Idiopathic club foot treated with the Ponseti method. Clinical and sonographic evaluation of Achilles tendon tenotomy. A review of 221 club feet

SummaryThe Ponseti method applied to treating idiopathic club foot consists in placing successive corrective casts, possibly an Achilles tendon tenotomy, then derotation braces, a method that has proven its efficacy. This study compared 221 cases of club foot treated with this method between 2002 and 2007 divided into two groups, based on whether or not Achilles tendon tenotomy was performed. Assessment was both clinical and sonographic. We observed clear improvement of the results in the group that underwent Achilles tendon tenotomy and a significant difference in the rate of secondary surgery. The sonographic evaluation also showed improvement of the morphological results. We now systematically propose Achilles tendon tenotomy however severe club foot may be

Application des recommandations dans la prise en charge du cancer de l’endomètre en pratique clinique. Étude rétrospective bretonne

National audienceObjective - To assess the use of French Cancer Institute recommendations for the diagnosis and treatment of endometrial cancer. Methods - Retrospective observational study involving 137 patients with endometrial cancer between 2011 and 2013. Results - Both MRI and pathological assessment with correct report as recommended were used for 66.4% of patients with endometrial cancer. For patients with correct preoperative assessment, 44.9% of patients were uncorrectly classified and upgraded on final pathological analysis of hysterectomy concerning lymph node involvement risk. These patients did not have confident surgical assessment, according this risk. Conclusion - To improve relevance of preoperative assessment in endometrial cancer, radiological and pathological expertise is required. However, even performed optimally, preoperative assessment does not allow correct risk stratification of lymph node involvement in endometrial cancer. This ineffective stratification leads to propose sentinel lymph node biopsy with hysterectomy in case of preoperative low risk endometrial cancer assessment

Quantifying the correlation between mobile continents and elevated temperatures in the subcontinental mantle

Continents influence the mantle's convective wavelength and the heat flow escaping from the planet's surface. Over the last few decades, many numerical and analytical studies have contributed to the debate about whether the continents can warm up the subcontinental mantle or not and if they do, then to what extent? However, a consensus regarding the exact nature and magnitude of this correlation between continents and elevated temperatures in the subcontinental mantle remains to be achieved. By conducting a systematic parameter study using 2‐D global mantle convection simulations with mobile continents, we provide qualitative and quantitative observations on the nature of this correlation. In our incompressible and compressible convection models, we observe the general processes of downwellings bringing cold material into the mantle along continental margins and a subsequent buildup of warm thermal anomalies underneath the continents. We compute the amplitude and degree of this correlation using spectral decomposition of the temperature and composition fields. The dominant degree of correlation evolves with time and changes with continental configuration. Using simple empirical fits, we observe that this correlation decreases with increasing core temperature, number of continents, internal heating, or decreasing reference viscosity. We also report simple regressions of the time dependence of this correlation. Additionally, we show that decompression melting as a result of a mantle upwelling or small‐scale sublithospheric convection leads to voluminous volcanism. The emplacement of this dense basalt‐eclogite material breaks the continents apart and destroys the correlation

On the self-regulating effect of grain size evolution in mantle convection models: application to thermochemical piles

ISSN:1869-9510ISSN:1869-952

Growing primordial continental crust self-consistently in global mantle convection models

The majority of continental crust formed during the hotter Archean was composed of Tonalite-Trondhjemite-Granodiorite (TTG) rocks. In contrast to the present-day loci of crust formation around subduction zones and intra-plate tectonic settings, TTGs are formed when hydrated basalt melts at garnet-amphibolite, granulite or eclogite facies conditions. Generating continental crust requires a two step differentiation process. Basaltic magma is extracted from the pyrolytic mantle, is hydrated, and then partially melts to form continental crust. Here, we parameterise the melt production and melt extraction processes and show self-consistent generation of primordial continental crust using evolutionary thermochemical mantle convection models. To study the growth of TTG and the geodynamic regime of early Earth, we systematically vary the ratio of intrusive (plutonic) and eruptive (volcanic) magmatism, initial core temperature, and internal friction coefficient. As the amount of TTG that can be extracted from the basalt (or basalt-to-TTG production efficiency) is not known, we also test two different values in our simulations, thereby limiting TTG mass to 10% or 50% of basalt mass. For simulations with lower basalt-to-TTG production efficiency, the volume of TTG crust produced is in agreement with net crustal growth models but overall crustal (basaltic and TTG) composition stays more mafic than expected from geochemical data. With higher production efficiency, abundant TTG crust is produced, with a production rate far exceeding typical net crustal growth models but the felsic to mafic crustal ratio follows the expected trend. These modelling results indicate that (i) early Earth exhibited a “plutonic squishy lid” or vertical-tectonics geodynamic regime, (ii) present-day slab-driven subduction was not necessary for the production of early continental crust, and (iii) the Archean Earth was dominated by intrusive magmatism as opposed to “heat-pipe” eruptive magmatism

On-line Fission Products measurements during a PWR severe accident the French DECA-PF project

