Histologic and radiological analysis on bone fractures: Estimation of posttraumatic survival time in skeletal trauma

Ante- and Post-Mortem Fracture Identification Protocol Based on Low- and High-Level Fusion Using Fourier Transform Infrared Spectroscopy and Raman Spectroscopy Association

In this study, the application of low-level fusion (LLF) and high-level fusion (HLF) strategies using a combination of Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy in the identification of antemortem and postmortem fracture at different postmortem intervals (PMIs) was investigated. On a technical level, the same hard tissue sample can be detected using a mix of FT-IR and Raman techniques. At the method level, two cutting-edge chemometrics approaches (LLF and HLF) combining FT-IR and Raman spectroscopic data are explored. The models were ranked in accordance with their parametric quality as follows: HLF and LLF + HLF models > LLF single model > Raman single model > FT-IR single model. The LLF model performed marginally better than the Raman model, however, when compared to other models, the HLF model performed considerably better. The HLF model achieved the best performance, with both cross-validation accuracy and test data set accuracy of 0.88. The importance of the feature wavelengths in the model construction process was subsequently evaluated by intersection fusion, and it was found that the absorbance bands of amide I, PO43- ν1 ν3, and CH2 in FT-IR and phenylalanine, CO32- ν1- PO43- ν3, and amide III in Raman have outstanding contributions to the construction of antemortem and postmortem fractures identification models. Overall, the combination of FT-IR and Raman with the HLF strategy is a novel and promising approach for developing antemortem and postmortem fracture identification models at different PMIs.

Autopsy-Based Comparative Study of Gross and Histopathological Findings at Bone Fracture Surfaces Before and After Death

ABSTRACT

Fractures of bones are commonly encountered in traumatic injuries, and distinguishing between antemortem (AM) and postmortem (PM) bone fractures is crucial for estimating the time since injury and has important medicolegal implications. Correct differentiation enables understanding the dynamics of the injury and, in some cases, the cause of death. The present study aims to evaluate the gross morphological and histopathological characteristics of bony fracture surfaces to determine whether they occurred before or after an individual's death.Fifty-seven sets of bone samples, including both antemortem and artificially created postmortem fractures, were collected from cadavers during medicolegal autopsies, meeting the inclusion criteria. Gross morphological and histopathological features were examined after staining the bony fracture edges with hematoxylin and eosin stain. The study revealed distinct morphological characteristics at fracture surfaces for both antemortem and artificially created postmortem fractures. In addition, signs of vital reaction were observed exclusively in antemortem fracture cases.In conclusion, the findings emphasize the importance of meticulous morphological and histopathological examination of bony fracture surfaces to differentiate between antemortem fractures and artificially created postmortem artifacts. This differentiation holds significant value in forensic investigations and medicolegal cases.

The potential of facial nevi in personal identification

Forensic anthropologists dealing with personal identification (PI) of human remains have recently stressed the need to explore the potential of "secondary identifiers" for identifying victims who died in particular events for whom images often represent the main antemortem data available. Being the face the part most exposed in images, characteristics as pigmented skin lesions (PSLs), can be crucial if combined with other input. Since no data is available on frequencies and distribution of facial PSLs in the general population, this study aims at systematically collecting such data to verify their potential in PI and to open a debate on the aid that "secondary identifiers", regardless of their specific nature, can give to the identification of the deceased in specific forensic contexts. A retrospective analysis on three-dimensional facial models of 1039 Italian subjects (from 4 to 84 years old) was conducted to examine the incidence of PSLs discriminated according to size and position in well-defined facial areas. From the collected data we developed a probabilistic approach providing the likelihood ratio (LR) for two settings: (1) the relative frequencies of nevi in the various facial areas, providing the deriving compound probability of owning a certain facial PSLs pattern; and (2) codes describing the facial nevi pattern of each individual of our population, thus testing their uniqueness and so their potential in PI. The calculated LRs mostly proved high identifying strength, particularly when provided by the compound probability-based approach. Data on incidence and position of facial nevi, their generated codes, and the probabilistic approach here presented, all constitute a starting point for advancing secondary identifiers. Nonetheless, although this preliminary study proved facial PSLs as valuable and potentially useful for identification, their significance and validity should be interpreted with caution as we are still at the first theoretical step clearly based on ideal conditions, and thus further investigations are due on the limitations of their use in practical identifying settings. Therefore, being this systematic study only a preliminary one in its nature, it is recommended not to use this kind of approach until further studies will test its validity in several practical conditions.

