Assessment and prediction of acute subdural hematomas in vehicle collision accidents

Establishment of a weighted injury criterion for evaluation of multiple types of head severe injuries for vulnerable road users

“…Traumatic brain injury can be divided into focal traumatic brain injury and diffuse traumatic brain injury according to clinical symptoms, with subdural hematoma (SDH), subarachnoid hemorrhage (SAH), and brain contusion being the more typical focal traumatic brain injuries, while DAI is more common in diffuse traumatic brain injury. According to previous studies, the injury criteria used to evaluate skull fractures were mainly the peak linear acceleration and HIC 15 13,37,38 , for SDH the main injury criteria were the peak angular velocity and angular acceleration of the head and the tensile strain rate of the bridging veins 22,23,34 , and for SAH the main injury criteria were the peak angular velocity, angular acceleration, linear acceleration and global strain energy of the subarachnoid space [40][41][42] . The injury criteria for evaluating contusion were mainly intracranial pressure, brainstem shear stress, and peak linear acceleration of the head; the injury criteria for evaluating DAI were mainly angular velocity, angular acceleration, linear acceleration, maximum principal strain, and brainstem stress-strain 8,19,43 .…”

“…7). Furthermore, there are two main methods for selecting the weight parameters, one is to determine the proportion of injuries in each body part according to the accident statistics, and then assign the weight parameters 32 ; the other is to obtain the prediction model according to the related algorithm and calculate each weight parameter directly 21,22,28 . In this work, the weight parameters were selected based on the proportion of different head injury types in 104 cases with detailed injury records from the VRU-TRAVi database (Table 1), which was similar to the rst method 32 .…”

“…For cases in which severe brain injury (AIS 4+) occurred (approximately twothirds of all accident cases), the angular acceleration exceeded 10,000 rad/s 2 ; in addition, for non-severe brain injury cases, there were also 12 cases in which the angular acceleration exceeded 10,000 rad/s 2 , indicating that the threshold for angular acceleration was set relatively conservatively 29 . Previous studies have shown that linear head acceleration and HIC 15 are good predictors of skull fracture 12,13,22 , which is usually accompanied by extradural hematoma 38 because the protective capacity of the brain is signi cantly reduced after skull fracture, which explains why linear head acceleration and HIC 15 are also good predictors of the risk of severe brain injury. Pure angular velocity is not su cient to predict brain injury, and the effects of angular acceleration as well as duration need to be considered 8 .…”

“…However, it is di cult to effectively assess the intracranial response with pure head kinematic parameters 18 . With the development of numerical models, evaluation criteria for predicting brain injury caused by intracranial reactions through numerical analysis methods were developed, which are known as brain tissue level-based injury criteria [19][20][21][22] . Willinger et al 20 .…”