Abstract:
A bone graft compaction pliers with removable inserts defines a bone graft harvesting and deployment system applicable to a wide variety of bone graft sized for use with bone anchors such as those employed in ACL repair. Cannulated bone anchors for encouraging bone regrowth employ an anchor with a axial cannulated bore and a plurality of fenestrations surrounding the bore to facilitate bone regrowth. A variety of sizes of single use inserts corresponding to a bone graft shape, or diameter, engage a single compaction pliers for forming various sized bone grafts from a single tool. A transparent transfer tube and corresponding base receives the formed bone graft for length adjustment, and engages protrusions on the recipient bone anchor for aligning the transfer tube to the anchor for disposing the bone graft into the cannulated bore of the anchor.

Description:
BACKGROUND 
       [0001]    Reconstructive surgical procedures often attach donor and prosthetic connection members to structural skeletal members of a patient. Often, bone grafts provide surgical attachment of reconstructive components such as tendons, ligaments, and prosthetic anchors. Various methods of attaching tissue, such as soft tissue, grafts or ligaments to bone have been employed. In anterior or posterior cruciate ligament reconstruction (ACL or PCL), for example, conventional approaches employ interference screws used to secure the graft against the walls of tunnels drilled in the tibia and the femur. The interference screws are wedged between the graft and a wall of the tunnel. To facilitate insertion and improve anchoring, some interference screws include cutting threads or other anchoring features. Alternately, in performing hip prosthesis surgery, it is frequently necessary or desirable to place bone graft material in the intramedullary canal of the femur in order to promote new bone growth. Insertion of harvested bone material at a surgical site facilitates regeneration of bone around the inserted anchors. 
       SUMMARY 
       [0002]    A bone graft compaction pliers with removable inserts defines a bone graft harvesting and deployment system applicable to a wide variety of bone graft sizes for use with bone anchors such as those employed in ACL repair. Cannulated bone anchors for encouraging bone regrowth employ an anchor with an axial cannulated bore and a plurality of fenestrations surrounding the bore to facilitate bone regrowth into and around the inserted anchor for strengthening the bone anchor and mitigating possible complications with exposed foreign surfaces at a surgical site. A variety of sizes of single use inserts corresponding to a bone graft shape, or diameter, engage a single compaction pliers for forming various sized bone grafts from a single tool. A transparent transfer tube and corresponding base receives the formed bone graft for length adjustment, and engages protrusions on the recipient bone anchor for aligning the transfer tube to the anchor for disposing the bone graft into the cannulated bore of the anchor. 
         [0003]    Configurations herein are based, in part, on the observation that conventional approaches to bone graft harvesting and insertion techniques encounter difficulties in matching the size of the graft to the size of the anchor cannula or bone hole to which the graft is to be inserted. Unfortunately, conventional approaches to bone graft deployment suffer from the shortcoming that substantial pressure and force are required to properly form the bone graft from harvested bone material, typically requiring sturdy metal tools, yet the surgical nature of the procedure mandates either single-use materials or extensive cleaning and sterilization. Considerable expense may be associated with the range of tools needed to anticipate a variety of bone graft sizes. 
         [0004]    Accordingly, configurations herein substantially overcome the above-described shortcomings by providing a compression pliers with removable single-use inserts sized to particular bone graft shapes (typically cylindrical). A single compaction pliers is receptive to a range of inserts corresponding to the various sizes of bone grafts, thus allowing the unitary inserts to remain single use, mitigating production costs, and allowing a single tool to accommodate a variety of bone graft sizes. The tool remains reusable, thus imposing only resterilization of a single tool, rather than a range of tools otherwise required for different sized grafts. Alternatively, a single use compaction pliers would still only impose a single tool usable with multiple inserts, rather than multiple compaction pliers, each corresponding to a particular bone graft size. 
         [0005]    Configurations herein disclose a bone graft formation and insertion device including a pair of pivotally coupled elongated handles having opposed compressive members drawn together in a compressive engagement by closure of the handles, such that each of the opposed compressive members, or jaws, has a receptacle for engaging an insert, the inserts in turn having compressive faces defining a compression cavity corresponding to a cannulated anchor, in which the cannulated anchor is receptive to a bone graft formed by drawing together and engaging the opposed compressive faces. Latches provide for detachable engagement with a plurality of inserts having different compressive faces. 
