Subject-specific finite element head models for skull fracture evaluation-a new tool in forensic pathology.

Post-mortem computed tomography (PMCT) enables the creation of subject-specific 3D head models suitable for quantitative analysis such as finite element analysis (FEA). FEA of proposed traumatic events is an objective and repeatable numerical method for assessing whether an event could cause a skull fracture such as seen at autopsy. FEA of blunt force skull fracture in adults with subject-specific 3D models in forensic pathology remains uninvestigated. This study aimed to assess the feasibility of FEA for skull fracture analysis in routine forensic pathology. Five cases with blunt force skull fracture and sufficient information on the kinematics of the traumatic event to enable numerical reconstruction were chosen. Subject-specific finite element (FE) head models were constructed by mesh morphing based on PMCT 3D models and A Detailed and Personalizable Head Model with Axons for Injury Prediction (ADAPT) FE model. Morphing was successful in maintaining subject-specific 3D geometry and quality of the FE mesh in all cases. In three cases, the simulated fracture patterns were comparable in location and pattern to the fractures seen at autopsy/PMCT. In one case, the simulated fracture was in the parietal bone whereas the fracture seen at autopsy/PMCT was in the occipital bone. In another case, the simulated fracture was a spider-web fracture in the frontal bone, whereas a much smaller fracture was seen at autopsy/PMCT; however, the fracture in the early time steps of the simulation was comparable to autopsy/PMCT. FEA might be feasible in forensic pathology in cases with a single blunt force impact and well-described event circumstances.

Citrate-based materials fuel human stem cells by metabonegenic regulation.

A comprehensive understanding of the key microenvironmental signals regulating bone regeneration is pivotal for the effective design of bioinspired orthopedic materials. Here, we identified citrate as an osteopromotive factor and revealed its metabonegenic role in mediating citrate metabolism and its downstream effects on the osteogenic differentiation of human mesenchymal stem cells (hMSCs). Our studies show that extracellular citrate uptake through solute carrier family 13, member 5 (SLC13a5) supports osteogenic differentiation via regulation of energy-producing metabolic pathways, leading to elevated cell energy status that fuels the high metabolic demands of hMSC osteodifferentiation. We next identified citrate and phosphoserine (PSer) as a synergistic pair in polymeric design, exhibiting concerted action not only in metabonegenic potential for orthopedic regeneration but also in facile reactivity in a fluorescent system for materials tracking and imaging. We designed a citrate/phosphoserine-based photoluminescent biodegradable polymer (BPLP-PSer), which was fabricated into BPLP-PSer/hydroxyapatite composite microparticulate scaffolds that demonstrated significant improvements in bone regeneration and tissue response in rat femoral-condyle and cranial-defect models. We believe that the present study may inspire the development of new generations of biomimetic biomaterials that better recapitulate the metabolic microenvironments of stem cells to meet the dynamic needs of cellular growth, differentiation, and maturation for use in tissue engineering.

Skull Fracture Patterns and Morphologies Among Fatal Motorcycle Traffic Accident Victims in Vietnam.

ABSTRACT: We aim to describe morphological structures of skull fractures and relevant factors in motorcycle accident victims in Vietnam. This work represents a retrospective cross-sectional study based on forensic reports of fatal motorcycle accident victims. Between January 2013 and August 2019, a total of 226 fatal motorcycle accident patients with skull fracture diagnoses were enrolled. Linear and depressed fractures were the common patterns (46.0% and 37.2% of cases, respectively), whereas stellate (11.5%) fractures were rare. Fractures of the temporal bone (68.6% of cases) and basilar skull (60.6%) were the most common, whereas fractures of the parietal bone were the least common (9.7%). Two or more patterns of skull fracture were recorded in 25.5% of cases, and 2 or more fracture locations were recorded in 76.6% of cases. Fractures of the parietal bone were associated with victims not wearing a helmet. In addition, fractures of the basilar skull were more likely to occur among victims with alcohol consumption. We found the common pattern of skull fractures was linear and depressed fractures, and the common location of skull fractures was temporal and basilar bone. Further studies that include larger sample sizes and collect more information should be conducted to better understand relationships between skull fractures and related factors.

Enhanced Bone Regeneration in Variable-Type Biphasic Ceramic Phosphate Scaffolds Using rhBMP-2.

