Cervical spine injury in patients with ankylosing spondylitis.

Fractures of the cervical spine associated with ankylosing spondylitis are rare. Relatively minor injury can cause a fracture of the vertebral body or through the ossified intervertebral space, because of the loss of normal flexibility, mobility, and elasticity in the rigid spine. Sixty-six per cent of the fracture subluxations of the ankylosed spine are associated with injury to the spinal cord, and the mortality rate is 40%. Because of the complete nature of fracture and instability, there is a high risk of neurologic deterioration. Immobilization of the cervical spine in a Halo cast appears to be the treatment of choice. If skull traction is applied the cervical spine should be immobilized in the neutral position, and overzealous traction exceeding 10 pounds should be avoided. Callus formation and fracture healing following immobilization is rapid. Four new cases are described and 44 previously reported cases in the literature have been reviewed.