Session VII - Spine

Management of Odontoid Fractures with Non-rigid Immobilization

Klaus C.J. Fischer, MD; Ernst J. Müller, MD; M. Wick, MD; Gert Muhr, MD, Dept. of Trauma Surgery, Kliniken Bergmannsheil, Bochum, Germany

Introduction: The appropriate treatment of type II and type III odontoid fractures still remains controversial; however, there seems to be a tendency toward preference for primary internal fixation with interfragmentary screws. In a retrospective analysis, we evaluated the indications, the treatment-related complications, and the outcome of non-rigid immobilization of stable type II and type III odontoid fractures.

Methods: From 1984 to 1998, 26 patients (13 women and 13 men) with an average age of 59.1 years (range, 15 to 86) with acute type II and III odontoid fractures were treated with non-rigid immobilization in a cervical collar. Included were those with a fracture gap of less than 2 mm, initial AP displacement of less than 5 mm and angulation of less than 11°, less than 2 mm of displacement on lateral flexion/extension radiographs, and without neurologic deficits. The majority of the fractures (n = 19; 73.1%) were classified as type II injuries, according to Anderson and d'Alonzo. The fractured odontoid was displaced and/or angulated on initial radiographs in 10 (38.5%) of the patients.

Results: The overall complication rate was 11.4% (n = 3). One patient (3.8%) with multiple injuries had a pulmonary embolism. Two patients (7.6%) with initially minimally displaced type II fractures required secondary internal fixation because of nonunion and instability of the odontoid process. All patients were followed up at 27.4 months on average (range, 12 to 75). In 20 (78%) of the remaining 24 fractures, healing was uneventful, in 10 (39%) of these the odontoid united in an anatomic position. Trabecular bridging was not evident radiographically in four (15%) undisplaced fractures; however, because of the absence of signs of instability on lateral flexion-extension views, all four were classified as stable pseudarthrosis. At follow-up, 10 patients (39 %) were completely free of symptoms, 11 patients had persistent neck pain, and 2 had inconsistent neck pain.

Discussion and Conclusion: The results of this retrospective analysis demonstrates that stable type II and type III odontoid fractures can be successfully treated with non-rigid immobilization, even if they are displaced. Lateral flexion/extension radiographs are mandatory to evaluate the stability of the injuries. According to our results, there is no obvious correlation between the clinical outcome and the radiological healing status of the odontoid. On the basis of our experience, we recommend a thorough assessment of the stability of odontoid fractures to evaluate the appropriate treatment option.