Prediction of subdural haematoma based on a 3D finite element human head model (original) (raw)
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Finite element modelling of human head injuries caused by a fall
International Journal of Legal Medicine, 2006
Finite element models (FEMs) can be used as prediction tools for human head injuries caused by falls. The purpose of this paper is to demonstrate the relevance of using human head FEM to assess the possible mechanism for the origin of head injuries. The FEM of the human head used in this study was developed in the late 1990s at the University Louis Pasteur of Strasbourg (ULP) and has been validated for human head impacts for simulating human head injuries caused by car accidents. Its use in legal medicine appears to be very useful for comparing different injury mechanisms. We present the simulation obtained for two witnessed falls of the same individual, and compare our results to tolerance limits of the main human head injuries. We show that this tool can be used to discuss the possible mechanism of injury encountered for the observed lesions in a forensic case. It can also help to distinguish between possible and impossible human head injury mechanisms.
The creation of three-dimensional finite element models for simulating head impact biomechanics
International Journal of Crashworthiness, 2003
Decay factor λ X , λ Y , λ Z X, Y and Z dimension length scale factors C 10 , C 01 Temperature dependent coefficients G 0 Short term shear modulus G ∞ Long term shear modulus t Time Abstract: A new 3 dimensional finite element representation of the human head complex has been constructed for simulating the transient occurrences of simple pedestrian accidents. This paper describes the development, features and validation of that model. When constructing the model, emphasis was placed on element quality and ease of mesh generation. As such, a number of variations of the model were created. The model was validated against a series of cadaveric impact tests. A parametric study (a High/Low study) was performed to investigate the effect of the bulk and shear modulus of the brain and cerebrospinal fluid (CSF). The influence of different mesh densities on the models and the use of different element formulations for the skull were also investigated. It was found that the short-term shear modulus of the neural tissue had the predominant effect on intracranial frontal pressure, and on the predicted Von-Mises response. The bulk modulus of the fluid had a significant effect on the contre-coup pressure when the CSF was modelled using a coupled node definition. Differences of intracranial pressure were reported that show the sensitivity of the method by which the skull is modelled. By simulating an identical impact scenario with a range of different finite element models it has been possible to investigate the influence of model topologies. We can conclude that careful modelling of the CSF (depth/volume) and skull thickness (including cortical/ trabecular ratio) is necessary if the correct intracranial pressure distribution is to be predicted, and so further forms of validation are required to improve the finite element models' injury prediction capabilities.
Development of a Human Head FE Model and Impact Simulation on the Focal Brain Injury
Journal of Computational Science and Technology, 2009
In this paper, a three-dimensional digital human-head model was developed and several dynamic analyses on the head trauma were conducted. This model was built up by the VOXEL approach using 433 slice CT images(512×512 pixels) and made of 1.22 million parallelepiped finite elements with 10 anatomical tissue properties such as scalp, CSF, skull, brain, dura mater and so on. The numerical analyses were conducted using a finite element code the authors have developed. The main features of the code are 1) it is based on the explicit time integration method and 2) it uses the one point integration method to evaluate the equivalent nodal forces with the hourglass control proposed by Flanagan and Belytschko (1) and 3) it utilizes the parallel computation system based on MPI. In order to verify the developed model, the head impact experiment for a cadaver by Nahum et al. (2) was simulated. The calculated results showed good agreement with the experimental ones. A front and rear impact analyses were also performed to discuss on the characteristic measure of the brain injury, in which the von-Mises stress was high in the frontal lobe in both of the analyses because of the large deformations of a frontal cranial base. This result suggests that the von-Mises stress can be a good measure of the brain injury since it is empirically well known that the frontal lobe tends to get injured regardless of the impact positions.
Finite element analysis of brain contusion: An indirect impact study
Medical & Biological Engineering & Computing, 2000
The mechanism of brain contusion has been investigated using a series of three-dimensional (3D) finite element analyses. A head injury mode/ was used to simulate forward and backward rotation around the upper cervical vertebra. Intracranial pressure and shear stress responses were calculated and compared. The results obtained with this model support the predictions of cavitation theory that a pressure gradient develops in the brain during indirect impact. Contrecoup pressuretime histories in the parasagittal plane demonstrated that an indirect impact induced a smaller intracranial pressure for backward rotation, and -65.5kPa for forward rotation) than that caused by a direct impact. In addition, negative pressures induced by indirect impact to the head were not high enough to form cavitation bubbles, which can damage the brain tissue. Simulations predicted that a decrease in skull deformation had a large effect in reducing the intracranial pressure. However, the areas of high shear stress concentration were consistent with those of clinical observations. The findings of this study suggest that shear strain theory appears to better account for the clinical findings in head injury when the head is subjected to an indirect impact.
