Biomechanics Section, Katholieke Universiteit Leuven, Belgium; Department of Experimental Neurosurgery and Neuroanatomy, KU Leuven, Belgium.
Biomechanics Section, Katholieke Universiteit Leuven, Belgium.
J Mech Behav Biomed Mater. 2014 May;33:3-15. doi: 10.1016/j.jmbbm.2013.06.011. Epub 2013 Jul 18.
The most frequent head injuries resulting from bicycle accidents include skull fracture acute subdural hematoma (ASDH), cerebral contusions, and diffuse axonal injury (DAI). This review includes epidemiological studies, cadaver experiments, in vivo imaging, image processing techniques, and computer reconstructions of cycling accidents used to estimate the mechanical parameters leading to specific head injuries. The results of the head impact tests suggest the existence of an energy failure level for the skull fracture, specific for different impact regions (22-24J for the frontal site and 5-15J for temporal site). Typical linear patterns were described for frontal, parietal and occipital skull fracture. Temporal skull fracture described considerably higher variability. In term of contusion mechanogenesis, the experiments proved that relative brain-skull motion will not be prevented if the maximum frequency of the impact frequency spectrum stays below 150Hz or below the frequency corresponding to the impedance peak of the head under investigation. The brain shift patterns in humans, both in dynamic and quasistatic situations were shown to be very complex, with maximum amplitudes localized at the level of the inferolateral aspects of the frontal and temporal lobes. The resulting brain maximum amplitudes differed when the head was subjected to a sagittal or lateral motion. Finally, the presented data support the existence of a critical elongation/stretch criterion for the occurrence of ASDH due to BV rupture, located around 5mm elongation or 25% stretch limit. In addition, a tolerance level lying around 10,000rad/s(2) for pulse durations below 10ms was established for BV rupture, which seems to decrease with increasing pulse duration. The described research indicates that injury specific tolerance criteria can provide a more accurate prediction for head injuries than the currently used HIC. Internal brain lesions are strongly related to rotational effects which are not appropriately accounted by the commonly accepted head injury criterion (HIC). The research summarized in this paper adds significantly to the creation of a fundamental knowledge for the improvement of bicycle helmets as well as other head protective measures. The described investigations and experimental results are of crucial importance also for forensic research.
自行车事故中最常见的头部损伤包括颅骨骨折、急性硬膜下血肿（ASDH）、脑挫裂伤和弥漫性轴索损伤（DAI）。本综述包括流行病学研究、尸体实验、体内成像、图像处理技术和用于估计导致特定头部损伤的机械参数的计算机重建。头部撞击测试的结果表明，颅骨骨折存在能量失效水平，特定于不同的撞击区域（额部 22-24J，颞部 5-15J）。描述了额部、顶骨和枕骨颅骨骨折的典型线性模式。颞骨骨折的描述则具有相当大的变异性。在挫伤的机械发生方面，实验证明，如果冲击频谱的最大频率保持在 150Hz 以下或低于所研究头部的阻抗峰值对应的频率，相对脑颅骨运动将不会被阻止。在动态和准静态情况下，人类的脑移位模式显示非常复杂，最大幅度位于额部和颞部的下外侧。当头部受到矢状或侧向运动时，产生的脑最大幅度会有所不同。最后，所提供的数据支持由于 BV 破裂导致 ASDH 发生存在一个关键的伸长/拉伸标准，位于大约 5mm 的伸长或 25%的拉伸极限处。此外，对于脉冲持续时间低于 10ms 的 BV 破裂，建立了大约 10,000rad/s(2)的脉冲持续时间容限，随着脉冲持续时间的增加，该容限似乎会降低。所述研究表明，与目前使用的 HIC 相比，损伤特异性耐受标准可以更准确地预测头部损伤。内部脑损伤与旋转效应密切相关，而旋转效应不能被普遍接受的头部损伤标准（HIC）适当考虑。本文综述中总结的研究为改进自行车头盔以及其他头部保护措施提供了重要的基础知识。所描述的研究和实验结果对于法医学研究也具有至关重要的意义。
