Osteonal Damage Patterns from Ballistic and Blunt Force Trauma in Human Long Bones.

Forensic anthropologists play a key role in skeletal trauma analysis and commonly use macroscopic features to distinguish between trauma types. However, this approach can be challenging, particularly in cases of highly comminuted or incompletely recovered fractures. Histological analysis of microscopic fracture characteristics in fractured bones may thus help provide additional information on trauma type and bone fracture biomechanics in general. This study analysed the extent of microcrack damage to osteons in long bones with blunt force trauma (BFT) and gunshot trauma (GST), from both traumatic death cases and post-mortem experimental fractures. We identified four types of osteonal damage (OD). In traumatic death cases, OD affecting the inside of the osteon and compromising the Haversian canal (type 1) was found to be indicative of BFT. Moreover, OD affecting the cement line (type 3) and interstitial lamellae (type 4) was more common in the GST samples. OD affecting the inside of the osteon without compromising the Haversian canal (type 2) was not found to be indicative of either trauma type. In cases of experimental fractures, our study revealed that post-mortem fractures in dry bone samples featured the highest amount of OD, particularly of type 4. This study also found that the experimentally produced GST featured similar OD patterns to GST death cases. These findings support our hypothesis that there are distinct osteonal damage patterns in human long bones with BFT and GST, which are of relevant value for trauma analysis in forensic anthropology.

Ballistic long bone fracture pattern: an experimental study.

When dealing with badly preserved cadavers or skeletal human remains, the assessment of death circumstances remains challenging. When forensic evidence cannot be taken from the skin and soft tissue, the information may only be deduced from more resistant elements such as bone. Compared to cranial gunshot injuries, reliable data on ballistic long bone trauma remains scarce. This study aims to define ballistic fracture characteristics in human long bones. The shaft of 16 femurs and 13 humeri from body donors was perpendicularly shot with a 9-mm Luger full metal jacket bullet at an impact velocity of 360 m/s from a distance of 2 m. Some bones were embedded in Clear Ballistics Gel®, and some were shot without soft tissue simulant in order to better visualise the fracture propagation on the high-speed camera. The fractures were examined macroscopically and compared between the sample groups. We consistently found comminuted fractures with a stellate pattern. Fracture details were classified into entrance, exit and general characteristics. For some traits, we detected different occurrence values in the group comparison. The results indicate that some of the traits depend on bone properties such as shaft diameter, bone length and cortical thickness. The presence of ballistic gel also influenced some fracture traits, emphasising the relevance of soft tissue simulant in osseous gunshot experiments. This study revealed new insights in the detailed fracture pattern of human long bones. These may serve as guidelines for the identification and reconstruction of gunshot trauma in human long bones.

Osteonal Microcracking Pattern: A Potential Vitality Marker in Human Bone Trauma.

In forensic anthropology, the differential diagnosis between peri- and postmortem bone fractures is mainly based on macroscopic criteria. In contrast, studies focusing on bone histology are very scarce. In a recent publication, we showed that (perimortem) fractures in fresh human bones exhibit a different osteonal microcracking pattern than (postmortem) damage in dry bones. In the current work, we explored whether this osteonal microcracking pattern is distinctive of the vitality of (perimortem) fresh bone fractures. To this end, we compared the number, length and structural distribution of microcracks in vital humeral fractures from forensic autopsy cases with experimentally reproduced, three point-bending fractures in fresh and dry human humeri. Half of the fresh experimental bones were fractured whilst applying axial compression, i.e., attempting to simulate intra vitam conditions more accurately. The results showed a similar osteonal microcracking pattern between vital fractures and experimental fractures of fresh humeri subjected to axial compression. Interestingly, this pattern was significantly different from the one observed in the experimental fractures of fresh humeri without axial compression and dry humeri. This supports our hypothesis that the osteonal microcracking pattern can potentially be used as a marker for vital perimortem trauma, providing a histomorphometric tool for fracture timing.

Microcracking pattern in fractured bones: new approach for distinguishing between peri- and postmortem fractures.

