Objective: To evaluate the clinical outcomes of posterior surgical corrective methods for ankylosing spondylitic kyphosis.
Methods: 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.
Results: 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%.
Conclusion: 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.