【作者】 赵辉；

【导师】 尹志勇；

【作者基本信息】 第三军医大学 ， 交通医学工程， 2009， 博士

【摘要】 头颅因外力作用而使运动受阻碍,除引起头皮、颅骨局限性创伤外,更严重的是由于脑组织滞后于头颅的运动,可导致脑着力部位、脑内及脑对冲部位出现挤压、撕裂及牵张等力学效应,造成颅脑减速伤(deceleration injury)。颅脑减速伤在TBI中较为常见,且损伤较重,常见于交通伤和坠落伤。缺乏保护的行人作为道路使用者在道路交通事故(Road traffic Accident, RTA)中易受到伤害,颅脑损伤是导致行人伤亡的主要原因之一。行人颅脑交通伤的典型损伤过程为减速-加速-减速或只有减速。进行汽车-行人交通事故调查分析对降低汽车-行人交通事故的发生及减轻颅脑损伤、特别是减速伤的危害有重要意义。应力、应变分布对创伤性颅脑损伤有重要影响,构建较精细、“标准”的国人头颅有限元(Finite Element,FE)模型,从颅脑减速伤的应力波传播和应力分布来探讨颅脑减速伤的发生机制,可为颅脑减速伤的防护和诊治提供生物力学依据。最后,开展动物颅脑减速伤实验研究,研究颅脑减速伤的伤情特点,并以此探讨颅脑减速伤的发生机制,其对颅脑减速伤的救治有积极意义。因此,本研究通过交通事故调查、有限元模拟和动物颅脑减速伤实验研究,从颅脑减速伤的发病规律、损伤特点以及生物力学等方面来研究颅脑减速伤的发生机制,其主要研究方法和结论如下:一、就我国多个地区的汽车-行人交通事故进行详细调查、分析,发现:汽车碰撞正横穿公路的行人比例最高;伤亡行人中,成年人所占比例高,男性多于女性;老年人受到的伤害重;行人损伤多发伤多,头部和肢体损伤比例高,均为68.5%,颅脑损伤是导致行人死亡的主要因素,占71.4%;儿童头部损伤程度明显比成年人更严重。结合经验公式、多刚体动力学模拟对事故进行分析,定量研究了汽车碰撞速度对行人损伤程度的影响,结果显示:汽车碰撞速度对行人损伤程度以及头部损伤有重要影响;行人头部损伤既有加速过程,又有减速过程,但颅脑减速伤发病率高、损伤重。二、中国可视化人体(Chinese Visible Human,CVH)数据集含有丰富的人体解剖信息,通过CVH头颅的三维图像重建、实体模型重建、FE模型网格划分、FE模型的装配等操作,构建了基于CVH的头颅FE模型。结果显示:网格单元节点数和单元数分别为31223和119911,所有单元均为实体单元;所构建头颅FE模型与国人解剖结构基本一致,更具有“代表性”和几何相似性,特别是将以往FE模型常简化的颌面骨和颅底部分进行了细化,有利于这些部分的损伤生物力学研究。首例基于CVH的国人头颅FE模型的构建是“数字化可视人”向“数字化物理人”发展的有益探索,对CVH的后续开发有重要意义。三、用Hypermesh软件建立头颅以额、颞部碰撞静止的、大质量钝性物体的模拟模型,以模拟颅脑减速伤。在LS-DYNA软件中进行求解计算,分析颅内应力波传播和颅内应力分布。结果显示:额、颞部碰撞钝性静止物体时,应力波由颅骨碰撞点沿四周辐射状传播;在颅骨断端自由端、薄弱处以及颅底不规则处有应力集中,碰撞颅骨部位的应力最大;脑组织冲击区下方的脑组织承受最大的应力,应力波从冲击区下方的脑组织向颅内传播,在颅内逐渐衰减,颅底有应力集中区域;额部碰撞的减速伤对侧未发现应力集中区域,颞部碰撞在对侧发现了应力集中区域。颅脑减速伤的FE模拟能从应力波传播和应力分布解释临床减速伤病例,对减少颅脑减速伤的临床漏诊和误诊有重要意义。四、研制了新型减速伤致伤装置,用家兔开展了颅脑减速伤实验研究,通过一般观察、影像学观察和病理观察来研究颅脑减速伤,结合伤情特点来探讨颅脑减速伤的发生机制。结果:研制的减速伤致伤装置可用于开展小动物减速伤致伤实验;复制了轻、中和重度兔颅脑减速伤实验模型;颅脑减速伤的伤情特点主要表现为碰撞部位和颅底颅骨骨折、邻近碰撞部位以及颅底骨折区域的脑挫伤、硬膜下出血、脑实质出血,其病理改变主要为出血性脑挫伤和脑水肿;颅脑减速伤的损伤部位与应力波传播和应力分布特点相吻合。更多还原