Our aim was to investigate the bone regeneration capacity of powder-type biphasic ceramic scaffold (BCP powder), block-type BCP (BCP block), and collagen-added block-type BCP (BCP collagen) with different concentrations of recombinant human bone morphogenetic protein 2 (rhBMP-2) in an animal model. Four rabbits were assigned to each of the following groups: no graft + rhBMP-2 (0.1/0.2 mg/mL), BCP powder + rhBMP-2 (0.1/0.2 mg/mL), BCP block + rhBMP-2 (0.1/0.2 mg/mL), and BCP collagen + rhBMP-2 (0.1/0.2 mg/mL), i.e., a total of 32 rabbits. Polycarbonate tubes (Φ 7 mm × 5 mm) for supporting scaffolds were fixed into a 7 mm round border. Subsequently, 0.1 mL of rhBMP-2 solutions with different concentrations was injected into the tubes. Both radiological and histomorphometric analyses showed that osteogenesis was not enhanced by increasing the concentration of rhBMP-2 in all groups at both 3 and 6 weeks. Radiological analysis showed that bone formation was higher in the BCP collagen group than in the BCP powder and BCP block groups at both rhBMP-2 concentrations at 3 weeks. rhBMP-2 enhanced bone formation; however, as the concentration increased, bone formation could not be enhanced infinitely. Collagen-added alloplastic graft material may be useful for mediating rapid bone formation in initial stages.

Autopsy or anatomical dissection: evidence of a craniotomy in a 17th-eighteenth century burial site (Ravenna, Italy).

Surgical procedures undergone in life, autopsies and anatomical preparations can all leave clearly identifiable traces on human skeletal remains. Several studies on skeletons from archeological contexts have identified traces of these practices. However, the distinction between medical/forensic autopsy and anatomical dissections for scientific research can be challenging. We report the case of a middle-aged female skeleton from the cemetery of the church of San Biagio (Ravenna, Italy), dating back to the 17th-19th centuries, that shows signs of a complete craniotomy. In an attempt to clarify the reason for this practice, we analyzed all pathological and non-pathological markers on the skeleton. We carried out anthropological analyses and osteometric measurements to determine the biological profile and the cranial capacity of the individual. Paleopathological investigation and analyses of traumatic injury patterns were carried out using both a morphological and a microscopic approach. While we observed that the craniotomy was performed with a rip saw, we identified perimortem blunt force trauma to the frontal bone and an osteolytic lesion on the inner surface of the frontal bone. No other pathology was recognizable on the skeleton. Our differential diagnosis confidently proved that the craniotomy was due to an autoptsy procedure and was not the result of an anatomical dissection. We believe that, among other possible reasons, failed surgery could likely be the motive behind the ordering of the autopsy.

Pedestrian hit by a car impacted metal pole: reconstructing the head load.

Fatal head injuries are frequently seen in pedestrians hit by motorized vehicles. In our case, the pedestrian sustained a devastating head injury with skull splitting in the mediosagittal plane. A car collided with a traffic sign causing a bending of the pole. The metal pole hit a man standing close beside it; the man had a head injury severity that is more commonly due to falling objects than due to traffic accidents. Assuming a head mass of 5 kg, simplified calculations yield maximum contact forces of ca. 36 kN exceeding mean parietal fracture forces which are in the order of magnitude of 12.5 kN. The influences of the effective body mass and the horizontal distance between the pole and the pedestrian on maximum contact forces are investigated. High contact forces in our case can be mainly explained by the comparably high impact velocity and by a partial mass transfer of the total car mass to the pole.

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.

In vivo evaluation of interactions between biphasic calcium phosphate (BCP)-niobium pentoxide (Nb2O5) nanocomposite and tissues using a rat critical-size calvarial defect model.

Natural or synthetic biomaterials are increasingly being used to support bone tissue repair or substitution. The combination of natural calcium phosphates with biocompatible alloys is an important route towards the development of new biomaterials with bioperformance and mechanical responses to mimic those of human bones. This article evaluated the structural, physical, mechanical and biological properties of a new mechanical improved nanocomposite elaborated by association of fish biphasic calcium phosphate (BCP) and niobium pentoxide (Nb2O5). The nanocomposite (Nb-BCP) and the pure BCP, used as a positive control, were obtained by powder metallurgy. The density, porosity and microhardness were measured. The structural analysis was determined by X-ray diffraction (XRD) and the biological properties were studied in histological sections of critical size calvaria defects in rats, 7, 15, 30, 45 and 60 days after implantation of disks of both materials. Morphological description was made after scanning electron microscopy (SEM) and optical microscopy analysis. After sintering, the Nb-BCP nanocomposite presented four crystalline phases: 34.36% calcium niobate (CaNb2O6), 21.68% phosphorus niobium oxide (PNb9O25), 42.55% ß-tricalcium phosphate (Ca3(PO4)2) and 1.31% of niobium pentoxide (Nb2O5) and exhibited increases of 17% in density, 66% in Vickers microhardness and 180% in compressive strength compared to pure BCP. In vivo study, showed biocompatibility, bioactivity and osteoconductivity similar to pure BCP. SEM showed the formation of globular accretions over the implanted nanocomposites, representing one of the stages of bone mineralization. In conclusion, the BCP and Nb2O5 formed a nanocomposite exhibiting characteristics that are desirable for a biomaterial, such as bioperformance, higher ß-TCP percentage and improved physical and mechanical properties compared to pure BCP. These characteristics demonstrate the promise of this material for supporting bone regeneration.

