Viscoelastic Characterization of Parasagittal Bridging Veins and Implications for Traumatic Brain Injury: A Pilot Study.

Many previous studies on the mechanical properties of Parasagittal Bridging Veins (PSBVs) found that strain rate had a significant effect on some mechanical properties, but did not extensively study the viscoelastic effects, which are difficult to detect with uniaxial simple tensile tests. In this study, relaxation tests and tests under cyclic loading were performed, and it was found that PSBVs do indeed exhibit clear viscoelastic effects. In addition, a complete viscoelastic model for the PSBVs is proposed and data from relaxation, cyclic load and load-unload tests for triangular loads are used to find reference values that characterize the viscoelastic behavior of the PSBVs. Although such models have been proposed for other types of blood vessels, this is the first study that clearly demonstrates the existence of viscoelastic effects from an experimental point of view and also proposes a specific model to explain the data obtained. Finally, this study provides reference values for the usual viscoelastic properties, which would allow more accurate numerical simulation of PSBVs by means of computational models.

Influence of anthopometric variables on the mechanical properties of human rib cortical bone.

Objective. The mechanical properties of ribs from a large number ofpost-mortemhuman subjects (PMHS) were analyzed to search for variation according to age, sex or BMI in the sample. A large sample of specimens from different donors (N= 64) with a very wide range of ages and anthropometric characteristics was tested.Methods. Uniaxial tensile tests were used for a sample of coupons machined from cortical bone tissue in order to isolate the purely mechanical properties from the geometrically influenced properties of the rib. Each coupon is about 25 mm long and has a thickness of about 0.5 mm. The mechanical properties measured for each specimen/coupon include YM, yield stress, ultimate stress (maximum failure stress), ultimate strain, and resilience (energy to fracture of SED). The study provides new methodological improvements in DIC techniques.Results. This study is notable for using an atypically large sample of number of PMHS. The size of the sample allowed the authors to determine that age has a significant effect on failure stress (p< 0.0001), yield stress (p= 0.0047), ultimate strain (p< 0.0001) and resilience (p< 0.0001) [numbers in parentheses represent the correspondingp- values]. Finally, there is a combined effect, so that for a given age, an increase of BMI leads to a decrease of the maximum strain (i.e. cortical bone is less stiff when both age and BMI are higher).

Prediction of mechanical properties of human rib cortical bone using fractal dimension.

A large number of post mortem human subjects was used to investigate the relation between the micro-structure of rib cortical bone and the mechanical properties using Fractal Dimension. Uniaxial tensile tests were performed on coupons of rib cortical bone. Tensile strength, yield stress, Young's Modulus, maximum strain, and work to fracture were determined for each coupon. Fractal dimension was computed using CT images and Digital Image Correlation procedures. A highly significant effect of fractal dimension in the mechanical properties was found. In addition, the variation in mechanical properties was found to be adequately represented by Generalized Extreme Value type distributions.

Biomecánica y mecanismo de producción del traumatismo cráneo-encefálico en el peatón atropellado. Evaluación de la normativa actual en la automoción / Pedestrian head injury biomechanics and damage mechanism. Pedestrian protection automotive regulation assessment

Introducción: Los atropellos son una de las principales causas de muerte entre los accidentes de tráfico. Recientemente, ha aumentado el estudio de los atropellos, principalmente debido a la aplicación de la normativa europea y japonesa en protección de peatones. Esta investigación presenta un análisis del traumatismo cráneo-encefálico del peatón atropellado, asociándolo con la estructura del vehículo responsable de la lesión, su mecanismo de daño y comparando el resultado con la normativa existente. Métodos: La metodología empleada ha consistido en un estudio epidemiológico descriptivo y transversal, mediante el estudio de datos de peatones atropellados recogidos en la base de datos americana (PCDS) que analiza a un total de 552 peatones atropellados y un total de 4.500 lesiones documentadas. Resultados: De acuerdo con este estudio, el capó es el causante del 15,1% de las lesiones de la cabeza del peatón, mientras que el parabrisas es responsable de 41,8% de todas las lesiones. En el caso de los vehículos tipo utilitario la ubicación del impacto de la cabeza se produce por encima de lo que se espera en la regulación actual y, por lo tanto, no se aplican las contramedidas necesarias. De todas las lesiones en la cabeza sufridas por los peatones solo el 20% tiene la aceleración lineal como mecanismo de lesión, el 40% de las lesiones se deben a la aceleración rotacional. Conclusiones: En esta investigación se pone de manifiesto la importancia de la aceleración rotacional como mecanismo de daño en la cabeza del peatón atropellado. En la normativa actual solo la aceleración lineal está contemplada en la formulación del principal criterio biomecánico utilizado para predecir el traumatismo cráneo-encefálico

