Atlantoaxial instability after minor trauma with os odontoideum in children.

An os odontoideum is mostly diagnosed coincidentally on the basis of either painful movement of the cervical spine or neurological symptoms, or both. Diagnostic and therapeutic options are subjects of controversial discussion in the literature.Our report is about an 11-year-old boy who developed neurological symptoms with transitory tetraparesis after a fall of 1.5 m. Conventional X-ray examination resulted in the diagnosis of a dens fracture; MRI showed atlantoaxial instability and an os odontoideum with significant cord compression. After 4 months of nonoperative treatment, the patient had complete relief of symptoms but a significant atlantoaxial instability remained. A dorsal C1/C2 fusion in a modified Brooks technique was performed.In the event of neurological symptoms or instability, the authors advocate early surgical stabilisation, even in patients with little infirmity, particularly in view of the possible consequences.