Multicentric case series of scuba diving fatalities: The role of intracardiac gaseous carbon dioxide in the forensic diagnosis

Scuba diving fatalities post-mortem diagnosis presents a higher level of forensic complexity because of their occurrence in a non-natural human life environment. Scuba divers are equipped with diving gas to breathe underwater. It is essential for them to be fully trained in order to be able to manage their dive safely despite the varying increase of ambient pressure and temperature decrease. Throughout the dive, the inhaled diving gas is dissolved in the diver's tissues during the descent and if the decompression steps are not respected during the ascent, the balance between the dissolved gas and the tissues (including blood) is disrupted, leading to a gaseous release in the organism. Depending on the magnitude of this gaseous release, free gas can occur in blood and tissue. Venous or arterial gas embolism can also occur as a consequence of decompression sickness or barotraumatism. It can also induce drowsiness that consequently leads to drowning. As a result, the occurrence of gas in dead scuba divers is very complex to interpret, as is the difficulty to distinguish it from resuscitation maneuver artifacts or body decomposition. Although the literature is scarce in this domain, significant work has been done to provide a precise intracadaveric gas sampling method to enlighten the cause and circumstances of death during the dive. The aim of this study is to obtain higher statistical significance by collecting a number of cases to confirm the gas sampling protocol and analysis and gain more information about the cause of death and the events surrounding the fatality through the establishment of clear management guidelines.

Sudden death after facial impacts: Is the brainstem involved?

Three deaths following facial impacts in the presence of witnesses and resulting in brain lesions that were visualized only on pathological examination were studied at the forensic medicine institute of Marseille. Craniofacial impacts, even of low intensity, received during brawls may be associated with brain lesions ranging from a simple knock-out to fatal injuries. In criminal cases that are brought to court, even by autopsy it is still difficult to establish a direct link between the violence of the impact and the injuries that resulted in death. During a facial impact, the head undergoes a movement of violent forced hyperextension. Death may thus be secondary to the transmission of forces to the brain, either by a mechanism involving nerve conduction that may be termed a reflex mechanism (for example by vagal hyperstimulation) or by injury to the central nervous system (axonal damage). In such situations, autopsy does not make it possible to determine the cause of death, but only to suspect it in a context of voluntary violence in the presence of witnesses, with or without violent injury observed on external examination or on superficial incisions to determine the extent of bruises or hematoma. Systemic and comprehensive investigation involving pathology and toxicology is essential in any medicolegal case for positive interpretation and discrimination of other causes of death.

Judicial handling of cases of non-accidental head trauma in infants: Review and analysis of expert assessments

INTRODUCTION

Good practice guidelines help clinicians to establish a suspected diagnosis of non-accidental head injury (NAHI) and help forensic experts to establish a level of certainty for the diagnosis. The objective of this study was to assess how the French Health Authority (HAS) guidelines contribute to the process of producing an expert assessment, on causation and certainty in cases of suspected NAHI.

METHOD

A retrospective study was conducted of the expert assessments that were conducted by a paediatric surgeon and forensic expert attached to our local court between 2002 and 2018, with the aim of determining the causal mechanism of the lesions and express a degree of certainty regarding the diagnosis.

RESULTS

In our study, we found that, despite the HAS guidelines, a number of documents deemed essential for the forensic expert were sometimes missing, and that, by applying these guidelines, the decisions reached in some expert assessments could been reclassified and certain factors formerly described as risk factors for injury could be excluded. A precise dating of the traumatic event was proposed in half of cases.

CONCLUSION

Our study highlights the vital role of the HAS guidelines, not only for patient management but also to ensure high-quality expert assessments. Unfortunately, guidelines were not yet being properly adhered to by medical teams.

Ontogeny of cranial base during the first two years of life

The integration of the growth of the brain and the cranial base suggests that each system may influence the other, notably during the first three years of life, although this influence has never been proven to be exclusive. The aim of our work was to analyse the dynamics of normal growth on the one hand, and the development and ontogenetic allometry of the cranial base in the infant on the other hand.

MATERIAL AND METHOD

A total of 32 infants (17 males/15 femeles) having been included in the unexpected infant death french protocol were analyzed. Three-dimensional reconstructions of the cranial base were performed from CT scans. The technique combined manual segmentation of regions of interest, contour extraction and surface reconstruction. Nineteen landmarks were positioned on each of the bone surfaces.

RESULTS

No correlation was observed between sex assigned at birth and shape, weight, crown-heel length, or head circumference. Principal component analysis showed that 85.5% of the variance observed on the first component was secondary to growth. After Procrustes superimposition, 25% of the shape variance observed was explained by the first principal component. It showed anteroposterior lengthening of the cranial base. In addition, the height, width and length of the posterior fossa increased and the relative position of the basion was displaced inferiorly and anteriorly with flexion of the sphenoid angle. Negative allometry was also observed.

