嵌入式椎体后凸成形与椎体成形治疗创伤后椎体骨坏死:骨水泥移位的有限元分析

Embedded percutaneous kyphoplasty and percutaneous vertebroplasty for treating post-traumatic vertebral osteonecrosis:finite element analysis of bone cement displacement

背景:创伤后椎体骨坏死的重要病理特征为伤椎内存在椎体裂隙,裂隙内的血性液体及肉芽组织会形成一层假膜,影响椎体成形治疗时骨水泥的渗透及分布,进而影响骨水泥把持力,导致骨水泥移位的风险升高。目的:对比嵌入式椎体后凸成形和椎体成形治疗创伤后椎体骨坏死术后椎体内骨水泥移位的风险。方法:收集1名接受嵌入式椎体后凸成形治疗的创伤后椎体骨坏死女性患者的术后胸椎CT DICOM数据,利用Mimics、Geomagic及Solidwork构建出T9-T11椎体成形治疗三维模型与嵌入式椎体后凸成形治疗三维模型(锚定点100%),同时构建锚定点等比例缩小的20%,40%,60%,80%嵌入式椎体后凸成形模型,然后利用有限元分析软件Ansys对6种模型分别施加150 N轴向压力和10 Nm力矩来模拟前屈、后伸、左右侧弯及左右旋转6种运动,观察受力后模型T10椎体内的骨水泥位移变化。结果与结论:①在6种运动状态下,嵌入式椎体后凸成形100%模型及嵌入式椎体后凸成形20%模型T10椎体内的骨水泥位移量均小于椎体成形模型(P<0.01);在前屈、后伸、右侧弯及左右旋转运动状态下,随着嵌入式椎体后凸成形模型锚定点的缩小,骨水泥受力后的位移呈逐渐增大趋势(P<0.001)。②结果表明,嵌入式椎体后凸成形治疗创伤后椎体骨坏死后骨水泥在椎体内移位的风险要小于椎体成形治疗。

BACKGROUND:Important pathological feature of post-traumatic vertebral osteonecrosis is fissures in the injured vertebra body,bloody fluid and granulation in the fissures.The tissue can form a pseudomembrane.The pseudomembrane formed by necrotic material and granulation tissue can affect the penetration and distribution of the bone cement during vertebroplasty,which can affect the holding power of the bone cement,and increase the risk of bone cement displacement.OBJECTIVE:To compare the risk of bone cement displacement in the vertebral body after the treatment of post-traumatic vertebral osteonecrosis with embedded percutaneous kyphoplasty and percutaneous vertebroplasty.METHODS:Dicom data of postoperative thoracic CT of a female patient with post-traumatic vertebral osteonecrosis who received embedded percutaneous kyphoplasty treatment were collected.Mimics,Geomagic and Solidwork were utilized to construct three-dimensional embedded percutaneous kyphoplasty treatment models of T_(9)-T_(11),then build percutaneous vertebroplasty treatment models(anchor point 100%).Embedded percutaneous kyphoplasty models with different size anchors(20%,40%,60%,and 80%)were constructed.The finite element analysis software Ansys was used to apply pressures of 150 N in the axial direction and 10 Nm of torque to simulate six movements:flexion,extension,left and right bending,and left and right rotation.The changes in the displacement of the bone cement were observed in the T10 vertebral body of the force model.RESULTS AND CONCLUSION:(1)In the six states,the displacement of the bone cement in the T10 vertebral body of the 100%embedded percutaneous kyphoplasty model and the 20%embedded percutaneous kyphoplasty model was smaller than that of the percutaneous vertebroplasty model(P<0.01).In the states of flexion,extension,right bending and left and right rotation,as the anchor point of the embedded percutaneous kyphoplasty model decreased,the displacement of the bone cement after the force gradually increased(P<0.001).(2)It is concluded that the risk of bone cement displacement in the vertebral body of embedded percutaneous kyphoplasty treatment is less than that of the percutaneous vertebroplasty treatment in post-traumatic vertebral osteonecrosis.