[Clinical efficacies of skipping two-level transpedicular wedge osteotomy for correction of severe kyphosis in ankylosing spondylitis].

OBJECTIVE To explore the clinical efficacies of skipping two-level transpedicular wedge osteotomy in the correction of severe kyphotic deformity in ankylosing spondylitis (AS). METHODS From January 2003 to December 2009, a total of 38 consecutive patients with AS and severe kyphosis (chin-brow vertical angle (CBVA) or global thoraco-lumbar kyphosis angle (TLKA) over 70°) undergoing skipping two-level transpedicular wedge osteotomy at the Department of Orthopedics of Chinese PLA General Hospital were reviewed retrospectively. There were 32 males and 6 females with an average age of 38.0 years (range: 22 - 65). The preoperative parameters of TLKA, T11-L2 kyphotic angle, L1-S1 lordosis angle, sagittal imbalance and CBVA were obtained from the total spine radiography or computed tomography and clinical lateral photograph. According to the characteristic curves and normal spinal alignment, their profiles of osteotomy location and angle were determined and confirmed by computer simulations. Improvement in postoperative parameters was observed and treatment satisfaction evaluated RESULTS The average operating duration was 309 minutes and the average volume of blood loss was 2050 ml. The parameters of TLKA, T11-L2 kyphotic angle and L1-S1 lordosis angle improved from 101.0° ± 21.3°, 45.2° ± 13.6°, -28.2° ± 23.3° at preoperation to 26.0° ± 12.1°, 2.8° ± 11.6°, 28.9° ± 13.3° postoperation respectively (P < 0.01). CBVA improved from 79.4° ± 15.9° to 13.6 ° ± 10.9° (P < 0.01). The sagittal imbalance distance improved from (49 ± 13) to (15 ± 7) cm (P < 0.01). All patients could walk with orthophoria and lie horizontally postoperatively. The average follow-up was 32 months (range: 24 ∼ 78 months). Fusion of osteotomy was achieved in all patients and there was no event of loss of correction or implant failure. The SRS-22 average score improved from 1.8 to 4.2. CONCLUSION For severe kyphosis in AS, skipping two-level transpedicular wedge osteotomy is a satisfactory and reliable approach for the correction of kyphotic deformity and it may improve appearance and function significantly.