Abstract:
A medical device that attaches to tissue without requiring stitching includes a tissue fixation device having a first sub-loop and a second sub-loop, and an assisting member disposed through the first sub-loop and through the second sub-loop. The tissue fixation device includes an adjustable, flexible member formed by inserting one end portion of the flexible member through another end portion of the flexible member, and first and second sub-loops formed by crossing a portion of the flexible member over a different portion of the flexible member.

Description:
TECHNICAL FIELD 
   This invention relates to medical devices, and more particularly to a fixation device. 
   BACKGROUND 
   To perform a surgical repair, e.g., of a torn anterior cruciate ligament (“ACL”), the surgeon typically connects a length of suture to the replacement ACL soft tissue graft. The suture enables the surgeon to pull the tissue graft through holes formed in the tibia and femur for receiving the tissue graft. Typically, the surgeon attaches the suture to the ACL soft tissue graft using a whipstitch. Stitching the suture to the tissue graft using a whipstitch usually takes over two minutes per tissue graft. 
   SUMMARY 
   This invention relates to a fixation device that attaches to a tissue graft without requiring stitching. One advantage is that the time it takes for the surgeon to attach the fixation device to the tissue graft is shorter than the time it takes to whipstitch a suture to the tissue graft. In one aspect, there is a tissue fixation device that includes a member having a first sub-loop and a second sub-loop, where each sub-loop is configured to receive a length of tissue therethrough. In one example, the member comprises suture. In another example, the member further includes a third sub-loop configured to receive a length of tissue therethrough. 
   In another aspect, there is a medical device including an adjustable loop and an assisting member. The adjustable member includes a first sub-loop and a second sub-loop configured to receive a length of tissue therethrough. The assisting member is disposed through the first sub-loop and through the second sub-loop. In one example, the assisting member comprises a medical grasping device. In another example, the assisting member comprises a cannula. In another example, the adjustable member is a first member. In this example, the medical device also includes a second adjustable member including a first sub-loop and a second sub-loop, wherein the assisting member is further disposed through the first sub-loop of the second adjustable tissue fixation device and through the second sub-loop of the second adjustable tissue fixation device. In another example, the adjustable member comprises suture. In yet another example, the adjustable member also includes a third sub-loop configured to receive a length of tissue therethrough. 
   In yet another aspect, there is a tissue fixation device including an adjustable, flexible member. The adjustable, flexible member is formed by inserting one end portion of the flexible member through another end portion of the flexible member. The adjustable member is further formed into a first sub-loop and a second sub-loop. Crossing a portion of the flexible member over a different portion of the flexible member forms the first sub-loop and the second sub-loop. The first sub-loop and the second sub-loop are configured to fixate onto tissue. 
   In one example, the flexible member comprises suture. In another example, the sub-loops are configured to fixate on ligament or tendon tissue. In another example, the adjustable member also includes a third sub-loop. In yet another example, the adjustable member is a first adjustable member. In this example, the fixation device further includes a second adjustable member including a first sub-loop and a second sub-loop. 
   In another aspect, there is a medical device that includes a plurality of adjustable suture members and a cannula. The plurality of adjustable suture members each include a first sub-loop, a second sub-loop, and a third sub-loop, where each sub-loop is configured to receive a length of tissue therethrough. The cannula is disposed through the sub-loops of each of the plurality of adjustable suture members. 
   In another aspect, there is a method for making a medical device. He method includes inserting one end portion of a flexible member through another end portion of the flexible member to form an adjustable loop. The method further includes locating a first portion of the adjustable loop over a second portion of the adjustable loop to form a first sub-loop and a second sub-loop, where the sub-loops configured to receive a length of tissue. 
   In one example, the method also includes locating a first portion of the second sub-loop over a second portion of the second sub-loop to form a third sub-loop. In another example, the flexible member comprises suture. In another example, the method also includes locating further comprises rotating a portion of the adjustable loop approximately 180 degrees of rotation. In another example, the method also includes sliding the first portion of the adjustable loop over the second portion of the adjustable loop to form a first sub-loop and a second sub-loop. 
   In yet another example, the method also includes locating a first portion of an assisting member within the first sub-loop and a second portion of the assisting member within the second sub-loop. In one example, the assisting member includes a medical grasping device. In another example, the assisting member comprises a cannula. In another example, the flexible member is a first flexible member. In this example, the method also includes inserting one end portion of a second flexible member through another end portion of the second flexible member to form a second adjustable loop, locating a first portion of the second adjustable loop over a second portion of the second adjustable loop to form a first sub-loop and a second sub-loop and locating a fourth portion of the assisting member within the first sub-loop of the second flexible member and a fifth portion of the assisting member within the second sub-loop of the second flexible member. 
