Pseudopseudarthrosis in a patient with ankylosing spondylitis.

There is a growing consensus that the mechanism leading to extensive discovertebral destruction (type III) in most patients with ankylosing spondylitis relates to fracture and subsequent pseudarthrosis. We introduced the term "pseudopseudarthrosis" to describe (in our case) the occurrence of abnormal motion between 2 fused spinal segments, resulting in extensive discovertebral destruction without fracture or pseudarthrosis.