward lateral surface situated in a plane parallel to the axis and opposite the tapered, radially outward, distally and laterally facing surface. Each tine also comprises a pair of opposed, tapered, distally and laterally facing surfaces perpendicular to the radially inward lateral surface and extending between the inward lateral surface and the tapered, radially outward distally and laterally facing surface for a predetermined longitudinal distance along the length of the tines. In a preferred embodiment the tapered, radially outward, distally and laterally facing surfaces proximal to the planar tip surfaces are conically shaped and may further be convex so as to enhance the laterally directed forces pushing the bone away from the axis of the inserter. 
     A preferred embodiment of the invention further comprises an inserter wherein the passage forming portion comprises a diametrically opposed pair of tines provided with tapered bone cutting surfaces and wherein the anchor carrying portion comprises a longitudinally extending space between the tines. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the distal end of an all-suture anchor inserter constructed in accordance with the principles of this invention. 
         FIG. 2  is a perspective view of an all-suture anchor as seen during a portion of its manufacture. 
         FIG. 3  is a side elevational view of  FIG. 1 . 
         FIG. 4  is an end-on elevation view of the distal end of the inserter of  FIG. 1 . 
         FIG. 5  is a perspective view of the inserter of  FIG. 1  with the all-suture anchor of  FIG. 2  assembled on the inserter and shown in an undeployed state. 
         FIG. 6  is a top plan view of  FIG. 5 . 
         FIG. 7  is a side elevation view of  FIG. 5 . 
         FIG. 8  is an end-on elevation view of the distal end of the inserter of  FIG. 7 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     This invention pertains to the percutaneous insertion of a soft, non-rigid suture anchor construct preloaded onto an inserter (also sometimes called a driver or applicator) which is “self-punching”. The preferred embodiment of the soft suture anchor disclosed herein is a suture anchor which is entirely comprised of soft, compressible and distendable materials. Commonly used for such purposes are filaments of suture materials (hence, the term “all-suture”) made of, for example, polyester or, preferably, Ultra High Molecular Weight Polyethylene (UHMWPE). 
     An example of a prior art all-suture anchor designed to be inserted into place at a surgical work site is shown in  FIG. 2 , and a preferred embodiment of an inserter which is intended to insert this anchor, and which is the subject matter of this invention, is shown in  FIG. 1 . The distinction between the subject invention and that disclosed in the aforementioned prior publication is that the inserter disclosed herein is further adapted to enable percutaneous insertion through the skin and soft tissue directly into the bone at the surgical site without predrilling or otherwise forming a hole in the bone. 
     A preferred embodiment of the invention disclosed herein comprises an all-suture anchor inserter which has a passage forming, distally facing distal tip portion followed, upon insertion and without having to remove the passage forming portion, by an anchor carrying portion which supports and delivers (e.g. by pushing) the all-suture anchor into the passageway formed by the distal tip portion. 
     The body (referred to below as web  42 ) of the all-suture anchor, even after it is interwoven with a suture filament to become a filament-carrying body, is malleable and non-rigid so it cannot be pushed into a bone tunnel in the same manner that a conventional rigid suture anchor can be. The term “pushing” is commonly used with rigid suture anchors because it reflects the fact that the prior art, rigid anchor inserters “push” the rigid suture anchors into place by applying a distally directed force to the proximal-most, proximally facing surface of the rigid anchors. However, an all-suture anchor having a malleable body with little or no column strength cannot really be “pushed”. Therefore, use of the term “push” is slightly misleading. While the term “push” has come to be commonly used with respect to the insertion of all-suture anchors into a bone hole, it is more technically accurate to say the all-suture anchor is “pulled” into place. That is, “pushing” on the distal-most part of the all-suture anchor has the effect of actually pulling the anchor into position. The distal-most parts of the anchor enter the bone tunnel first, with the trailing (i.e., proximal) parts of the anchor being pulled along by the distal parts, and this is true whether the body of the all-suture anchor is folded back on itself, to enable it to be pushed at a midpoint, or straight, to enable it to be pushed at the distal end. Nevertheless, the term “push” may still be used herein when applied to all-suture anchors. 
       FIG. 2  shows an all-suture anchor  40  which comprises, for example, a fibrous, braided or woven fabric-type structure such as flexible web  42  of ribbon-like or tape-like material which is assembled by interweaving filaments  44  and  46  through web  42  as shown to form a construct which, when folded on itself about center point  48  (as best seen in  FIGS. 5-8 ), becomes an undeployed all-suture anchor  40  carried by inserter  10 . The deployment of this type of construct and its deformation within a bone tunnel are more fully explained in the aforementioned U.S. patent publication. It will be understood that in the preferred embodiment web  42  is, in an undeployed state, formed as a substantially flat tape-like element having a rectangular cross-section when viewed end-on. However, it can also have a variety of other cross sectional configurations such as circular, oval, etc. (While  FIG. 2  shows web  42  as having an undulating structure, this is exaggerated merely to convey the soft nature of the web material. (Compare this to  FIGS. 5-8  where web  42  is shown in a flat folded configuration.) 