Structural violence and institutionalized individuals: A paleopathological perspective on a continuing issue

Past and present institutions (e.g., state and public hospitals, assisted living facilities, public nursing homes) have struggled with structural issues tied to patient care and neglect, which often manifests in the form of fracture trauma, and may explain why institutionalized individuals are at higher risk for this injury. Six hundred individuals from the Robert J. Terry Anatomical Collection born between 1822-1877 were examined to investigate hip fracture prevalence. Analysis of associated records and documentary data, including death, morgue, and census records, revealed that 36.3% (n = 218) of these individuals died in institutions such as the St. Louis State Hospital, City Infirmary, and Missouri State Hospital No. 4. Of the institutionalized individuals, 4.3% had evidence of hip fracture, significantly higher than the non-institutionalized (2.3%). Records revealed that many hip fractures were suffered around the time of death in state hospitals and were preventable, resulting from structural issues tied to understaffing and underfunding. Forensic and clinical literature, as well as current news media, indicate that structural violence in the forms of underfunding and understaffing continues to manifest as hip fractures harming institutionalized individuals today. This paper demonstrates how an anthropological perspective using paleopathological analysis sheds light on the chronicity and time depth of this issue, with the aim of driving public policy to entrench the equitable care of institutionalized people as a human right.

Osteoimmunology: The effect of autoimmunity on fracture healing and skeletal analysis

Understanding factors that affect bone response to trauma is integral to forensic skeletal analysis. It is essential in forensic anthropology to identify if impaired fracture healing impacts assessment of post-traumatic time intervals and whether a correction factor is required. This paper presents a synthetic review of the intersection of the literature on the immune system, bone biology, and osteoimmunological research to present a novel model of interactions that may affect fracture healing under autoimmune conditions. Results suggest that autoimmunity likely impacts fracture healing, the pathogenesis however, is under researched, but likely multifactorial. With autoimmune diseases being relatively common, significant clinical history should be incorporated when assessing skeletal remains. Future research includes the true natural healing rate of bone; effect of autoimmunity on this rate; variation of healing with different autoimmune diseases; and if necessary, development of a correction factor on the natural healing rate to account for impairment in autoimmunity.

Analysis of the risk of traumatic brain injury and evaluation neurogranin and myelin basic protein as potential biomarkers of traumatic brain injury in postmortem examination

In forensic pathology, traumatic brain injury (TBI) is a frequently encountered cause of death. Unfortunately, the statistic autopsy data, risk investigation about injury patterns, and circumstances of TBI are still sparse. Estimates of survival time post-TBI and postmortem diagnosis of TBI are especially important implications in forensic medicine. Neurogranin (Ng) and myelin basic protein (MBP) represent potential biomarkers of TBI. The present study analyzed retrospectively the forensic autopsy records of TBI cases at a university center of medico-legal investigation from 2008 to 2020. Immunohistochemistry and enzyme-linked immunosorbent assays (ELISA) were used to investigate the expression changes of Ng and MBP in the cortical brain injury adjacent tissues and serum, respectively, from cases of TBI at autopsy with different survival times post-TBI. The results show that the major mechanism of death of TBI is assault, and accident was the major manner of death. Ng and MBP are mainly expressed in the cortical nerve cells and the myelin sheath, respectively. The serum levels of Ng and MBP in each TBI group were higher compared with those in the controls. The brain cortical levels of Ng and MBP decreased at first and then steadily increased with extended survival time post-TBI. The immunopositive ratios and serum concentration of Ng and MBP have shown significant differences among control group and all TBI group (p < 0.001). Collectively, the immunohistochemical analyses of Ng and MBP in human brain tissues may be useful to determine the survival time after TBI, and Ng and MBP level in the human blood specimens could be considered as a postmortem diagnostic tools of TBI in forensic practice.

A method for the development of cranial fracture histology slides

Cranial vault fractures are of medicolegal interest as they have long-term impacts to someone's health and may contribute to an individual's death. The ability to distinguish antemortem from perimortem fractures and to assess the age of the injury is increasingly dependent on histology. Despite the increasing role of histology in assessing the microanatomy of osseous fractures, there are no methods currently available which account for the nuances and difficulties in creating high-quality histologic slides of cranial vault fractures that allow visualization of cellular features associated with healing bone. The authors present a modified method specific to slide development of human cranial vault fractures derived from the trial-and-error process of creating 730 such slides over a 3-year period which are suitable for the evaluation of the tissues, cells, and nuclei involved in fracture healing. This method adapts and troubleshoots typical histological procedures including sample excision, fixation, decalcification, dehydrating, clearing, embedding, microtomy, and staining, and introduces new procedures including preprocessing photography and cassette placement. By implementing these modifications, the number of poor-quality slides that required a new section to be sent to the histology laboratory was greatly reduced. Proactively implementing this new method into cranial fracture histologic slide development significantly reduces the number of slide rejections due to common issues like folding, chatter, or insufficient staining, saving both time and financial resources for forensic practitioners, researchers, and histotechnologists.

