Atlanto-axial deformity secondary to a neglected odontoid fracture: a report of six cases.

We reviewed 6 patients with atlanto-axial (C1-2) deformities secondary to neglected odontoid fractures. All patients (except one with recent injury) were asymptomatic for a long period before development of neck pain or myelopathy, despite obvious subluxation and kyphotic deformities at the C1-2 joint complex. Patients were treated conservatively, except for one who underwent posterior spinal fusion and occiput-to-C2 decompression for progressive myelopathy. The reactive new bone formation around the odontoid fracture may play a role in preventing further movement and development of myelopathy. Conservative treatment should be considered for neglected odontoid fractures in elderly patients with stable non-progressive C1-2 deformity.