Serratome vertebral cortical endplate cutter

Abstract

The invention relates to spinal fusion implants or grafts and to apparatus for the installation thereof. More specifically, the invention is a serrated cutting or abrading tool designed to be pushed into an intervertebral space and thereby remove and partially penetrate the cortical bone layer that defines the endplates of the respective mutually adjacent vertebral bodies.

We claim:  
     
         1 . A spine surgery instrument for cutting and removing a controlled amount of cortical endplate bone from at least one vertebral body adjacent to an intervertebral space remaining after excision of all or part of an intervertebral disc, said instrument comprising a tome having a body with a parallelepiped shape and having a distal end and a proximal end, said parallelepiped having a top surface and a bottom surface when inserted into the intervertebral space, said distal end being substantially planar, said tome being substantially hollow and at least the distal end being open, said top surface and said bottom surface having at the distal end a plurality of sharp edged serrations configured to cut or abrade the endplate of the at least one vertebral body.  
     
     
         2 . The instrument of  claim 1  in which the parallelepiped shape is a truncated four sided pyramid.  
     
     
         3 . The instrument of  claim 1  in which the parallelepiped shape is a rectangular parallelepiped.  
     
     
         4 . The instrument of  claim 1  in which the serrations comprise the end edges of protrusions in the top surface and the bottom surface.  
     
     
         5 . The instrument of  claim 4  in which the serrations are shaped so as to present the maximum surface area at the distal end of the tome.  
     
     
         6 . The instrument of  claim 1  further comprising a shaft having a first end connected to the proximal end of the tome, and a second end having attached thereto an extension for engagement with mechanical energy transmission means.  
     
     
         7 . The instrument of  claim 6  further comprising a depth stop on the shaft between the body and the extension.  
     
     
         8 . A spine surgery instrument for cutting and removing a controlled amount of cortical endplate bone from at least one vertebral body adjacent to an intervertebral space remaining after excision of all or part of an intervertebral disc, said instrument comprising a tome having a body with a parallelepiped shape and having a distal end and a proximal end, said parallelepiped having a top surface and a bottom surface when inserted into the intervertebral space, said distal end having a blunt front end region, said top surface and said bottom surface having set back from the blunt front end of the distal end a plurality of sharp edged serrations configured to cut or abrade the endplate of the at least one vertebral body.  
     
     
         9 . The instrument of  claim 8  in which the parallelepiped shape is a truncated four sided pyramid.  
     
     
         10 . The instrument of  claim 8  in which the parallelepiped shape is a rectangular parallelepiped.  
     
     
         11 . The instrument of  claim 8  in which the serrations comprise the end edges of protrusions in the top surface and the bottom surface.  
     
     
         12 . The instrument of  claim 8  in which the blunted front end region comprises a tip that is circular, parabolic, or ogive in shape, joined with flat inclined faces which are arranged symmetrically with one another, joined with parallel flat surfaces.  
     
     
         13 . The instrument of  claim 8  further comprising a shaft having a first end connected to the proximal end of the tome, and a second end having attached thereto an extension for engagement with mechanical energy transmission means.  
     
     
         14 . The instrument of  claim 13  further comprising a depth stop on the shaft between the body and the extension.