Utility of micro-CT for dating post-cranial fractures of known post-traumatic ages through 3D measurements of the trabecular inner morphology

Fracture dating is an issue at the forefront of forensic sciences. While dating fracture is crucial to understanding and verifying the chronology of events in cases of abuse and violent death, its application is the subject of considerable discussion in the scientific community, filled with limitations and difficulties. Current methods for fracture dating are mainly based on a qualitative assessment through macroscopy, microscopy, and imaging and subject to variations depending on the experience of the observer. In this paper, we investigated the potential of quantifiable micro-CT analysis for fracture dating. Five histomorphometric parameters commonly used for the study of the 3D bone trabecular microarchitecture with micro-CT were calculated based on nine fractures of known post-traumatic ages, including the degree of anisotropy, connectivity density, bone volume fraction, trabecular thickness, and trabecular separation. As a result, trends in the evolution of the microarchitecture of the bone relative to age of the callus could be identified, in particular concerning anisotropy, trabecular separation and connectivity density, consistent with the healing bone process. The findings obtained in this pilot study encourage further research in quantifiable parameters of the bone microarchitecture as they could represent useful features for the construction of objective models for fracture dating.

Postmortem and Antemortem Forensic Assessment of Pediatric Fracture Healing from Radiographs and Machine Learning Classification

Simple Summary

Being able to estimate from X-rays alone how long ago a child’s bone was fractured is important for prosecuting suspected child abuse of living or dead children. This estimate can also help identify a child when all that remains are bones. Experts use various indicators to make these estimates of the age of healing and fully healed fractures, in living and deceased persons, even years after the injury occurred. However, it is not a precise science. We proposed a method using a new combination of indicators to classify fracture healing in children and adolescents. We tested its accuracy with a public database of X-rays of children’s fractures taken during the treatment and healing process. We used part of the X-ray database for training artificial intelligence (AI, or machine learning) programs to classify stages of bone healing when using our new system. We used another portion of the same database to test the performance of the AI system that had been trained with our new classification system. Our new system addresses certain classification ambiguities of a currently used system and is similar in accuracy.

Abstract

A timeline of pediatric bone healing using fracture healing characteristics that can be assessed solely using radiographs would be practical for forensic casework, where the fracture event may precede death by days, months, or years. However, the dating of fractures from radiographs is difficult, imprecise, and lacks consensus, as only a few aspects of the healing process are visible on radiographs. Multiple studies in both the clinical and forensic literature have attempted to develop a usable scale to assess pediatric bone healing on radiographs using various healing characteristics. In contrast to the orthopedic definition, a fracture in forensic casework is only considered to be healed when the area around the fracture has been remodeled to the point that the fracture is difficult to detect on a radiograph or on the surface of the bone itself, a process that can take several years. We subjectively assessed visible characteristics of healing in radiograms of fractures occurring in 942 living children and adolescents. By dividing these assessments into learning and test (validation) sets, the accuracy of a newly proposed fracture healing scale was compared to a previous study. Two machine learning models were used to test predictions of the new scale. All three models produced similar estimates with substantial imprecision. Results corroborate the Malone model with an independent dataset and support the efficacy of using less complex models to estimate fracture age in children.

The Repository of Antemortem Injury Response (REPAIR): an online database for skeletal injuries of known ages

An accurate assessment of time since fracture is an essential component of abuse and death investigations; however, little evidence-based research exists on dating fractures, especially those of the cranial vault. This is primarily due to difficulties in procuring human fracture specimens of known posttraumatic survival times. The aim of this article is to introduce a new database through which limitations imposed by sample procurement may be mitigated. The Repository of Antemortem Injury Response (REPAIR) is a digitally accessible database of cranial vault fractures of known ages with extensive contextual information and visual documentation in the form of photography, radiography, and histological photomicrographs. This repository is a multifunctional tool that serves as a case submission portal for cranial fractures of known posttraumatic survival time, a sample database for research on fracture healing and rates of repair, a resource for comparative assessments of cranial fractures in forensic casework, and an educational tool for healing fracture histomorphology.