Head and Brain Postmortem Computed Tomography-Autopsy Correlation in Hospital Deaths.

The use of postmortem computed tomography (PMCT) to support autopsy pathology has increased in recent decades. To some extent, PMCT has also been contemplated as a potential alternative to conventional postmortem examination. The purpose of this study was to investigate the ability of PMCT to detect specific pathologic findings in the head and brain in natural hospital deaths.We examined postmortem CT images and autopsy data from 31 subjects who died at SUNY (State University of New York) Upstate University Hospital between 2013 and 2018. Each subject underwent a noncontrast PMCT and a traditional autopsy. A neuroradiologist analyzed PMCT images for head and brain abnormalities. The autopsies were performed by pathologists who were aware of the radiology results.In our series, PMCT was able to detect the majority of the significant space-occupying lesions, although it was not always reliable in ascertaining their nature. Postmortem computed tomography revealed findings usually challenging to detect at autopsy. Unfortunately, there were also situations in which PMCT was misleading, showing changes that were difficult to interpret, or that could be related to postmortem events. Therefore, we conclude PMCT should be used as an adjunct rather than a substitute to autopsy.

Postmortem Magnetic Resonance Imaging and Postmortem Computed Tomography in Ligature and Manual Strangulation.

PURPOSE: The aim of this study was to evaluate magnetic resonance imaging (MRI) findings in cases of fatal manual or ligature strangulation. Verification of strangulation by computed tomography (CT), MRI, and at autopsy as well as its detectability in each modality was assessed. METHODS: We retrospectively analyzed 6 manual and ligature strangulation cases between 2013 and 2019 who all underwent a whole-body CT, head and neck MRI, and an autopsy. Two radiologists examined head and neck imaging data and compared the data to autopsy findings. RESULTS: Magnetic resonance imaging showed a high efficiency in verifying intramuscular hemorrhages, which were confirmed in autopsy. Moreover, in one case without a visible strangulation mark, soft tissue injuries associated with strangulation were detected. Fractures, especially thyroid cartilage fractures, were successfully diagnosed by CT. CONCLUSIONS: As MRI showed a successful detection of soft tissue lesions in relation to strangulation, it can serve as an alternative method or provide additional value to an autopsy. Intramuscular hemorrhages are a common finding in manual and ligature strangulation, providing a useful sign of applied pressure on the neck. However, to evaluate fractures, an additional CT or autopsy is recommended.

Closed-head injuries followed by detached brain tissue in the external auditory canals.

We describe five cases of fatally injured males (occupational accident, car driver, pedestrian, motorcyclist and suicidal jump from great height) with one universal autopsy finding - the presence of brain tissue in one or both auditory canals. Internal examination revealed that all victims had multiple head fractures with dura lacerations. In four cases, the petrous part of the temporal bone was fractured (hinge fracture), while in one case the fracture of both the petrous part of the temporal bones and the occipital bone (ring fracture) was present. In all of these cases, considerable pressure was applied to the head, pushing brain tissue equally in all directions (due to incompressibility of the tissue). The tissue followed the path of least resistance, going through the lacerated dura into the fractured petrous part of the temporal bones and finally reaching the middle ear cavity and auditory canal. This phenomenon is almost exclusively encountered in closed-head injuries. In an open-head injury, brain tissue would be expelled through the open bone fracture and scalp wound. The presence of brain tissue in the ears could indicate a hinge or ring fracture in a closed-head injury which occurred as the result of excessive impulse force or considerable pressure applied to the head, i.e. the head was compressed and/or squeezed.

Skull fractures in forensic putrefied/skeletonised cases: The challenge of estimating the post-traumatic interval.

