Design of a simplified cranial substitute with a modal behavior close to that of a human skull.

Individuals exposed to the propagation of shock waves generated by the detonation of explosive charges may suffer Traumatic Brain Injury. The mechanism of cranial deflection is one of many hypotheses that could explain the observed brain damage. To investigate this physical phenomenon in a reproducible manner, a new simplified cranial substitute was designed with a mechanical response close to that of a human skull when subjected to this type of loading.

Cerebral and cognitive modifications in retired professional soccer players: TC-FOOT protocol, a transverse analytical study.

Introduction: Soccer is the most popular sport in the world. This contact sport carries the risk of exposure to repeated head impacts in the form of subconcussions, defined as minimal brain injuries following head impact, with no symptom of concussion. While it has been suggested that exposure to repetitive subconcussive events can result in long-term neurophysiological modifications, and the later development of chronic traumatic encephalopathy, the consequences of these repeated impacts remain controversial and largely unexplored in the context of soccer players.

Use of Brain Biomechanical Models for Monitoring Impact Exposure in Contact Sports.

Head acceleration measurement sensors are now widely deployed in the field to monitor head kinematic exposure in contact sports. The wealth of impact kinematics data provides valuable, yet challenging, opportunities to study the biomechanical basis of mild traumatic brain injury (mTBI) and subconcussive kinematic exposure. Head impact kinematics are translated into brain mechanical responses through physics-based computational simulations using validated brain models to study the mechanisms of injury.

Influence of double rods and interbody cages on range of motion and rod stress after spinopelvic instrumentation: a finite element study.

Purpose: To compare instrumentation configurations consisting of bilateral single or double rods and additional interbody cages (IBCs) at different levels in terms of Range of Motion (ROM) and distribution of von Mises stress in rods.

Methods: A previously validated L1-pelvis finite element model was used and instrumented with configurations consisting of single or double bilateral rods and IBCs at multiple levels. Pure moments of 7.

Application of complex neck loads to human spine at the occipital condyle joint: Implications for nonstandard postures for automated vehicles.

Objective: The automotive industry's shift toward automated vehicles allows the occupants to assume postures different from the standard upright seated position. Injury criteria assessments are needed under these nonstandard postures to advance safety. The objective of this study is to develop a new device that can position the human cadaver head-neck structures in different nonstandard pre-postures using custom devices and apply external loading anticipated in modern and future automotive and military scenarios.

Development of a flexible instrumented lumbar spine finite element model and comparison with in-vitro experiments.

Surgical corrections of degenerative lumbar scoliosis and sagittal malalignment are associated with significant complications, such as rod fractures and pseudarthrosis, particularly in the lumbosacral junction. Finite element studies can provide relevant insights to improve performance of spinal implants. The aim of the present study was to present the development of non-instrumented and instrumented Finite Element Models (FEMs) of the lumbopelvic spine and to compare numerical results with experimental data available in the literature.

Development of a detailed human neck finite element model and injury risk curves under lateral impact.

Advanced neck finite element modeling and development of neck injury criteria are important for the design of optimal neck protection systems in automotive and other environments. They are also important in virtual tests. The objectives of the present study were to develop a detailed finite element model (FEM) of the human neck and couple it to the existing head model, validate the model with kinematic data from legacy human volunteer and human cadaver impact datasets, and derive lateral impact neck injury risk curves using survival analysis from the upper and lower neck forces and moments.

Protection performance of bicycle helmets.

Introduction: The evaluation of head protection systems needs proper knowledge of the head impact conditions in terms of impact speed and angle, as well as a realistic estimation of brain tolerance limits. In current bicycle helmet test procedures, both of these aspects should be improved.

Method: The present paper suggests a bicycle helmet evaluation methodology based on realistic impact conditions and consideration of tissue level brain injury risk, in addition to well known headform kinematic parameters.

Lung injury risk assessment during blast exposure.

Blast pulmonary trauma are common consequences of modern war and terrorism action. To better protect soldiers from that threat, the injury risk level when protected and unprotected must be assessed. Knowing from the literature that a possible amplification of the blast threat would be provided by some thoracic protective systems, the objective is to propose an original approach to correlate a measurable parameter on a manikin with a pulmonary risk level.

Evaluation of a novel bicycle helmet concept in oblique impact testing.

Background: A novel bicycle helmet concept has been developed to mitigate rotational head acceleration, which is a predominant mechanism of traumatic brain injury (TBI). This WAVECEL concept employs a collapsible cellular structure that is recessed within the helmet to provide a rotational suspension. This cellular concept differs from other bicycle helmet technologies for mitigation of rotational head acceleration, such as the commercially available Multi-Directional Impact Protection System (MIPS) technology which employs a slip liner to permit sliding between the helmet and the head during impact.

Forces and moments in cervical spinal column segments in frontal impacts using finite element modeling and human cadaver tests.

Experiments have been conducted using isolated tissues of the spine such as ligaments, functional units, and subaxial cervical spine columns. Forces and or moments under external loading can be obtained at the ends of these isolated/segmented preparations; however, these models require fixations at the end(s). To understand the response of the entire cervical spine without the artificial boundary/end conditions, it is necessary to use the whole body human cadaver in the experimental model.

Development of a finite-element eye model to investigate retinal hemorrhages in shaken baby syndrome.

