Cauda Equina Syndrome Associated with Dural Ectasia in Ankylosing Spondylitis: Case Report.

Cauda equina syndrome (CES) associated with dural ectasia is a rare manifestation in patients with ankylosing spondylitis (AS). We report a case of a 53-year-old female with a 10-year history of AS who developed CES in the past 1 year. The CT and MRI findings revealed the unique appearances of dural ectasia, multiple ventral dural diverticula, erosion of lumbar vertebral bodies, adhesion of the nerve roots of the cauda equine, and the conus medullaris to the wall of the dural sac. Due to progressive clinical deterioration, surgical decompression was performed via laminoplasty with filum terminale resection to release adhesions involving the conus medullaris and nerve root. Postoperatively, constipation, urinary incontinence, and muscle strength improved. The possible mechanisms of CES associated with chronic AS are discussed.