Introduction: Pedestrian-vehicle collisions are a leading cause of death among motor vehicle accidents. Recently, pedestrian injury research has been increased, mostly due to the implementation of European and Japanese regulations. This research presents an analysis of the main head injury vehicle sources and injury mechanisms observed in the field, posteriorly the data are compared with the current pedestrian regulations. Methods: The analysis has been performed through an epidemiologic transversal and descriptive study, using the Pedestrian Crash Data Study (PCDS) involving 552 pedestrians, sustaining a total of 4.500 documented injuries. Results: According to this research, the hood surface is responsible for only 15,1% of all the head injuries. On the other hand, the windshield glazing is responsible for 41,8%. In case of sedan vehicles the head impact location exceeds what is expected in the current regulation, and therefore no countermeasures are applied. From all the head injuries sustained by the pedestrians just 20% have the linear acceleration as isolated injury mechanism, 40% of the injuries are due to rotational acceleration. Conclusions: In this research, the importance of the rotational acceleration as injury mechanism, in case of pedestrian-vehicle collision is highlighted. In the current pedestrian regulation just the linear acceleration is addressed in the main injury criteria used for head injury prediction

[Pedestrian head injury biomechanics and damage mechanism. Pedestrian protection automotive regulation assessment]. / Biomecánica y mecanismo de producción del traumatismo cráneo-encefálico en el peatón atropellado. Evaluación de la normativa actual en la automoción.

INTRODUCTION: Pedestrian-vehicle collisions are a leading cause of death among motor vehicle accidents. Recently, pedestrian injury research has been increased, mostly due to the implementation of European and Japanese regulations. This research presents an analysis of the main head injury vehicle sources and injury mechanisms observed in the field, posteriorly the data are compared with the current pedestrian regulations. METHODS: The analysis has been performed through an epidemiologic transversal and descriptive study, using the Pedestrian Crash Data Study (PCDS) involving 552 pedestrians, sustaining a total of 4.500 documented injuries. RESULTS: According to this research, the hood surface is responsible for only 15,1% of all the head injuries. On the other hand, the windshield glazing is responsible for 41,8%. In case of sedan vehicles the head impact location exceeds what is expected in the current regulation, and therefore no countermeasures are applied. From all the head injuries sustained by the pedestrians just 20% have the linear acceleration as isolated injury mechanism, 40% of the injuries are due to rotational acceleration. CONCLUSIONS: In this research, the importance of the rotational acceleration as injury mechanism, in case of pedestrian-vehicle collision is highlighted. In the current pedestrian regulation just the linear acceleration is addressed in the main injury criteria used for head injury prediction.

Injury pattern in lethal motorbikes-pedestrian collisions, in the area of Barcelona, Spain.

INTRODUCTION: There are several studies about M1 type vehicle-pedestrian collision injury pattern, and based on them, there has been several changes in automobiles for pedestrian protection. However, the lack of sufficient studies about injury pattern in motorbikes-pedestrian collisions leads to a lack of optimization design of these vehicles. The objective of this research is to study the injury pattern of pedestrians involved in collisions with motorized two-wheeled vehicles. METHODS: A retrospective descriptive study of pedestrian's deaths after collisions with motorcycles in an urban area, like Barcelona was performed. The cases were collected from the Forensic Pathology Service database of the Institute of Legal Medicine of Catalonia. The selected cases were categorized as pedestrian-motorcycle collision, between January 1st, 2005 and December 31st, 2014. Data were collected from the autopsy, medical, and police report. The collected information was then analyzed using Microsoft Excel statistical functions. RESULTS: Traumatic Brain Injury is the main cause of death in pedestrian hit by motorized two-wheeled vehicles (62.85%). The most frequent injury was the subarachnoid hemorrhage, in 71.4% of cases, followed by cerebral contusions and skull base fractures (65.7%). By contrast, pelvic fractures and tibia fractures only appeared in 28.6%. CONCLUSIONS: The study characterizes the injury pattern of pedestrians involved in a collision with motorized two-wheeled vehicles in an urban area, like Barcelona, which has been found to be different from other vehicle-pedestrian collisions, with a higher incidence of brain injuries and minor frequency of lower extremities fractures in pelvis, tibia and fibula.