The objective of our study was to assess the reliability of the estimation of posttraumatic survival time (PTST) in forensic cases based on microCT and histology of putrefied/dry bone samples with comparison of initial macroscopic fracture classification performed during autopsy. Macroscopic morphological patterns of bone fracture are routinely used in forensic pathology and anthropology to distinguish between antemortem, perimortem and postmortem injuries. Based on macroscopic and microscopic analysis of six craniofacial fractures, our study results illustrate the need to complete macroscopical findings and initial fracture classification with microscopic analysis to avoid any inaccuracy. MicroCT has become a powerful technique to identify early bone healing signs but histology remains the gold standard to estimate the PTST and determine vital fracture based on hemorrhage marker. Raman microspectroscopy can identify a blood clot in the fracture line.

[Ergometric evaluation of impact strength that lead to skull fracture: features of individual methods, typical expert mistakes and methods of their prevention]. / Érgometricheskaia otsenka sily udara, povlekshego perelom cherepa: osobennosti chastnykh metodik, tipichnye ékspertnye oshibki i sposoby ikh predotvrashcheniia.

Two current approaches to the ergometric evaluation of the impact strength that lead to skull fracture are described. Within each of them, the features of particular techniques, typical expert errors, ways and means of preventing them are analyzed. Quantitative data on the contribution of various initial parameters (fracture type, age, bone thickness, skull radius of curvature, body weight, height, etc.) to the result of computational diagnostics are presented.

Infant skull fracture risk for low height falls.

Skull fractures are common injuries in young children, typically caused by accidental falls and child abuse. The paucity of detailed biomechanical data from real-world trauma in children has hampered development of biomechanical thresholds for skull fracture in infants. The objectives of this study were to identify biomechanical metrics to predict skull fracture, determine threshold values associated with fracture, and develop skull fracture risk curves for low-height falls in infants. To achieve these objectives, we utilized an integrated approach consisting of case evaluation, anthropomorphic reconstruction, and finite element simulation. Four biomechanical candidates for predicting skull fracture were identified (first principal stress, first principal strain, shear stress, and von Mises stress) and evaluated against well-witnessed falls in infants (0-6 months). Among the predictor candidates, first principal stress and strain correlated best with the occurrence of parietal skull fracture. The principal stress and strain thresholds associated with 50 and 95% probability of parietal skull fracture were 25.229 and 36.015 MPa and 0.0464 and 0.0699, respectively. Risk curves using these predictors determined that infant falls from 0.3 m had a low probability (0-54%) to result in parietal skull fracture, particularly with carpet impact (0-1%). Head-first falls from 0.9 m had a high probability of fracture (86-100%) for concrete impact and a moderate probability (34-81%) for carpet impact. Probabilities of fracture in 0.6 m falls were dependent on impact surface. Occipital impacts from 0.9 m onto the concrete also had the potential (27-90% probability) to generate parietal skull fracture. These data represent a multi-faceted biomechanical assessment of infant skull fracture risk and can assist in the differential diagnosis for head trauma in children.

Fibrinolysis in trauma patients: wide variability demonstrated by the Lysis Timer.

Hyperfibrinolysis contributes to the pathophysiology of trauma-induced coagulopathy. At present, systematic administration of tranexamic acid (TXA) is recommended in all patients in the early phase of trauma. However, there is some debate regarding whether TXA is beneficial in all trauma patients. A rapid and accurate tool to diagnose hyperfibrinolysis may be useful for tailoring TXA treatment. We conducted a proof-of-concept study of consecutive adult trauma patients. A first blood sample was obtained at the time of pre-hospital care (T1). Patients received 1 g of TXA after T1. A second sample was obtained on arrival at the emergency unit (T2). We examined coagulation, fibrin and fibrinogen formation and degradation. Fibrinolysis was assessed by determining tissue plasminogen activator (t-PA) antigen and plasminogen activator inhibitor 1 (PAI-1) activity and global fibrinolysis capacity assay using a device developed by Hyphen BioMed: the Lysis Timer (GFC/LT). The study population consisted of 20 patients (42 ± 21 years, index of severity score 32 ± 21). Both coagulation and fibrinolysis were altered at T1. GFC/LT values exhibited hyperfibrinolysis only in five patients. Principal component analysis carried out at T1 showed two main axes of alteration. The major axis was related to coagulation, altered in all patients, while the second axis was related to fibrinolysis. GFC/LT was mainly influenced by PAI-1 activity while fibrin monomers were related to the severity of trauma. At T2, GFC/LT exhibited the marked effect of TXA on clot lysis time. In conclusion, GFC/LT demonstrated huge variation in the fibrinolytic response to trauma.

