Ventral cancellous bone augmentation of the dens and temporary instrumentation C1/C2 as a function-preserving option in the treatment of dens pseudarthrosis.

ABSTRACT

STUDY DESIGN: An innovative function preserving technique for the treatment of odontoid nonunion via ventral cancellous bone augmentation of the dens is described. A retrospective clinical study of 17 patients, thus treated by this technique is reported. OBJECTIVES: Assessment of a new method, which preserves the rotational mobility of the C1/C2 joint. SUMMARY OF BACKGROUND DATA Nonunion after odontoid fractures are usually treated by posterior fusion of C1/C2. Although there are reports of good clinical results, restriction of rotational mobility is inevitable. METHODS: Seventeen patients with dens pseudarthrosis or delayed healing were operated on between the year 1991 and 2005. A hole was drilled in the dens and packed with autologous bone graft. Temporary Instrumentation C1/C2 (anteriorly or posteriorly) was performed for 3 to 4 months. Patients were evaluated clinically and radiographically, rotation computed tomography or magnetic resonance imaging studies were conducted. RESULTS: Fifteen patients were available for follow-up. Nine patients demonstrated healing of the pseudarthrosis with preservation of C1/C2 joint mobility (confirmed by rotation-computed tomgraphy or rotation -magnetic resonance imaging in 7 cases, average segmental rotation 37.3 degrees). Four patients showed persistent pseudarthrosis (2 were fused by posterior C1/C2 fixation) and 2 patients demonstrated spontaneous C1-C2 fusion. CONCLUSIONS: Ventral cancellous bone augmentation of the dens and temporary instrumentation C1/C2 is a function-preserving option in the treatment of dens pseudarthrosis.