Towards a better understanding of abdominal wall biomechanics: In vivo relationship between dynamic intra-abdominal pressure and magnetic resonance imaging measurements.

Background: In vivo mechanical behaviour of the abdominal wall has been poorly characterised and important details are missing regarding the occurrence and post-operative recurrence rate of hernias which can be as high as 30 %. This study aimed to assess the correlation between abdominal wall displacement and intra-abdominal pressure, as well as abdominal compliance.

Methods: Eighteen healthy participants performed audio-guided passive (breathing) and active (coughing, Valsalva maneuver) exercises.

Unravelling the mechanics of gastric tissue: A comparison of constitutive models, damage probability and microstructural insights.

With the increasing prevalence of obesity worldwide, bariatric surgery is becoming increasingly common. However, the mechanic of the gastric wall related to bariatric surgery complications remains to be investigated. This study aims to understand mechanical behaviour of stomach by developing advanced material laws for gastric tissue incorporating microstructure.

Assessment of the Smartpill, a Wireless Sensor, as a Measurement Tool for Intra-Abdominal Pressure (IAP).

The SmartPill, a multisensor ingestible capsule, is marketed for intestinal motility disorders. It includes a pressure sensor, which could be used to study intra-abdominal pressure (IAP) variations. However, the validation data are lacking for this use.

A better understanding of daily life abdominal wall mechanical solicitation: Investigation of intra-abdominal pressure variations by intragastric wireless sensor in humans.

Intra-abdominal pressure (IAP), as the main mechanical load applied to the abdominal wall, is decisive in the occurrence of ventral hernia. The objective of the study was to propose a comprehensive evaluation of IAP based on a limited risk and discomfort method. A prospective study was carried out in 20 healthy volunteers.

Analysis of the Acoustic Transcranial Bone Conduction.

Objectives: (1) To analyze the preferential pathways of sound transmission and sound waves travelling properties in the skull and (2) to identify the location(s) on the skull where bone conduction to the cochlea is optimal.

Study Design: Basic research Methods: Nine cadaveric heads were placed in an anechoic chamber and equipped with six Bone Anchored Hearing Aids (BAHA™) implants (Cochlear™, Sydney, NSW, Australia) and fifteen accelerometers. A laser velocimeter was used to measure cochlear response by placing a reflector on the round window.

Dynamic-MRI quantification of abdominal wall motion and deformation during breathing and muscular contraction.

Background And Objective: Biomechanical assessment of the abdominal wall represents a major prerequisite for a better understanding of physiological and pathological situations such as hernia, post-delivery recovery, muscle dystrophy or sarcopenia. Such an assessment is challenging and requires muscular deformations quantification which have been very scarcely reported in vivo. In the present study, we intended to characterize abdominal wall deformations in passive and active conditions using dynamic MRI combined to a semiautomatic segmentation procedure.

Impact of HIV on Cognitive Performance in Professional Drivers.

Background: The intellectually demanding modern workplace is often dependent on good cognitive health, yet there is little understanding of how neurocognitive dysfunction related to HIV presents in employed individuals working in high-risk vocations such as driving. HIV-associated neurocognitive impairment is also associated with poorer long-term cognitive, health, and employment outcomes.

Setting: This study, set in Cape Town, South Africa, assessed the effects of HIV on neuropsychological test performance in employed male professional drivers.

Testosterone administration in women increases the size of their peripersonal space.

Peripersonal space (PPS) is the space immediately surrounding the body, conceptualised as a sensory-motor interface between body and environment. PPS size differs between individuals and contexts, with intrapersonal traits and states, as well as social factors having a determining role on the size of PPS. Testosterone plays an important role in regulating social-motivational behaviour and is known to enhance dominance motivation in an implicit and unconscious manner.

About some factors influencing safety mattress performances in head impact collisions: A pilot study.