   In another aspect, there is a method for attaching a fixation device to tissue. The method includes moving a first sub-loop and a second sub-loop of the fixation device over a portion of the tissue and pulling an end portion of the fixation device to reduce the size of the sub-loops to fixate the fixation device to the portion of the tissue. In one example, the method also includes moving a third sub-loop over the portion of tissue. In another example, the method also includes grasping tissue with an assisting member located within the first and second sub-loops. In another example, the method also includes sliding the first sub-loop and the second sub-loop off of the assisting member. In another example, the fixation device comprises suture. In another example, the tissue comprises ligament or tendon graft. 
   The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 

   
     DESCRIPTION OF DRAWINGS 
       FIG. 1  is a side view of a fixation device connected to tissue. 
       FIG. 2  is a side view of an adjustable loop. 
       FIG. 3  is a perspective view of the adjustable loop. 
       FIG. 4  is a side view of two sub-loops formed from the adjustable loop. 
       FIG. 5  is a side view of three sub-loops formed from the adjustable loop to produce the fixation device. 
       FIG. 6  is a side view of an alternative embodiment of three sub-loops formed from the adjustable loop of  FIG. 2  to produce the fixation device. 
       FIG. 7A  is a side view of the fixation device over a cannula. 
       FIG. 7B  is a side view of a plurality of fixation devices over a cannula. 
       FIG. 8  is a side view of the fixation device over a cannula being used with a medical grasping device. 
       FIG. 9  is a side view of the fixation device over a medical grasping device. 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , a fixation device  100  includes a length of flexible material, e.g., a suture  108  formed into a first sub-loop  110 , a second sub-loop  115 , and a third sub-loop  120 . As described in more detail below, sub-loops  110 ,  115 , and  120  are formed and wrapped around tissue  105  such that when a surgeon pulls an end  125  of suture  108  in a direction indicated by arrow  130 , sub-loops  110 ,  115 , and  120  constrict around and thus fixate on a portion  105   a  of tissue  105 . This allows the surgeon to pull tissue  105  by pulling end  125  of fixation device  100  and provides a limitless gripping force in that as the tension applied to  125  increases, the constriction of the loops around tissue  105  increases. In other words, the harder the surgeon pulls, the tighter sub-loops  110 ,  115 , and  120  constrict around portion  105   a  of tissue  105 . Tissue  105  includes, for example, a replacement ligament or tendon. Suture  108  includes, for example, medical grade suture suitable for use in a surgical procedure. 
   Referring to  FIGS. 2 and 3 , fixation device  100  is constructed by initially forming suture  108  into an adjustable loop  205 . Adjustable loop  205  is formed by passing end  125  of suture  108  through an opposite end  210  of suture  108 . For example, suture end  125  is pushed through end  210  such that portions  108   a  and  108   b  of suture end  210  define a hole  305 . Alternatively, hole  305  is preformed in suture end  210  and suture end  125  is passed through the hole. As constructed, suture  108  easily slides through hole  305  to increase or decrease the size of adjustable loop  205 . This mechanism also allows the surgeon to increase and decrease the size of any sub-loops formed from adjustable loop  205  when the surgeon pulls on end  125 . 
   Referring to  FIG. 4 , rotating adjustable loop  205  one-half turn, approximately 180 degrees, around an axis  400  generates sub-loops  110  and  115 . As illustrated, the rotation is in a direction indicated by arrow  405 . This rotation causes a first portion  410  of adjustable loop  205  to cross and overlap a second portion  415  of adjustable loop  205 . The overlapping portions  410  and  415  define part of the boundaries of sub-loops  110  and  115 . Axis  400  also represents how tissue  105  ( FIG. 1 ) passes through sub-loops  110  and  115 . As illustrated, tissue  105  goes into the center of second sub-loop  115 , under (with respect to the illustrated viewing angle) overlapping portions  410  and  415 , and out of the center of the first sub-loop  110 . 