International audienceFollowing the Fukushima accident, a lot of recommendations was drawn by international organizations (IAEA, OECD, NUGENIA network ) in order to improve the safety in such accidental conditions and mitigate their consequences. One of these recommendations was to improve the robustness of the instrumentation, which was dramatically lacking at Fukushima, as well as to better determine the Source Term involved in nuclear accident.The DECA-PF project (Diagnosis of a degraded reactor core through Fission Product measurements) was elaborated in this context and selected as one of 21 collaborative RandD projects in the field of nuclear safety and radioprotection, funded in May 2013 by the French National Research Agency.Over the months following the Fukushima accident, a CEA crisis team was held in order to analyze on-line the situation taking into account the data delivered by TEPCO and other organizations. Despite the difficulties encountered concerning the reliability of these data, the work performed showed the high capacity of Fission Products (FP) measurements to get a diagnosis relative to the status of the reactors and the spent fuel pools (SFP). Based on these FP measurements, it was possible to conclude that the main origin of the releases was coming from the cores and not from the SFP, in particular for SFP-4 which was of high concern, and that the degradation level of the reactors was very large, including probably an extensive core melting. To improve the reliability of this kind of diagnosis, the necessity to get such measurements as soon as possible after the accident and as near as possible from the reactor was stressed.In this way the present DECA-PF project intends to develop a new and innovative instrumentation taking into account the design of the French nuclear power plants on which sand bed filters have been implemented for severe accident management. Three complementary techniques, devoted to measure the FP release on-line, are being studied Gamma spectrometry, with an industrial objective to build a prototype aimed at improving the capacity of the present radiation monitoring system,Gas chromatography, for the quantification of the fission gases (Xe, Kr) as well as potential carbon oxides produced in case of Molten Corium Concrete Interaction,Optical absorption spectroscopy, the objective of this most innovative technique being to quantify the tetra-oxide of ruthenium, which could be produced in case of lower head failure, and the gaseous forms of iodine (molecular and organic) released in the environment.A global description and the present status of this project is presented, focusing on the Source Term establishment at the outlet stack of the sand bed filters and on the perspectives of implementation of the on-line gamma spectrometry equipment

Can Grain Size Reduction Initiate Transform Faults?—Insights From a 3-D Numerical Study

Oceanic transform faults formed at mid-ocean ridges are intrinsic features of modern plate tectonics. Nevertheless, numerical mantle convection models typically struggle to reproduce the strike-slip movement observed along transform faults on Earth. Instead, mantle convection models tend to produce mostly convergent and divergent plate boundaries. Based on regional visco-(elasto)-plastic thermomechanical models it has been demonstrated that a strong strain-induced weakening of rocks has to be assumed in order to initiate and stabilize the characteristic orthogonal ridge-transform spreading patterns. However, the physical origin of such intense rheological weakening remains unclear. Considering that in nature oceanic transform faults show a strongly reduced grain size, a potentially strong influence of grain size reduction processes on the rheological strength of these structures can be assumed. Employing 3-D thermomechanical visco-plastic models, we study the effect of grain size reduction on oceanic transform fault initiation. Our results show that ductile weakening induced by grain size reduction indeed results in sufficient localization to initiate a transform fault. Without any additional weakening mechanisms, transform faults in our models remain stable up to 2 Myr. We identify parameters that affect stability and longevity of the transform fault during the initiation phase, such as the grain damage formulation and grain growth prefactor. In our models, transform faults initiate in the brittle crust and propagate downward, thus indicating a top-down initiated localization process. The observed grain size, rheology, and strain rate inside the shear zone of our models agree well with observations in nature; however, the longevity of natural examples cannot be reached. ©2020. American Geophysical Union. All Rights Reserved

Isolated neonatal MRI punctate white matter lesions in very preterm neonates and quality of life at school age

International audienceOBJECTIVE: To study the quality of life at school age of very preterm infants presenting isolated punctate periventricular white matter lesions (IPWL) on late-preterm or term magnetic resonance imaging (MRI). METHODS: In 1996-2000, 16 of the 131 very preterm neonates explored by MRI were found to have IPWL. At the age of 9-14, 12 children from the IPWL group were compared with 54 children born preterm but with a normal MRI (no lesion). Quality of life (Health Status Classification System Pre School questionnaire), school performance, and motor outcome were investigated. RESULTS: Overall quality of life did not differ between the groups (classified as perfect in 2/12 of the IPWL vs 20/54 in the no-lesion). The sub-items mobility and dexterity differed significantly between the two groups, with impairment in the IPWL group (p < 0.001 and p < 0.05). This group also displayed higher levels of motor impairment: they began walking later [20(4) vs. 15(3) months, p < 0.01], had higher frequencies of cerebral palsy (6/12 vs. 2/54, p < 0.05), and dyspraxia (4/12 vs. 0/54, p < 0.001). The rate of grade retention did not differ between the groups (3/12 in the IPWL group vs. 17/54 in the no-lesions group) but, as expected, was higher than that of the French general population (17.4%) during the study period. CONCLUSION: This long-term follow-up study detected no increase in the risk of subsequent cognitive impairment in very preterm infants with IPWL, but suggests that these children may have a significantly higher risk of dyspraxia, and motor impairment. © 2017 IOS Press and the authors. All rights reserved

Arterial spin labeling in clinical pediatric imaging

International audienceArterial spin labeling (ASL) perfusion- weighted magnetic resonance imaging is the only approach that enables direct and non-invasive quantitative measurement of cerebral blood flow in the brain regions without administration of contrast material and without radiation. ASL is thus a promising perfusion imaging method for assessing cerebral blood flow in the pediatric population. Concerning newborns, there are current limitations because of their smaller brain size and lower brain perfusion. This article reviews and illustrates the use of ASL in pediatric clinical practice and discusses emerging cerebral perfusion imaging applications for children due to the highly convenient implementation of the ASL sequence. (C) 2015 Editions francaises de radiologie. Published by Elsevier Masson SAS. All rights reserved