Fracture of the cervical spine in ankylosing spondylitis

The radiological features, clinical findings and mortality rates of patients with ankylosing spondylitis complicated by cervical trauma have been reviewed. All patients had long-standing disease and half had sustained their fractures as a result of trivial accidents. There were 19 cervical fractures in 18 patients, which were chalkstick in type and occurred predominantly at the 6th and 7th cervical levels. Ten fractures passed through the upper part of the vertebral body, one through the mid-vertebral body and the final eight were through the disc space. The site of the fracture line was related to neurological outcome. Those patients whose fracture line ran through the disc space had significantly less neurological injury and a much better prognosis. Distraction at the fracture site had some relation to prognosis but horizontal displacement and angulation were not found to be of importance. This study confirms that cervical fracture with neurological complications may follow minor trauma in ankylosing spondylitis. The site of the fracture in relation to the vertebral bodies and discs appears to be of some prognostic relevance and careful radiological assessment of all patients with ankylosing spondylitis and cervical injury should be undertaken.