Abstract:
A medical device is provided comprising a suture thread coated with a stiffening agent and having a shape of a coil having a plurality of windings. The suture thread may be used to reconnect soft tissue to bone tissue. The suture thread may be used in conjunction with a suture sheath which is inhibited from movement relative to the suture thread.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority of U.S. provisional application No. 61/469,386, filed Mar. 30, 2011, the teachings of which are incorporated herein by reference. 
    
    
     FIELD 
     This disclosure relates to systems, devices and methods for the repair of defects that occur in tissue of a body, particularly a human body. 
     BACKGROUND 
     In tissue repair, to repair a torn rotator cuff of a shoulder, surgeons may reattach the supraspinatus tendon to the humerous of a body. Preferably, an attachment method should offer sufficient strength with a minimal amount of foreign hardware in the construct, to minimize rejection by the body. As such, the use of tranosseous sutures may be preferred to mechanical anchors to reattach the supraspinatus tendon to the humerous. 
     With the use of transosseous sutures, transosseous tunnels may be formed in the humerous. There are numerous methods of generating bone tunnels, however, the challenge often lies with the means of shuttling suture through the prepared blind bone holes. Known methods are generally unfavorable due to size, cost or overall reliability. They are sometimes cumbersome, particularly when trying to retrieve a loose end of the suture thread. 
     SUMMARY 
     The present disclosure may provide systems, devices and methods to tissue repair, particularly to reattach soft tissue to bone. More particularly, the present disclosure may provide systems, devices and methods to reattach soft tissue such as connective tissue to bone such as the pelvis, a vertabrae or a long bone which may include the humerous, femur and tibia. Specific examples may include reattaching the supraspinatus tendon to the humerous to repair a torn rotator cuff as part of shoulder surgery; reattaching an anterior cruciate ligament or a medial collateral ligament to the femur or tibia as part of knee surgery; or rettaching a bicep tendon to the glenoid or elbow. 
     In one embodiment, the present disclosure may provide a suture thread coated with a stiffening agent to increase a rigidity of the suture thread. The suture thread may be formed into self-supporting predetermined shape, such as a coil. The suture coil may then be introduced into a first blind bone bore and retrieved from a second blind bone bore intersecting the first blind bone bore, which creates a continuous tissue tunnel having an opening at each end thereof. The suture coil may be retrieved with a suture retriever having a helical coil or “cork screw” at the distal end thereof. The coil may function as a hook at the distal end of the suture retriever which may be rotated to present several opportunities for the retriever coil to engage the suture coil and successfully pass the suture thread from the first blind bone bore to the second blind bone bore. The space required to achieve this union can be very small, and may be considered as being more minimally invasive, when being compared to other repair options. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features and advantages of the present invention are set forth by description of embodiments consistent with the present invention, which description should be considered in conjunction with the accompanying drawings wherein: 
         FIG. 1  is a side view showing a suture thread formed on a mandrel into a suture coil according to the present disclosure; 
         FIG. 2  is a side view of the suture thread of  FIG. 1 , including the suture coil, having a stiffening agent applied thereto according to the present disclosure; 
         FIG. 3  is a side view of the suture thread of  FIG. 1 , including the suture coil, with the stiffening agent applied thereto and the mandrel removed according to the present disclosure; 
         FIG. 4  is a side view of the suture thread of  FIG. 1  with a loose end section of the suture thread passed through the suture coil to form a closed end loop at one end of the suture coil according to the present disclosure; 
         FIG. 5  is a close-up perspective view of the suture thread of  FIG. 1  with the end section of the suture thread passed through the suture coil such that the closed loop is now at the end of the coil according to the present disclosure; 
         FIG. 6  is a cross-sectional view of a bone, particularly a humerous, with the suture thread formed into the suture coil of  FIG. 1  inserted into a first bone tunnel and a suture retriever device inserted into a second bone tunnel according to the present disclosure; 
         FIG. 7  is a close-up cross-sectional view of the bone with the suture thread formed into the suture coil of  FIG. 1  inserted into the first bone tunnel and the suture retriever device inserted into the second bone tunnel according to the present disclosure; 
         FIG. 8  is a side view of a distal end portion of a suture retriever device according to the present disclosure; 
         FIG. 9  is a side view of a distal end portion of another suture retriever device according to the present disclosure; 
         FIG. 10  is a close-up cross-sectional view of the bone with the suture thread formed into the suture coil of  FIG. 1  inserted into the first bone tunnel and a suture retriever device inserted into the second bone tunnel with the suture coil retrieved by the suture retriever device according to the present disclosure; 
         FIG. 11  is a side view of a suture thread and first suture reinforcing tube according to the present disclosure; 
         FIG. 12  is side view of a suture thread and another suture reinforcing tube according to the present disclosure; 
         FIG. 13  is a side view of a suture thread and another suture reinforcing tube according to the present disclosure; and 
         FIG. 14  is a side view of a suture thread and a suture reinforcing tube according to the present disclosure in combination with a reinforcing plate and tissue. 
