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[Pedicle subtraction osteotomy for correction of kyphosis in ankylosing spondylitis].

OBJECTIVE
To assess the effectiveness of single-level lumbar pedicle subtraction osteotomy for correction of kyphosis caused by ankylosing spondylitis.


METHODS
Between July 2006 and July 2010, 45 consecutive patients with kyphosis caused by ankylosing spondylitis underwent single-level pedical subtraction osteotomy. There were 39 males and 6 females with an average age of 36.9 years (range, 21-59 years). The average disease duration was 18.6 years (range, 6-40 years). All patients had low back pain, fatigue, abnormal gaits, and disability of looking and lying horizontally. Radiological manifestations included sacroiliac joints fusion, bamboo spine, pelvic spin, and kyphosis. Cervical spine was involved in 30 patients; thoracolumbar spine was affected in 15 patients.


RESULTS
Wound hydrops and dehiscence occurred in 1 case, and was cured after debridement; primary healing of incision was obtained in the other patients. Two patients had abdominal skin blisters, which were cured after magnesium sulfate wet packing. Forty-two patients were followed up 24-74 months (mean, 30 months). All osteotomy got solid fusion. The average bony fusion time was 6.8 months (range, 3-12 months). All patients could walk with brace and looked or lied horizontally postoperatively. The Scoliosis Research Society-22 Patient Questionnaire (SRS-22) score, T1-Sl kyphosis Cobb angle, L1-S1 lordosic Cobb angle, sagittal imbalance distance, and chin-brow vertical angle at 1 week and last follow-up were significantly improved when compared with those at preoperation (P < 0.05), but no significant difference was found between at 1 week and last follow-up (P > 0.05).


CONCLUSION
Single-level pedicle subtraction osteotomy has satisfactory effectiveness for the correction of kyphosis caused by ankylosing spondylitis.