后向跌倒过程中脊柱胸腰段受力的 实验及有限元研究

张霄翔1、2，孙培栋3，王  哲1，吴彦超1，吴晓宇1，余星亮1、2，艾子政1、2，董谢平1

（1 江西省人民医院骨科 330006 南昌市；2 江西中医药大学研究生院 330004 南昌市；3 南方医科大学 人体解剖学教研室 广东省医学生物力学重点实验室 510515 广州市）

基金项目：国家自然科学基金（编号：81460346）

第一作者简介：男（1995-），硕士研究生在读，

研究方向：骨科生物力学

电话：（0791）86895809  

E-mail：zhangxiaoxiang9503@163.com

通讯作者：董谢平  

E-mail：jxzhyxh@163.com

【摘要】 目的：以动力学仿真软件获取志愿者后向跌倒过程中胸腰段受力状况的运动、动力学数据，作为有限元加载条件，评估跌倒过程中脊柱局部应力情况。方法：选取1名健康志愿者（男性，27岁，175cm，70kg），随后对志愿者躯干进行CT扫描。然后，在Anybody人体建模仿真系统软件中建立骨骼肌肉模型，志愿者站立并后向倾斜30°，在无防备状态下后向摔倒构建跌倒过程中人体骨骼肌模型。根据志愿者CT数据建立并优化有限元模型，模型在施加7.5N·m力矩模拟前屈、后伸、左右侧弯及旋转范围，验证模型有效性后，将获取后向跌倒状态下着力点、应力传导方向及受力区应力值作为加载条件并赋予人体胸腰段有限元模型进行有限元分析。结果：Anybody人体建模仿真系统软件模拟后向跌倒实验中，志愿者呈无意识后向跌倒姿态，骶尾部最先着地；臀部与测力台冲击的总时间为1.14s，最大冲击力达4056N；模型以坐骨结节为力加载点，由骶尾部沿脊柱长轴向头部进行力学加载。有限元结果显示，应力经传导主要集中于T11~L2节段；在该节段中，椎体前缘平均应力达16.6MPa；上下关节突平均载荷达25.4MPa，椎板及椎弓根与椎体连接处也出现明显的应力集中，平均应力为26.2MPa。结论：后向跌倒时胸腰段所受应力较大，骨折风险较高。

【关键词】 后向跌倒；有限元分析；胸腰椎损伤

doi：10.3969/j.issn.1004-406X.2020.09.09

中图分类号：R318.01    

文献标识码：A    

文章编号：1004-406X（2020）-09-0827-06

Experimental and finite element study on the stress of thoracolumbar spine during backward fall/ZHANG Xiaoxiang, SUN Peidong, WANG Zhe, et al//Chinese Journal of Spine and Spinal Cord, 2020, 30(9): 827-832

【Abstract】 Objectives: To evaluate the local stress of thoracolumbar vertebra after falling by constructing real backward falling down model based on the finite element loading condition obtained from volunteers. Methods: A healthy volunteer (male, 27 years old, 175cm, and 70kg) was selected, and the torso of the volunteer was scanned by CT. Then the skeletal muscle model was established using the dynamic simulation software Anybody Modeling System. The volunteers stood at a backward tilt of 30° and fell backward to construct a human skeletal muscle model in the state of fall. The finite element model was established and optimized based on the CT data of the volunteer. Applied 7.5N·m moment to simulate the range of flexion, extension, left and right lateral bending and rotation, and validated the effectiveness of the model. The stress point, stress conduction direction and stress value in the stress area in the backward fall state were collected as loading conditions, and the finite element model of human thoracolumbar segment was given for finite element analysis. Results: In the backward fall experiment simulated by Anybody Modeling System, the volunteer fell backward unconsciously, and the sacrum was the first part to land; the total impact time between the hip and the force platform was 1.14s, and the maximum impact force was 4056N; the model took the ischial tubercle as the force loading point, and the sacral part was mechanically loaded to the upper vertebral body along the long axis of the spine. The finite element results showed that the stress conduction was mainly concentrated in the T11-L2 segment, in which the average stress at the anterior edge of the vertebral body was 16.6MPa, the average load of the upper and lower articular process was 25.4MPa, and the average stress concentration at the lamina and the connection between the pedicle and the vertebral body was 26.2MPa. Conclusions: During falling backward, there was higher stress on the thoracolumbar segment, and therefore the risk of fracture was higher.

【Key words】 Fall backward; Finite element analysis; Thoracolumbar injury

【Author′s address】 Department of Orthopedics, Jiangxi Provincial People′s Hospital, Nanchang, 330006, China

图1  标记点粘贴于人体正面观及背面观示意图，前胸部和双侧髂前上棘共贴4个标记，下肢左右两侧各贴5个标记，上肢左右臂及肩部各7个标记，头部前后各2个标记，背部肩胛骨、髂后上嵴、脊柱共7个标记  图2  模拟跌倒示意图，志愿者站立并后倾30°，助手分散受试者注意力，在无准备状态下松开牵引绳，模拟跌倒

Figure 1  Markers were pasted on the front view and the back view of the human body. 4 markers were pasted on the front chest and bilateral anterior superior iliac spine, 5 markers on the left and right sides of the lower extremities, 7 markers on the right and left arms and shoulders of the upper limbs, 2 markers on the front and back of the head, 7 markers on the back scapula, posterior superior iliac crest and the spine  Figure 2  Schematic diagram of simulated fall, the volunteers tilted back 30°,and the assistant distracted the subjects, loosened the traction rope without preparation, and simulated the fall

图3  Anybody软件模拟后向跌倒过程，人体跌倒过程中骶尾部最先着地，随后躯干及四肢伸展  图4  有限元模型力学加载示意图，力量由坐骨结节沿脊柱长轴向上加载  图5  a~c 跌倒后正面、背面及侧面脊柱有限元分析，可见跌倒过程中，应力主要集中于胸腰段椎体，其中该节段椎体前缘及椎弓根部应力较大

Figure 3  The Anybody modeling system simulated a backward fall, in which the sacrococcyx was the first to land after the fall, and then the torso and limbs were extended  Figure 4  The mechanical loading diagram of the finite element model showed that the force was loaded upward along the long axis of the spine by the ischial tubercle  Figure 5  a-c The picture showed the finite element results of the spine after the fall. It can be seen that after the fall, the stress was mainly concentrated in the thoracolumbar segment of the spine, in which the stress in the anterior edge of the vertebral body and the pedicle of the vertebral arch was larger