         [0006]    The device performs a system and method for harvesting, forming and inserting bone grafts, by forming a bone graft between opposed compressive faces of a compaction pliers, such that each of the opposed compressive faces defines a removable insert corresponding to a shape of the bone graft, and transferring the bone graft to a transfer tube, such that the transfer tube has a shape corresponding to the shape of the bone graft for receiving the bone graft. A transfer block measures, during the transfer of the bone graft to the transfer tube, a length of the bone graft to correspond to a length of a receptive anchor for receiving the bone graft, following which the transfer tube is engaged to the receptive anchor, in which the anchor has been previously inserted in a surgical site and has a cannulated bore corresponding to the shape of the bone graft. A plunger inserts the bone graft into the cannulated bore by disposing the plunger through an opposed end of the transfer tube, in which the plunger corresponds to the shape of the transfer tube for driving the bone graft to a predetermined depth corresponding to the anchor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The foregoing and other objects, features and advantages of the invention will be apparent from the following description of particular embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
           [0008]      FIG. 1  is a context diagram of compaction pliers in a surgical environment; 
           [0009]      FIG. 2  is a perspective view of inserts in the compaction pliers of  FIG. 1 ; 
           [0010]      FIG. 3  is a perspective view of the sliding inserts of  FIG. 2  partially disposed; 
           [0011]      FIG. 4  is a cutaway view of a retention mechanism for retaining the sliding inserts of  FIG. 3 ; 
           [0012]      FIG. 5  is a perspective view of a compression cavity formed between a pair of opposed inserts; 
           [0013]      FIG. 6  is a perspective view of a compaction pliers with a latched retaining mechanism for the removable inserts; 
           [0014]      FIG. 7  is a side perspective view of the compaction pliers of  FIG. 6 ; 
           [0015]      FIG. 8  is a top perspective view of a removable insert corresponding to the compaction pliers of  FIGS. 6 and 7 ; 
           [0016]      FIG. 9  is a side perspective view of the insert of  FIG. 8 ; 
           [0017]      FIG. 10  is a perspective view of a transfer tube for receiving a bone graft formed by the inserts of  FIGS. 8 and 9 ; 
           [0018]      FIG. 11  is a plunger for disposing the bone graft into the transfer tube; 
           [0019]      FIG. 12  is a transfer block for receiving the transfer tube of  FIG. 10  and adjusting bone graft length of the graft material therein; and 
           [0020]      FIGS. 13-17  show usage of the disclosed device at various stages of deployment. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]      FIG. 1  is a context diagram of compaction pliers in a surgical environment. Referring to  FIG. 1 , in ACL repair and other procedures, a compaction pliers  100  and corresponding removable inserts  120 - 1 ,  120 - 2  are employed as a surgical instrument for use with bone graft techniques. The compaction pliers  100  are a device for shaping harvest bone material to a consistent size corresponding to a bone tunnel (surgical excavation or hole)  110  for receiving the bone graft material. The compaction pliers  100  include cutting inserts  120 - 1 ,  120 - 2  ( 120  generally) on opposed jaws  122 - 1 ,  122 - 2  ( 122  generally) drawn together by closure of handles  102 ,  103  attached at a pivot point  104 . The sliding and cutting insets  120  may be spring ( FIG. 4 )  128  loaded with knobs  124  to lock and slide around graft material while it is engaged and advanced into the surgical excavation  110 , typically via a hand driven plunger tool. Alternatively, the inserts  120  may be latched onto the opposed jaws  122 , both discussed further below. 
         [0022]      FIG. 2  is a perspective view of inserts in the compaction pliers of  FIG. 1 . In operation of the proposed approach, manual closure of handles  102 ,  103  forces a compression face  130 - 1  of the inserts  120  drawn to be into a compressive mating with a harvest material between an opposed compressive face  130 - 2  ( 130  generally). Each of the compression faces  130  is slideably engageable with the articulated jaws  122  that pivot to close the respective compressive faces  130  in engagement around the donor graft material such that the graft takes the shape defined by the faces  130 . In a particular approach, the compression faces  130  define a cylindrical shape  132  flanked by axial cutting edges  134 - 1 ,  134 - 2  along each side of the cylindrical shape  132  and running parallel to the cylindrical axis. 
