Results of long-term follow-up in patients undergoing anterior screw fixation for type II and rostral type III odontoid fractures

Study Design. Retrospective analysis of the fusion rate of a group of 38 patients having undergone anterior screw fixation for type II and "shallow" type III odontoid fractures. Objective. To determine primarily the long-term fusion rate after anterior screw fixation and to study the clinical characteristics of patients that have a statistically significant or nonsignificant influence on successful outcome. Summary of Background Data. Long-term outcome of anterior screw fixation for odontoid fractures has been evaluated in very few studies. This information should be critical for further establishing this technique as a major therapeutic strategy for these cases. Methods. Thirty-eight patients, 25 males and 13 females ( with mean age 48.4 +/- 0.4 years), with type II and rostral type III odontoid fractures, underwent anterior cannulated screw fixation during a 62-month period. Radiologic examination of the cervical spine with plain radiographs was performed at 6 weeks, and 2, 6, 12, and 24 months, while computerized tomography of the upper cervical spine (C1 - C3) was obtained at 6 months after surgery. Follow-up was available for 31 patients, and the follow-up time ranged from 39 to 87 months ( mean 58.4). Results. Radiographic evaluation of the follow-up group showed satisfactory bony fusion and no evidence of abnormal movement at the fracture site in 27 (87.1%) patients. Pseudarthrosis developed in 4 (12.9%) patients; however, 3 (9.6%) of them without instability and 1 (3.2%) with instability. One ( 3.2%) patient had an instrumentation failure without instability. Conclusions. In our series, anterior odontoid screw fixation comprised a safe therapeutic modality with high stability and low mechanical failure rates during short-term and long-term follow-up.