a Department of Biomedical Engineering , Wayne State University , Detroit , Michigan.
Traffic Inj Prev. 2013;14(8):845-52. doi: 10.1080/15389588.2013.774084.
The compressive tolerance of the cervical spine has traditionally been reported in terms of axial force at failure. Previous studies suggest that axial compressive force at failure is particularly sensitive to the alignment of the cervical vertebra and the end conditions of the test methodology used. The present study was designed to develop a methodology to combine the data of previous experiments into a diverse data set utilizing multiple test methods to allow for the evaluation of the robustness of current and proposed eccentricity based injury criteria.
Data were combined from 2 studies composed of dynamic experiments including whole cervical spine and head kinematics that utilized different test methodologies with known end conditions, spinal posture, injury outcomes, and measured kinetics at the base of the neck. Loads were transformed to the center of the C7-T1 intervertebral disc and the eccentricity of the sagittal plane resultant force relative to the center of the disc was calculated. The correlation between sagittal plane resultant force and eccentricity at failure was evaluated and compared to the correlation between axial force and sagittal plane moment and axial force alone.
Accounting for the eccentricity of the failure loads decreased the scatter in the failure data when compared to the linear combination of axial force and sagittal plane moment and axial force alone. A correlation between axial load and sagittal plane flexion moment at failure (R² = 0.44) was identified. The sagittal plane extension moment at failure did not have an identified correlation with the compressive failure load for the tests evaluated in this data set (R² = 0.001). The coefficients of determination for the linear combinations of sagittal plane resultant force with anterior and posterior eccentricity are 0.56 and 0.29, respectively. These correlations are an improvement compared to the combination of axial force and sagittal plane moment.
Results using the outlined approach indicate that the combination of lower neck sagittal plane resultant force and the anterior-posterior eccentricity at which the load is applied generally correlate with the type of cervical damage identified. These results show promise at better defining the tolerance for compressive cervical fractures in male postmortem human subjects (PMHS) than axial force alone. The current analysis requires expansion to include more tolerance data so the robustness of the approach across various applied loading vectors and cervical postures can be evaluated.
颈椎的抗压耐受性传统上是用失效时的轴向力来报告的。先前的研究表明，失效时的轴向压缩力特别敏感于颈椎的排列和所使用的测试方法的末端条件。本研究旨在开发一种方法，将以前实验的数据结合到一个多样化的数据集中，利用多种测试方法来评估当前和提出的基于偏心的损伤标准的稳健性。
数据来自 2 项研究，这些研究包括使用不同测试方法的动态实验，这些方法具有已知的末端条件、脊柱姿势、损伤结果以及颈部底部的测量动力学。将载荷转换到 C7-T1 椎间盘的中心，并计算矢状面合力相对于椎间盘中心的偏心。评估了矢状面合力与失效时的偏心之间的相关性，并与轴向力与矢状面弯矩和轴向力的相关性进行了比较。
与轴向力和矢状面弯矩以及轴向力的线性组合相比，考虑失效载荷的偏心度可以减少失效数据的离散度。在本数据集评估的测试中，确定了失效时轴向载荷与矢状面前屈弯矩之间的相关性（R²=0.44）。失效时的矢状面伸展力矩与压缩失效载荷之间没有确定的相关性（R²=0.001）。矢状面合力与前、后偏心的线性组合的确定系数分别为 0.56 和 0.29。与轴向力和矢状面弯矩的组合相比，这些相关性有所提高。
使用所概述的方法得到的结果表明，较低颈部矢状面合力与载荷施加的前后偏心度的组合通常与所确定的颈椎损伤类型相关。这些结果表明，与单独使用轴向力相比，更好地定义了男性尸体人体（PMHS）的压缩性颈椎骨折的耐受性。目前的分析需要扩展到包括更多的耐受数据，以便评估该方法在各种应用加载矢量和颈椎姿势下的稳健性。
