The influence of closing-opening wedge osteotomy on sagittal balance in thoracolumbar kyphosis secondary to ankylosing spondylitis: a comparison with closing wedge osteotomy.

Abstract

A retrospective study. To compare the radiographical and clinical outcomes between closing wedge osteotomy (CWO) and closing-opening wedge osteotomy (COWO) for thoracolumbar kyphosis secondary to ankylosing spondylitis. Several surgical techniques have been used to correct the fixed thoracolumbar kyphosis caused by ankylosing spondylitis. To date, the comparison of the outcomes between CWO and COWO has not yet been addressed. According to the association with anterior edge opening or not shown on the postoperative radiographs, 64 patients were divided into 2 groups (35 patients in the CWO group and 29 patients in the COWO group). The radiographical and clinical outcomes were compared between the 2 groups, with a mean follow-up of 36 months (range, 24-84 mo). Radiographical measurements included thoracic kyphosis, lumbar lordosis, global kyphosis, sagittal vertical axis, osteotomized vertebra angle, and the height of the osteotomized vertebra. Oswestry Disability Index was evaluated at the final follow-up. Thoracic kyphosis did not change significantly between postoperatively and the final follow-up in both groups. The mean corrections of lumbar lordosis, global kyphosis, sagittal vertical axis, and osteotomized vertebra angle were significantly larger in the COWO group than in the CWO group (P < 0.05). Notably, statistically significant differences (P < 0.05) were observed in the variation of height of the osteotomized vertebra (1.3 cm in the CWO group vs. 0.7 cm in the COWO group). In both groups, no patients had pseudarthrosis at the osteotomy level at the last follow-up. There was no significant difference of Oswestry Disability Index scores between the 2 groups at the final follow-up. Both CWO and COWO are safe and effective surgical methods for correction of thoracolumbar kyphosis. COWO can obtain larger correction and better sagittal alignment without additional neurological complications.