The problem of dating fractures: A retrospective observational study of radiologic features of fracture healing in adults

Accurate dating of bone fractures can be crucial in the context of forensic trauma analysis since it may provide essential information for the corroboration or contradiction of statements by victims or suspects in cases of domestic abuse or torture. The different stages of bone healing have been well described in the existing literature, and some previous studies attempted to define related timelines particularly in the paediatric population. However, the bone healing process can be very variable and despite the importance of the topic in the forensic field, so far little is known about the radiological appearance of bone fractures at different healing stages, and how this correlates with time, especially in an adult population. The aim of this retrospective observational study was to describe the temporal aspect of pre-defined healing stages as they appear on radiographs of tubular bone fractures in adults, and explore the effect of potential cofounding variables. A dynamic nomogram was developed as a user-friendly tool to be eventually applied in clinical or medico-legal settings. This study showed that the posttraumatic time interval (PTTI) increased progressively with the pre-defined healing stages. However, confounding factors, such as patients' age, sex, and location of the fracture need to be accounted for in the final estimation model. Further studies are needed to explore more potentially confounding variables to refine the presented outcomes. Better knowledge of the effect of different confounding variables in the dating of fracture healing will contribute to greater accuracy of PTTI estimation of bone fractures in adults.

An evaluation of the differences in paediatric skeletal trauma between fatal simple short falls and physical abuse blunt impact loads: An international multicentre pilot study

In cases where a deceased child exhibits trauma as a result of a physical abuse blunt impact load, a parent/caregiver may provide a simple short fall (SSF) as the justification for that trauma. The skeletal fractures remain difficult to differentiate between a SSF and physical abuse however, as both are the result of a blunt impact load, and are therefore biomechanically alike, and the rare nature of these fatalities means only anecdotal research has been available to validate such claims. The aim of this pilot study was to investigate if there may be differences in the skeletal fracture patterns and types resulting from SSFs compared with those resulting from physical abuse blunt impacts. Paediatric (<10 years) cases of fatal SSFs (≤1.5 m) and physical abuse were collected from the Victorian Institute of Forensic Medicine (Australia), Institut Médico-Légal de Paris (France), University of Pretoria (South Africa) and Great Ormond Street Hospital (England). For each case the intrinsic and extrinsic variables were recorded from medico-legal reports and skeletal trauma was documented using post-mortem computed tomography scans and/or skeletal surveys. Three SSFs and 18 physical abuse cases were identified. Of the SSF cases, two exhibited fractures; both of which were simple linear neurocranial fractures. Comparatively, 12 of the physical abuse cases exhibited fractures and these were distributed across the skeleton; 58% located only in the skull, 17% only in the post-cranial and 25% located in both. Skull fracture types were single linear, multiple linear and comminuted. This pilot study suggests, anecdotally, there may be differences in the fracture patterns and types between blunt impact loads resulting from a SSF and physical abuse. This data will form the foundation of the Registry of Paediatric Fatal Fractures (RPFF) which, with further multicentre contributions, would allow this finding to be validated.

The potential of micro-CT for dating post-cranial bone fractures: a macroscopic, radiographic, and microtomography study of fractures of known post-traumatic ages

The estimation of the post-traumatic survival time (PTST) in case of bone injuries remains a tricky issue in the forensic field, especially when dealing with dry bones. Newer high-resolution imaging, and in particular microcomputed tomography (micro-CT), has the potential to significantly improve our abilities to interpret antemortem and perimortem lesions and accurately date fractures in a less destructive analysis. In this paper, nine costal fractures of known post-traumatic ages were analyzed through gross examination, conventional radiography, and microcomputed tomography, in order to test the potential of microcomputed tomography for dating fractures. As a result, microcomputed tomography provided images of high quality and definition and allowed the observation of the internal microarchitecture of the fractures and calluses. While microcomputed tomography cannot substitute histological examination for the estimation of the post-traumatic survival time, it constitutes a potent and helpful complementary tool for the analysis of bone trauma.

Identification of antemortem, perimortem and postmortem fractures by FTIR spectroscopy based on a rabbit tibial fracture model

The identification of antemortem, perimortem and postmortem fractures is very important for forensic pathologists and anthropologists. However, traditional methods are subjective, time-consuming, and have low accuracy, which do not fundamentally solve the problem. In this study, we utilized Fourier transform infrared (FTIR) spectroscopy and chemometrics to identify antemortem, perimortem and postmortem fractures in a rabbit tibial fracture model. Based on the results of the principal component analysis (PCA), changes in the ante-perimortem fracture repair process are mainly associated with protein variations, while postmortem fractures are more likely to result in lipid changes during degradation. Then, a partial least squares discriminant analysis (PLS-DA) was performed to assess the classification ability of the training and predictive datasets, with classification accuracies of 88.9% and 86.7%, respectively. According to the latent variable 1 (LV1) loading plot, amide I and amide II (proteins) are mostly classified as ante-perimortem and postmortem fractures. In conclusion, FTIR spectroscopy is a reliable tool to identify antemortem, perimortem and postmortem fractures. FTIR has the advantages of rapid, objective and strong discrimination. and shows great potential for analyzing forensic cases under actual natural conditions.

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.