Age at death estimation by cementochronology: Too precise to be true or too precise to be accurate?

OBJECTIVES: Cementochronology based on annual deposition of acellular cementum is acknowledged for its superior performance for estimating age-at-death but is also disregarded because of its suspicious effectiveness. This article aims to provide a standardized framework for the validation of the technique and to define and test cementochronology's performance and limitations. MATERIALS AND METHODS: To determine the boundaries of the cementum aging technique, we applied a certified protocol on a sample of 200 healthy canines from individuals of known age, sex, postmortem, and inhumation intervals from anthropological and anatomical collections. We scored readability and preservation of cementum and measured the agreement between estimates, i.e., the precision, and assessed the quality of the accordance between estimates and chronological age, i.e., the accuracy. To investigate the applicability on ancient material, 200 additional canines extracted from archeological assemblages were included. Accuracy and precision were analyzed for each age group in considering postmortem intervals and taphonomical conditions. RESULTS: A strong correlation was found between chronological age and estimates (r = .927; p = .000) but results reveal an association between readability of incremental lines and chronological age (p < .05) and a notable difference in both precision and accuracy between individuals under and over 50 years. Results also demonstrate that taphonomy can be a serious obstacle increasing imprecision by a factor of three. DISCUSSION: Improperly adopted, cementochronology can lead to precise but inaccurate estimations. If methodological, physiological, and taphonomical factors are taken into account, then, and only then, cementochronology will serve as a versatile and powerful tool for age-at-death estimation.

Use of 3D printed models in student education of craniofacial traumas.

A low-cost 3D printed model has been introduced into the oral and maxillofacial surgery teaching program of undergraduate students to improve education and mechanical comprehension of craniofacial trauma. Steps of the 3D printed haptic model building process are listed. 3D printed models of facial fractures were obtained from Data Imaging and Communications in Medicine (DICOM) data. Computed Aided Design and Manufacturing (CAD-CAM) freeware was used to create new fractures on the standard tessellation language (STL) file. 3D printed haptic model appears to be an efficient low-cost support for craniofacial trauma education of undergraduate students.

Medico-legal considerations for Morel-Lavallée lesions.

The Morel-Lavallée lesion is an infrequent traumatic lesion that the forensic physician may need to evaluate during examination of a victim. Using a review of the literature and an illustrative case, the objective of this paper is to discuss the medico-legal issues (accountability, functional recovery and healing times, and aftermath) associated with Morel-Lavallée lesions. We describe the case of a 24-year-old motorcycle driver who was hit by a car. Clinically, the right lumbar region had a large 16 × 15 cm ecchymosis with subcutaneous fluid swelling found by palpation. A body scan revealed a Morel-Lavallée lesion among other lesions. On day 7, its thickness was decreased by half. Morel-Lavallée lesions are specifically induced by shearing force with moderate-to-high kinetics in an anatomical area with an underlying fascia. The associated functional disability is globally moderate, but a large lesion or recurrences can extend the time needed to recover. Apart from some exceptions, care without any delay in diagnosis and treatment allows evolution of the lesion without functional consequences, but these lesions are frequently unnoticed in the initial phase.

Organ Procurement in Forensic Deaths: Specific Features of Nonheart-Beating Donors.

The need for organs has increased in the recent years, and this shortage will only worsen. In addition to the organs procured from brain-dead donors, a procedure for non-heart-beating donors was therefore developed. When deaths involve legal proceedings, the medical examiner makes the decision of whether or not to remove organs. To assist medical examiner in their decision-making, a number of forensic scientific societies aimed to develop recommendations, and legal adjustments were adopted. Nevertheless, these do present certain limits in special cases of procurement: Maastricht class I and II non-heart-beating donors. The peculiarity of this procedure stems from the urgency of the process. Compliance with temporal criteria would require that the deceased subject be removed from the crime scene even before the arrival of the authorities. This is extremely problematic legally and technically because forensic teams must collect evidence at crime scenes. Developments will have to be made to further minimize the restrictions on donations in forensic deaths.

[Performing autopsies of all sudden deaths: a public health prevention strategy]. / Pratiquer l'autopsie de toutes les morts subites : un moyen de prévention en santé publique.