         [0023]    Depicted below are various configurations of the surgical instrument including compaction pliers  100  having compressive faces  130  formed to define the desired shape  132  of a bone graft. The compaction pliers  100  perform a method of delivering compacted bone as bone graft material from the pliers  100  and into an attachment member, such as a screw or threaded member, for disposing the graft material into contact with native bone material for facilitating reconstructive growth. Bone graft material may be inserted directly into a bone tunnel, or may be inserted into a cannulated, fenestrated anchor for providing additional holding strength as the bone regrows around the anchor. Typically, the graft is a cylindrical size  132  substantially similar to a drilled receptacle (hole)  110  in the skeletal (bone) structure  160  for attachment. The compaction pliers  100  are therefore for use with bone graft techniques for shaping harvest bone material to a consistent size corresponding to a surgical excavation (graft hole)  110 , in which the pliers include sliding and cutting inserts  120  attached by an retention mechanism, such as an engaging slot, or may be spring  128  loaded with knobs  124  to lock and slide around graft material on opposed jaws  122  drawn together by closure of handles  102 ,  103  attached at a pivot point  104 . 
         [0024]      FIG. 3  is a perspective view of the sliding inserts of  FIG. 2  partially disposed, and  FIG. 4  is a cutaway view of a retention mechanism for retaining the sliding inserts of  FIG. 3 . Referring to  FIGS. 3 and 4 , in an example arrangement using a drill system for extracting donor bone, once the harvest bone is removed from a drill or other harvesting mechanism, the bone is shaped with the compaction pliers  100  to the predetermined size diameter  132 . The sliding and cutting insets  120  have the ability to advance from one position to another position and lock in place. A plunger  150  ( FIG. 11 , below) is employed to push the shaped bone from the sliding and cutting inserts into the attachment member, such as a cavitized bone screw having a cannulated bore or void for receiving the graft material and maintaining contact with the native bone  160 . 
         [0025]    In operation, the knobs  124  are spring  128  loaded to lock and slide the inserts  120 . The locking and sliding mechanism provides improved control and provides for a built in transfer insert. 
         [0026]      FIG. 5  is a perspective view of a compression cavity  140  formed between a pair of opposed inserts. Referring to  FIGS. 4 and 5 , In contrast to conventional approaches, the proposed approach employs sliding and cutting inserts  120  anchored into articulated jaws  122  with spring loaded knobs  124  to slide and lock into place. The proposed approach further differs because a compression face  130 - 1  is drawn into a compressive mating with a harvest material between an opposed compressive face  130 - 2 , and is slideably engageable with the articulated jaws  122  that pivot to close the respective compressive faces  130  to form the compression cavity  140 . In the proposed approach, the compression faces  130  define a cylindrical shape  132  flanked by axial cutting edges  134 - 1 ,  134 - 2  along each side of the cylindrical shape  132  and running parallel to the cylindrical axis. The novel cutting edges  134  sever and extract excess harvest material resulting in a uniform cylindrical shape of the desired diameter. Conventional approaches do not employ opposed compression faces  130  pivotally coupled via articulated handles  102 ,  103  and drawn together in an arcuate manner via closure of the handles. 
         [0027]      FIG. 6  is a perspective view of a compaction pliers  200  with a latched retaining mechanism for the removable inserts. Referring to  FIG. 6 , the compaction pliers  200  employs a latch  210  on each compressive face  122  as a retention mechanism, rather than the threaded knobs of  FIGS. 1-5 . The latch  210  employs a graduated ramp surface  212  and a locking aperture  214  for engaging an insert  220 , discussed further below. As in 
         [0028]      FIGS. 1-5 , opposed handles  102 ,  103  are attached at a pivot point  104 . A locking member  205  is hinged on the handle  103  for engaging a pin or slot  207  on handle  102 , for fixing the handles and the articulated jaws  122  in position. Engagement slots  215 - 1 ,  215 - 2  ( 215  generally), on each respective opposed member, or jaw  122 - 1 ,  122 - 2  are receptive to the inserts  220 . 
         [0029]      FIG. 7  is a side perspective view of the compaction pliers of  FIG. 6 . Referring to  FIGS. 6 and 7 , the engagement slots  215  are shown as an annular shape receptive to a circular insert, however any suitable engagement shape could be employed. 