     
    
    
     DETAILED DESCRIPTION 
     It may be appreciated that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The embodiments herein may be capable of other embodiments and of being practiced or of being carried out in various ways. Also, it may be appreciated that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
     Referring now to  FIG. 1 , a suture thread  10  may be wound or otherwise formed into the shape of a spiral (helical) coil  12 . Suture thread  10  may be formed into the shape of a coil  12  by being wrapped around a suitable forming mandrel  14 , such as a cylindrical rigid rod made of metal, plastic or ceramic. 
     As shown, suture coil  12  may have a length defined by a plurality of circular windings  16  arranged along a longitudinal axis  18  of forming mandrel  14 . Windings  16  may be of uniform diameter and arranged side-by-side, particularly with adjacent windings  16  in contact with one another. The outside diameter OD of suture coil  12  may be in a range of, for example, 1 mm to 6 mm (more particularly, 1 mm to 3 mm) and the inside diameter ID of the suture coil  12  may be in the range of, for example, 0.5 mm to 5.5 mm. The suture coil  12  may have a length from, for example, 2 mm to 25 mm and may be made of a suture thread  10  having a diameter from, for example, 0.1 mm to 2 mm. 
     The suture thread  10  may be made of a nonabsorbable or absorbable material (a material which has a substantial decrease in tensile strength within 60 days under the skin). The suture thread  10  may be a monofilament, or may be made of multiple filaments (e.g. twisted or braided) together. The suture thread  10  may be made of nature or synthetic materials, including polymers. Exemplary nonabsorbable suture thread  10  may be made of silk (e.g. flexible multifilament, braided or twisted, composed of organic protein such as fibroin), nylon, polypropylene, polyester and polybutester. Exemplary absorbable suture thread  10  may be made of catgut (e.g. collagen strands), chromic gut, polyglycolic acid, polyglactic acid, polydioxanone and polyglyconate. 
     Referring now to  FIG. 2 , after being formed into the shape of a coil  12 , a stiffening agent  20  may be applied (e.g. sprayed) to the outer surface  24  of the windings  16  of suture coil  12  to form a coating  26  thereon. Stiffening agent  20  may increase the rigidity of the suture thread  10  and hold the position of the windings  16  stationary and fixed relative to one another so that the suture thread  10  may be removed from the forming mandrel  14  without substantial deformation thereof. For example, suture thread  10  may be made sufficiently rigid with stiffening agent  20  such that suture coil  12  does not deform under its own weight with manipulation thereof and windings  16  do not separate or change in size (e.g. diameter). 
     The stiffening agent  20  may be sprayed or otherwise applied to the outer surface  24  of the suture thread  10  as a liquid containing volatile compounds which thereafter air dries (e.g. through the evaporation of the volatile compounds) leaving behind coating  26  which stiffens as it solidifies. The stiffening agent  20 /coating  26  may comprise one or more nature or synthetic polymers such as polyvinylpyrrolidone (PVP, also called polyvidone), polydimethylsiloxane (PDMS), copolymers with vinyl acetate and maleic anhydride and vegetable gums dissolved in alcohol. 
     Alternatively, the stiffening agent  20  may be applied to the suture thread  10  as a heated melt, such as a polymer melt with a temperature above melt temperature, which solidifies as it cools to provide a polymer coating  26  and does not have an evaporative carrier. In this manner, the stiffening agent  20 , which may comprise a thermoplastic polymer, may be applied the suture thread  10  prior to the suture thread  10  being formed into suture coil  12 . Thereafter, the suture thread  10  with thermoplastic coating  26  may be reheated (e.g. above room temperature and below melt temperature) prior to and during the formation of suture coil  12 , and then be subsequently cooled (e.g. to room temperature) after formation of suture coil  12 . 
     Referring now to  FIG. 3 , once the suture coil  12  is formed and stiffening agent  20  has been applied to maintain the form (shape) of the coil  12 , the suture coil  12  may be removed from mandrel  14 . The mandrel  14  may include a stick-resistant coating on the outer surface thereof, such as a PTFE coating, to inhibit the suture coil  12  from sticking to the mandrel  14 . 
