Abstract:
A method and apparatus for joining opposite ends of a severed tendon or ligament. A core suture is attached to one of the severed ends. A cap is attached to the severed end by the core suture. The cap protects the severed end from trauma and fraying as it is pulled back toward the opposite severed end of the tendon. The cap is removed prior to reattachment of the severed ends. The cap may have a coating applied to it to reduce friction and add other properties such as improved healing to the tendon after it is reattached.

Description:
RELATED APPLICATION 
       [0001]    This application claims the priority of U.S. Provisional Application No. 60/989,156 filed Nov. 20, 2007. 
     
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
       [0002]    When a tendon is severed, the proximal tendon end retracts similar to a cut rubber band. A surgeon must reconnect the tendon by guiding at least one severed end through the fibrous/osseous tunnels comprising the pulley system along the bones in the hand and fingers to re-attach the severed proximal and distal ends. The tendon must be safely pulled through the passageways so that minimal tearing or fraying of the ends occurs. Passing lacerated or divided tendons underneath pulley systems and through fibro osseous and osseous tunnels can often result in tendon injury, tendon end fraying and traumatic injury to the tendon epitenon. This has been related to increased tendon adhesion formation, increased bulk at repair sites, decreased repair strength, and increased risk of tendon rupture and loss of tendon excursion upon final healing. 
         [0003]    In the inventive procedure, once the tendon is pulled through the pulleys, the ends of the tendons are normally secured together by sutures tied to the opposed ends of the tendons in a conventional surgical procedure. Upon re-attachment, the body will undergo a normal healing process to repair the severed tendon. 
         [0004]    A major problem found in this procedure is that the ends of the tendons can fray as they are being pulled back through the pulleys. Prior passing techniques normally utilize sutures or a grasper that manage to pull the tendon through the pulleys along the bone but cause tearing or fraying of the tendon in the process. The fraying can cause damage to the tendon and increase the amount of time necessary to allow the tendons to heal once they have been re-connected. In order to achieve a more successful tendon repair surgery, both ends of the tendons should be free from frayed ends. The surgical procedure also takes more time to complete if there are frayed ends on the tendon, which makes the reattachment more difficult. This can increase the risk of complications. 
         [0005]    Recent advances in tendon research have demonstrated that certain growth factors, mesemchymal cell, mucopolysaccharides, organic and inorganic lubricants, and virus mediated gene transfer of growth factors can promote tendon healing and/or decrease adhesion formation after tendon repair. Thus it is an object of this invention to use a method and apparatus that promotes healing by applying one or more of the above mentioned healing substances. 
     