         [0030]      FIG. 8  is a top perspective view of a removable insert corresponding to the compaction pliers of  FIGS. 6 and 7 , and  FIG. 9  is a side perspective view of the insert of 
         [0031]      FIG. 8 . Referring to  FIGS. 6-9 , the inserts  220  have wings  222  biased for detachable engagement with latches on the opposed compressive jaws  122 . The wings  222  have tabs  224  that engage the locking aperture  214  as the insert  220  is inserted into the engagement slots  215 . As the insert  220  is inserted onto the engagement slots  215  from a distal end  221 (distal end inserted first), the tabs  224  slideably contact the ramp surface  212  forcing the wing  222  away from the insert  212  as shown by arc  226 . The ramp surface  212  biases the wing  222  apart a particular distance  228  to pass the edge of aperture  214 , following which the biased wing  222  “snaps” the tab  224  into the aperture as the wing  222  locks the tab  224  into the aperture  214 , securing the insert  220  in the engagement slot  215 . 
         [0032]    The bone graft is formed from harvested bone shaped between the inserts  220 , as each of the pair of inserts  220  have complementary compressive faces  230  for enclosing the harvested bone and forming a shape engaged by the cannulated anchor, discussed further below. The inserts  220  generally define complementary pairs of faces  230  defining a circular or other shaped compression cavity  140 . In the example arrangement of  FIGS. 6-9 , the inserts  222  define a cylindrical shape having a diameter corresponding to a diameter of a bore through the cannulated anchor that is to receive the graft. Each of the engagement slots  215  defines a receptacle that is responsive to a plurality of inserts  220 , such that each of the inserts  222  corresponds to a specific bone graft size, based on the compressive faces  230  defining the compression cavity corresponding to the bone graft size. Therefore, each complementary pairs of inserts  220  defines a circular graft shape based on the bone graft size when engaged on the opposed compressive faces  230 . 
         [0033]    Each of the inserts  220  further includes a transfer tab  240  for engaging an annular groove or ridge on a transfer tube for receiving the graft, discussed further below. 
         [0034]      FIG. 10  is a perspective view of a transfer tube  250  for receiving a bone graft formed by the inserts  220  of  FIGS. 8 and 9 . Referring to  FIGS. 8-10 , the inserts  220  are adapted for engagement with a transfer tube  250  having a diameter  252  corresponding to the bore receptive to the bone graft. The transfer tube  250  also has a rotary groove or lip  254  for engagement with the inserts, such that the transfer tube  250  is adapted for receiving the cylindrical shape of the formed bone graft. The transfer tabs  240  of the respective inserts  220  draw together such that the tab  240  engages the underside of the lip  254  and an annular surface  242  of the tab  240  engages an outer surface  256  of the transfer tube  250  upon closure of the handles  102 ,  103 , as the inserts  220  remain engaged on the slots  122 . The tabs  240  define a distance  256  from the opening of the compression cavity  140  to the underside of the lip  254 , matched to distance  256 ′ such that the transfer tube is flush with the compression cavity  140  for receiving the bone graft. 
         [0035]      FIG. 11  is a plunger for disposing the bone graft into the transfer tube. Referring to  FIG. 11 , and continuing to refer to  FIGS. 8-10 , the plunger  150  has a shaft  260  with a diameter  262  corresponding to the interior of the compression cavity  140 . Upon engagement of the inserts  220  with the transfer tube  250 , the plunger  150  is disposed through the compression cavity  140  to transfer the formed graft into the transfer tube  250  at a proximal end  258 . 
         [0036]      FIG. 12  is a transfer block for receiving the transfer tube of  FIG. 10  and adjusting bone graft length of the graft material therein. Referring to  FIGS. 8-12 , once the graft is disposed in the transfer tube  250 , the tube  250  is placed in a receptacle  272  in a transfer block  270 . The transfer block  270  is adapted to measure the length of the bone graft, such that the block  270  acts as a base having markings  274  for ascertaining the length and the transfer tube  250  being transparent for comparing the bone graft to the markings. Following plunger  150  insertion of the graft into the transfer tube  250 , and positioning of the transfer tube  250  in the transfer block  270 , a truncation arm  276  pivots to cut any excess graft material to trim the graft to the proper length. Alternatively, the inserts  220  have a cutting edge for severing excess shaped material. 
         [0037]    Once graft material is fixed at the proper length in the transfer tube  250 , the transfer tube  250  is disposed to the recipient anchor that was previously inserted at the surgical site. The transfer tube  250  has a mating surface  263  having protrusions  264  or other suitable alignment mechanism. The protrusions  264  correspond to a mating surface on the recipient anchor, such that the corresponding protrusions  264  maintain axial alignment along the cannulated bore for insertion of the bone graft. 