INTRODUCTION: In France, the management of sudden death (including nion-forensic autopsies) among adults could be improved. Thee number of sudden deaths may require a change in practice to promote screening for hereditary diseases. The purpose of this study was to identify areas for improvement and to assess the prevalence of non-forensic autopsies. METHODS: A retrospective study (2005-2010) conducted at Lille University Hospital resulted in the selection of 174 non-forensic autopsies of adults who died suddenly. The criteria used were: the geographical origin of the bodies, indication, age, gender and the diagnosis ofdeath. RESULTS: The study found that the annual number of non-forensic autopsies was very low, with proportions ranging from 1.06 to 1.73 per 1,000 deaths in the case of hospital deaths and from 0 to 0.43 per 1,000 deaths in the case of non-hospital deaths. Only 11 non-forensic autopsies of people who died at home were recorded over the study period, including 4 heart disease-related deaths. Overall, the results indicate that sudden death autopsies are poorly managed. DISCUSSION: Non-forensic autopsies are in decline, particularly in the case of deaths outside hospital, despite the fact that they are a crucial consideration for screening among relatives of a person who died sud!denly. The findings suggest that there needs to be an improvement in practice, a fact made possible by recent legislative developlments in France. A number of initiatives have been successful arId give hope that, like the reference centers specializing in unexpected infant deaths, reference centers specializing in sudden de'aths, which allow for more systematic non-forensic autopsies ofadults who die suddenly, might be created.

Automated age-at-death estimation by cementochronology: Essential application or additional complication?

It has been repeatedly acknowledged that age-at-death estimation based on dental cementum represents a partial and time-consuming method that hinders adoption of this histological approach. User-friendly micrograph analysis represents a growing request of cementochronology. This article evaluates the feasibility of using a module to accurately quantify cementum deposits and compares the module's performance to that of a human expert. On a dental collection (n = 200) of known-age individuals, precision and accuracy of estimates performed by a developed program (101 count/tooth; n = 20,200 counts) were compared to counts performed manually (5 counts/tooth; n = 975 counts). Reliability of the software and agreement between the two approaches were assessed by intraclass correlation coefficient and Bland Altman analysis. The automated module produced reliable and reproducible counts with a higher global precision than the human expert. Although the software is slightly more precise, it shows higher sensitivity to taphonomic damages and does not avoid the trajectory effect described for age-at-death estimation in adults. Likewise, for human counts, global accuracy is acceptable, but underestimations increase with age. The quantification of the agreement between the two approaches shows a minor bias, and 94% of individuals fall within the intervals of agreement. Automation gives an impression of objectivity even though the region of interest, profile position and parameters are defined manually. The automated system may represent a time-saving module that can allow an increase in sample size, which is particularly stimulating for population-based studies.

Formative Assessment of Diagnostic Testing in Family Medicine with Comprehensive MCQ Followed by Certainty-Based Mark.

INTRODUCTION: The choice of diagnostic tests in front of a given clinical case is a major part of medical reasoning. Failure to prescribe the right test can lead to serious diagnostic errors. Furthermore, unnecessary medical tests are a waste of money and could possibly generate injuries to patients, especially in family medicine. METHODS: In an effort to improve the training of our students to the choice of laboratory and imaging studies, we implemented a specific multiple-choice questions (MCQ), called comprehensive MCQ (cMCQ), with a fixed and high number of options matching various basic medical tests, followed by a certainty-based mark (CBM). This tool was used in the assessment of diagnostic test choice in various clinical cases of general practice in 456 sixth-year medical students. RESULTS: The scores were significantly correlated with the traditional exams (standard MCQ), with matched themes. The proportion of "cMCQ/CBM score" variance explained by "standard MCQ score" was 21.3%. The cMCQ placed students in a situation closer to practice reality than standard MCQ. In addition to its usefulness as an assessment tool, those tests had a formative value and allowed students to work on their ability to measure their doubt/certainty in order to develop a reflexive approach, required for their future professional practice. CONCLUSION: cMCQ followed by CBM is a feasible and reliable evaluation method for the assessment of diagnostic testing.

Three-Dimensional Printing Model Enhances Craniofacial Trauma Teaching by Improving Morphologic and Biomechanical Understanding: A Randomized Controlled Study.