    
     DESCRIPTION OF THE INVENTION 
       [0006]    The present invention proposes a solution to these problems by providing a tendon cap which is simple for a surgeon to use. The present invention greatly reduces fraying by encompassing the entire end of the tendon in elastic material. The tendon cap can be made of a solid or elastic synthetic or non-synthetic material that encompasses the end of the tendon as described herein. 
         [0007]    As seen in  FIGS. 1 and 2 , a tendon cap  10  is formed from a thin membrane tube with a flexible membrane cap that is placed over an end  16  of a lacerated or divided tendon  12 . The lacerated tendon  12  has an opposite end  38  to which end  16  is to be re-attached. There are two zones to the tendon cap  10 . There is a head  14  that fits directly over the end  16  of the tendon  12  and a body  18  which shrouds the tendon  12  for some length from the end  16 . This protective tendon cap  10  is designed for minimizing friction and injury when passing the tendon  12  under pulley systems or through a fibro osseous/osseous tunnel. The tendon  12  will be delivered to the surgical repair site with much less injury to the tendon end  16  and epitenon. This allows for less bulky repair, increased repair strength and decrease in adhesion formation. Upon final healing, tendon strength and excursion will be maximized. The tendon cap  10  can be made of an elastic synthetic or non-synthetic material that encompasses the end  16  of the tendon  12 . 
         [0008]    The tendon cap  10  can also be coated with specific substances to: (1) decrease friction when passing the tendon  12  with the tendon cap  10  beneath pulleys or through fibro osseous/osseous tunnels; (2) decrease trauma to the tendon end  16  and epitenon when passing the tendon  12  beneath pulleys and through the fibro osseous/osseous tunnels; (3) promote stronger more rapid healing at the repair site; and (4) decrease adhesion formation between the tendon and the surrounding tissue. 
       Tendon Cap Inside Surface Coatings 
       [0009]    The inside area of the head  14  is the membrane portion of the tendon cap  10  that is in intimate contact with the tendon end  16 . The inside of the head  14  can be coated with various substances which will be transferred to the tendon end  16  during the tendon passing process by direct contact with the tendon end  16 . These substances are utilized for their ability to promote rapid strong healing at the repair site and to prevent adhesion formation between the tendon  12  and the surrounding tissue. The substances that may be placed on the inside of the tendon cap include but are not limited to: (1) all growth factors that will promote tendon healing and decrease tendon adhesion formation; (2) Platelet derived growth factors; (3) Fibroblast derived growth factors; (4) Mesemchymal stem cells; (5) Virus mediated gene transfer vectors to promote expression of genes for formation of growth factors that promote tendon healing and decrease tendon adhesions; (6) Virus mediated transfer of basic fibroblast growth factor (bFGF) gene through adenosine associated viral-2 (AAV2); (7) growth/differentiation factor 5 (GdF5), recombinant growth/differentiation factor 5 (rhGdF5); and (8) Fibronectin. 
       Head Outside Surface Coatings 
       [0010]    The outside area of the head  14  is the membrane portion of the head that is in contact with the surrounding tissue through which the tendon  12  is being passed. The outside of the head  14  can be coated with various substances that will be transferred to the tendon and surrounding tissue by direct contact to decrease: (1) friction when passing the tendon  12  with the tendon cap  10  beneath pulleys or through fibro osseous/osseous tunnels; (2) trauma to the tendon end  16  and epitenon when passing the tendon  12  beneath pulleys and through the fibro osseous/osseous tunnels; and (3) adhesion formation between the tendon  12  and the surrounding tissue. 
         [0011]    Substances that can be utilized to coat the outside of the tendon cap  10  include but are not limited to: (1) growth/differentiation factor 5 (GdF5), recombinant growth/differentiation factor 5 (rhGdF5); (2) Phospholipids; (3) Lipid derivatives; (4) Muccopolysaccharided; (5) Synthetic or organic lubricants; (6) Virus mediated gene transfer vectors to promote expression of genes for formation of growth factors that promote tendon healing and decrease tendon adhesions; (7) Virus mediated transfer of basic fibroblast growth factor (bFGF) gene through adenosine associated viral-2 (AAV2); and (8) Mesencymal stem cells. 
       Body Outside and Inside Coatings 
       [0012]    The body  18  on both the outside membrane and inside membrane of the tendon cap  10  can be coated with various substances that can be transferred to the tendon  12  epitenon and surrounding tissue by direct contact to decrease: (1) friction when passing the tendon  12  with the tendon cap  10  beneath pulleys or through fibro osseous/osseous tunnels; (2) trauma to the tendon end  16  and epitenon when passing the tendon  12  beneath pulleys and through the fibro osseous/osseous tunnels; and (3) adhesion formation between the tendon  12  and the surrounding tissue. 
         [0013]    Substances that can be utilized to coat the outside of the tendon cap  10  include but are not limited to: (1) growth/differentiation factor 5 (GdF5), recombinant growth/differentiation factor 5 (rhGdF5); (2) Phospholipids; (3) Lipid derivatives; (4) Muccopolysaccharided; (5) Synthetic or organic lubricants; (6) Virus mediated gene transfer vectors to promote expression of genes for formation of growth factors that promote tendon healing and decrease tendon adhesions; (7) Virus mediated transfer of basic fibroblast growth factor (bFGF) gene through adenosine associated viral-2 (AAV2); and (8) Mesencymal stem cells. 
       Technique for Passing Cut Flexor Tendons Beneath Pulleys and Through Fibro Osseous Tunnels/Osseous Tunnels 
       [0014]    As seen in  FIG. 3 , a core grasping suture  20  is placed into the cut tendon end  16 , exists one side of the tendon  12 , passes diametrically back through the tendon  12  and exits the other side of the tendon  12 . It then reenters the tendon  12  at the same side through which it just exited and goes back up the central core of the tendon  12  and exits through the cut end  16 . Alternatively, any core suture can be utilized as long as there are two to 6 six strands of suture that exit the tendon end  16  to be passed through the tendon cap  10 . As seen in  FIG. 3 , the suture  20  has two free ends  22 ,  24  which are passed through tendon cap suture target markings  26 ,  28  in the head  14  in an “inside to outside” fashion. The tendon is then pulled into and secured to the tendon cap  10  utilizing the core sutures  20  as a traction device. Alternatively, the suture  20  can be initially passed through target marking  26 , through the end  16  and the tendon  12 , back through the end  16  and the other target marking  28 . Jeweler&#39;s forceps are utilized to help guide the tendon cap  10  over the tendon end  16 . The core sutures  20  are then shuttled beneath the pulley system or through the fibro osseous tunnel utilizing a tendon cap suture passing tool  30  such as the one illustrated in  FIG. 4 . There is a hole  32  at one end of the tool  30  through which the core sutures  20  pass. A malleable wire  34  passes through the center of the tool  30 . A synthetic plastic coating  36  covers the malleable wire  34  and encapsulates the entire tool  30  so that it can be manufactured as a prepackaged sterile tool that can be discarded after use. Alternatively it can be made of materials that allow it to be sterilized and re-used. 
         [0015]    As the sutures  20  are withdrawn beneath the pulley or through the fibro osseous tunnel, the tendon  12  with the tendon cap  10  in place is gently pulled and passes beneath the pulley system or through the fibro osseous tunnel. The tendon  12  with the tendon cap  10  in place is initially guided beneath the pulley system or into the fibro osseous tunnel utilizing forceps without teeth. During this process, the substances coated on the tendon cap head  14  are transferred onto the tendon end  16  by direct contact. The substances that are placed on the inside and outside of the tendon cap body  18  are transferred onto the tendon epitenon and surrounding pulley system and fibro osseous tunnel by direct contact. 
         [0016]    Once the end  16  of the severed tendon is pulled a sufficient distance to be re-attached to the distal end  38  of the tendon  12 , the tendon cap  10  can be removed from the tendon  12  and easily slid off the suture  20 . The two ends  16 ,  38  of the tendon  12  can be re-connected through conventional medical procedures such as placing the core suture  20  through the distal end  38 . Additional sutures can be used to re-connect the two ends  16 ,  38  of tendon  12  as necessary or desired by the surgeon or a free or French eye needle can be used with the already placed core suture  20 . 
         [0017]    By fully encompassing the end  16  of the tendon  12  with the tendon cap  10 , tendon fraying is greatly reduced and the patient will enjoy a shorter time to achieve a complete recovery. 
         [0018]    Thus there has been provided a method and apparatus for tendon repair that fully satisfies the objects set forth herein. While the invention has been described in conjunction with a specific embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the appended claims.