Computer assisted tomography of the apophyseal changes in patients with ankylosing spondylitis.

We have examined the appearances by computed tomography of the apophyseal joints in 28 patients with ankylosing spondylitis (AS), as well as in 10 patients with noninflammatory lumbar disease. The number of changes noted in the apophyseal joints in each patient correlated significantly with the degree of restriction of spinal flexion seen (p = 0.002), but did not correlate with the clinical duration of disease (p greater than 0.2). No specific abnormalities were seen in patients with AS that were not also noted in the non-AS subjects.