Objectives: In recreational snow sports activities, safety mattresses are placed on obstacles to prevent injuries from a collision with users. However, the performances of these devices in field conditions remain unclear. The objective of this study is to evaluate the effect of mattress thickness, impact speed, impacting mass and atmospheric conditions on head acceleration during an in-field impact on safety mattress.

Semiautomatic quantification of abdominal wall muscles deformations based on dynamic MRI image registration.

Quantitative analysis of abdominal organs motion and deformation is crucial to better understand biomechanical alterations undermining respiratory, digestive or perineal pathophysiology. In particular, biomechanical characterization of the antero-lateral abdominal wall is central in the diagnosis of abdominal muscle deficiency. Here, we present a dedicated semiautomatic dynamic MRI postprocessing method enabling the quantification of spatial and temporal deformations of the antero-lateral abdominal wall muscles.

The predictive capacity of the MADYMO ellipsoid pedestrian model for pedestrian ground contact kinematics and injury evaluation.

Pedestrian injuries occur in both the primary vehicle contact and the subsequent ground contact. Currently, no ground contact countermeasures have been implemented and no pedestrian model has been validated for ground contact, though this is needed for developing future ground contact injury countermeasures. In this paper, we assess the predictive capacity of the MADYMO ellipsoid pedestrian model in reconstructing six recent pedestrian cadaver ground contact experiments.

Assessing HIV provider knowledge, screening practices, and training needs for HIV-associated neurocognitive disorders. A short report.

Management of HIV-associated neurocognitive disorders (HAND) is becoming increasingly important with HIV-positive people living normal life spans. We aimed to establish the level of HAND awareness among doctor and nurse occupational health practitioners, screening used to detect impairment, factors limiting screening for HAND, and training needs. One-hundred-and-five members of the nursing and physician professional societies for occupational health practitioners in South Africa and Occupational Health Departments at five South African universities responded to an email invitation to complete an online survey addressing demographics, HAND knowledge, screeners being used to screen for HAND and related training needs.

Abdominal wall morphometric variability based on computed tomography: Influence of age, gender, and body mass index.

Introduction: Ventral hernia surgery does not usually account for the individuality of the abdominal wall anatomy. This could be both because medical imaging is rarely performed before surgery and because data on abdominal wall variability are limited. The objective of the present study was to perform an exhaustive morphometric analysis of abdominal wall components based on computed tomography (CT) scans.

An Experimental Study of Intraluminal Hyperpressure Reproducing a Gastric Leak Following a Sleeve Gastrectomy.

Introduction: A gastric leak (GL) represents the main post-operative complication following a sleeve gastrectomy (SG) and occurs most commonly at the top of the stapling, without any clear explanation.

Objective: This experimental study evaluates the biomechanical behavior of post-SG gastric specimens using both insufflation and tensile tests.

Materials And Methods: A total gastrectomy followed by an ex vivo SG was performed in 15 pigs.

A novel method to quantitate bioprosthetic valve leaflet mechanical stress: a numerical and in vitro study.

An original in vitro/in silico method was developed to estimate the local and global mechanical stress applied on the bioprosthetic valve leaflet, which can be important for better understanding of the valve durability. A non-contact system based on stereophotogammetry and digital image correlation enabled filming and studying the valve leaflet movement frame by frame and performing three-dimensional analysis. The deformation was applied in a finite element model in order to calculate the local mechanical stress applied.

Analysis of trunk impact conditions in motorcycle road accidents based on epidemiological, accidentological data and multibody simulations.

Motorcycle accidents lead to a high rate of traffic mortality and morbidity. While helmet development and mandatory wearing have reduced head injuries, little progress has been made regarding trunk protection. Wearable airbag devices represent a promising solution to prevent trunk injuries.

Numerical Reconstruction of Traumatic Brain Injury in Skiing and Snowboarding.

Purpose: Proper evaluation of ski helmet designs and safety standards should rely on head impact conditions involved in skiing and snowboarding head injuries. To study these impacts, main crash scenarios involving head injuries are numerically replicated.

