Twenty-seven cases of RA who had had atlantoaxial dislocation were followed up for five years and seven months in average to examine the sequence of the dislocation. The dislocation progressed in five, but none of them developed myelopathy. Superior migration of C2 occurred in eight and spontaneous fusion of Cl-2 in eight. Those of spontaneous fusion were all in stage IV. 1 It is concluded that the X-ray examination should be performed periodically to check the subluxation. And fusion surgery should be given before the dislocation progresses severe.
