The "moustache" sign: localized intervertebral disc fibrosis and panligamentous ossification in ankylosing spondylitis with kyphosis.

Localized intervertebral disc and ligamentous ossification may precipitate neurological deficits at any time during the natural course of ankylosing spondylitis (AS). We report 2 patients with AS with "moustache' sign (localized intervertebral disc fibrosis and panligamentous ossification) and neurological deficits. One patient had syndesmophytosis (with paraparesis secondary to thoracic spinal canal stenosis), and the other had "bamboo spine" above and below the involved level. A laminectomy in the former relieved paraparesis, and posterior element excision in both the patients relieved focal tenderness and pain; and both of them could lie supine following surgery.