Methods: Multibody models of skiers and snowboarders were developed to investigate five common crash scenarios involved in traumatic brain injury: forward and sideways skiing falls, snowboarding backward falls, collisions between users and collisions with obstacles.

Effect of Helmet Use on Traumatic Brain Injuries and Other Head Injuries in Alpine Sport.

Introduction: Sport helmet effectiveness in preventing traumatic brain injury (TBI) has been repeatedly questioned. This study assesses the effect of helmet use on risk of TBI and other types of head injury (OTHI) in alpine sports.

Methods: From 2012 to 2014, data on the injured population were collected by physicians in on-mountain clinics in 30 French ski resorts, and interviews were conducted on the slope to sample a noninjured control population.

Analysis of the influence of passenger vehicles front-end design on pedestrian lower extremity injuries by means of the LLMS model.

Objective: This work aims at investigating the influence of some front-end design parameters of a passenger vehicle on the behavior and damage occurring in the human lower limbs when impacted in an accident.

Methods: The analysis is carried out by means of finite element analysis using a generic car model for the vehicle and the lower limbs model for safety (LLMS) for the purpose of pedestrian safety. Considering the pedestrian standardized impact procedure (as in the 2003/12/EC Directive), a parametric analysis, through a design of experiments plan, was performed.

Analysis of Injury Mechanisms in Head Injuries in Skiers and Snowboarders.

Purpose: Mechanisms of injury and description of head impacts leading to traumatic brain injury (TBI) in skiers and snowboarders have not been extensively documented. We investigate snow sport crashes leading to TBI 1) to identify typical mechanisms leading to TBI to better target prevention measures and 2) to identify the injury mechanisms and the head impact conditions.

Methods: The subjects were skiers and snowboarders diagnosed of TBI and admitted between 2013 and 2015 to one of the 15 medical offices and three hospital centers involved in the study.

Issues and challenges for pedestrian active safety systems based on real world accidents.

The purpose of this study was to analyze real crashes involving pedestrians in order to evaluate the potential effectiveness of autonomous emergency braking systems (AEB) in pedestrian protection. A sample of 100 real accident cases were reconstructed providing a comprehensive set of data describing the interaction between the vehicle, the environment and the pedestrian all along the scenario of the accident. A generic AEB system based on a camera sensor for pedestrian detection was modeled in order to identify the functionality of its different attributes in the timeline of each crash scenario.

Temporal bone fracture under lateral impact: biomechanical and macroscopic evaluation.

This work was conducted to study biomechanical properties and macroscopic analysis of petrous fracture by lateral impact. Seven embalmed intact human cadaver heads were tested to failure using an electrohydraulic testing device. Dynamic loading was done at 2 m/s on temporal region with maximal deflection to 12 mm.

Temporal bone fractures: sequelae and their impact on quality of life.

Purpose: To present a prospective temporal bone fracture database, and study facial and cochleovestibular sequelae and their impact on quality of life.

Materials And Methods: Prospective study of consecutive cases of 39 patients with 45 temporal bone fractures over 11-month period in a university tertiary referral center. Based on epidemiological data, clinical and imaging findings, treatment modalities and outcome of patients with follow-up of one year, the present study focused on facial and cochleovestibular sequelae and their impact on quality of life after one-year period.

Geometrical and material parameters to assess the macroscopic mechanical behaviour of fresh cranial bone samples.

The present study aims at providing quantitative data for the personalisation of geometrical and mechanical characteristics of the adult cranial bone to be applied to head FE models. A set of 351 cranial bone samples, harvested from 21 human skulls, were submitted to three-point bending tests at 10 mm/min. For each of them, an apparent elastic modulus was calculated using the beam's theory and a density-dependant beam inertia.

Three-dimensional variability of the mesentery and the superior mesenteric artery: application to virtual trauma modeling.

Introduction: Trauma is a major cause of death worldwide, mainly affecting a young male population. Blunt trauma of the abdomen can cause a trauma of the mesentery in 5 % of cases. Rapid decelerations and injuries by seat belts are the most common pathophysiological mechanisms.