Margulies S S, Thibault L E, Gennarelli T A
Department of Bioengineering, University of Pennsylvania, Philadelphia 19104.
J Biomech. 1990;23(8):823-36. doi: 10.1016/0021-9290(90)90029-3.
Diffuse brain injuries resulting from non-impact rotational acceleration are investigated with the aid of physical models of the skull-brain structure. These models provide a unique insight into the relationship between the kinematics of head motion and the associated deformation of the surrogate brain material. Human and baboon skulls filled with optically transparent surrogate brain tissue are subjected to lateral rotations like those shown to produce diffuse injury to the deep white matter in the brain of the baboon. High-speed cinematography captures the deformations of the grids embedded within the surrogate brain tissue during the applied load. The overall deformation pattern is compared to the pathological portrait of diffuse brain injury as determined from animal studies and autopsy reports. Shear strain and pathology spatial distributions mirror each other. Load levels and resulting surrogate brain tissue deformations are related from one species to the other. Increased primate brain mass magnified the strain amplified without significantly altering the spatial distribution. An empirically-derived value for a critical shear strain associated with the onset of severe diffuse axonal injury in primates is determined, assuming constitutive similarity between baboon and human brain tissue. The primate skull physical model data and the critical shear strain associated with the threshold for severe diffuse axonal injury were used to scale data obtained from previous studies to man, and thus derive a diffuse axonal injury tolerance for rotational acceleration for humans.
借助颅-脑结构的物理模型，对非撞击性旋转加速导致的弥漫性脑损伤进行了研究。这些模型为头部运动学与替代脑组织相关变形之间的关系提供了独特的见解。将填充有光学透明替代脑组织的人类和狒狒头骨进行侧向旋转，类似于已证明会对狒狒大脑深部白质造成弥漫性损伤的旋转方式。高速摄影记录了在施加负荷期间替代脑组织内嵌入的网格的变形情况。将整体变形模式与根据动物研究和尸检报告确定的弥漫性脑损伤的病理特征进行比较。剪应变和病理空间分布相互对应。不同物种之间的负荷水平和由此产生的替代脑组织变形存在关联。灵长类动物脑质量的增加放大了应变，但没有显著改变空间分布。假设狒狒和人类脑组织之间存在本构相似性，确定了与灵长类动物严重弥漫性轴索损伤发作相关的临界剪应变的经验值。利用灵长类动物头骨物理模型数据和与严重弥漫性轴索损伤阈值相关的临界剪应变，对先前研究中获得的数据进行缩放以适用于人类，从而得出人类对旋转加速的弥漫性轴索损伤耐受性。
