中文摘要：

目的建立PUMCⅡd1型青少年特发性脊柱侧凸（AIS）的三维有限元模型，模拟后路三维矫形手术操作并分析其生物力学特征。方法采集1例14岁PUMCⅡdl型AIS女性志愿者T，至骶尾骨的CT影像图像，应用Mimics16．0、GeomagicStudio11．0、ANSYS14．0软件建立完整的AIS三维有限元模型，进一步构建椎弓根钉一棒系统内固定模型并模拟后路三维矫形手术操作，记录脊柱侧凸矫正的临床指标变化，采用VonMises应力峰值分析椎弓根钉一棒系统应力分布。结果成功建立了PUMCⅡd1型AIS三维有限元模型，模型包括523617个单元，159008个节点。模拟后路三维矫形手术后，AIS有限元模型的胸弯和腰弯矫形率分别达到55．7％和71．4％；顶椎区L1和L2椎体去旋转角度分别为22．77°和23．42°，其椎体质心偏移中线距离分别为6．72mm和8．91mm。L1椎体凸侧（左侧）螺钉应力峰值为257．82MPa，远小于其屈服强度。顶椎区各椎体（T12～L3）凸侧螺钉应力大于凹侧，且应力集中于钉尾与钉身交界处以及钉尾与矫形棒联接处。结论AIS有限元模型的建立及手术模拟能为AIS生物力学研究提供量化指标，并为PUMCⅡd1型AIS手术方案的制定以及治疗效果的预测提供一定的理论基础。

英文摘要：

Objective To establish three-dimensional finite element models of the Peking Union Medical College （PUMC） type Ⅱd1 adolescent idiopathic scoliosis （AIS） for simulating the posterior surgical correction and analyzing the biomechanical characteristics of pedicle screws fixation. Methods CT images were collected from a 14-year-old female volunteer. By using several kinds of software, such as Mimics 16.0, Geomagic Studio 11.0 and ANSYS 14.0, the three dimensional finite element models of AIS was established and analyzed. The individual finite element model was applied to simulate the posterior surgical correction. The clinical indicators of AIS were recorded and the distribution of Von Mises stresses in internal fixation system was evaluated. Results The three-dimensional finite element model of PUMC typeⅡd1 AIS was established successfully, which was consisted of 523 617 elements and 159 008 nodes. After simulation of posterior surgical correction, the correction rate of thoracic curve and main lumbar curve were 55.7% and 71.4%, respectively. Apical region L1, L2 vertebra to the rotation angles were 22.77° and 23.42°, the distances from their vertebral body to the midline were 6.72 mm and 8.91 mm, and the Von Mises stress of pedicle screws of L1 convex side （left side） was 257.82 MPa, far less than the yield strength. The stress of screws in the convex side was greater than the concave side, and the stress concentrated on the conjunction of rod to screw and the conjunction of nail to shank. Conclusion Three-dimensional finite element simulation is able to provide quantitative indicators of AIS biomechanics experiments, which could further establish the theoretical basis for the sureical Dlannin and effectiveness evaluation.