Arun Mike W J, Hadagali Prasannaah, Driesslein Klaus, Curry William, Yoganandan Narayan, Pintar Frank A
Department of Neurosurgery, Medical College of Wisconsin.
Stapp Car Crash J. 2017 Nov;61:1-25. doi: 10.4271/2017-22-0001.
Recent epidemiology studies have reported increase in lumbar spine injuries in frontal crashes. Whole human body finite element models (FEHBM) are frequently used to delineate mechanisms of such injuries. However, the accuracy of these models in mimicking the response of human spine relies on the characterization data of the spine model. The current study set out to generate characterization data that can be input to FEHBM lumbar spine, to obtain biofidelic responses from the models. Twenty-five lumbar functional spinal units were tested under compressive loading. A hydraulic testing machine was used to load the superior ends of the specimens. A 75N load was placed on the superior PMMA to remove the laxity in the joint and mimic the physiological load. There were three loading sequences, namely, preconditioning, 0.5 m/s (non-injurious) and 1.0 m/s (failure). Forces and displacements were collected using six-axis load cell and VICON targets. In addition, acoustic signals were collected to identify the times of failures. Finally, response corridors were generated for the two speeds. To demonstrate the corridors, GHBMC FE model was simulated in frontal impact condition with the default and updated lumbar stiffness. Bi-linear trend was observed in the force versus displacement plots. In the 0.5 m/s tests, mean toe- and linear-region stiffnesses were 0.96±0.37 and 2.44±0.92 kN/mm. In 1.0 m/s tests, the toe and linear-region stiffnesses were 1.13±0.56 and 4.6±2.5 kN/mm. Lumbar joints demonstrated 2.5 times higher stiffness in the linear-region when the loading rate was increased by 0.5 m/s.
近期的流行病学研究报告称,正面碰撞中腰椎损伤有所增加。全人体有限元模型(FEHBM)经常被用于描述此类损伤的机制。然而,这些模型在模拟人体脊柱反应方面的准确性依赖于脊柱模型的特征数据。当前的研究旨在生成可输入到FEHBM腰椎模型的特征数据,以便从模型中获得生物逼真的反应。对25个腰椎功能脊柱单元进行了压缩载荷测试。使用液压试验机对标本的上端进行加载。在上方的聚甲基丙烯酸甲酯上施加75N的载荷,以消除关节松弛并模拟生理载荷。有三种加载序列,即预处理、0.5米/秒(无损伤)和1.0米/秒(失效)。使用六轴力传感器和VICON靶标收集力和位移数据。此外,收集声学信号以确定失效时间。最后,针对这两种速度生成了反应走廊。为了展示这些走廊,在正面碰撞条件下使用默认和更新后的腰椎刚度对GHBMC有限元模型进行了模拟。在力与位移图中观察到双线性趋势。在0.5米/秒的测试中,平均起始段和线性段刚度分别为0.96±0.37和2.44±0.92千牛/毫米。在1.0米/秒的测试中,起始段和线性段刚度分别为1.13±0.56和4.6±2.5千牛/毫米。当加载速率提高0.5米/秒时,腰椎关节的线性段刚度提高了2.5倍。