Retinal hemorrhages (RH) are among injuries sustained by a large number of shaken baby syndrome victims, but also by a small proportion of road accident victims. In order to have a better understanding of the underlying of RH mechanisms, we aimed to develop a complete human eye and orbit finite element model. Five occipital head impacts, at different heights and on different surfaces, and three shaking experiments were conducted with a 6-week-old dummy (Q0 dummy).

Chest response assessment of post-mortem swine under blast loadings.

To better protect soldiers from blast threat, that principally affect air-filled organs such a lung, it is necessary to develop an adapted injury criterion and, prior to this, to evaluate the response of a biological model against that threat. The objective of this study is to provide some robust data to quantify the chest response of post-mortem swine under blast loadings. 7 post-mortem swine (54.

Head injury assessment of non-lethal projectile impacts: A combined experimental/computational method.

The main objective of this study is to develop a methodology to assess this risk based on experimental tests versus numerical predictive head injury simulations. A total of 16 non-lethal projectiles (NLP) impacts were conducted with rigid force plate at three different ranges of impact velocity (120, 72 and 55m/s) and the force/deformation-time data were used for the validation of finite element (FE) NLP. A good accordance between experimental and simulation data were obtained during validation of FE NLP with high correlation value (>0.

New functional pavements for pedestrians and cyclists.

When many fields of pedestrian and cyclist safety have been extensively studied, the surfacing has long been left unquestioned, despite being developed for another mode of transport and being one of the main causes for falls and fall injuries. In this project new surfacing materials for pedestrian and cyclist safety have been produced. Focusing on augmenting previously largely disregarded parameters as impact absorption, comfort and visibility at the same time as avoiding deteriorating of crucial parameters as friction and wear resistance.

A critical literature review on primary blast thorax injury and their outcomes.

Since World War II, researchers have been interested in exploring the injury mechanisms involved in primary blast on the thorax by using animal model surrogates. These studies were mostly concerned with the finding of the lung injury threshold, the relationship between the physical components of the air blast wave, and the biological response. Studies have also been conducted to investigate the effect of repeated blast exposures on the injury outcome threshold.

Brain injury tolerance limit based on computation of axonal strain.

Traumatic brain injury (TBI) is the leading cause of death and permanent impairment over the last decades. In both the severe and mild TBIs, diffuse axonal injury (DAI) is the most common pathology and leads to axonal degeneration. Computation of axonal strain by using finite element head model in numerical simulation can enlighten the DAI mechanism and help to establish advanced head injury criteria.

Evaluation of overpressure prediction models for air blast above the triple point.

The increase of blast exposures leads to the need for better assessment of the blast threat. Empirical models describing the blast propagation in ideal conditions as free-field or surface detonations are commonly employed, but in some configurations the ground-reflected shock should be treated explicitly. Empirical models permit the prediction of the blast characteristics with the ground-reflected shock.

Development of skull fracture criterion based on real-world head trauma simulations using finite element head model.

The objective of this study was to enhance an existing finite element (FE) head model with composite modeling and a new constitutive law for the skull. The response of the state-of-the-art FE head model was validated in the time domain using data from 15 temporo-parietal impact experiments, conducted with postmortem human surrogates. The new model predicted skull fractures observed in these tests.

Influence of stiffness and shape of contact surface on skull fractures and biomechanical metrics of the human head of different population underlateral impacts.

The objective of this study was to determine the responses of 5th-percentile female, and 50th- and 95th-percentile male human heads during lateral impacts at different velocities and determine the role of the stiffness and shape of the impacting surface on peak forces and derived skull fracture metrics. A state-of-the-art validated finite element (FE) head model was used to study the influence of different population human heads on skull fracture for lateral impacts. The mass of the FE head model was altered to match the adult size dummies.

Influence of head mass on temporo-parietal skull impact using finite element modeling.

The effect of head mass on its biomechanical response during lateral impact to the head is investigated in this computational study. The mass of the head of a state-of-the-art validated finite element head model is altered by ± 10 % from the base value of 4.7 kg.

Update on injury mechanisms in abusive head trauma--shaken baby syndrome.

Violently shaking a baby leads to clinical presentations ranging from seizures to cardiopulmonary arrest. The main injuries sustained are retinal hemorrhages, subdural hemorrhages, and sometimes fractures and spine injury. It is important to have a global view of the injuries sustained by the infant to correctly discuss the biomechanical aspects of abusive head trauma.

Development and validation of an advanced anisotropic visco-hyperelastic human brain FE model.

This paper proposes the implementation of fractional anisotropy and axonal fiber orientation from diffusion tensor imaging (DTI) of 12 healthy patients into an existing human FE head model to develop a more realistic brain model with advanced constitutive laws. Further, the brain behavior was validated in terms of brain strain against experimental data published by Hardy et al. (2001, 2007) and for brain pressure against Nahum et al.

Anisotropic composite human skull model and skull fracture validation against temporo-parietal skull fracture.

A composite material model for skull, taking into account damage is implemented in the Strasbourg University finite element head model (SUFEHM) in order to enhance the existing skull mechanical constitutive law. The skull behavior is validated in terms of fracture patterns and contact forces by reconstructing 15 experimental cases. The new SUFEHM skull model is capable of reproducing skull fracture precisely.