BACKGROUND: Teaching about craniofacial traumas is challenging given the complexity of the craniofacial anatomy and the necessity for good spatial representation skills. To solve these problems, three-dimensional printing seems to be an appropriate educative material. In this study, the authors conducted a randomized controlled trial. The authors' main objective was to compare the performance of the undergraduate medical students in an examination based on the teaching support: three-dimensionally printed models versus two-dimensional pictures. METHODS: All participants were randomly assigned to one of two groups using a random number table: the three-dimensionally-printed support group (three-dimensional group) or the two-dimensionally-displayed support group (two-dimensional group). All participants completed a multiple-choice question evaluation questionnaire on facial traumatology (first, a zygomatic bone fracture; then, a double mandible fracture). Sex and potential confounding factors were evaluated. RESULTS: Four hundred thirty-two fifth-year undergraduate medical students were enrolled in this study. Two hundred six students were allocated to the three-dimensional group, and 226 were allocated to the two-dimensional group. The three-dimensionally printed model was considered to be a better teaching material compared with two-dimensional support. The global mean score was 2.36 in the three-dimensional group versus 1.99 in the two-dimensional group (p = 0.008). Regarding teaching of biomechanical aspects, three-dimensionally-printed models provide better understanding (p = 0.015). Participants in both groups exhibited similar previous student educational achievements and visuospatial skills. CONCLUSIONS: This prospective, randomized, controlled educational trial demonstrated that incorporation of three-dimensionally-printed models improves medical students' understanding. This trial reinforces previous studies highlighting academic benefits in using three-dimensionally-printed models mostly in the field of understanding complex structures.

Effect of body length and temperature on the crawling speed of Protophormia terraenovae larvae (Robineau-Desvoidy) (Diptera Calliphoridae).

This work investigates variation in the crawling speed of Protophormia terraenovae larvae (Robineau-Desvoidy) (Diptera Calliphoridae) as a function of body length and ambient temperature. A video-tracking system was used to follow the movement of larvae in an experimental arena, and to estimate their average crawling speed. Recordings were carried out at various temperatures using larvae of different developmental stages. As temperature increased, the larvae crawled at a faster speed. Furthermore, speed increased as a function of body length. We present a general allometric relationship to express the average crawling speed of larvae as a combined function of temperature and body length, expressed in the following equation: speed (cm/min)=5.45 x log[length (mm)]+0.66 x temperature (degrees C)-12.8. These results are particularly useful in forensic entomology for estimating the time that elapsed following the larva's departure from the corpse. This information can provide more accuracy for post-mortem interval estimations and a better comprehension of larvae behaviour and displacement.

Suicidal hanging resulting in complete decapitation--forensic, radiological, and anthropological studies: a case report.

The authors report a case of complete posthanging decapitation. The decapitated corpse lay against a pillar of a road bridge. The head had rolled 5 m from the trunk. The bridge was 7.2 m above the road level. The rope was 3.6 m long, its lower end was 3.6 m from the ground and its diameter was 10 mm. The noose used was a slip knot. Plain X-rays of the skull and cervical spine were obtained. The skull X-rays showed air in the meningeal spaces, in both lateral and third ventricles. The severance plane of the cervical spine was between the third and the fourth cervical vertebrae. No other cervical vertebral injuries were noted. At autopsy, the brain was macroscopically unremarkable except for air in the meningeal veins. The decapitation injuries of the head and the torso corresponded perfectly, without apparent loss of substance. The severance plane was confirmed. Dry bone study was carried out. Except for fractures of the extremities of the spinous processes of the second and third cervical vertebrae, no other bone injury of the spine was seen. The cervical vertebrae displayed numerous osteoarthritic lesions. The traditional hangman's fracture was not found. To the best of our knowledge, this is the first report of complete posthanging decapitation with a severance plane between the third and fourth cervical vertebrae.

Accuracy of script concordance tests in fourth-year medical students.

OBJECTIVES: This investigation aimed to determine the validity of script concordance test (SCT), compared with clinical-case-related short-answer management problems (SAMP), in fourth-year medical students. METHODS: This retrospective study was conducted at the Medical School of Lille University. Cardiology and gynecology examinations both included 3 SCT and 2 clinical-case-related SAMP.  Final score did not include SCT results, and was out of 20 points. The passing score was ≥10/20. Wilcoxon and McNemar tests were used to compare quantitative and qualitative variables, respectively. Correlation between scores was also analyzed. RESULTS: A total of 519 and 521 students completed SAMP and SCT in cardiology and gynecology, respectively. Cardiology score was significantly higher in SCT than SAMP (mean ± SD 13.5±2.4 versus 11.4±2.6, Wilcoxon test, p<0.001). In gynecology, SCT score was significantly lower than SAMP score (10.8±2.6 versus 11.4±2.7, Wilcoxon test, p=0.001). SCT and SAMP scores were significantly correlated (p <0.05, Pearson's correlation). However, percentage of students with SCT score ≥ 10/20 was similar among those who passed or failed cardiology (327 of 359 (91%) vs 146 of 160 (91%), χ2=0.004, df =1, p=0.952), or gynecology (274 of 379 (65%) vs 84 of 142 (59%), χ2=1.614, df=1, p=0.204) SAMP test. Cronbach alpha coefficient was 0.31 and 0.92 for all SCT and SAMP, respectively. CONCLUSIONS:  Although significantly correlated, the scores obtained in SCT and SAMP were significantly different in fourth-year medical students. These findings suggest that SCT should not be used for summative purposes in fourth-year medical students.

