Surgical outcome after spinal fractures in patients with ankylosing spondylitis.

BACKGROUND: Ankylosing spondylitis is a rheumatic disease in which spinal and sacroiliac joints are mainly affected. There is a gradual bone formation in the spinal ligaments and ankylosis of the spinal diarthroses which lead to stiffness of the spine.The diffuse paraspinal ossification and inflammatory osteitis of advanced Ankylosing spondylitis creates a fused, brittle spine that is susceptible to fracture. The aim of this study is to present the surgical experience of spinal fractures occurring in patients suffering from ankylosing spondylitis and to highlight the difficulties that exist as far as both diagnosis and surgical management are concerned.

METHODS: Twenty patients suffering from ankylosing spondylitis were operated due to a spinal fracture. The fracture was located at the cervical spine in 7 cases, at the thoracic spine in 9, at the thoracolumbar junction in 3 and at the lumbar spine in one case. Neurological defects were revealed in 10 patients. In four of them, neurological signs were progressively developed after a time period of 4 to 15 days. The initial radiological study was negative for a spinal fracture in twelve patients. Every patient was assessed at the time of admission and daily until the day of surgery, then postoperatively upon discharge.

RESULTS: Combined anterior and posterior approaches were performed in three patients with only posterior approaches performed on the rest. Spinal fusion was seen in 100% of the cases. No intra-operative complications occurred. There was one case in which superficial wound inflammation occurred. Loosening of posterior screws without loss of stability appeared in two patients with cervical injuries. Frankel neurological classification was used in order to evaluate the neurological status of the patients. There was statistically significant improvement of Frankel neurological classification between the preoperative and postoperative evaluation. 35% of patients showed improvement due to the operation performed.

CONCLUSION: The operative treatment of these injuries is useful and effective. It usually succeeds the improvement of the patients' neurological status. Taking into consideration the cardiovascular problems that these patients have, anterior and posterior stabilization aren't always possible. In these cases, posterior approach can be performed and give excellent results, while total operation time, blood loss and other possible complications are decreased.