Timing bone fractures is one of the main tasks of a forensic anthropologist, but still an uncertain diagnostic. In the literature, there are many macroscopic methods to distinguish perimortem from postmortem fractures, based on the distinct structural and mechanical properties of fresh and dry bones. However, this differentiation is still challenging, in particular when the bones are fragmented or still exhibit fresh properties. Although histologic analysis is often used as a complementary diagnostic tool in forensic pathology, its application in the evaluation of bone fractures is uncommon. The aim of this study was to investigate whether fractures of fresh bones reveal a distinct microcracking pattern compared to fractures of dry bones, in order to optimise the fracture timing. To this purpose, we histologically analysed perimortem and postmortem fractures in human humeri. The fresh bones were retrieved from traumatic autopsy cases, and the dry bones from donors which were experimentally fractured. Our results showed that the highest density and length of microcracks (MCKs) were found in the interstitial area of dry fractured bones, which may be considered a marker of postmortem damage. In fresh fractured bones, we generally observed a lower density of MCKs, but a higher proportion of osteonal MCKs, which may be considered a marker of perimortem trauma. In summary, the results of our exploratory study suggest that changes in intrinsic bone factors (mineral/organic components) result in a different microcracking pattern that can be used in fracture timing.

Diagnóstico diferencial etiológico del hematoma subdural agudo en la edad pediátrica / Etiological differential diagnosis of the acute subdural hematoma in pediatric age

El presente estudio se centra en el diagnóstico diferencial etiológico del hematoma subdural agudo (HSD) infantil. El principal objetivo es aportar herramientas diagnósticas que faciliten la diferenciación entre el HSD espontáneo y el HSD traumático, ya sea por causa accidental o intencional en el contexto de un maltrato infantil. Con este propósito, se ha realizado un estado del arte completo a través de una revisión de la literatura más reciente, recogiendo en el mismo trabajo los criterios clínicos, radiológicos y anatomopatológicos más relevantes para el diagnóstico de los HSD infantiles. Con el objetivo de simplificar y clarificar el manejo de los pacientes con HSD, se desarrolla un algoritmo diagnóstico que cuenta con un enfoque multidisciplinar, combinando la información aportada por diversos autores y planteando por primera vez 3 diagnósticos finales posibles en los casos de HSD infantiles: HSD traumático accidental, HSD traumático intencional y HSD espontáneo. (AU)

This article is focused on the differential diagnosis of infantile acute subdural hematoma (SDH). The objective is to focus on bringing more diagnostic tools when it comes to differentiate a spontaneous SDH from the traumatic SDH, being this accidental or intentional in the context of a child abuse. A complete state of the art is made from the review of the most recent available literature, collecting in the same paper the most relevant clinical features, radiologic findings and anatomopatological criteria for the diagnosis of infantile SDH. With the aim to simplify and clarify the handling of the patients with SDH, a multidisciplinary diagnostic algorithm has been developed in this article, combining the provided information from several authors and raising for the first time the possibility of 3 final diagnostic options in the cases of infantile SDH: accidental traumatic SDH, intentional traumatic SDH, and spontaneous SDH. (AU)

Intracerebral and subarachnoid hemorrhage after suicidal "near-hanging".

Hanging is one of the most common methods of attempting suicide with a fast occurring death and a high lethality rate. Depending on how fast the hanged individuals are found, they may be rescued, which is referred to as "near-hanging." Whilst hypoxic and ischemic brain damage are common findings in hanging, intracranial hemorrhages seem to be a rare occurrence. To the authors' knowledge, this is the first autopsy case report of an intracerebral and subarachnoid hemorrhage in a delayed death after incomplete hanging. We hypothesize that the combination of two mechanisms is involved in the development of such hemorrhages. First, the persistent venous hypertension during incomplete hanging causing endothelial damage resulting in vascular leakage. Second, the reperfusion of the brain due to recovery of venous blood return after the release form the rope. Whereas intracranial hemorrhage is not a common finding in daily autopsy cases of fatal hanging, it might be a severe complication in rescued cases.

Gunshot trauma in human long bones: towards practical diagnostic guidance for forensic anthropologists.