Estudio descriptivo de la violencia de género: análisis de 404 casos / Descriptive study on gender-based violence: analysis of 404 cases

Introducción. La violencia de género es un problema de salud pública en el que el médico forense ocupa un papel protagonista. El objetivo del estudio fue ampliar el conocimiento existente acerca de las características de la violencia de género en L’Hospitalet de Llobregat, para favorecer la identificación de los grupos de riesgo y la posible incorporación de medidas protectoras necesarias hacia los colectivos más vulnerables. Material y métodos. Estudio prospectivo de víctimas y agresores evaluados entre el 01.01.2009 y el 30.09.2009 en L’Hospitalet de Llobregat. Resultados. La muestra incluyó 404 casos en este periodo: el 80,7% fueron mujeres, la franja de edad se encontraba entre 20 y 40 años en el 69% de los casos y eran de nacionalidad española en el 30,2%. El alcohol y los celos estaban presentes en el 39 y el 29% de los casos respectivamente, registrándose el 47,5% de los casos durante el fin de semana. La contusión fue el mecanismo lesivo hallado en el 94,7% de los casos, siendo las extremidades superiores la zona corporal más frecuententemente lesionada. El 94% requirieron una primera asistencia facultativa desde el punto de vista médico-legal. Los primeros años de la relación aglutinan la mayoría de episodios de violencia. Discusión y conclusiones. El mayor conocimiento de las características de la violencia de género y los perfiles de víctima y agresor puede repercutir en una mejora en la calidad pericial(AU)

Introduction. Gender-based violence is a public health problem where the forensic doctor plays a key role. Material and methods. Prospective study of victims and offenders between 01-01-09 and 09-30-09 in L’Hospitalet de Llobregat was conducted. The aim of study is, on the one hand, to broaden the knowledge about the characteristics of gender violence in L’Hospitalet de Llobregat in order to favor the identification of risk groups; on the other hand, the possible incorporation of necessary protective measures for the most vulnerable groups. Results. The sample included 404 cases in this period: 80.7% of women that were between the ages of 20 and 40 in 69% of the cases; 30.2% of them being from Spain. Alcohol and jealousy were present in 39 and 29% of the cases respectively, and 47.5% occurred during the weekend. The main injury mechanism was bruising, affecting 94.7% of cases, where upper extremities were the most frequently injured parts of the body. First medical aid was required in 94% of the cases. The early years of the relationship are shown to be the ones where most of the violence occurred. Discussion and conclusions. A greater knowledge of the characteristics of gender-based violence and victim and offender profiles can help to improve the quality of expert reports(AU)

Traumatismo penetrante de cráneo y muerte diferida: a propósito de un caso / Skull penetrating trauma and delayed death: presentation of a case

Presentamos un caso de traumatismo penetrante en el cráneo por arma blanca de morfología desconocida con muerte diferida. El estudio necrópsico puso de manifiesto herida cutánea cicatrizada y lesión encefálica modificada por hemorragias y edema secundarios a la lesión. Las pruebas de imagen (TC y reconstrucción 3D) efectuadas durante el proceso asistencial fueron útiles para localizar el orificio óseo en el cráneo, necesario para valorar las características del arma homicida. Hubo que modificar la técnica de autopsia ampliando la retirada del cuero cabelludo y del músculo temporal derecho, puesto que la lesión ósea quedaba por debajo del plano de apertura habitual, y de otra forma hubiera pasado desapercibido. Esto pone de manifiesto que las pruebas de imagen son útiles tanto para la toma de decisiones clínicas como para facilitar la valoración médico-forense posterior, por lo que es importante la colaboración entre los servicios clínicos en general, y de radiología en particular, con los servicios de patología forense(AU)

A case is presented involving a skull penetrating trauma with an unknown sharp weapon with a delayed death. The autopsy showed skin injury as a scar and brain injury modified by haemorrhage and swelling. Imaging techniques such as CT scan and 3D reconstruction performed during the healthcare process were useful to find the skull orifice, and needed to assess the characteristics of the homicide weapon. We had to modify the autopsy technique by removing a larger area of anterior scalp and right temporal muscle, because the injured bone was lower than the usual level, and otherwise it would not have been noticed. This shows that imaging techniques are useful for making clinical decisions and for medico-legal investigations, so once again we would like to emphasise the importance of collaboration between clinical services in general, and Radiology Service in particular, with the Forensic Pathology Service(AU)