Compression bone staple, apparatus and method of the invention

Abstract

A method and apparatus for interosseous bone fixation uses a compression staple, generally U-shaped, having a pair of legs with sharp front ends and proximal ends interconnect by a bridge portion that is resilient and bowed, the staple having an initial configuration and capable of a tensioned configuration by spreading apart the legs by a certain amount causing the curvature of the bowed bridge to lessen and the legs urged towards each other with certain compressive spring force. A staple applicator supports and guides the staple and positions the tensioned staple with its pointed ends forward, adjacent an ejection port at the front of the applicator. A powered strike member is mounted for longitudinal movement and has a front end that will strike the rear of the tensioned staple with percussive force and eject it in tensioned configuration from the applicator.

1 . A bone staple applicator for driving one or more bone staples into bone segments to secure the bone segments across a fracture site, each bone staple comprising two legs and a substantially flat bridge portion coupling the two legs to one another, the two legs and substantially flat bridge portion each having inside surfaces, the bone staple applicator comprising:
 an elongate main body having a proximal end, a distal end, and a longitudinal axis extending therethrough;   a bone staple feeder having a proximal end, a distal end coupled to the distal end of the elongate main body to define a bone staple receiving channel, and a longitudinal axis extending between said proximal and distal ends that is substantially perpendicular to the longitudinal axis of the elongate main body, the bone staple feeder being adapted to feed a bone staple into the bone staple receiving channel,   wherein the bone staple feeder comprises an elongate ramp member and a pusher slidably coupled to the elongate ramp member, the elongate ramp member being adapted to slideably engage the substantially flat inside surfaces of the two legs and substantially flat bridge portion of each bone staple, the ramp member further being adapted to accommodate a plurality of bone staples in a side-by-side configuration wherein the two legs of a first bone staple are adjacent to the two legs of an adjacent second bone staple; and   a staple striker slidably coupled to the elongate main body and adapted to strike the substantially flat bridge portion of the bone staple placed in the bone staple receiving channel with sufficient percussive force to drive the legs of said bone staple into bone.   
     
     
         2 . The bone staple applicator of  claim 1 , wherein each bone staple does not any protrusions extending proximally from the substantially flat bridge portion. 
     
     
         3 . The bone staple applicator of  claim 1 , wherein each bone staple has a relaxed configuration wherein the two legs of the bone staple converge toward one another and a tensioned configuration wherein the two legs of the bone staple are substantially parallel. 
     
     
         4 . The bone staple applicator of  claim 3 , wherein the elongate ramp member has a proximal end and a distal end, and wherein the elongate ramp member is shaped to urge a bone staple from the relaxed configuration to the tensioned configuration as the pusher advances the bone staple from the proximal end of the elongate ramp member to the distal end of the elongate ramp member. 
     
     
         5 . The bone staple applicator of  claim 4 , wherein the elongate ramp member comprises side surfaces adapted to face the inside surfaces of the two legs of a bone staple. 
     
     
         6 . The bone staple applicator of  claim 5 , wherein the side surfaces have a convergent orientation at the proximal end of the elongate ramp member. 
     
     
         7 . The bone staple applicator of  claim 5 , wherein the side surfaces have a substantially parallel orientation at the distal end of the elongate ramp member. 
     
     
         8 . The bone staple applicator of  claim 3 , wherein the elongate ramp member has a proximal end and a distal end, wherein the distal end of the elongate ramp member is adapted to maintain a bone staple fed into the bone staple receiving channel in the tensioned configuration. 
     
     
         9 . The bone staple applicator of  claim 1 , wherein the pusher is adapted to advance a second bone staple into the bone staple receiving channel after a first bone staple has been driven out of the bone staple receiving channel by the staple striker. 
     
     
         10 . The bone staple applicator of  claim 8 , wherein the bone staple feeder comprises a spring coupled to the pusher to advance the pusher. 
     
     
         11 . The bone staple applicator of  claim 1 , wherein the staple striker is adapted to drive the legs of a bone staple into bone such that the legs are maintained in a substantially parallel orientation in the bone.