     The suture thread  10  with suture coil  12  may include uncoiled terminal end sections  30  and  32  at each end of the coil  12 . As shown in  FIG. 4 , uncoiled section  32  may be passed through the inner passage  34  of the coil  12  (previously occupied my mandrel  14 ) to form a closed loop  36  at one end of the suture coil  12  and have both end sections  30  and  32  at one common end of coil  12 . Alternatively, as shown in  FIG. 5 , end section  32  may be passed through the inner passage  34  of the coil  12  such that the loop  36  is now at the end of the coil  12  (i.e. formed by a winding  16 ). 
     Referring now to  FIG. 6 , the suture coil  12  may then be inserted into an opening  42  of a first linear (straight) cylindrical blind bore passage or bone tunnel  44  in bone  50 , which may be formed by a drill. A distal end portion  46  of the bone tunnel  44  may be intersected by the distal end portion  56  of a second linear (straight) cylindrical blind bore passage or bone tunnel  54  having opening  52 , which may also be formed by a drill. In the foregoing manner, a non-linear continuous tissue tunnel having an opening at each end thereof is formed, and suture thread  10  including suture coil  12  may then pass through bone tunnel  44  and into bone tunnel  54  where it may subsequently exit from opening  52 . As shown, bone tunnels  44  and  54  are formed at an angle relative to one another, here acute, and do not share a common longitudinal axis. Depending on the size of coil  12 , bone tunnels  44  and  54  may have a slightly larger diameter (e.g. 0.1-2 mm). For example, the inside diameter in a range of, for example, 1.1 mm to 8 mm. 
     As shown in  FIGS. 6 and 7 , in order to more easily pass suture coil  12  through bone tunnel  54  so that it may exit from opening  52 , a suture retriever device  60  may be inserted into bone tunnel  54  to make contact with suture coil  12 . As best shown in  FIG. 7 , suture retriever device  60  comprises a helical coil  62  at the distal end of a shaft  64 , with coil  62  having a distal pointed end  68 . As shown in  FIG. 8 , the distal end  68  of coil  62  may be linear and project distally or, as shown in  FIG. 9 , may arc proximally with a hook configuration. 
     Referring now to  FIG. 10 , in order to engage and retain suture coil  12  with suture retriever device  60 , retriever device  60  may be rotated within bone tunnel  54 , here counterclockwise (relative to the user), until a portion  70  of a winding  16  of the suture coil  12  is hooked by coil  62 . In order to hook suture coil  12 , for example, distal end  68  of coil  62  may enter passage  34  from the end of suture coil  12  and thereafter hook a winding  16  thereof. Alternatively, distal end  68  of coil  62  may pass between two adjacent windings  16  to hook a winding  16 . Thereafter, suture thread  10  may be extracted through bone tunnel  54  and from opening  52  as suture retriever device  60  is retracted from bone tunnel  54  and opening  52 . 
     Thus, the present disclosure may provide a suture thread  10  coated with a stiffening agent  20  to increase a rigidity of the suture thread  10 . The suture thread  10  may be formed into a suture coil  12 . The suture coil  12  may then be introduced into a first blind bone bore  44  and retrieved from a second blind bone bore  54  intersecting the first blind bone bore  44 . The suture coil  10  may be retrieved with a suture retriever device  60  having a helical coil  62  at the distal end thereof. The coil  62  may function as a hook at the distal end of the suture retriever device  60  which may be rotated to present several opportunities for the retriever coil  62  to engage the suture coil  12  and successfully pass the suture thread  10  from the first blind bone bore  44  to the second blind bone bore  54 . The space required to achieve this union can be very small, and may be considered as being more minimally invasive, when being compared to other repair options. 
     In certain embodiments, once the suture thread  10  is extracted through bone tunnel  54  from opening  52 , one of the end sections  30 ,  32  of the suture thread  10  may now be pulled though bone tunnels  44  and  54  such that one end section  30  of the suture thread extends from bone tunnel  44  and the other end section  32  extends from bone tunnel  54 , during which time at least a portion of the coil  12  may be uncoiled to pull the suture thread taught from each bone tunnel  44  and  54  and more easily slide within. Thereafter, the suture thread  10  may be used to connect soft tissue such as connective tissue to the bone tissue as discussed in greater detail below. Alternatively the suture thread  10  may be cut at the closed loop  36  to provide two separate pieces of suture thread passing through bone tunnels  44  and  54 , which may both be connect soft tissue such as connective tissue to the bone tissue. 
