Ninety of 110 consecutive patients with rheumatoid deformities of the cervical spine surgically treated had associated neurologic deficits. Fifty-five patients had atlantoaxial subluxation. In this group, there were 16 Ranawat Class I patients (normal), 21 Class II (weakness, hyperreflexia, dysesthesia), 13 Class IIIA (paresis and long-tract findings but can ambulate), and five Class IIIB (quadriparesis and inability to ambulate). After C1-C2 stabilization, 94.8% improved at least one class. Twenty-two patients had AAS-SMO (atlanto-axial subluxation and superior migration of the odontoid) only one before surgery was Class I, five Class II, eight Class IIIA, and eight Class IIIB. Seventy-six percent improved at least one class after surgery. Nineteen had isolated subaxial subluxation (SAS). Three were Class I, two Class II, nine Class IIIA, and five were Class IIIB. After surgery, 94% improved at least one class, and all were ambulating. Fourteen had combined AAS-SMO-SAS deformities. There were no Class I patients, only four Class II, four Class IIIA, and six Class IIIB. After surgery, 71% improved. The four deaths that occurred in the immediate postoperative period were Class IIIB. Fifteen patients had worsening or recurrence of their symptoms. Thirteen of these were related to the later development of subaxial subluxation. Neurologic symptoms and recovery were related to severity of the deformity. Those with SMO had greater neurologic deficits and worse results. In general, neurologic recovery is encouraging even in the IIIB patient. Earlier surgery should be done, however, particularly before SMO develops, if possible.(ABSTRACT TRUNCATED AT 250 WORDS)