Salvage of a malpositioned anterior odontoid screw

Study Design. Description of surgical technique with case correlation. Objective. This article presents an alternative approach to anterior odonto id screw salvage in a patient with established nonunion. Summary of Background Data. Type II odontoid fractures are often treated su rgically because of their risk of nonunion. Anterior odontoid screw fixatio n offers stable fixation without loss of atlantoaxial motion. Treatment fai lure may occur despite adequate screw placement but is more likely when fix ation is inadequate. The traditional solution is a posterior fusion. In sel ected cases the surgeon may want to revise the anterior instrumentation wit h the hope of retaining as much C1-C2 motion as possible. Methods. A 43-year-old man presented 16 months after Type II odontoid fract ure treated by anterior odontoid screw fixation. He had neck pain, instabil ity, and a pseudarthrosis confirmed on radiographs. The screw was excessive ly long, piercing the C3 vertebral body and providing inadequate fixation. To avoid posterior fusion, a modified anterior approach was used. An entry point was selected 10 mm lateral to the midline, along the anterior rim of the C2 vertebral body. A large-diameter lag screw was then passed to the ti p of the fragment. An angled curette was introduced into the fracture gap t hrough the interval between the odontoid and the C1 ring. Autogenous bone w as packed into the gap and along the old screw tract. Results. At the 2-year follow-up the patient had a solid union with no neck pain, no headaches, no radicular symptoms, and excellent range of motion. The approach is described. Conclusion. In properly selected patients an anterior revision approach can provide a better outcome than posterior cervical fusion. This modified app roach allows placement of an adequate fixation screw in a vertebra damaged by previous screw failure.