Detection of hepatitis C virus antibodies and RNA among medicolegal autopsy cases in Northern France.

Forensic medical personnel are at risk of exposure to blood-borne viruses including hepatitis C virus (HCV). The aim of this study was to determine prevalence of HCV markers among a cadaver population at the medicolegal institute in Lille. Seventy-seven consecutive cadavers were screened for antibodies to HCV and for HCV RNA. Positive results were confirmed by an immunoblot assay. Fifty-three cadavers had a histopathologic study. Anti-HCV was detected in 13 (16.9%) and accompanied by HCV RNA in 7 (9%) cases. The rate of HCV RNA detection among seropositive cases was 53.8%. Five cases had histopathologic lesions suggestive of hepatitis. This is the first HCV RNA screening in forensic cadavers. The results highlight the high prevalence rate of HCV cases in medicolegal practice in Lille. All forensic specimens should be treated as potentially infectious and universal precautions should be taken.

Fatal accidental intrathecal injection of vindesine.

A 25-year-old woman being treated for non-Hodgkin's lymphoma was accidentally given vindesine intrathecally. The error was recognized immediately and a spinal cord washing was performed through syringing with isotonic saline. However, the patient died 6 weeks later with increasing paralysis, which was followed by neurologic failure. The deceased was autopsied and the central nervous system was removed for a microscopic examination. The results showed microscopic lesions extending from the lumbar to the thoracic portion of the spinal cord, which included pseudocystic transformation of the cells, degeneration of myelin, and microhemorrhages. The brain was edematous and, in the cerebellum, the vermis showed a loss of granule and Purkinje cells. The authors compare this report on vindesine toxicity with cases in the literature involving vincristine. The treating physician admitted responsibility and was sentenced to both a fine and imprisonment.

Organ procurement in forensic deaths: French developments.

Organ procurement and transplantation have grown steadily, and the need for organs will only rise in the future. Increasing the number of potential donors is therefore paramount. However, transplant coordination teams face refusals that can be linked to the contexts of the deaths, especially when they involve legal issues. In France, deaths involving legal proceedings are not uncommon (7-10%). In these cases, the prosecutor is immediately contacted, and makes the decision of whether to remove the involved organs. Refusals of this type represent 4% (approximately 30 cases per year) of obstacles to organ removals, and are governed by specific legislation. Thus, the prosecutor must arrange contact with a forensic pathologist and with the organ transplant teams to assemble all of the necessary elements for him to take the decision. To assist prosecutors in their decision making and to ensure them scientific rigour, the French Society of Forensic Medicine sought to develop a national recommendation to harmonise practices; it emerged in early 2013. The guideline makes practical recommendations, including among others: nominating local referents; writing regional protocols between judicial authorities, forensic pathologists and transplant teams; establishing terms for the forensic pathologist's intervention on the donor's body before and after a procurement. This recommendation by the French Society of Forensic Medicine aimed to combine two interests: addressing the shortage of organs, and fulfilling the requisites of a criminal investigation by standardising practices and encouraging communication.

The mechanism of the keyhole lesion reassessed: An experimental approach.

The initial description of the keyhole defect was detailed as a peculiar gunshot entrance wound in the cranial vault due to firearm discharge in a tangential path. This injury may be described in two parts: a rounded section with inner table beveling and a triangular section with outer table beveling. We report a case of a gunshot skull wound "keyhole" shaped, appeared to have been made perpendicularly to the bone. Performing an experimental study on cranial bones with shots made perpendicularly to the skull approved this hypothesis, and bone injuries were then architecturally characterised using high-resolution micro computed tomography. The singular link between the tangential gunshot path and the keyhole pattern has been refuted several times, and some authors have hypothesised that there is an important role for concentric fractures that occur far away from the initial impact point of the bullet. Micro computed tomography analysis of the bone showed these keyhole defect features with a particular high description. Then, the whole pattern has a spider-web effect, and these concentric fractures could explain the keyhole pattern even in a perpendicular gunshot path.