In contrast to cranial gunshot trauma, diagnosis and interpretation of gunshot trauma to long bones remains difficult and controversial. The aim of this study is to review the published literature on fracture patterns resulting from gunshot trauma in human long bones, and to use the described characteristics to provide practical guidance for the forensic anthropologist. In order to achieve this, medical and forensic publications on this topic were reviewed. Several types of fractures, such as linear, oblique, comminuted and butterfly fractures, have been observed in either the shaft or the ends of long bones. Indirect fractures that are not caused by bullets striking bone directly but by bullet-induced forces to the surrounding soft tissue have been found as well. Some of these fractures are related to a specific context or mechanism which might help in the forensic reconstruction of events. It is recommended that future research should focus on available medical data to provide more detailed descriptions on fracture patterns for forensic purposes. Experimentation with bone surrogates and computer modelling might also provide better and more realistic reconstructions of gunshot trauma in the future and provide valuable insights for its diagnosis and interpretation in forensic anthropology.

Taphonomic model of decomposition.

After death human body is subject to the processes of autolysis and putrefaction. Notably, the changes in cadaver during decomposition complicate its forensic analysis and particularly the estimation of the post-mortem interval (PMI). The process and rate of decomposition is impacted by various intrinsic and extrinsic factors that vary across countries and regions. Studying the decomposition pattern in different regions in the world helps us to understand the process and improve the precision of the PMI estimation of decomposed bodies. With the aim to develop a taphonomic model of decomposition in the province of Barcelona (Catalonia, Spain), this study analyses the influence of several intrinsic and extrinsic factors in the pattern and rate of decomposition in this geographical area. Our statistical model concluded that the most significant factors affecting the decomposition pattern and rate are temperature and PMI. Nevertheless, there are other intrinsic factors such as cause, manner of death and underlying pathological conditions which also have an important role. Moreover, considering the various variables studied in this research, two predictive machine learning algorithms were developed as a probabilistic approach to estimate the PMI. Reliable classification results are obtained for three interval groups (1-2 days, 3-10 days, and > 10 days) and two interval groups (>1 week, < 1 week). Machine learning algorithm is a promising tool to gain objectivity in forensic PMI assessments. The results of this study could potentially assist further research in forensic taphonomy.

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.

Mechanical Behavior of Blood Vessels: Elastic and Viscoelastic Contributions.

The mechanical properties of the cerebral bridging veins (CBVs) were studied using advanced microtensile equipment. Detailed high-quality curves were obtained at different strain rates, showing a clearly nonlinear stress-strain response. In addition, the tissue of the CBVs exhibits stress relaxation and a preconditioning effect under cyclic loading, unequivocal indications of viscoelastic behavior. Interestingly, most previous literature that conducts uniaxial tensile tests had not found significant viscoelastic effects in CBVs, but the use of more sensitive tests allowed to observe the viscoelastic effects. For that reason, a careful mathematical analysis is presented, clarifying why in uniaxial tests with moderate strain rates, it is difficult to observe any viscoelastic effect. The analysis provides a theoretical explanation as to why many recent studies that investigated mechanical properties did not find a significant viscoelastic effect, even though in other circumstances, the CBV tissue would clearly exhibit viscoelastic behavior. Finally, this study provides reference values for the usual mechanical properties, as well as calculations of constitutive parameters for nonlinear elastic and viscoelastic models that would allow more accurate numerical simulation of CBVs in Finite Element-based computational models in future works.

Investigación forense sobre muerte súbita publicada en España / Forensic research on sudden death published in Spain

