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.

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.

Modeling one-handed grip strangulation: Intentionality of the gesture and age influence.

Strangulation is a violent act which can be lethal and is often studied in forensic context. The neck includes several anatomical elements that can evolve with aging. We therefore created a numerical human neck model including the main anatomical elements and simulated one-handed grip strangulation cases. In addition, we created 3 models each representing age groups: 20-30 years old, 30-50 years old and over 50 years old. The main changes between the different age groups are the ossification of the cartilages and the muscles mechanical properties. Several initial and boundary conditions have been tested to perform a realistic simulation of one-handed grip strangulation. Stress analysis and fracture observation were compared with the grip strength of an average man, 552 N, to look at the intentionality of the gesture. In each age group, the results show no model fracture for a force of 552 N. It is necessary to reach a minimum of 1406 N before observing a first fracture on the hyoid bone. However, it is possible to get stresses on the hyoid bone and on the thyroid cartilage way before 552 N. It thus appears that the force created by one-handed grip strangulation is not sufficient to cause fractures of the bony elements of the neck, but it remains sufficient to compress the larynx and at least reduce airflow.

Virtual reconstruction of paranasal sinuses from CT data: A feasibility study for forensic application.

PURPOSE: The purpose of this study was to report the feasibility of computed modelization and reconstitution of the paranasal sinuses, before and after trauma, from CT data. MATERIALS AND METHODS: We modeled and reconstructed the paranasal sinuses of two patients (A and B), before and after trauma, using two different softwares (3DSlicer® and Blender®). Both patients had different numbers and locations of fractures. The 3DSlicer® software was used to create a 3D model from CT data. We then imported the 3D data into the Blender® software, to reconstruct and compare the dimensions of the paranasal sinuses before and after trauma. RESULTS: The 3 fragments of patient A and the 7 fragments of patient B could be repositioned in the pre-traumatic configuration. Distance measurements proved to be similar between pre- and post-traumatic 3D volumes. CONCLUSION: After simple trauma, bone facial anatomy reconstruction is manually feasible. The whole procedure could benefit from automatization through machine learning. However, this feasibility must be confirmed on more severely fractured paranasal sinuses, to consider an application in forensic identification.

Diagnostic value of unenhanced postmortem computed tomography in the detection of traumatic abdominal injuries.

OBJECTIVE: To determine the diagnostic capabilities of unenhanced postmortem computed tomography (UPMCT) in detecting traumatic abdominal injuries. MATERIAL AND METHODS: Cases of traumatic death with both UPMCT and classical autopsy were collected retrospectively from our institution "virtopsy" database in a period of 5 years. Cadavers with gunshot injuries were excluded. Sensitivity, specificity, accuracy, negative (NPV) and positive (PPV) predictive values of PMCT globally and for hemoperitoneum, liver, spleen, pancreas and kidney injuries individually were estimated using the autopsy report as gold standard. RESULTS: Seventy-one cadavers were included. UPMCT had a sensitivity of 80% and a specificity 94%, with an accuracy of 83%, a PPV of 98% and a NPV of 59% for the diagnosis of traumatic abdominal injuries. The highest sensitivity was obtained for the detection of hepatic injuries (71%) and the lowest for pancreatic injuries (12%). UPMCT had a specificity of 100% for the detection of hemoperitoneum. A NPV of 98% was found for the detection of perihepatic hematomas. CONCLUSION: The low sensitivity and low NPV do not support the use of UPMCT as an alternative to conventional autopsy to diagnose and/or rule out traumatic abdominal injuries. Nevertheless, UPMCT remains a helpful tool as it helps detect hemoperitoneum and virtually exclude presence of perihepatic hematomas.

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.

[Litigation in obstetrics and gynaecology: experience of a university hospital in France]. / Analyse de la sinistralité en gynécologie-obstétrique: expérience d'un CHU en France.

OBJECTIVES: To analyse the nature of medico-legal claims in a high-risk speciality. MATERIALS AND METHODS: Retrospective review of the causes of medico-legal disputes at the department of Obstetrics and Gynaecology of the North University Hospital of Marseilles between November 1997 and December 2010. Disputes were defined by complaints, judicial or conciliatory claims and intentional declaration of potential medico-legal case by physicians. RESULTS: Fifty-nine controversial medico-legal cases were identified within this 13-year period. Ninety percent (n=53) of cases concerned obstetrics and 10% (n=6) gynaecology. The rate of litigations tripled in a decade. Half of the litigations led to judicial or conciliatory expertise. The average rate of malpractice litigations was 2.4 per physician. Uterine rupture was the most common cause of complaints. CONCLUSION: Increased awareness of the nature of litigations may help elaborate risk reduction management programs in order to reduce professional liability on the long run.

[Contribution of immunohistochemistry and electron microscopy for the diagnosis of meningeal hemangiopericytomas. 15 case reports]. / Apport de l'immunohistochimie et de la microscopie électronique dans le diagnostic des hémangiopéricytomes méningés. A propos de 15 cas.

Meningeal hemangiopericytomas (HPC) are rare CNS tumors with a pour prognosis compared to meningiomas. In order to define diagnosis criteria, we performed an immunohistochemical and ultrastructural study in respectively 15 and 5 meningeal HPC. The following antibodies anti-KL1, EMA, vimentin, CD34, factor VIII, alpha-smooth actin, estrogen and progesteron receptors (RE, RP) were used in paraffin embedded sections whereas anti-NCAM and E-cadherin antibodies were used on frozen sections when available. We can differentiate meningeal HPC from meningioma because of a complete lack of immunostaining with epithelial markers as well as with NCAM antibody or RE and RP receptors. Besides a positivity with CD34 and alpha-smooth actin antibodies was always observed even focally in HPC. On the other hand, solitary fibrous tumor showed a strong and diffuse positivity with anti CD34 and anti-vimentin antibodies. Electron microscopy can be helpful in some instances showing membrane basal-like substance and absence of desmosomes.

[Interstitial pneumopathy revealing type B Niemann Pick disease in an adult]. / Pneumopathie interstitielle révélatrice d'une maladie de Niemann-Pick de type B chez un adulte.

INTRODUCTION: Niemann-Pick disease is an autosomal recessive disorder due to partial or total deficit in sphingomyelinase. EXEGESIS: We report a case of type B Niemann-Pick disease revealed by pneumonia and splenomegaly associated with blue histiocyte syndrome. Investigations that were done 2 years prior to diagnosis had shown the existence of isolated chronic lipid pneumonia which is specific of overloading. CONCLUSION: Though diagnosis is based on biochemistry, the morphology of alveolar histiocytes after simple bronchoalveolar lavage is of value.