Laboratoire de Biomécanique Appliquée, UMRT24 IFSTTAR/Université de la Méditerranée, Marseille, France.
J Trauma Acute Care Surg. 2012 Mar;72(3):727-32. doi: 10.1097/TA.0b013e3182395e68.
To prevent abdominal organs' traumas in crash situations, the definition of efficient safety devices should be based on a detailed knowledge of human tolerance, i.e., injury mechanisms and related injury criteria. This knowledge should be based on experimental observation of these mechanisms through damage and failure analysis.
In this study, 10 human cadaveric livers are uniaxially compressed using three different loading velocities (0.0013, 0.2, and 1 m/s). Injuries induced are analyzed at two observation levels through a macroscopic study of internal and external cracks and a histologic study of damage initiation.
Liver global behavior is similar for the three loading velocities, but loading rate seems to influence the stiffness and the severity of failure process. Macroscopic injury analysis showed four patterns of laceration because of organ spreading during its compression exhibiting liver structure incidence. Histologic analysis shows two different damage occurrences: microcracking and cavitation. The crack propagation is observed to occur preferentially within the lobules. Influence of the vascular system is also highlighted. Both macroscopic and histologic injuries obtained are relevant with those clinically observed under trauma situations.
Based on experimental investigation of human liver under compression, this work provides a multiscale evaluation of injury process coupling mechanical and histologic analysis. Injury mechanisms postulated involve vascular structures and capsule. All this information is essential for the design of dedicated behavior laws and finite element models.
为了防止碰撞情况下腹部器官受伤，有效安全装置的定义应基于对人体耐受度的详细了解，即损伤机制和相关损伤标准。这些知识应基于通过损伤和失效分析对这些机制进行的实验观察。
在这项研究中，使用三种不同的加载速度（0.0013、0.2 和 1 m/s）对 10 个人体尸体肝脏进行单轴压缩。通过对内、外裂纹的宏观研究和损伤起始的组织学研究，在两个观察水平上分析所引起的损伤。
肝脏在三种加载速度下的整体行为相似，但加载速度似乎会影响刚度和失效过程的严重程度。宏观损伤分析显示，由于器官在压缩过程中扩散而导致肝脏结构发生率出现四种撕裂模式。组织学分析显示了两种不同的损伤发生：微裂纹和空化。裂纹扩展被观察到优先发生在小叶内。还强调了脉管系统的影响。在创伤情况下临床观察到的宏观和组织学损伤都与本研究中获得的损伤相符。
基于对人类肝脏在压缩下的实验研究，本工作提供了对机械和组织学分析相结合的损伤过程的多尺度评估。提出的损伤机制涉及血管结构和包膜。所有这些信息对于专用行为定律和有限元模型的设计都是必不可少的。
