不同入路经皮内窥镜下关节成形术对椎间盘生物力学影响的三维有限元分析

Three dimensional finite element analysis of the biomechanics influence of L4 inferior articular process and L5 superior articular process foraminoplasty under percutaneous endoscopy on the intervertebral disc

中文关键词:  腰椎经皮内窥镜  关节突成形术  三维有限元分析

英文关键词:Lumbar percutaneous endoscopy  Foraminoplasty  Three-dimensional finite element

中文摘要:

  【摘要】 目的：通过三维有限元法分析经皮内窥镜下L4下关节突成形术与L5上关节突成形术对椎间盘生物力学的影响。方法：选取1例健康青年男性志愿者，对其进行薄层螺旋CT扫描，建立正常的L3~L5三维有限元模型，将上述有限元模型与经典文献数据进行验证。验证后，模拟腰椎经皮内窥镜技术分别于侧后方入路对L5上关节突与后方入路对L4下关节突做直径7.5mm的圆柱状骨切除以模拟椎间孔成形，从而获得正常模型、L5上关节突成形模型（A模型）和L4下关节突成形模型（B模型）３种模型。在L3椎体上表面向终板施加负荷为400N的垂直于水平面压力模拟正常人腰椎承载重力，在前屈、后伸、左右侧弯、左右旋转的方向上分别施加7.5N·m的纯扭矩，比较３种模型在前屈、后伸、左右侧曲、左右旋转状况下L3/4、L4/5椎间盘应力变化情况。结果：A模型前屈、后伸、左侧屈、右侧屈、左旋、右旋状态下L4/5椎间盘的最大应力分别为0.390MPa、0.520MPa、0.450MPa、0.430MPa、0.510MPa和0.498MPa；B模型前屈、后伸、左侧屈、右侧屈、左旋、右旋状态下L4/5椎间盘的最大应力分别为0.375MPa、0.490MPa、0.440MPa、0.420MPa、0.482MPa和0.478MPa。A模型前屈、后伸、左侧屈、右侧屈、左旋、右旋状态下L3/4椎间盘的最大应力分别为0.369MPa、0.480MPa、0.442MPa、0.432MPa、0.468MPa和0.452MPa；B模型前屈、后伸、左侧屈、右侧屈、左旋、右旋状态下L3/4椎间盘的最大应力分别为0.368MPa、0.478MPa、0.436MPa、0.430MPa、0.465MPa和0.444MPa。结论：腰椎经皮内窥镜技术下，侧后入路L5上关节突成形较后方入路L4下关节突成形对L4/5椎间盘在后伸、旋转状态下的生物力学影响较大。两者对邻近节段L3/4椎间盘的应力变化的影响较小。

英文摘要:

  【Abstract】 Objectives: To evaluate the biomechanical effects of lumbar 4-facet arthroplasty and lumbar 5-facet arthroplasty under percutaneous endoscopy using three dimensional finite element analysis. Methods: a healthy young male volunteer was selected and scanned under the thin-layer spiral CT to establish a normal L3-L5 three-dimensional finite element model. The above normal finite element model and classical literature data were verified. The simulated lumbar percutaneous endoscopic technique was used to resect the L5 superior articular process and L4 inferior articular process through the lateral posterior approach. The normal model, L4 model (A model) and L5 model (B model) were obtained. The load of 400N was applied to the endplate on the upper surface of L3 vertebral body to simulate the load-bearing gravity of normal human lumbar spine. The pure torque of 7.5N·m was applied in the direction of forward bending, backward stretching, left and right side bending and left and right rotation respectively. The stress changes of L3/4 and L4/5 intervertebral discs of the three models were compared under the conditions of forward bending, backward stretching, left/right side bending and left/right rotation. Results: The maximum stress of L4/5 intervertebral disc was 0.390MPa, 0.520MPa, 0.450MPa, 0.430MPa, 0.510MPa and 0.498MPa respectively in flexion, extension, left flexion, right flexion, left rotation and right rotation after L5 superior articular process was formed; the maximum stress of L4/5 intervertebral disc was 0.375MPa, 0.490MPa, 0.440MPa, 0.420MPa, 0.482MPa and 0.478MPa respectively in flexion, extension, left flexion, right lateral flexion, left rotation and right rotation after L4 inferior articular process was formed. The maximum stress of L3/4 intervertebral disc was 0.368MPa, 0.478MPa, 0.436MPa, 0.430MPa, 0.465MPa and 0.444MPa after L5 superior articular process was formed under the condition of forward flexion, backward extension, left flexion, left rotation and right rotation, respectively. The maximum stress of L3/4 intervertebral disc was 0.369MPa, 0.480MPa, 0.442MPa, 0.432MPa, 0.468MPa and 0.452MPa under flexion, right flexion, left rotation and right rotation after L4 inferior articular process was formed, respectively. Conclusions: The biomechanics of L4/5 disc in the state of extension and rotation is more affected by the L5 superior articular process foraminoplasty through the lateral posterior approach than that through L4 inferior articular processforaminoplasty through the posterior approach. Both of them have little effect on the six kinds of stress changes of L3/4 disc.