[Clinical outcomes of surgical correction for ankylosing spondylitic kyphosis]

To evaluate the clinical outcomes of posterior surgical corrective methods for ankylosing spondylitic kyphosis.

From June 2003 to June 2008, 21 cases of ankylosing spondylitic kyphosis received posterior surgical correction. There were 17 male and 4 female, and the average age was 39.5 years (range, 20 to 57 years). The total spine X-ray and CT were used to evaluate sagittal balance and thoracolumbar spine kyphosis angle, and chin brow-vertical angle was obtained from clinical lateral photograph. The surgical goal was to correct sagittal imbalance and chin brow-vertical angle. The simulated osteotomy was performed in computer before surgery to determine the correction methods. The surgical methods included: 16 cases of monosegmental closing osteotomy correction, 3 cases of anterior opening-posterior closing osteotomy correction, and 2 cases of combined pedicle subtraction osteotomy in thoracolumbar spine and Smith-Peterson osteotomy in lumbar spine. All patients were followed up after surgery, and the improvement of sagittal imbalance, chin brow-vertical angle and thoracolumbar spine kyphosis angle were assessed. The symptoms relief and satisfied rate were also evaluated.

The average operation time was 4.4 hours, and the average blood loss was 1770 ml. Before surgery, the average thoracolumbar kyphosis angle was 62.1°, the average anterior shift of C(7) plumb line was 172.9 mm, and the average chin brow-vertical angle was 34.9°. The average follow-up was 28.8 months after surgery. The average correction rate of thoracolumbar kyphosis angle was 60%, the average improvement rate of anterior shift of C(7) plumb line was 64%, and the average correction rate of chin brow-vertical angle was 98%. The improvement rate of back pain was 64% during follow-up. The total surgical satisfactory rate was 95%.

Based on the simulated osteotomy in computer before surgery, according to the characteristics of ankylosing spondylitic kyphosis, different posterior osteotomy and correction methods can achieve good results.