Screw placement in repair of ankylosing spondylitis complicated by severe wheel-like kyphosis:stress distribution in multiple segments / 中国组织工程研究

ABSTRACT

BACKGROUND:Kyphotic deformity in ankylosing spondylitis is the flexion deformity of spine sagittal plane in the late lesion. Spinal osteotomy is the only treatment method in patients with severe wheel-like kyphosis. For thoracic and thoracolumbar ankylosing spondylitis patients with lumbar severe wheel-like kyphosis, osteotomy at a single site cannot obtain safe and effective orthopedic effect. OBJECTIVE:To observe the orthopedic effect of total spine osteotomy combined with V-shaped osteotomy for correction of severe wheel-like kyphosis deformity due to ankylosing spondylitis, and to analyze stress distribution. METHODS:From May 2003 to October 2012, total spine osteotomy combined with V-shaped osteotomy and pedicle screw fixation were adopted for repair of concurrent thoracic, thoracolumbar and lumbar severe wheel-like kyphosis deformity due to ankylosing spondylitis in 36 male cases in the Sixth Affiliated Hospital of Xinjiang Medical University. Spinal convex angle, chin-brow vertical angle and C 7 plumb line were measured to evaluate orthopedic effect. RESULTS AND CONCLUSION:The whole spine convex Cobb angle was corrected from preoperatively (89.6±9.8)° to (32.2±6.7)° at 1 week after treatment, showing significant difference (P0.05). Radiographs demonstrated that fixation position was good in al patients. These results confirmed that in patient with severe wheel-like kyphosis deformity due to ankylosing spondylitis, the application of total spine osteotomy combined with V-shaped osteotomy is a safe and effective method, can better correct the spinal sagittal curvature and reduce the risk of sagittal angle, result in the stress distribution in many segments and the shortening of the spine and epidural buckling in relatively long segment, can avoid nerve damage induced by spinal cord shortening and epidural excessive buckling within short segment.