Fractures of the thoracolumbar spine complicating ankylosing spondylitis.

OBJECT: In this clinical review of ankylosing spondylitis, the authors emphasize the fragility of the spine and the degree of neurological deficit that can result from minor injury. The management of thoracolumbar fractures complicating ankylosing spondylitis is discussed.
METHODS: Six thoracic and five lumbar fractures were identified in a review of patients in whom ankylosing spondylitis had been diagnosed. Nine fractures were associated with an extension deformity. The mechanism of injury was regarded as major in three and minor in eight. The mean age in patients suffering fractures after minor traumatic injury was 59.6 +/- 14.5 years (+/- standard deviation), whereas the mean age in patients suffering fractures after major traumatic injury was 49.3 +/- 10.1 years. Two patients were treated with bedrest and brace therapy, and nine underwent instrument-assisted fusion. Postinjury neurological deficits were demonstrated in six patients, in three of whom neurological improvement was observed.
CONCLUSIONS: Patients with ankylosing spondylitis are at risk of injury, particularly extension fractures of the thoracic and lumbar spine. The incidence of trauma-induced neurological deficit is by no means negligible. Management consists of surgery in patients with vertebral instability and neural compression, and recumbency in those with stable fractures.