Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario, Canada.
Int J Numer Method Biomed Eng. 2023 Nov;39(11):e3761. doi: 10.1002/cnm.3761. Epub 2023 Jul 29.
Computational human body models (HBMs) can identify potential injury pathways not easily accessible through experimental studies, such as whiplash induced injuries. However, previous computational studies investigating neck response to simulated impact conditions have neglected the effect of pre-impact neck posture and muscle pre-tension on the intervertebral kinematics and tissue-level response. The purpose of the present study was addressing this knowledge gap using a detailed neck model subjected to simulated low-acceleration rear impact conditions, towards improved intervertebral kinematics and soft tissue response for injury assessment. An improved muscle path implementation in the model enabled the modeling of muscle pre-tension using experimental muscle pre-stretch data determined from previous cadaver studies. Cadaveric neck impact tests and human volunteer tests with the corresponding cervical spine posture were simulated using a detailed neck model with the reported boundary conditions and no muscle activation. Computed intervertebral kinematics of the model with pre-tension achieved, for the first time, the S-shape behavior of the neck observed in low severity rear impacts of both cadaver and volunteer studies. The maximum first principal strain in the muscles for the model with pre-tension was 27% higher than that without pre-tension. Although, the pre-impact neck posture was updated to match the average posture reported in the experimental tests, the change in posture was generally small with only small changes in vertebral kinematics and muscle strain. This study provides a method to incorporate muscle pre-tension in HBM and quantifies the importance of pre-tension in calculating tissue-level distractions.
计算人体模型 (HBM) 可以识别通过实验研究不易获得的潜在损伤途径，例如挥鞭伤。然而，以前研究颈部对模拟冲击条件的反应的计算研究忽略了冲击前颈部姿势和肌肉预张紧对椎间运动和组织水平反应的影响。本研究的目的是使用详细的颈部模型来解决这个知识空白，该模型模拟了低加速度的后向冲击条件，以改善用于损伤评估的椎间运动和软组织反应。模型中肌肉路径的改进实现了使用从以前的尸体研究中确定的实验肌肉预拉伸数据来模拟肌肉预张紧。使用详细的颈部模型模拟了带有报告边界条件和无肌肉激活的尸体颈部冲击试验和相应的颈椎姿势的人体志愿者试验。首次使用带有预张力的模型计算出了椎间运动，模拟了尸体和志愿者研究中低严重程度后向冲击中观察到的颈部 S 形行为。带有预张力的模型中肌肉的最大第一主应变比没有预张力的模型高出 27%。尽管预冲击颈部姿势已更新为与实验测试中报告的平均姿势匹配，但姿势的变化通常很小，只有椎体运动和肌肉应变的微小变化。本研究提供了一种在 HBM 中纳入肌肉预张紧的方法，并量化了在计算组织水平拉伸时预张紧的重要性。
