The ankylosed osteoporotic spines of patients with long-standing ankylosing spondylitis are prone to fracture. The spinal trauma is of a trivial nature in many patients and the diagnosis may be overlooked, unless neurologic damage occurs. The fractures most commonly occur in the cervical region and may be multiple. Because of spinal osteoporosis and deformity, radiographic visualization of the fracture site may be difficult. Tomography may be helpful in some patients. Management may be conservative or surgical and is complicated by increased instability of the fracture site, spinal osteoporosis, and deformity. Conservative management of cervical fractures is probably best accomplished by halo traction and body cast. Progression of the neurologic deficit is an indication for surgical intervention.

Twenty-two spinal fractures in 20 patients with chronic ankylosing spondylitis are reported. Nineteen fractures occurred in the cervical region. Fourteen of the fractures were caused by minor falls, 3 by falls down steps, 4 by motor vehicle accidents, and 1 by cardiopulmonary resuscitation. Long-term followup (mean 3.2 years) of 9 fractures diagnosed early and managed conservatively showed bony union of all fractures. No patient deteriorated neurologically and 3 patients made maor recovery. Long-term followup is also reported on 6 patients in whom the diagnosis was delayed. The difficulties in diagnosis and management are discussed.In 1978 we reported 8 patients with chronic ankylosing spondylitis complicated by spinal fracture and we reviewed 56 patients previously reported in the English language literature (1). The experience from these small series gathered from a number of centers suggested that the ankylosed cervical region was the most common site of fracture, that minor trauma was the most common cause of the fracture, and that radiographic visualization of the fracture site may be difficult. We have now enlarged our experience to 22 spinal fractures in 20 patients with chronic ankylosing spondylitis. The purpose of this study is first, to determine whether the statements we made previously still hold true for a large series of patients from one center. Second, since we have conducted a clinical and radiographic followup of these patients, we are now able to report on the natural history of these fractures and the long-term results of conservative management. PATIENTS AND METHODSThe clinical records of all patients with ankylosing spondylitis complicated by spinal fractures, admitted to the Health Sciences Centre or St. Boniface General Hospital, Winnipeg between 1965 and 1982, were reviewed. Clinical and radiographic followup was then obtained.For the purpose of assessing the natural history of these fractures and the results of conservative management, the patients were divided into 2 groups. Group I consisted of patients in whom the diagnosis of spinal fracture was made immediately and conservative management instituted.Group I1 consisted of patients in whom the diagnosis of spinal fracture was delayed. RESULTSTwenty patients with ankylosing spondylitis had suffered fractures of the ankylosed spine. All the patients were male. The clinical data, including nature of the trauma, level and type of bony and neurologic injury, management, and results of long-term followup, are listed in Table 1 for Group I and Table 2 for Group 11. Two patients had suffered a second cervical fracture during the period of followup, and the details of these fractures are included.