INTRODUCCIÓN: Uno de los pilares básicos en la labor de la medicina legal y forense en España es la investigación. Tomando como referencia la muerte súbita, tema clásico de la patología forense, se pretende realizar un estudio del estado de salud de la investigación forense que se publica en las dos revistas españolas más relevantes del ámbito medicolegal. METODOLOGÍA: Se recogen artículos sobre muerte súbita de los últimos 10años (2009-2018) de la Revista Española de Medicina Legal y de Cuadernos de Medicina Forense. Como comparador, una revista internacional con factor de impacto medio-intermedio (segundo cuartil año 2018). Se contempla una tercera búsqueda abierta de artículos del ámbito médico indexadas en PubMed para detectar y tratar el posible sesgo derivado. RESULTADOS Y DISCUSIÓN: La muerte súbita cardíaca es la más estudiada a nivel nacional, con buena tasa de colaboración entre centros y especialidades, pero sin traducirse en tasas mayores de artículos originales, aunque sí en artículos especiales y case-reports. A nivel internacional, los case-reports son el formato predominante, seguidos de los artículos originales, sobre todo centrados en muerte súbita no cardíaca. CONCLUSIONES: Como perspectiva de futuro, sugerimos potenciar las políticas dirigidas a fomentar la investigación y, sobre todo, a la creación de redes de colaboración con otras especialidades, con el fin de dar un enfoque multidisciplinar preventivo y clínico a la investigación en muerte súbita

INTRODUCTION: One of the main pillars of the work of legal medicine in Spain is research. Taking sudden death (SD), a classical subject in forensic pathology, as the reference this paper aims to examine developments in Spanish forensic research papers published in the two most relevant Spanish legal medicine journals. METHODS: Articles on SD over the last 10 ears from the two most relevant Spanish forensic journals were gathered. An international journal with medium-intermedium impact factor (second quartile in 2018) was the comparator. A third open search of PubMed indexed medical journals was conducted to detect and treat potential derivative bias. RESULTS AND DISCUSSION: Cardiac SD is the most studied SD at a national level, with high rates of collaboration among centres and specialties. However, this does not result in higher rates of original papers, but in more special articles and case-reports. At an international level, case-reports are the main publication format followed by original articles, mainly focussing on non-cardiac SD. CONCLUSIONS: As a prospect for the future, we suggest strengthening policies to promote research and, above all, to create collaboration networks among specialties towards a multidisciplinary, preventive and clinical approach to SD research

Technical note: preliminary insight into a new method for age-at-death estimation from the pubic symphysis.

Age-at-death estimation methods are important in forensic anthropology. However, age assessment is problematic due to inter-individual variation. The subjectivity of visual scoring systems can affect the accuracy and reliability of methods as well. One of the most studied skeletal regions for age assessment is the pubic symphysis. Few studies on Spanish pubic symphysis collections have been conducted, making further research necessary as well as the sampling of more forensic skeletal collections. This study is a preliminary development of an age-at-death estimation method from the pubic symphysis based on a new simple scoring system. A documented late twentieth century skeletal collection (N = 29) and a twenty-first century forensic collection (N = 76) are used. Sixteen traits are evaluated, and a new trait (microgrooves) is described and evaluated for the first time in this study. All traits are scored in a binary manner (present or absent), thus reducing ambiguity and subjectivity. Several data sets are constructed based on different age intervals. Machine learning methods are employed to evaluate the scoring system's performance. The results show that microgrooves, macroporosity, beveling, lower extremity, ventral and dorsal margin decomposition, and lipping are the best preforming traits. The new microgroove trait proves to be a good age predictor. Reliable classification results are obtained for three age intervals (≤ 29, 30-69, ≥ 70). Older individuals are reliably classified with two age intervals (< 80, ≥ 80). The combination of binary attributes and machine learning algorithms is a promising tool for gaining objectivity in age-at-death assessment.

La especialidad de Medicina Legal y Forense en España: La consolidación por el sistema de residencia / Legal and Forensic Medicine Specialty in Spain: the consolidation by the medical residency system

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Distinction between perimortem and postmortem fractures in human cranial bone.

Timing of cranial trauma is challenging in forensic cases and literature on the subject is scarce. This study analysed the macroscopic fracture patterns of perimortem cranial fractures and compared them to experimentally reproduced cranial fractures on dry human craniums. The results showed nine traits associated with fresh cranial fractures: undulated margin, flake defects, peels with peel defects, fissures, crushed margins, bridge, bone scales and beveling. All the traits appear on the outer table or on the inner table of the cranium. Although not all characteristics must be present at the same time in all cranial fractures, they do define a new perimortem fracture pattern. Statistical analyses showed that six of these traits (undulated margins, flake defects, crushed margins, bone scales, fissures and peels) are distinctly related with perimortem (fresh) bone conditions. Considering the most discriminant perimortem traits, a decision-making algorithm is developed as a probabilistic approach to distinguish peri- from postmortem cranial fractures with an accuracy of 87%. This algorithm allows the forensic practitioner to incorporate more confidence during cranial trauma evaluation.