Simon's hemorrhages in a case of a fatal construction site accident as the result of body hyperextension in the upside-down position - a possible reconstruction of the injury mechanism.

An accident occurred at a construction site and a 27-year-old worker was fatally injured. Equipped with personal protective equipment (helmet and a safety belt), he was standing on an 8-meter-high platform holding a large hose that was attached to a pipe connected to a concrete pump truck. Whilst in use the pipe broke and the hose sent the man flying with force, knocking down the platform railing. Autopsy examination showed that man fell to the ground landing on his head. Prominent Simon's hemorrhages were noted on the L5-S1 and L4-L5 intervertebral discs. When the hose threw the man from the platform, for one brief moment he was suspended in the air, with the safety belt tied firmly to his waist. Simon's hemorrhages most probably emerged at that moment, due to forceful hyperextension and traction of the body in the upside-down position. A relatively unexpected appearance of Simon's hemorrhages contributed to the reconstruction of the injury mechanism.

Axe injury pattern in homicide.

Chop or slash wounds are produced by sharp-edged tools such as an axe, or a machete. This paper presents a case of a violent death of a 57 year-old-man. Autopsy revealed deformation of the right side of the head. A total of 23 slash, stab and cut wounds as well as contused lacerations were identified on the scalp as well as the face and the neck. In addition, superficial abrasions and bruises were identified on the skin. The immediate cause of death was due to extensive brain contusion following fragmentation of the neurocranium. The injuries resulting in the death of the victim were sustained during an assault on the head with an axe, which was used both as a slashing tool and a blunt instrument.

Violence in the Early Bronze Age. Diagnosis of skull lesions using anthropological, taphonomic and scanning electron microscopy techniques.

In this paper we present the study of a skull belonging to a young male from the Italian Bronze Age showing three perimortem injuries on the frontal and parietal bones; the peculiarity of the frontal injury is represented by its singular shape, which may be indicative of the weapon that caused the lesion. The aim of the present study is to examine the traumatic evidence in relation to possible etiological factors, in order to attempt to establish if the lesion occurred peri or post-mortem, and to evaluate if these traumatic injuries could be interpreted as an evidence of interpersonal violence, by combining anthropological, taphonomic and ESEM investigations. The combination of multidisciplinary methods of study can provide important new insights into inter-personal violence.

Surviving a transfixing gunshot wound to the head 70 years ago.

Surviving a gunshot wound to the head is a rare event, particularly in the past when medical treatment was much less advanced than it is today. Moreover, the finding of such a case as an identified specimen within a museum collection is even more uncommon. This led us to report on this unique case in this paper as it poses a challenge to forensic anthropology and provides a unique educational oppourtunity. The skull from the Collection at the Cranium Museum in the Department of Morphology and Genetic at the Federal University of São Paulo (UNIFESP) dates back to 1946. For trauma registration the bone location, severity, trauma aetiology, trauma classification, description, callus formation, periosteal reaction, degree and success of repair, and an estimate of the time elapsed since the trauma, were all assessed. To explore the case radiologically a CT scan of the skull was performed. Considering the survival of the patient and the morphology of the wound it is likely that the injury was caused by a small calibre, low-velocity gunshot. The bullet path shows an almost vertical direction on the right side of the individual's splanchno and neurocranium. The path of the projectile is consistent with a suicide attempt, although the possibility of a homicide simulating a suicide cannot be discarded. This case highlights how informative such cases can be to the practice of forensic anthropology.

Biomechanical approach for the assessment of contacts with deformable objects.

Forensic and biomechanical assessment in case of blunt force trauma can be a challenging task especially when deformable striking objects are used. Evaluations solely based on empirical knowledge can lead to misjudgments. Semi-quantitative and quantitative investigations give the forensic assessment a scientific basis comprising experimental and calculation methods. Based on a real case where a car wheel was used as a striking object, our work presents a simple test setup for contact force estimation in head contacts with deformable contact partners. Our approach combines experimental measurements using a single accelerometer and calculations applying the conservation of linear momentum and Newton's second law. Both experimental and calculation results are discussed in terms of validity, reproducibility, and plausibility. With regard to our case, we can conclude that the injury pattern without skull fractures does not confound multiple strikes with a wheel. Skull fractures and potential fatal injuries had not to be expected assuming a head-carcass contact in case of a non-supported head. The approach presented can be applied to any case where deformable or uncommon blunt objects are used.