Subaxial caudal dislocation of the cervical spine in rheumatoid arthritis.

Subaxial (below the C 2) caudal dislocation is in the present study defined as a complete or partial dislocation caudally of a vertebral body (C 3 or below) into the plane of a lower vertebral body. In rheumatoid arthritis this dislocation is combined with erosive lesions of the vertebral bodies. In the present retrospective study seven such cases are presented. All were middle-aged or elderly women with a long history of disease and all also had a horizontal dislocation at the same level. Two patients had this dislocation at more than one level of the cervical spine and in two patients there was encroachment on the spinal canal. Most patients also had dislocations at the atlanto-axial level. Neurologic sequelae were rare.