[Ankylosing spondylarthritis. Pathogenesis of the destructive disco-vertebral lesions. 15 cases]

Fifteen cases of destructive disco-vertebral lesions discovered in patients with ankylosing spondylitis are reported. The incidence of these lesions was 5.5% and they were unrelated to underlying conditions. Radiologically, they fell into five categories: pseudodystrophic, pseudotuberculous, extensive erosions, bone condensation and isolated narrowing of the intervertebral spaces. From an analysis of these 15 cases and of published data, it would appear that these forms result from different pathogenetic processes: an inflammatory process for the pseudodystrophic and pseudotuberculous forms and for early extensive erosions; a mechanical process for bone condensation and perhaps also (though this is more controversial) for late extensive erosions and isolated intervertebral narrowing.