[Clinical features and strategies for treatment of spinal fracture complicating ankylosing spondylitis].

OBJECTIVE

To explore the clinical features and strategies for treatment of spinal fracture complicating ankylosing spondylitis (AS).

METHODS

The clinical data of 15 patients with spinal fracture in AS, 13 males and 2 females, aged 49.8 (10 - 45), with the average history of AS of 24.6 years, were studied. Fractures were found in the cervical spine in 6 patients and in the thoracolumbar spine in 9. Of the 6 cervical spine fracture patients, 2 were treated with conservative therapy, 2 underwent anterior internal fixation and fusion, 1 was stabilized with posterior fixation and fusion, and 1 underwent decompression, posterior fixation and fusion. Seven of the 9 thoracolumbar fracture patients developed thoracolumbar kyphosis with a mean Cobb angle of 64 degrees (46 - 106 degrees). Three techniques were used in thoracolumbar fracture: posterior transpedicular vertebral osteotomy coupled with internal fixation and autogenous bone grafting was performed in 3 patients; anterior interbody fusion and internal fixation was performed for 2 patients; and combined anterior and posterior surgery (using posterior osteotomy with instrumentation and autogenous bone grafting in stage 1, and anterior focal debridement and autogenous bone grafting in stage 2) was performed on 4 patients.

RESULTS

Of the patients with cervical fracture, three had the fracture lines through the disc spaces; the other 3 had their fracture lines through the vertebral bodies near the end plate. Both the two patients treated with conservative therapy died of severe pulmonary infection. One patient with incomplete neurological deficit undergoing posterior decompression and fixation could independently ambulate with the help of walking device at the final follow-up. Radiographic evidence of fusion was observed in the four patients with cervical fracture who underwent anterior or posterior fixation in the final follow-up. Of the patients with thoracolumbar fracture, three had the fracture lines through the vertebral bodies near the end plate; the other 6 patients had their fracture lines through the disc spaces with the formation of pesudoarthrosis. Postoperatively, the thoracolumbar kyphosis ranged 26 degrees (22 - 42 degrees) and the correction of the kyphotic angle was 38 degrees. In the latest follow-up, the range of thoracolumbar kyphosis was 28 degrees (24 - 44 degrees) with 2 degrees loss of correction. At the final follow-up, solid bony fusion had been achieved in all patients.

CONCLUSION

The cervical fracture in AS patient tends to be unstable, and conservative treatment cannot get better outcome. Prompt anterior or posterior stabilization can achieve reconstruction of spinal stability and fracture union. Thoracolumbar fracture patients without kyphosis deformity can be treated with anterior debridement and fusion with autogenous bone grafting. The transpedicular osteotomy technique can be used in patients with fracture or pseudoarthrosis with kyphotic deformity in AS, which can not only correct the kyphosis deformity, but also facilitate the union of fracture simultaneously. After posterior osteotomy, in order to prevent the intervertebral disc space anteriorly opening, which may result in deficiency of anterior column, anterior fusion with autogenous bone grafting is needed to strut anterior column and to prevent failure of correction.