Odontoid bullet

Abstract

Cervical fixation devices, systems and methods for repairing odontoid fractures to the C2 vertebral body, including an anchoring feature that crosses the fracture site to be positioned external to the fractured bone fragment and which provides compressive and radial forces externally to the bone to immobilize the bone fragment(s) for fixation to the main bone structure.

What is claimed is: 
     
         1 . A cervical fixation system, comprising:
 a first fastening device for engagement with a first surface portion of a cervical body, the first fastening device having a generally elongated shape, the first fastening device having a plurality of openings extending generally transversely therethrough, at least a first opening of the plurality of openings positioned proximate to a midpoint of the generally elongated shape and a second opening of the plurality of openings positioned proximate to an end of the generally elongated shape, at least a portion of a side surface of the first fastening device having a concave shape for engagement with the first surface portion of the cervical body;   a second fastening device having a side surface for engaging a second surface portion of the cervical body, the second device having at least one opening formed therethrough; and   a flexible tension member attached between the first and second fastening devices, the flexible tension member extending through the first opening of the first fastening device and the at least one opening of the second fastening device,   wherein when the flexible tension member is tensioned, the first and second fastening devices apply a compressive force across at least a portion of the cervical body and an odontoid associated with the cervical body.   
     
     
         2 . The cervical fixation system of  claim 1 , further comprising a flexible recovery member attached to the first fastening device, the flexible recovery member extending through the second opening in the first fastening device. 
     
     
         3 . The cervical fixation system of  claim 2 , wherein the first fastening device includes a first end comprising a generally rounded conical shape. 
     
     
         4 . The cervical fixation system of  claim 3 , wherein the first fastening device includes a second end comprising a generally rounded conical shape. 
     
     
         5 . The cervical fixation system of  claim 1 , wherein at least a portion of a second side surface of the first fastening device comprises a generally flattened shape. 
     
     
         6 . The cervical fixation system of  claim 1 , wherein the plurality of openings in the first fastening device further includes a third opening positioned proximate to a midpoint of the generally elongated shape, the first and third openings located on opposing sides of the midpoint of the generally elongated shape. 
     
     
         7 . A cervical fixation system, comprising:
 a first fastening device for engagement with a first surface portion of a cervical body, the first fastening device having a generally elongated shape, the first fastening device having a plurality of openings extending generally transversely therethrough, at least a first and a second opening of the plurality of openings positioned proximate to a central region of the generally elongated shape and a third opening of the plurality of openings positioned proximate to a first end region of the generally elongated shape, at least a portion of a side surface of the first fastening device having surface features adapted and configured for engagement with the first surface portion of the cervical body;   a second fastening device having a side surface for engaging a second surface portion of the cervical body, the second device having at least one opening formed therethrough; and   a flexible tension member attached between the first and second fastening devices, the flexible tension member extending through the first and second openings of the first fastening device and the at least one opening of the second fastening device,   wherein when the flexible tension member is tensioned, the first and second fastening devices apply a compressive force across at least a portion of the cervical body.   
     
     
         8 . The cervical fixation system of  claim 7 , further comprising a flexible recovery member attached to the first fastening device, the flexible recovery member extending through the third opening in the first fastening device. 
     
     
         9 . The cervical fixation system of  claim 7 , wherein the portion of the side surface of the first fastening device having surface features adapted and configured for engagement with the first surface portion of the cervical body comprises a patient-specific surface. 
     
     
         10 . The cervical fixation system of  claim 7 , wherein an end of the first fastening device distal from the first end region comprises a generally blunt rounded shape. 
     
     
         11 . The cervical fixation system of  claim 7 , wherein the first end region of the first fastening device comprises a rounded tip with flattened sides. 
     
     
         12 . A method of fixating a spinal bone fragment to a spinal bone comprising:
 exposing at least a portion of the spinal bone or an associated patient;   placing a guide wire through a portion of the spinal bone into the spinal bone fragment across a fracture site;   forming a void through at least a portion of the spinal bone and the spinal bone fragment;   inserting a first fastening device and an attached flexible tension member through the void in the spinal bone and the spinal bone fragment such that the first fastening device exits the spinal bone fragment with the first tension member extending through the void, the first fastening device having a generally elongated shape and including a plurality of openings extending generally transversely therethrough, at least a first opening of the plurality of openings positioned near a midpoint of the generally elongated shape and a second opening of the plurality of openings positioned proximate to an end of the generally elongated shape, at least a portion of a side surface of the first fastening device shaped for engagement with a surface of the spinal bone fragment;   positioning a second fastening device against the spinal bone at a location proximate to the void, at least a portion of the first tension member extending through an opening in the second fastening device; and   tensioning the first tension member to draw the first fastening device towards the second fastening device, thereby causing a compressive force to be applied across the fracture site.   
     
     
         13 . The method of  claim 12 , wherein the spinal bone comprises a C2 cervical body of the patient's spine and the spinal bone fragment comprises an odontoid bone fragment. 
     
     
         14 . The method of  claim 12 , wherein bi-planer fluoroscopy is performed to guide placement of at least one of the guide wire and the first fastening device. 
     
     
         15 . The method of  claim 12 , wherein the first fastening device further includes a flexible recovery member attached through the second opening, with at least a portion of the flexible recovery member extending through the void in the spinal bone and the spinal bone fragment. 
     
     
         16 . The method of  claim 15 , further comprising the steps of severing the attached flexible tension member and subsequently tensioning the flexible recovery member to align a longitudinal axis of the first fastening device with the void in the spinal bone and the spinal bone fragment, and drawing the first fastening device through the void in the spinal bone and the spinal bone fragment, thereby removing the first fastening device from the spinal bone and the spinal bone fragment. 
     
     
         17 . The method of  claim 12 , further comprising the steps of:
 obtaining a preoperative image of at least a portion of the spinal bone fragment; and   selecting the first fastening device from a kit containing a plurality of fastening devices of different sizes, the selected first fastening device including the side surface portion shaped for engagement with the preoperatively imaged portion of the spinal bone fragment.   
     
     
         18 . The method of  claim 13 , further comprising the steps of:
 obtaining a preoperative image of at least a portion of the odontoid bone fragment; and   selecting the first fastening device from a kit containing a plurality of fastening devices of different sizes, the selected first fastening device including the side surface portion shaped for engagement with the preoperatively imaged portion of the odontoid bone fragment.   
     
     
         19 . The method of  claim 13 , further including adjusting alignment of the odontoid to an anatomically desired position. 
     
     
         20 . The method of  claim 12 , further including adjusting alignment of the spinal bone fragment to an anatomically desired position.