         [0038]    Referring collectively to  FIGS. 6-12 , the above described apparatus provide a method for harvesting and inserting bone grafts, which may be undertaken by a surgeon or operating team for deploying the bone graft, including forming a bone graft between opposed compressive faces  230  of a compaction pliers, such that each of the opposed compressive faces  230  has a removable insert  215  corresponding to a shape of the bone graft, and transferring the bone graft to an transfer tube  250 , in which the transfer tube  250  has a shape corresponding to the shape of the bone graft for receiving the bone graft into the transfer tube  250 . A transfer block  270  is employed to measure, during the transfer of the bone graft, a length of the bone graft to correspond to a length of a receptive anchor for receiving the bone graft. From the proper length graft disposed in the transfer tube, the transfer tube  250  is engaged to the receptive anchor, such that the anchor has been previously inserted in a surgical site and has a cannulated bore corresponding to the shape of the bone graft. Alternatively, as indicated above, the graft may be inserted directly into a drilled bone tunnel or other surgical aperture. A plunger  150  has a shaft  260  that inserts the bone graft into the cannulated bore by disposing the shaft  260  through an opposed end of the transfer tube  250 , in which the plunger corresponds to the shape of the transfer tube for driving the bone graft to a predetermined depth corresponding to the anchor. 
         [0039]      FIGS. 13-17  show usage of the disclosed device at various stages of deployment. Referring to  FIGS. 6-17 ,  FIG. 13  shows the inserts  220  engaging the jaws  122 - 1 ,  122 - 2  for defining the compression cavity  140 .  FIG. 14  shows the inserts  220  grasping the transfer tube  240  via the tabs  240  on the inserts  220 . It should be noted that the transfer tube  250  employs a groove  254 ′ as an alternative to the lip  254  of  FIG. 10 .  FIG. 15  shows an assembly of the compaction pliers  200  engaging the transfer tube  250  (shown as a transparent/cutaway for clarity) between the inserts  222  by grasping with the tabs  240  and inserting the transfer tube  250  into the receptacle  272  in the transfer block  270 . In the receptacle  272 , the plunger  150  is disposed through the compression cavity  140 , and has a shaft  260  which matches the diameter  252  of the inside of the transfer tube  150  for receiving the graft material. Markings  284  on the plunger, or alternatively markings  274  on the transfer block  270  are employed to ensure the proper length of the formed graft material. 
         [0040]      FIG. 17  shows engagement of the transfer tube  250  with the cannulated anchor  280  for insertion of the formed graft, trimmed to length. In practice, the cannulated anchor  280  would have been previously inserted in a bone tunnel. Alternatively, graft material may be deposited directly into a surgical cavity such as a bone tunnel. The plunger  150  forces the shaft  260  through the insertion tube  250 , thus disposing the grant material into the cannulated anchor  280 , where fenestrations  282  facilitate bone growth, facilitated by markings  284 . 
         [0041]    In the example configuration, measuring the bone graft further includes inserting the engaged compaction pliers  100  and transfer tube  250  in a transfer block  270  adapted to measure the length of the bone graft, such that the block  270  has marking for ascertaining the length and the transfer tube  250  is transparent for comparing the bone graft to the markings. The transfer tube  250  has an annular lip  254  or groove for engaging the compaction pliers  100  via the a tab  240  on the inserts  220 , which provide gripping engagement for forcing the bone graft into the transfer tube by disposing the plunger  260  through a compression cavity  140  of the closed compaction pliers  100 . The removable inserts  220  are adapted for latchable engagement with each of the engageable slots  214 , and define a cylindrical shape adapted for insertion in a bone tunnel or cannulated bone anchor. 
         [0042]    The transfer tube  250  has a mating surface  263  having protrusions  264 , and the protrusions correspond to a mating surface on the anchor, facilitating the use of the corresponding protrusions for maintaining axial alignment along the cannulated bore for insertion of the bone graft. The anchor  280  has fenestrations  282  for facilitating bone growth with the inserted bone graft, and is inserted to a predetermined depth is such that the bone graft substantially extends through the length of the cannulated bore of the bone anchor. 
         [0043]    While the system and methods defined herein have been particularly shown and described with references to embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.