高处坠落时脊柱损伤机制研究

With the fast development of high buildings in recent years, the incidence of falling from height has the rising trend year by year, and the injury of spine is often caused by falling from height. In order to explore the injured mechanism of the spine while falling from height, the researches of the relevant problem in this project are carried out using the method that the experiment combines with finite element analysis. The main contents of research are as follows, (1) The static mechanical properties of every tissue of spine: the tests of mechanical properties of every tissue of the spine are carried on through dividing into groups according to age; the injured models of spine are constructed, the tests of mechanical properties of tissues for injured spine are carried, and variations of mechanical properties for tissues of spine are compared with different ages, normal and injured tissues of spine; (2) Dynamic responses of the whole spine: experiments of compressed and dropping hammer for the segmented spine are launched, and dynamic responses of spine are analyzed; at the same time the finite element model of the spine is established, the injured state of the spine is analyzed under different falling situations; (3) "In vivo" injury analysis: experiments of falling from height for living animals and spinal injured analysis are carried out, combining with the finite element analysis, the influence of factors, such as falling height, posture, age, etc., on the injury of spine is determined, and the tolerance range of spine is provided. Understanding and grasping the injured mechanism of spine while falling from height, can provide the significant reference basis for safety protection in the production and living.

近年来随着高层建筑的快速发展，高处坠落的发生率呈逐年上升的趋势，而坠落后常常导致脊柱的损伤。为了探索高处坠落时脊柱的损伤机制，本项目使用实验和有限元相结合的方法，开展相关问题的研究。主要研究内容有：（1）脊柱各组织的静态力学性能：按年龄分组进行脊柱各组织材料力学性能的测试；构建脊柱损伤模型，并对受损后的脊柱各组织再进行力学性能测试，对比不同年龄之间、正常与受损后脊柱各组织材料力学性能的变化；（2）脊柱整体的动态力学响应：进行脊柱分节段的压缩实验、落锤实验，分析脊柱的动态力学响应；同时建立脊柱的有限元模型，分析不同坠落情况时脊柱的损伤状况；（3）"在体"损伤分析：进行多种工况的动物活体坠落实验及脊柱损伤情况分析，结合有限元仿真分析，确定坠落高度、姿势、年龄等因素对脊柱损伤的影响，给出脊柱耐受范围。了解和掌握高处坠落时脊柱的损伤机制，可为生产生活中的安全防护提供有价值的参考依据。

生物组织的组成成分、结构、年龄等因素会影响组织材料的力学性能，从而影响对外载荷的力学响应。本项目为研究脊柱组织在外载作用下的力学行为，具体开展了五个方面的工作：1）采用纳米压痕技术测试了兔腰椎各椎体的生物力学参数，发现胸腰椎结合处、腰尾椎结合处径向方向的力学性能明显低于轴向方向，约为轴向方向的1/2；2）使用Micro-CT扫描兔胸、腰椎椎体，获得了不同年龄椎体中与力学性能相关的细观结构参数，明确了年龄因素对参数的影响；3）采用材料试验机、动态应变仪、三维全场应变系统等设备，进行了兔脊柱各单椎体、节段的准静态压缩实验，确定了各组织的材料参数，可知年龄因素对同名椎体的极限载荷、最大应力有影响；颈胸、胸腰结合处易发生损伤；从胸椎到腰椎，极限载荷、最大应力呈增长趋势；单个椎体的极限载荷明显大于同名的脊柱节段；椎间盘相比于上下椎体有着明显的位移变化；4）仿真模拟了不同能量冲击下兔椎体的生物力学行为，并对损伤情况进行了分析；随着能量的增加，损伤范围越来越大；进行了椎体5种骨密度的有限元分析，发现骨密度越低越易损伤；5）进行了人体头-颈椎后碰撞过程的仿真模拟并对可能的损伤区域进行了分析。. 本项目从微观-细观-宏观多角度系统地研究脊柱在静载和动载下的力学行为；从颈椎、胸椎到腰椎，分椎体和节段进行全面系统的力学性能研究，明确脊柱中最易损伤的位置；给出了年龄对脊柱耐受性的影响。了解脊柱的耐受范围，采取对应的保护措施，可以有效的减少脊柱损伤，降低相关人员死亡或瘫痪的风险，减轻由于脊柱损伤而引起的经济损失和家庭负担。