Symptomatic spinal stenosis associated with ankylosing spondylitis

Patients with ankylosing spondylitis frequently experience back pain and they have a well-known propensity for spinal fractures, but they rarely manifest motor and sensory nerve root impairment. We recently encountered a patient with ankylosing spondylitis who complained of classical spinal claudication with urinary sphincter dysfunction. Computed axial tomography revealed marked lumbosacral lateral recess and foraminal spinal stenosis that was not evident on the myelogram; at operation the stenosis appeared to be the result of extensive posterior soft tissue ossification. This heretofore unrecognized yet potentially treatable complication of ankylosing spondylitis is discussed.