Chronic atlanto-axial dislocation with spontaneous bony fusion

A case of long standing atlanto-axial subluxation following relatively minor trauma is reported. Progressive development of pain and spastic quadriparesis led to clinical and radiological investigation at Groote Schuur Hospital which revealed a spontaneous fusion of C1 and C2 with marked compromise of the spinal cord. The possibility of a pre-existing unfused odontoid process (os odontoideum) is discussed. A brief review of the literature is presented.