Atlanto-Axial Subluxation and Cervical Myelopathy in Rheumatoid Arthritis

Abstract

One hundred patients, 27 males and 73 females, suffering from rheumatoid arthritis have been studied radiologically and clinically to establish the incidence of atlanto-axial subluxation (A.A.S.) and of cervical myelopathy. The diagnosis of A.A.S. was made in 36 patients on the basis of an atlanto-odontoid separation of 3 mm or more on the lateral tomogram in flexion but no particular features of the disease were identified which predisposed to this complication except that it was more common in those with subcutaneous nodules and hand deformities. Neck symptoms were not more conspicuous in those with A.A.S. Twenty-four of the 36 patients with A.A.S. had cervical myelopathy as judged by a pathological increase in the deep tendon reflexes and this became increasingly common the greater the degree of atlanto-odontoid separation. Ten patients without subluxation also had myelopathy and in only three of these was there radiological evidence of moderate or severe subaxial spondylosis. The anatomy and pathology of the atlanto-axial joint is discussed and the mechanism of production of the myelopathies is considered.