额、枕部直接冲击导致中脑损伤的力学机制研究

目的分析额、枕部直接冲击造成中脑应力响应,探讨颅脑直接冲击导致脑干损伤的力学机制。方法构建头颅三维有限元模型,模拟计算额、枕部直接冲击损伤,分析中脑上、下交界面节点应力分布,总结中脑应力响应。结果中脑-间脑界面在冲击初始阶段,2ms即出现应力增高,中脑-桥脑界面应力升高开始于冲击后期(10ms),两交界面节点应力在冲击时程中均持续升高,额部冲击比枕部冲击在中-间脑界面造成的应力峰值高。结论中脑在颅脑直接冲击伤的致伤机制中占有突出地位,中脑的应力改变可解释脑震荡的意识障碍及部分原发脑干伤的临床表现。

Mechanics of midbrain injure by frontal or occipital direct head impact

Objective To analyze the stress corresponding of midbrain during frontal or occipital direct head impact and discuss the mechanisms of direct impact head injury. Methods Using a three-dimensional finite element model, the frontal and occipital direct impacts were studied. A sine-squared pulse with a 6. 8-KN peak and 18-ms duration was applied to the fronlal bone and occipital bone. The results of Von Mises stress of niesencephalon were investigated. Results The Von Mises stress of mesencephalon changed at very beginning of loading. It increased in the full loading time history. The stress results of those simulations were compared to the clinical imaging findings of head injury cases. A good correlation was found between niesencephalon response, in terms of Von Mises stress, and observed brain injuries in clinical findings. Conclusion The stress of the mesencephalon caused by direct head impact is one of the major cause of brain stem injury.