去松质骨截骨治疗强直性脊柱炎后凸畸形的有限元分析

Finite element analysis of vertebral column decancellation for treatment of ankylosing spondylitis kyphosis

背景:强直性脊柱炎后凸畸形是一类脊柱矢状面失平衡的脊柱畸形,由于重心移位,脊柱的生物力学也较复杂,目前对其后凸畸形矫形后的生物力学研究鲜有报道。目的:应用计算机辅助软件建立强直性脊柱炎后凸截骨三维有限元模型,并分析其生物力学特性。方法:建立强直性脊柱炎后凸畸形三维有限元模型,根据20°,30°,40°截骨角度模拟去松质骨截骨矫形手术方案,并分析其矫形效果及生物力学。结果与结论:(1)成功建立了完整强直性脊柱炎后凸截骨矫形三维有限元模型,并且模拟手术操作建立了截骨角度分别为20°,30°,40°的去松质骨截骨模型;(2)3组不同截骨矫形方案中,去松质骨截骨30°矫形程度最佳,并且应力分布较小,其T12、L1、L2、L4、L5、S1、钉棒应力分别为7.346 1,11.952,72.783,81.368,28.144,41.114,109.69 MPa;(3)在去松质骨截骨术30°截骨方式下,术后矫正Cobb角为1.4°,既可获得较佳的矫形程度,同时也能降低由于内固定应力分布集中导致并发症的发生率。

BACKGROUND:Kyphosis in ankylosing spondylitis is a kind of spinal sagittal imbalance;due to center of gravity displaced and complicated biomechanical properties of the spine,the spinal biomechanics after kyphosis correction is little reported.OBJECTIVE:To establish a three-dimensional finite element model of the spine after osteotomy for kyphosis.METHODS:A three-dimensional finite element model of kyphosis in ankylosing spondylitis was established,simulating three kinds of osteotomy orthopedic programs(osteotomy angle in 20°,30°and 40°),and the orthopedic effect and biomechanics were analyzed.RESULTS AND CONCLUSION:(1)The three-dimensional finite element model of finite element model of kyphosis in ankylosing spondylitis was established successfully,and simulated three kinds of osteotomy orthopedic programs at the angles of 20°,30°,and 40°.(2)The best osteotomy angle was 30°,the stress distribution was less,and the stress on the T12,L1,L2,L4,L5,S1 and rod was 7.346 1,11.952,72.783,81.368,28.144,41.114,and 109.69 MPa,respectively.(3)Under 30°osteotomy angle,the postoperative Cobb angle is 1.4°,which not only obtains better orthopedic effect,but also reduces the incidence of complications caused by stress concentration.