On Several Challenges in Finite Element Modeling of Head Injuries
International Review of Mechanical Engineering
In this paper, several challenges existing in finite element modeling of head injuries are reviewed. The reviewed challenges include complexities in biomechanical model, mesh quality, material properties, loading and constraint conditions, experimental validation and verification. Recent efforts made to meet the above challenges are also discussed. Copyright © 2010 Praise Worthy Prize S.r.l.-All rights reserved.
Finite Elements Models of the Head in Craniocerebral Trauma – Review
BRAIN. BROAD RESEARCH IN ARTIFICIAL INTELLIGENCE AND NEUROSCIENCE, 2020
Head injuries are a major health and socioeconomic problem. To better protect the head against various crash, sport, or fall events, the underlying mechanisms and tolerances need to be investigated. Many investigations have been conducted using cadaver heads, animal heads, physical head models, and in vitro models throughout the world. These experiments, together with the development of computational techniques, have subsequently led to the development of numerical head models, especially finite element (FE) models, to allow more in-depth biomechanical studies. A large number of FE head models have been developed during the years and authors are trying to find the best solutions for a correct explanation of the lesional mechanisms. The finite element method (FEM) is based on the energy formulation of the mechanics of the structures and on approximation methods. It consists of approximating the actual structure through a model consisting of finite elements interconnected in points called nodes. By nodes, each item is under compatibility and balance conditions with adjacent elements. The present paper is a literature review, underlying some of the finite element models, which allowed a good explanation of the head trauma mechanisms.
SAE Technical Paper Series, 2008
The objective of this study was to investigate potential for traumatic brain injuries (TBI) using a newly developed, geometrically detailed, finite element head model (FEHM) within the concept of a simulated injury monitor (SIMon). The new FEHM is comprised of several parts: cerebrum, cerebellum, falx, tentorium, combined pia-arachnoid complex (PAC) with cerebro-spinal fluid (CSF), ventricles, brainstem, and parasagittal blood vessels. The model's topology was derived from human computer tomography (CT) scans and then uniformly scaled such that the mass of the brain represents the mass of a 50 th percentile male's brain (1.5 kg) with the total head mass of 4.5 kg. The topology of the model was then compared to the preliminary data on the average topology derived from Procrustes shape analysis of 59 individuals. Material properties of the various parts were assigned based on the latest experimental data. After rigorous validation of the model using neutral density targets (NDT) and pressure data, the stability of FEHM was tested by loading it simultaneously with translational (up to 400 g) combined with rotational (up to 24,000 rad/s 2) acceleration pulses in both sagittal and coronal planes. Injury criteria were established in the manner shown in Takhounts et al. (2003a). After thorough validation and injury criteria establishment (cumulative strain damage measure-CSDM for diffuse axonal injuries (DAI), relative motion damage measure-RMDM for acute subdural hematoma (ASDH), and dilatational damage measure-DDM for contusions and focal lesions), the model was used in investigation of mild TBI cases in living humans based on a set of head impact data taken from American football players at the collegiate level. It was found that CSDM and especially RMDM correlated well with angular acceleration and angular velocity. DDM was close to zero for most impacts due to their mild severity implying that cavitational pressure anywhere in the brain was not reached. Maximum principal strain was found to correlate well with RMDM and angular head kinematic measures. Maximum principal stress didn't correlate with any kinematic measure or injury metric. The model was then used in the investigation of brain injury potential in NHTSA conducted side impact tests. It was also used in parametric investigations of various "what if" scenarios, such as side versus frontal impact, to establish a potential link between head kinematics and injury outcomes. The new SIMon FEHM offers an advantage over the previous version because it is geometrically more representative of the human head. This advantage, however, is made possible at the expense of additional computational time.
Predicting brain mechanics during closed head impact : numerical and constitutive aspects
2002
Annually, motor vehicle crashes world wide cause over a million fatalities and over a hundred million injuries. Of all body parts, the head is identified as the body region most frequently involved in life-threatening injury. To understand how the brain gets injured during an accident, the mechanical response of the contents of the head during impact has to be known. Since this response cannot be determined during an in-vivo experiment, numerical Finite Element (FE) modelling is often used to predict this response. Current FE head models contain a detailed geometrical description of anatomical components inside the head but lack accurate descriptions of the brain material behaviour and contact between e.g. skull and brain. Also, the numerical solution method used in current models (explicit Finite Element Method) does not provide accurate predictions of transient phenomena, such as wave propagation, in the nearly incompressible brain material. The aim of this study is to contribute ...