Nontraumatic atlantoaxial and occipitoatlantal instability in children

Abstract

Nontraumatic instability of the atlantoaxial and occipitoatlantal articulations in children is a treatment challenge. Associated spinal cord compression should be evaluated with static and dynamic magnetic resonance imaging. Procedures that stabilize the atlantoaxial articulation with wire and autologous bone are relatively straightforward and work well in uncomplicated cases. Transarticular C1–C2 screw fixation has the advantage of rigid fixation, which obviates the need for halo immobilization. However, screw placement requires considerable expertise to avoid direct injury to the spinal cord and vertebral arteries. Extension of the fusion to the occiput should be considered based on the underlying condition (e.g., Down syndrome), the presence of cord compression, and the inability to achieve a complete reduction. The complications of treatment include neurologic injury, nonunion, pin tract infection, instability of unfused segments, and crankshaft phenomenon.