CONCLUSION

Our study, carried out in a rigorously selected population of infants, presents a fundamental approach to ontogeny through study of shape, growth and ontogenetic allometry.

Study of the growth and shape of the brain and cranial base during the first two years of life

Ontogeny of the cranial base and the brain integrates data on growth, maturation and ontogenetic allometry of these two systems in the course of development. The aim of our work was to study the ontogeny of the cranial base and the brain in order to understand their growth dynamic and shape changes using a traditional morphometric approach in individuals with normal (non-pathological) development.

MATERIEL AND METHOD

Forty-seven infants having been included in the unexpected infant death french protocol were analyzed. Medical imaging (CT and MRI) exams, followed by an autopsy and pathology examination allowed us to include only infants free from brain disease or pathology affecting growth.

RESULTS

Testing of measurement reliability validated 12 distances and 3 angles as well as the positioning of the landmarks that had been used to obtain the distances and the angles. No correlation between sex and the various variables studied was found. However, a correlation was observed between these variables and age, making it possible to propose a growth curve. A medium to strong correlation was found between brain variables and the bone variables of the cranial base, underlining the parallel development of the two systems.

CONCLUSION

Our study, carried out in a rigorously selected population of infants, presents a fundamental approach to the study of ontogenesis.

Biomechanical study of the thyroid cartilage: A model of bi-digital strangulation

The presence of fracture on neck elements is an indication of violence. Both the hyoid bone and the larynx can be damaged by a strangulation mechanism. Thyroid cartilage, more specifically, may present lesions in response to this mechanical stress. These lesions result in fractures at the bases of the horns of the thyroid cartilage. This study focuses on the thyroid cartilage behavior in cases of bi-digital strangulation, using an anthropometric and biomechanical approach. To develop a biomechanical model, we performed an anthropometric study taking into account 14 distances measurements as well as 3 measurements of angles. These measures allowed us to determine a significant sexual dimorphism between individuals. Then, we define 6 morphologies models, composed of 3 females and 3 males individuals. In order to visualize the ossification of the cartilage, each model has been tested with bone properties. Strangulation cases were simulated by applying an imposed velocity of 0.4m/s then 1m/s. We observed different behaviors of the thyroid cartilage according to the sex and the morphology.

Diagnosis of congenital abnormalities with post-mortem ultrasound in perinatal death

PURPOSE

To determine the sensitivity and specificity of post-mortem ultrasound in the diagnosis of major congenital abnormalities of fetuses using conventional autopsy as the standard of reference.

MATERIAL AND METHODS

All fetuses coming from terminations of pregnancy or intrauterine fetal deaths in a single institution were included. A total of 75 fetuses were included during the study period. The results of post-mortem ultrasound examinations were compared to those of conventional autopsy that served as standard of reference.

RESULTS

Gestational age of the fetuses ranged from 15 to 38 weeks gestation. A complete post-mortem ultrasound assessment was possible in all fetuses. Regarding detection of brain abnormalities, post-mortem ultrasound had a sensitivity of 81.5% or 4/5 (95% CI: 63.3-91.8%), and a specificity of 97.9% (95% CI: 89.1-99.6%). Specificities for the diagnosis of thoracic, cardiac, urinary tract, spinal and bone abnormalities were 100%.

CONCLUSION

Post-mortem ultrasound shows high sensitivity and specificity for the diagnosis of congenital structural abnormalities as compared to conventional autopsy, with the exception of congenital cardiac diseases.

[Post-mortem perinatal imaging: State of the art and perspectives, with an emphasis on ultrasound]

The fields of application of post-mortem imaging have been exponentially growing for 10 years. Its potential to identify the cause of death in trauma and ballistic cases is now properly documented. In pediatric and perinatal practice, large significant series are less available, except for MRI and central nervous system analysis where scientific evidence is now robust. After a short historical and state-of-the-art review, we will try to depict the way we see the future of this sub-specialty of post-mortem imaging, especially in specific perinatal situations.

Liability under post-tonsillectomy lethal bleeding of the tonsillar artery: a report of two cases

Post-operative haemorrhage is a frequent complication of tonsillectomy: a primary haemorrhage occurring in the first hours is rapidly dealt with by the surgical team. A secondary haemorrhage, which commonly occurs once the child has returned home, can be fatal if it is not dealt with quickly. We present two cases of a lethal outcome in children following a secondary post-tonsillectomy haemorrhage, for which the parents filed legal proceedings. Medical liability can be exercised during all stages of health care. Performing an autopsy associated with histological analyses is found to be indispensable for the identification of the causes of bleeding, as well as its mechanism.