     In certain instances, suture thread  10  may rub and chafe (wear away) against bone  50 , particularly at abrasive corners or edges, for example of bone bores  44  and  54  at openings  42  and  52 , respectively, which may cause the suture thread  10  to break prematurely. Alternatively, if the suture thread  10  is used in conjunction with soft tissue, the suture thread  10  may migrate and “cut through” the soft tissue. 
     Referring now to  FIGS. 11-13 , the suture thread  10  of the present disclosure, with or without the stiffening agent  20 , may be used in conjunction with one or more hollow suture reinforcing tubes  80   a ,  80   b  and  80   c , which may provide a cylindrical sheath around at least a portion of the length of the suture thread  10 . As best shown in  FIG. 11 , suture thread  10  may extend through the lumen  82  of a flexible suture tube  80   a  and extend from each end thereof. Suture tubes  80   a ,  80   b  and  80   c  may be made have a braided filament tubular structure, which may be made of polytetrafluoroethylene. 
     In the case of hard tissue, the suture tube  80   a ,  80   b  or  80   c  may shield the suture thread  10  from abrasive bone corners, or at other locations against which the suture thread  10  may rub and chafe. In the case of soft tissue, cutting forces placed on the soft tissue by the suture thread  10  may be distributed over the larger surface area occupied by the suture tube, which may reduce the likelihood of the suture thread  10  from cutting or pulling though the soft tissue. 
     As shown in  FIG. 11 , suture tube  80   a  may freely slide along suture thread  10  so that it may be freely positioned anywhere along the length of suture thread  10  during surgery. However such may be problematic when suture thread  10  is passed through a narrow tissue aperture, for example, which may be created by a needle to which the suture thread  10  is connected and passes through. In such case, while it may be possible to pass the suture thread  10  through the aperture created by the needle, the increased diameter of the suture tube  80   a  may inhibit the suture tube  80   a  from passing through the aperture. 
     Alternatively, as shown in  FIG. 12 , suture tube  80   b  may be bonded (e.g. fused thermally or adhesively) to suture thread  10 , for example, at each end  84  thereof by heat staking as to be held in a fixed (stationary) position. Such may be useful to inhibit the suture tube  80   b  from moving relative to suture thread  10 . Such may be desirable, for example, when suture thread  10  is passed through a narrow aperture which may be created by a needle to which the suture thread  10  is connected. The suture thread  10  may then be used to pull the suture tube  80   b  through the aperture. 
     As shown in  FIG. 13 , suture tube  80   c  may freely slide along suture thread  10  so that it may be positioned anywhere along the length of suture thread  10  during surgery, similar to suture tube  80   a . However, suture tube  80   c  may further include attachment means  86 , which may comprise threads, to connect to the suture thread  10 . As indicated above, such may be desirable, for example, when suture thread  10  is passed through a narrow aperture which may be created by a needle to which the suture thread  10  is connected. The suture thread  10  may then be used to pull the suture tube  80   c  through the aperture. 
     Referring now to  FIG. 14 , suture tube  80 , which may include any of suture tubes  80   a ,  80   b  or  80   c  may be used in conjunction with one or more localized reinforcement members  90  (e.g. buttress plates, pledgets) to further inhibit suture thread  10  from pulling through soft tissue  92  in direction  94 . Furthermore, as shown in  FIG. 14 , suture tube  80  includes attachment means  86 , which comprise threads, to connect to the suture thread  10 . As shown, when suture thread  10  is passed through a narrow aperture  96  which may be created by a needle  98  to which the suture thread  10  is connected, the suture thread  10  may then be used to pull the suture tube  80  through the aperture  96 . 
     Thus, the present disclosure may provide a suture tube  80   a ,  80   b  or  80   c  to inhibit inadvertent damage to a suture thread  10  or to tissue  50  or  92  contacted by the suture thread  10  (e.g. tissue held in place by the suture thread  10  or through which the suture thread  10  may pass through). 
     While the principles of the present disclosure have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. The features and aspects described with reference to particular embodiments disclosed herein are susceptible to combination and/or application with various other embodiments described herein. Such combinations and/or applications of such described features and aspects to such other embodiments are contemplated herein. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims. 
     All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms. 
     The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” 
     The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified, unless clearly indicated to the contrary. 
     All references, patents and patent applications and publications that are cited or referred to in this application are incorporated in their entirety herein by reference. 
     Additional disclosure in the format of claims is set forth below: