Rieger Laura Kathrin, Junge Mirko, Cutlan Rachel, Peldschus Steffen, Stemper Brian D
Biomechanics and Accident Analysis, Ludwig-Maximilians-Universität (LMU), Occupant Protection System & Virtual Function Development, Volkswagen AG, Letter Box 011/1606 Wolfsburg, Munich, 38436, Germany.
Volkswagen AG, Wolfsburg, Germany.
Int J Legal Med. 2024 Sep;138(5):1831-1844. doi: 10.1007/s00414-024-03225-z. Epub 2024 May 2.
Injury mechanisms of the lumbar spine under dynamic loading are dependent on spine curvature and anatomical variation. Impact simulation with finite element (FE) models can assist the reconstruction and prediction of injuries. The objective of this study was to determine which level of individualization of a baseline FE lumbar spine model is necessary to replicate experimental responses and fracture locations in a dynamic experiment.Experimental X-rays from 26 dynamic drop tower tests were used to create three configurations of a lumbar spine model (T12 to L5): baseline, with aligned vertebrae (positioned), and with aligned and morphed vertebrae (morphed). Each model was simulated with the corresponding loading and boundary conditions from dynamic lumbar spine experiments. Force, moment, and kinematic responses were compared to the experimental data. Cosine similarity was computed to assess how well simulation responses match the experimental data. The pressure distribution within the vertebrae was used to compare fracture risk and fracture location between the different models.The positioned models replicated the injured spinal level and the fracture patterns quite well, though the morphed models provided slightly more accuracy. However, for impact reconstruction or injury prediction, the authors recommend pure positioning for whole-body models, as the gain in accuracy was relatively small, while the morphing modifications of the model require considerably higher efforts. These results improve the understanding of the application of human body models to investigate lumbar injury mechanisms with FE models.
腰椎在动态载荷下的损伤机制取决于脊柱曲度和解剖变异。使用有限元(FE)模型进行冲击模拟有助于损伤的重建和预测。本研究的目的是确定基线FE腰椎模型的个体化程度达到何种水平,才能在动态实验中复制实验响应和骨折位置。
来自26次动态落塔试验的实验X射线被用于创建三种腰椎模型配置(T12至L5):基线模型、椎体对齐模型(定位模型)以及椎体对齐并变形的模型(变形模型)。每个模型都采用动态腰椎实验中的相应载荷和边界条件进行模拟。将力、力矩和运动学响应与实验数据进行比较。计算余弦相似度以评估模拟响应与实验数据的匹配程度。利用椎体内的压力分布来比较不同模型之间的骨折风险和骨折位置。
定位模型能较好地复制受伤的脊柱节段和骨折模式,尽管变形模型的准确性略高。然而,对于冲击重建或损伤预测,作者建议全身模型采用单纯定位,因为准确性的提高相对较小,而模型的变形修改需要付出更高的努力。这些结果有助于增进对利用人体模型和FE模型研究腰椎损伤机制的应用的理解。