【Abstract】 The movement of head was suffocated due to the outside force, the trauma on skull by the force could result in trauma of localization. Whereas several movement of the brain tissues were lagging after that of head, seriously, the trauma on tissues from the impacts brings about some mechanics effects as crushing, laceration and stretch was considered as the deceleration injury, which is a kind of traumatic brain injury (TBI), with great possibility of occurrence in traffic and falling injury. This research applied the investigations in the traffic incidents, finite elment(FE) simulation and the experiments of the deceleration injury of rabbit heads for the study of invasions, occurrence mechanism and the specialty of injury of the deceleration injury.The pedestrians who are walking along without any protection from these accidents would be such an inclination in suffering from the road traffic Accident (RTA) that the brain injury was the main reason resulting in the injury and death of the pedestrian. The processes of acceleration and deceleration are performing in the process of the brain injury among the passengers in traffic incidents, with the process of deceleration-acceleration-deceleration or only deceleration. The investigation on vehicle-pedestrian accident in multi-areas in China could play an important role in cutting down the accident rate and mitigating the brain injury, espicially brain deceleration injury.TBI were significantly affected by the distribution of the stress and strian meeting the injury threshold. The FE model which be constructed with precision and standard by imitation of Chinese head, it could be operated in discussion the stress wave from the deceleration injury as well as the distribution in stress, so as to study the occurrence mechanism for the application in a certain protection, diagnosis and treatment of the deceleration injuryFinally, the development of the experiment of the deceleration injury on animals could be applied in the study on the occurrence mechanism of that on the basis of injury characteristic of the deceleration injury on animal and biomechanics mechanism, however, the advanced treatment of the deceleration injury are also been improved. The main methods and conclusions as following,I, An specific investigation among the Car- pedestrian traffic incidents were studied according to a multi-dimensional model including human– car– environment. The results show that the pedestrian who are crossing the road tends to have more possibility of injury in the traffic incidents. The adult was observed in recent and temporal cases, whereas the highest occurrence in the injuring and dead pedestrian, male and the old were also observed with more possibility in the injury and death than that among female and other ages. The multi-injury observed in cases was more than other injury in pedestrian injury, the percentage of head and extremities injury were higher than these of injury. Consequently, the fatality of pedestrian was mostly resulted in the brain injury. The severity of injury among children was obviously worse than the injury among adult. According to the analyses of traffic imitating by means of empirical formula and multi-body dynamatics, the results show that the severity of injury including head injury was mainly affected by the velocity of car impacting, the process of head injury of pedestrian contains acceleration and deceleration, the latter could result in the brain deceleration injury which be characteristic as the high incidence of disease and the severity of injury.Ⅱ, By terms of three-dimensional image reconstruction of the head, geometry model reconstruction, meshing of finite element model and assembling of finite element models et al, a plenty of information related to the human anatomy was contained in the Chinese Visible Human Data for the propose of contracting finite element model of the visible human head. The results show that the number of nodes and elements are 31223 and 119911 respectively, all the elements are soild elements, the head constructed in finite element model which is essentially similar with the head structured in anatomization could be more typical and comparable geometrically. Specifically, the paRTAcular operation on cranium viscerale and cranium viscerale which were constructed coarsely formerly could be applied in the biomechanical researches on the viscerale. The first FE model based on CVH was an important step to transplant Visible Human to Digital physics Human, which could take more effect in developing the CVH.Ⅲ, The model of imitating the brain deceleration injury which be caused by the heavy, still and blunt objects impacting on forehead or pars temporalis by means of Hypermesh software. The diffusion and distribution of brain stress wave could be calculated in LS-DYNA for further study. The results show when the deceleration injury occurred on forehead and pars temporalis, the movement of stress wave was a radiate diffusion around from the brain impact point. The stress impacted on brains was centralized in the positions of the free extremity on the broken and weak extremity of skull as well as the irregular extremity on cranium viscerale, the stress on skull was the strongest of these. The below of brain tissues were endured the strongest stress of which wave diffuses from the below of brain tissues to inner brain with the velocity of attenuation. The bottom of the brain contains the position of stress centralization. The stress centralization in opposite position of deceleration injury on forehead impact position was not found. The stress centralization in opposite position of deceleration injury on pars temporalis impact position was found. The finite element simulation of deceleration injury could analyze a certain clinical case by means of stress diffusion and distribution for propose of decreasing the missed diagnosis and misdiagnosis of brain deceleration injury.Ⅳ, A new type of injuring setting for researching the deceleration injury has been developped and applied for invention patent. The experience on rabbit brain deceleration injury was operated from the procedure of general observation, CT observation and pathological observation. The results show that the setting could be applied in the researching on small animal deceleration injury experiment. The three rabbit brain deceleration injury models constructed by the degrees of slightness, mildness and severity. The injury on deceleration injury specifically includes skull fracture, cerebral contusion, subdural hemorrhage, brain substance hemorrhage and contrecoup. The pathological change in deceleration injury mainly includes hemorrhagic contusion and cerebral edema. The brain decelaRTAon injury could be deduced by stress wave propagation and stress distribution.更多还原