骨质疏松症患者腰椎有限元模型的建立与骨强度分析

Establishment of Finite Element Model of Lumbar Spine in Patients with Osteoporosis and Analysis of Bone Strength

目的:基于骨质疏松症患者CT图像个体化精准建立单个腰椎(L_2)的有限元模型,并对模型进行骨强度分析。方法:采用交互式医学图像控制系统MIMICS软件对患者的CT图片进行预处理后,导入大型通用有限元软件ANSYS中个体化精准建立L_2有限元模型。通过模拟正常站立、一般活动和突然跌倒时,分别在上终板施加0.3,1.0,4.0MPa轴向载荷,计算最大应变数值以及von Mises应变值高于5 000με骨体积占总体积比率。结果:随着载荷逐步加大,位移、应力和应变也分别变大,具有骨折风险的骨体积也明显增加,分别增加0.08%,38.39%,57.80%.结论:本研究建立的有限元模型符合骨质疏松性单个腰椎的临床特点,模拟了其生物力学特性。

Objective：To establish a finite element model of individual lumbar spine（L_2）based on individualized precision CT images of osteoporosis patients,and to analyze the bone strength of the model.Methods：The CT images of the patients were pretreated by the MIMICS software of the interactive medical image control system and then introduced into the large-scale general finite element software ANSYS to establish the L_2 finite element model accurately.By simulating normal standing,general activity and sudden falling,the axial load of 0.3,1.0,4.0MPa was applied to the upper endplate respectively,and the ratios of the maximum strain values and the von Mises strain higher than bone volume to total volume of 5 000μεwere calculated.Results：As the load gradually increased,the displacement,stress and strain were also increased,and the bone volume with fracture risk increased significantly,with 0.08%,38.39% and 57.80% respectively.Conclusion：The finite element model established in this study is consistent with the clinical characteristics of osteoporotic single lumbar spine,and it simulates the biomechanical properties.