Compression-distraction spinal fixation system

Abstract

Compression-distraction spinal fixation systems, and methods of performing compression-distraction spinal fixation, are provided that include screw-rod constructs having a ratcheting mechanism. Bone screws of the screw-rod constructs can have a pawl that engages ratchet teeth on the rod of the screw-rod construct. The bone screw can be ratcheted along the length of the rod to apply distractive or compressive forces.

1 .- 19 . (canceled) 
     
     
         20 . A compression-distraction spinal fixation system comprising:
 at least one bone screw having a head;   a pawl mounted to the head of the at least one bone screw; and   a toothed rod extending in a longitudinal direction and connected to the at least one bone screw, the toothed rod having a plurality of ratchet teeth,   wherein the toothed rod extends through a first side of the head,   wherein the pawl is configured to extend from the first side of the head and engage the ratchet teeth of the toothed rod at the first side of the head from which the pawl extends.   
     
     
         21 . The compression-distraction spinal fixation system of  claim 20 , wherein the toothed rod further extends through a second side of the head, wherein the pawl is movable to extend from the second side of the head and engage the ratchet teeth of the toothed rod at the second side of the head. 
     
     
         22 . The compression-distraction spinal fixation system of  claim 21 , wherein the second side of the head is about 180° from the first side of the head. 
     
     
         23 . The compression-distraction spinal fixation system of  claim 21 , wherein the pawl is connected to a side surface of the head with a fastener. 
     
     
         24 . The compression-distraction spinal fixation system of  claim 23 , wherein the pawl is rotatable between the first side and the second side of the head about an axis of the fastener. 
     
     
         25 . The compression-distraction spinal fixation system of  claim 23 , wherein the pawl is slidable along the side surface of the head and between the first side and the second side of the head. 
     
     
         26 . The compression-distraction spinal fixation system of  claim 25 , the pawl further comprising a fastener groove therethrough, wherein the fastener groove is configured to receive the fastener. 
     
     
         27 . The compression-distraction spinal fixation system of  claim 26 , wherein the fastener groove is configured to slide along the fastener when the pawl slides between the first side and the second side of the head. 
     
     
         28 . The compression-distraction spinal fixation system of  claim 20 , further comprising a set screw, wherein the head of the at least one bone screw is configured to receive the set screw therein in order to maintain the toothed rod in the head of the at least one bone screw. 
     
     
         29 . The compression-distraction spinal fixation system of  claim 28 , wherein the set screw is configured to be tightened in the head of the at least one bone screw to maintain the at least one bone screw in a fixed position relative to the toothed rod. 
     
     
         30 . The compression-distraction spinal fixation system of  claim 20 , wherein the pawl includes a blade configured to engage the ratchet teeth of the toothed rod. 
     
     
         31 . The compression-distraction spinal fixation system of  claim 20 , wherein the first side of the head defines at least a part of the perimeter of the head, and the pawl is configured to extend beyond the perimeter of the head. 
     
     
         32 . The compression-distraction spinal fixation system of  claim 20 , wherein the at least one bone screw is a first bone screw, wherein the compression-distraction spinal fixation system further comprises:
 a second bone screw comprising a pawl;   wherein the toothed rod is connected to both the first bone screw and the second bone screw, the pawl of the first bone screw is configured to engage the ratchet teeth of the toothed rod, and the pawl of the second bone screw is configured to engage the ratchet teeth of the toothed rod.