Surgical treatment of spinal pseudoarthrosis in ankylosing spondylitis.

BACKGROUND In ankylosing spondylitis (AS), the spine with osteoporotic changes is fragile and vulnerable to trauma. Patients may develop spinal pseudoarthrosis (SP), whose clinical features are usually misdiagnosed as a tuberculous infection. This study reports our experience with surgical treatment for SP in AS. METHODS Eight patients with AS and SP at the thoracolumbar area were treated surgically and followed-up for at least 3 years. All had persistent back pain and progressive kyphosis. One patient had neurologic deficits preoperatively. Anterior debridement and interbody fusion followed by posterior stabilization were performed in all patients. A posterior corrective osteotomy was additionally done in 3 patients whose kyphotic angle exceeded 45 degrees. RESULTS All patients with persistent back pain obtained significant pain relief postoperatively. On a visual analogue scale, there was an average improvement of 43 points on the clinical scores. The patient with neurologic deficits showed improvement after the operation. Solid bony fusion was achieved in an average of 7.5 months, and correction of the kyphotic angle averaged 18.6 degrees. CONCLUSIONS Spinal pseudoarthrosis should be considered in patients with AS, and must be differentiated from tuberculous and other infections. The results of this study show that pain relief and correction of the kyphotic deformity can be achieved by surgical treatment for ankylosing spondylitis complicated with pseudoarthrosis.