173. Unilateral Posterior Atlantoaxial Transarticular Screw Fixation in Patients with Atlantoaxial Instability: Comparison with Bilateral Method

Abstract

BACKGROUND CONTEXT: Simultaneous bilateral posterior transarticular screw fixation (TAF) and bone grafting with wire loop provides immediate, rigid internal fixation for atlantoaxial instability (AAI). It is the most effective biomechanical technique to attain C1-2 stability, and is superior to conventional wiring methods by virtue of more rigid fixation. Solid atlantoaxial fusion has been reported in 80 to 100% of patients who were treated with this method. However, bilateral TAF across the C1-2 may be contraindicated or impossible in up to 20% of patients because of its structural disfigurements such as anomalous course of the vertebral artery (VA), comminuted fractures of C-1 or C-2, or other pathological processes.