Cervical fracture complicating ankylosing spondylitis: a report of eight cases and review of the literature.

Fracture of the cervical spine is a serious and often fatal complication of ankylosing spondylitis. An evaluation of eight patients and a review of 75 additional cases from the literature are presented. Although this complication is relatively uncommon, it is clear that people with advanced disease and complete ankylosis of the cervical spine are at increased risk of sustaining cervical fracture. When fracture occurs it usually stems from minor trauma resulting most commonly in disruption of the lower cervical segments (fifth through the seventh cervical vertebrae). Fracture is most likely the result of a hyperextension type injury, occurs through what was formerly an intervertebral space, and is unstable. Severe neurologic sequelae occur in 57 percent of the cases and the mortality rate (35 percent) is twice that observed with similar fracture involving normal spines. The majority of patients are best treated with closed reduction with halo traction together with body cast or jacket. Laminectomy is rarely indicted except in the event of an advancing neurologic deficit. With appropriate understanding and execution of management principles, the outcome in these patients can be favorable. Unfortunately, recognition of cervical fracture in patients with ankylosing spondylitis is often needlessly delayed. Distortion of normal anatomy in spondylitics, predominant fracture location in lower cervical spine segments and lack of obvious displacement make identification difficult. Thus, management is often inappropriate resulting in excessive neurologic injury and mortality.