     As shown in  FIG. 2 , all-suture anchor  40  comprises a plurality of parallel filaments of suture material woven through a ribbon-shaped element which can itself be made of filaments of suture material. For example, in a preferred embodiment web  42  may be a piece of conventional suture tape. It will be understood, however, that the ribbon-shaped element  42  need not literally be formed of suture filaments and other methods may be used to manufacture this element provided that it performs the same or substantially the same as the preferred embodiment disclosed herein. One can envision, for example, other soft constructs such as molded, woven or braided structures made of soft, deformable material not normally used for sutures (although they would need to be biocompatible of course). The construct may be formed of parallel filaments or randomly interlaced or entangled filaments, short pieces of fiber, etc. In view of the above, the term “all-suture” as used herein includes all structures such as all-suture anchor  40  constructed of suitable soft materials, whether or not such materials are actually suture materials. 
     As shown in  FIG. 1 , inserter or driver  10  is a preferred embodiment of the invention and comprises an elongated shaft  12  having a distal end  14 , a proximal end  16  and an axis  18 . Proximal end  16  can be attached to a handle (not shown) to facilitate use of the inserter. Distal end  14  is provided with a forked structure  22  having a pair of tines  24 ,  26  symmetrically situated on opposite sides of axis  18  with a longitudinally extending slot  28  therebetween. The flat, radially inward, lateral surfaces  27  of tines  24  and  26  are situated in a plane parallel to axis  18  and form the lateral boundary of slot  28 . Slot  28  is adapted to receive the all-suture anchor  40  folded about surface  29  at the proximal-most end of slot  28  as best seen in  FIGS. 3 ,  4  and  5 . (In an alternative embodiment shaft  12  may, depending on the application, be cannulated with an axial lumen adapted to receive a guide wire which could be pierced through the fold at point  48  of the construct  40 .) 
     Unlike the inserter shown in the aforementioned patent publication, in order to minimize the resistance encountered by the distally facing area of distal end  14  as the tip of inserter  10  pierces the cortical bone and broaches a hole in the bone, various tapering and relief surfaces and edges are formed at distal end  14 . For example, as best seen in  FIGS. 1 and 4 , each tine  24  and  26  of the inserter distal end  14  contains a tapered, optionally slightly convex, radially outward, distally and laterally facing surface  36  formed at its distal end. These surfaces are immediately proximal to distally facing planar tip surfaces  25 . Surfaces  36  are designed to deflect the tines radially inwardly to counteract forces which may otherwise cause the tines  24 ,  26  to splay open as end  14  is pushed into the bone. Surfaces  25  are perpendicular to axis  18  and are designed to concentrate distally directed forces from the inserter to the cortical bone. Relief is also provided by two diametrically opposed tapering cuts  30  at the base of slot  28 . These cuts serve to taper the overall transverse size of the anchor/inserter assembly to facilitate the insertion of the assembly into the bone hole. The distal ends of taper cuts  30  blend smoothly into convex surface  29  formed at the proximal-most end of slot  28 . 
     A preferred embodiment of the invention includes, at the approximate longitudinal midpoint of slot  28 , four opposed broaching projections  32  having distally facing surfaces  32   a  which serve as a broaching feature to facilitate cutting through bone to reduce the frictional resistance encountered by anchor  40  as it passes through the cortical bone. These projections extend laterally in substantially opposite directions from each of the tines. Behind (i.e., distally of) the slot  28  are two opposed flat surfaces  34  designed to provide clearance for web ends  41   a  and  b , and sutures  44   a, b  and  46   a, b  to pass alongside inserter  10  to minimize interference with the cortical bone. The proximal-most ends  39  of surfaces  34  are tapered to blend in with the cylindrical surface  50  of shaft  12 . Also, opposite lateral sides of tine  24  are provided with distally and laterally facing broaching surfaces  38  which are perpendicular to the lateral surface  27  on one side of the tine. Symmetrical surfaces  38  are also formed on opposed sides of tine  26 . Surfaces  38  also facilitate cutting/broaching the bone as inserter  10  is advanced and, in the preferred embodiment, are slightly convex. It will also be understood that the preferred embodiment includes rounded edges and corners between adjacent surfaces (e.g.,  38  and  32   a ) as needed to facilitate manufacture and performance. 
     All-suture anchor  40  can be externally loaded onto inserter  10 . As used herein, “externally loaded” means, as best seen in  FIG. 5 , that the construct  40  is attached to the inserter with the construct (which includes the sutures) lying along the surface of the inserter. In a preferred embodiment construct  40  is folded on itself about the distal end of inserter  10  such that suture ends  44   a  and  b  and  46   a  and  b  extend proximally relative to inserter distal end  14  along the outer surface of shaft  12 . Alternatively, the construct could be “internally” loaded if the construct  40  and inserter  10  were to be inserted into a tubular sheath (not shown) to thereby protect the construct until it could be pushed distally from the sheath. One concern with this alternative is that it makes the assembled structure larger in diameter and, therefore, possibly unsuitable for certain applications. 
     It will be understood that a different embodiment of the invention could be constructed with a soft construct having a linear structure which is attached to the inserter by means other than being folded upon itself. For example, a linear ribbon-like construct could have one or more filaments threaded therethrough with the distal end of the filament(s) knotted or otherwise engaged on one side of tines  24 ,  26  and the ribbon body extending proximally from the tip on the other side of tines. 
     The preferred embodiment of inserter  10  is comprised of stainless steel or other biocompatible material hard enough to form a hole in the bone without drilling. The sizes of the construct  40  and inserter  10  may vary depending on the forces encountered in various applications, bone density, etc. 
     It will be understood by those skilled in the art that numerous improvements and modifications may be made to the preferred embodiment of the invention disclosed herein without departing from the spirit and scope thereof.