Camille Rérolle

Contribution of distal femur MRI to the determination of the 18-year limit in forensic age estimation.

Dear Editors: We have read with great attention the article “Forensic age estimation in living individuals using 3.0 T MRI of the distal femur” written by Krämer et al. [1]. In this letter, we would like to comment on the contribution of distal femur MRI to determine whether a male is aged 18 years or more. For the paper, Krämer et al. conducted a retrospective study on 3.0 TMR scans of the distal femurs of 290 individuals (166 males and 124 females). The evaluation was based on an analysis of T1-weighted turbo spin-echo (T1-TSE) sequences in sagittal orientation. The authors found that the inferior age limit of stage 4, which was defined as follows: “The epiphyseal cartilage is fully ossified, and the epiphyseal scar is visible,” was 18.3 years in males. They stated that stage 4 did not occur in males before the 18th birthday. This is a crucial finding because in forensic age estimation, the search for the “perfect” indicator regarding the 18-year age limit, i.e., the one that would positively allow an expert to distinguish between minors and majors, is always topical. We decided to verify this result with a simple study. We retrospectively reviewed MR scans of the distal femur obtained in the picture archiving and communication system (McKesson Medical Imaging Group, Richmond, BC, Canada) of the radiology department of Tours, France. We selected only males aged between 14 and 20 years over a 5year period (2009–2013). As usual in this kind of study, subjects were excluded if they had any pathology of the knee (tumor, trauma, infection, or surgical fixation), hormonal disturbance, or general pathology. The socioeconomic status was not taken into account because we had no access to this data. The examinations were performed with a 1.5-T whole-body scanner (Intera, Philips Medical Systems, Amsterdam, The Netherlands). We used a T1-TSE sequence in sagittal orientation. Images were anonymized by deleting the patient’s names and ages, and two observers (PSM and CR) evaluated the images separately and with only one criterion: whether the metaphyseal-epiphyseal junction was totally fused on all images or not. The first observer (PSM) also reviewed each MR scan after 2 weeks. Statistical analysis was performed by R-2.15 [2]. Intraand interobserver variabilities were calculated using Cohen’s nonparametric kappa test [3]. We included 214 patients. Cohen’s kappa test between the two observers was 0.86. Intraobserver variability was also 0.86. All patients younger than 18 years old were evaluated as incompletely fused. Full ossification first occurred at the age of 18.1 years. Table 1 shows the distribution of the sample by age and the number of individuals with a full ossification of the distal femur for each age. This study confirms the results of Krämer et al. [1] on a different sample. It strengthens their statement that if a male has a completely fused distal femur on all MR images of a T1TSE sequence in sagittal orientation, he is at least 18 years old. If the union between the metaphysis and the epiphysis is not complete, no conclusion can be made with regard to the 18year age limit. One major difference between our sample and P. Saint-Martin : C. Rérolle : F. Dedouit :N. Telmon Laboratoire d’Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR 5288, CNRS, 37 allées Jules Guesde, 31073 Toulouse Cedex, France

Is a CT-scan of the medial clavicle epiphysis a good exam to attest to the 18-year threshold in forensic age estimation?

Computed tomography (CT) scan of the medial clavicular epiphysis is one of the methods recommended by the Study Group on Forensic Age Diagnostics to estimate the age of living individuals. The aim of our study was to assess the relationship between the skeletal maturation of the sternal end of the clavicle and the chronological age in a sample of French individuals, using a nine-stage classification. We retrospectively reviewed 319 chest CT-scans of individuals aged 15-30 years old (252 males, 67 females). Among males and females, all individuals with a complete fusion, or an ongoing fusion of more than one third of the total surface of the metaphysis were at least 18 years old. Our results were consistent with data in the literature indicating that individuals with a complete fused clavicle were at least 18 years old. Similar studies with the same methods allow for creating a database of samples from different countries to confirm the validity of this method and its excellent results in forensic age estimation of living individuals.

Is the corticomedullary index valid to distinguish human from nonhuman bones: a multislice computed tomography study.

The first step in the identification process of bone remains is to determine whether they are of human or nonhuman origin. This issue may arise when only a fragment of bone is available, as the species of origin is usually easily determined on a complete bone. The present study aims to assess the validity of a morphometric method used by French forensic anthropologists to determine the species of origin: the corticomedullary index (CMI), defined by the ratio of the diameter of the medullary cavity to the total diameter of the bone. We studied the constancy of the CMI from measurements made on computed tomography images (CT scans) of different human bones, and compared our measurements with reference values selected in the literature. The measurements obtained on CT scans at three different sites of 30 human femurs, 24 tibias, and 24 fibulas were compared between themselves and with the CMI reference values for humans, pigs, dogs and sheep. Our results differed significantly from these reference values, with three exceptions: the proximal quarter of the femur and mid-fibular measurements for the human CMI, and the proximal quarter of the tibia for the sheep CMI. Mid-tibial, mid-femoral, and mid-fibular measurements also differed significantly between themselves. Only 22.6% of CT scans of human bones were correctly identified as human. We concluded that the CMI is not an effective method for determining the human origin of bone remains.

Twenty-five years of French jurisprudence in criminal medical liability

We report on a comprehensive 25-year study on criminal medical liability in France, undertaken to establish trends in the number of cases being brought before the criminal courts. We did this by interrogating the database on the Légifrance website using a Boolean equation (‘pénal’ (criminal) AND ‘médecin’ (physician) OR ‘docteur’ (doctor)). In total 539 cases were selected, in which the status of the physician either influenced the punishment imposed, or was a prerequisite for the commission of the offence. The results of the search produced two outcomes: offences and the dates of the most recent criminal judgements (which had been left blank). Further data were also collected: references to court cases, hearing dates, offence dates, procedural time limits, numbers of accused parties, types of punishments and physician characteristics. The number of court hearings increased from the 1980s until the late 1990s. Since then, it has remained stable at around 25 cases per year. Of the defendants appearing before the courts, 39.2% have been found guilty. On average, 10 to 13 physicians every year – that is, one per month – are punished. Those most often punished are obstetrician-gynaecologists (13%), followed by intensive care anaesthetists (11%) and then by general practitioners (6.7%). The offences most frequently occurring are manslaughter (36.5%), illegal profits (12%), unintentional injuries (11.5%) and sexual offences (10.1%). The results are most reassuring in terms of the risks posed by the practice of medicine in France. Such a risk does indeed exist; however, it is at a low level and stable.