Effects of the environment on bone mass: A human taphonomic study.

An experiment was designed using human ribs placed in different environments to document how moisture and temperature affect the bone mass according to the postmortem interval. The bones were defleshed, weighed and partially buried, with some ribs being left unburied as controls. The ribs were weighed daily, and the mass loss was monitored over a period of 90days. The results showed that significant differences in bone mass loss exist between environments, where the bone mass loss was significantly faster in an environment with low moisture content. This mass loss is thought to be primarily associated with the desiccation of the body and then for a greater part, with the atmospheric moisture content. However, the loss of bone mass can also be explained by early alterations in the organo-mineral matrix which were highlighted by Raman spectroscopy method.

Experimental study of Lucilia sericata (Diptera Calliphoridae) larval development on rat cadavers: Effects of climate and chemical contamination.

Household products such as bleach, gasoline or hydrochloric acid have been used to mask the presence of a cadaver or to prevent the colonization of insects. These types of chemicals affect insect development and alter the forensic entomology analysis. This study was designed to test the effects of six household products (bleach, mosquito repellent, perfume, caustic soda, insecticide and unleaded gasoline) on blowfly (Lucilia sericata, Diptera: Calliphoridae) larval development. Furthermore, the effects of climate (rain or dry conditions) on larval development were analyzed. For each replication, 100 first instars were placed on a rat cadaver on which one household product was spilled. We observed a decrease in the survival rates of the larvae but no significant effect on their development times or the adult size. The same trends were observed under rainy conditions. However, the rain altered the effects of some tested household products, especially gasoline. These results demonstrate for the first time the successful development of necrophagous larvae on chemically contaminated cadavers, and provide evidence for the range of possible effects to expect.

In vitro effects of household products on Calliphoridae larvae development: implication for forensic entomology.

Several parameters can delay the first arrival of flies on a corpse and the subsequent development of the larvae. This study focuses on the development of Lucilia sericata (Diptera: Calliphoridae) (Meigen, 1826) on household chemical-contaminated substrates. bleach, perfume, hydrochloric acid, caustic soda, insecticide, mosquito repellent, and gasoline in quantities consistent with an amount that could possibly be spilled on a corpse were mixed with beef liver to simulate contaminated fleshes. Larvae were bred at 25 °C on these media until emergence. Four developmental parameters were followed: survival rates, development times, sex ratios, and adult sizes. Hydrochloric acid, insecticide, and gasoline killed all larvae. In low quantities, caustic soda and mosquito repellent increased the development time and decreased the adult size. However, high quantities of these chemicals killed all larvae. Lastly, bleach and perfume did not affect the survival rate and barely impacted the development time or adult size. These results demonstrate common household products spilled on a corpse can strongly affect the development of Calliphoridae larvae. The effects of such products should be considered in forensic entomology cases.

Specific patterns of canine scavenging in indoor settings.

Postmortem animal mutilations due to domestic dogs in isolated domestic deaths are taphonomic modifications regularly observed by forensic pathologists. They are rarely described in the literature; however, even though they present specific patterns. Through 41 cases, 10 at the forensic institute in Lille (France) and 31 at the New York City Office of Chief Medical Examiner (USA), plus 22 cases from the literature, specific locations and patterns of postmortem scavenging lesions are proposed. These lesions are mainly distributed in three locations: the face, especially the nose and the mouth (73.1%), the neck (43.1%), and the arm (shoulder/upper limb [29.2%], hand [26.8%]). We discuss the time span between death and scavenging, the consequences on identification, and comparison with outdoor settings. Outdoor scavenging lesions are mainly located on the trunk and limbs usually sparing the head, which strongly differs from indoor distribution and imply different animal motivations.

Flies eggs: a new method for the estimation of short-term post-mortem interval?

Three modeling methods were used to estimate the time for laying of Lucilia sericata eggs (Diptera, Calliphoridae) after measurements of hatching times at several constant temperatures. These models were tested first under controlled conditions with 19 profiles of fluctuating temperatures, and on the other hand under field conditions on mice. All three models were allowed to determine the time of laying within a period of about 2h, and consequently this determines the time of death, as this species lays immediately after death under favorable conditions. Rearing of eggs sampled on a corpse may therefore contribute to the determination of a short post-mortem interval (PMI).