Tesis doctorales en medicina forense en España / Doctoral theses on forensic medicine in Spain

INTRODUCCIÓN: El análisis de las tesis doctorales es un indicador de la actividad científica y de investigación. MATERIAL Y MÉTODO: Análisis descriptivo retrospectivo de las tesis en España sobre medicina forense entre 2000-2019 a partir de TESEO, usando el descriptor «medicina forense». RESULTADOS: Se obtuvieron 179 tesis (9,42 tesis/año). El 51,4% de doctorandos fueron mujeres, presentándose tesis en 33 universidades distintas. La Universidad de Murcia aglutina el 24% de las tesis de la muestra. En 41 tesis hubo un solo director/a, en 118 dos y en 20 tres. El 65,28% de directores/as fueron varones. El 38,55% de tesis pertenecían a patología forense, seguidas de toxicología y psiquiatría forense. DISCUSIÓN: La producción de tesis doctorales sobre medicina forense en España es estable, a excepción del año 2016, por aspectos normativos. Destaca una gran diversidad de temáticas acorde con el carácter multidisciplinar de la medicina legal y forense

INTRODUCTION: The analysis of doctoral theses can be a good indicator of scientific and research activity. METHODS: A descriptive and retrospective analysis of theses in Spain on Forensic Medicine, was conducted between 2000-2019, through the TESEO database, using the descriptor "forensic medicine". RESULTS: A total of 179 theses were identified (9.4 theses per year). Fifty one point four percent of the doctoral students were females, presenting theses in 33 different Spanish Universities (24% from Murcia University). In 41 theses there was only one director, two in 118 and three in 20. Sixty-five point twenty-eight percent of the thesis directors were male. Most frequently the theses related to Forensic Pathology (38.55%), Toxicology or Forensic Psychiatry. DISCUSSION: The production of theses in Forensic Medicine could be considered stable, except for in 2016 in relation to regulatory issues. The wide variety of topics for theses should be highlighted, according to multidisciplinary contents of Forensic and Legal Medicine

Visualization and documentation of perimortem traits in long bone fractures using computed tomography.

Perimortem fracture patterns in long bones, defined in previous publications, include layered breakage, bone scales, crushed margins, flakes with flake defect, wave lines, and plastic deformation. The traits help professionals during trauma analysis to differentiate peri- from post-mortem fractures. This study will therefore investigate whether these traits can be recorded with Computed Tomography (CT) as the non-invasive 3D imaging technique is becoming more popular in forensic science. CT scans of macerated bone samples (n = 15; humerus: n = 1; ulna: n = 1; radius: n = 1; femur: n = 12) were investigated using multi-planar reconstructions (MPRs) and volume renderings. Tension lines and severe plastic deformation were visible on the individual multi-planar reconstructions (MPRs) and the 3D models. Additionally, layered breakage and flake defects were also clearly distinguishable on the volume renderings. Based on the results, CT imaging may be a useful and fast tool to document, visualize, and analyze findings of blunt force trauma.

Intoxicación letal por piedras chinas con ideación suicida / Poisoning by Chinese rocks: fatal outcome of a suicide attempt

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Differentiation between perimortem trauma and heat-induced damage: the use of perimortem traits on burnt long bones.

Burnt human remains present a difficult interpretative dilemma to forensic pathologists and anthropologists. Distinguishing postmortem damage in long bones as a result of fire damage from perimortem fractures is an important challenge in trauma analysis. During our case investigation of a burnt body from a fiery car crash, distinct perimortem traits on long bone fractures were still distinguishable along the charred areas. Next to timing of fractures and shortening the perimortem time gap suggesting that the fractures occurred when soft tissue was still present, the traits make it possible to distinguish blunt trauma caused by the accident from heat-induced bone damage. Applying this specific perimortem pattern could be an additional macroscopic tool to interpret blunt force trauma more accurately in the analysis of burnt remains.