   Referring to  FIG. 5 , rotating sub-loop  115  another one-half turn, approximately 180 degrees, around axis  400  generates the third sub-loop  120 . This rotation causes a third portion  510  of adjustable loop  205  to cross and overlap a fourth portion  515  of adjustable loop  205 . The overlapping portions  510  and  515  define part of the boundaries of sub-loops  115  and  120 . Axis  400  also represents how tissue  105  ( FIG. 1 ) passes through sub-loops  110 ,  115  and  120 . As illustrated, tissue  105  goes into the center of third sub-loop  120  and over (with respect to the illustrated viewing angle) overlapping portions  510  and  515 . Tissue  105  also goes into the center of second sub-loop  115 , under (with respect to the illustrated viewing angle) overlapping portions  410  and  415 , and out of the center of the first sub-loop  110 . This process can be repeated multiple times to generate multiple sub-loops from adjustable loop  205 . An advantage to having three sub-loops over two sub-loops, as depicted in  FIG. 4 , is that additional loops provide greater tissue to suture purchase, along with greater capacity for load distribution. 
   Rotating adjustable loop  205 , or a portion thereof, is one way to generate sub-loops  110 ,  115 , and  120 . There are, however, other processes to generate sub-loops  110 ,  115 , and  120 .  FIG. 6  illustrates one of those alternative processes to generate sub-loops  110 ,  115 , and  120 . As illustrated in  FIG. 6 , starting with the adjustable loop  205  of  FIG. 2 , one side of adjustable loop  205  is moved in the direction of arrow  605  while an opposite side of adjustable loop  205  is moved in the direction of arrow  610 . The moving sides eventually overlap at portions  410 ,  415 ,  510 , and  515 , generating sub-loops  110 ,  115 , and  120 . In this process, unlike the rotation process illustrated in  FIG. 5 , fourth portion  515  of adjustable loop  205  crosses and overlaps third portion  510  of adjustable loop  205  (with respect to the illustrated viewing angle). 
   Referring to  FIG. 7A , to aid in positioning sub-loops  110 ,  115 , and  120  around tissue  105 , a device, e.g.,  705  is placed through sub-loops  110 ,  115 , and  120  along axis  400 . Referring to  FIG. 7B , cannula  705  can include a plurality of fixation devices  100  and  100 ′. In another example (not shown), cannula  705  includes four fixation devices  100 . 
   Referring to  FIG. 8 , to transfer fixation device  100  from cannula  705  onto tissue  105 , a surgeon uses a grasping device  805 , inserted through cannula  705 , to grasp tissue  105 . With tissue  105  located at an end  810  of cannula  705 , the surgeon manually slides sub-loops  110 ,  115 , and  120  in a direction indicated by arrow  815 . Sub-loops  110 ,  115 , and  120  slide off of cannula  705  and onto tissue  105 . As illustrated, fixation device  100  slides off of cannula  705 , onto grasping device  805  and then onto tissue  105 . 
   In an alternative example, the surgeon can locate end  810  of cannula  705  directly over tissue  105  so that when fixation device  100  slides off of cannula  705 , it falls directly onto tissue  105 . In yet another alternative example, with a plurality of fixation devices  100  located on cannula  705 , after attaching a first fixation device to tissue  105 , the surgeon grasps another piece of tissue and slides second fixation device onto the other piece of tissue without the need to reload a fixation device between attachments. 
   Referring to  FIG. 9 , cannula  705  can be eliminated and the fixation device  100  located directly on the grasping device  805 . Like  FIG. 8 , the surgeon slides sub-loops  110 ,  115 , and  120  in a direction indicated by arrow  815 . Sub-loops  110 ,  115 , and  120  slide off of grasping device  805  and onto tissue  105 . 
   In use, fixation device  100  allows a surgeon to easily fix suture  108  to tissue  105  so the surgeon can manipulate and direct tissue  105  as needed using suture end  125 . As described above, while the surgeon pulls end  125  to direct tissue  105  during a surgical procedure, the sub-loops  110 ,  115 , and  120  formed from adjustable loop  205  constrict and grip the tissue  105  tighter. The surgeon is able to pull and move tissue  105  to direct tissue  105 , for example, through holes for receiving the tissue formed in a bone or other soft tissue. When the surgeon is done, the surgeon typically cuts off tissue portion  105   a  from tissue  105  and discards portion  105   a.    
   A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example only and not limit the alternatives the following are some variations to the above examples. For example, other materials can be used in addition to suture for a flexible member. Also, the number of sub-loops and the process used to generate those sub-loops can vary. Also, any device can be used to help temporarily hold the fixation device so that a surgeon can locate the sub-loops onto the tissue. Also, although the term surgeon was used for clarity, any medical personnel can use the fixating device. Accordingly, other embodiments are within the scope of the following claims.