Study of physical properties of the Li0.5MgFe1.5O3.5 ferrite nanoparticles.

In the present research study, the structural, optical, magnetic, electrical and dielectrical properties of the spinel ferrite Li0.5MgFe1.5O3.5, synthesized using a sol-gel auto-combustion method were studied. X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy revealed that this sample crystallizes in a cubic spinel structure with space group Fd3̄m. Moreover, the optical investigation by UV-visible spectroscopy has revealed that the band gap for our sample is (E g = 2.87 eV), which shows that our compound is a potential candidate for optoelectronic applications. The values of the remanent magnetization M r = 0.13 emu g-1, of the coercive field H C = 4.65 Oe deduced from the hysteresis loop, are very low, suggesting the superparamagnetic behavior of our sample. Additionally, the temperature coefficient of resistance (TCR) is -19% affirmed that Li0.5MgFe1.5O3.5 ferrite is a good candidate for detecting infrared radiation and infrared bolometric applications. Indeed, the activation energies were calculated from the imaginary part of the impedance, the electrical conductivity, and the imaginary part of the modulus, thus demonstrating that the charge carriers involved in the processes of conduction and relaxation are the same.

The concept of first metacarpal M1-M2 arch. New interest in trapeziometacarpal prostheses.

Analysis of the M1-M2 arch, otherwise known as the M1-M2 metacarpal hanger, objectively helps all surgeons treating basal thumb osteoarthritis to fit a trapeziometacarpal prosthesis that respects the physiological length of the thumb column and thus the physiological tensions of the APL, EPL, and EPB tendons as well as the interossei and thenar muscles. Kapandji X-ray views are a gold-standard in the radiological study of basal thumb osteoarthritis, to classify progression, measure trapezium height, and assess the deformity. Ledoux's M1/M2 ratio is the only method for assessing the normal length of the thumb column but cannot be easily used during surgery. We describe the first metacarpal arch, obtained by a radiological anteroposterior X-ray of the hand and wrist with the thumb in 45° abduction. It may be broken or conserved, depending on the form of osteoarthritis. It can objectively predict whether a prosthesis must be placed iso-long or so as to lengthen the thumb column. This overcomes the subjectivity of the notion of "intraoperative piston" and avoids excessive tensioning of the prosthesis, which would increase stress on the prosthetic components and thus the risk of wear and complications. We applied this technical principle to 148 dual mobility prostheses fitted between January 2019 and May 2021. By respecting the arch, the right trade-off is found between intraoperative stability and mobility while protecting the long-term performance of the prosthesis.

Raman Spectroscopy Imaging of Exceptional Electronic Properties in Epitaxial Graphene Grown on SiC.

Graphene distinctive electronic and optical properties have sparked intense interest throughout the scientific community bringing innovation and progress to many sectors of academia and industry. Graphene manufacturing has rapidly evolved since its discovery in 2004. The diverse growth methods of graphene have many comparative advantages in terms of size, shape, quality and cost. Specifically, epitaxial graphene is thermally grown on a silicon carbide (SiC) substrate. This type of graphene is unique due to its coexistence with the SiC underneath which makes the process of transferring graphene layers for devices manufacturing simple and robust. Raman analysis is a sensitive technique extensively used to explore nanocarbon material properties. Indeed, this method has been widely used in graphene studies in fundamental research and application fields. We review the principal Raman scattering processes in SiC substrate and demonstrate epitaxial graphene growth. We have identified the Raman bands signature of graphene for different layers number. The method could be readily adopted to characterize structural and exceptional electrical properties for various epitaxial graphene systems. Particularly, the variation of the charge carrier concentration in epitaxial graphene of different shapes and layers number have been precisely imaged. By comparing the intensity ratio of 2D line and G line-"I2D/IG"-the density of charge across the graphene layers could be monitored. The obtained results were compared to previous electrical measurements. The substrate longitudinal optical phonon coupling "LOOPC" modes have also been examined for several epitaxial graphene layers. The LOOPC of the SiC substrate shows a precise map of the density of charge in epitaxial graphene systems for different graphene layers number. Correlations between the density of charge and particular graphene layer shape such as bubbles have been determined. All experimental probes show a high degree of consistency and efficiency. Our combined studies have revealed novel capacitor effect in diverse epitaxial graphene system. The SiC substrate self-compensates the graphene layer charge without any external doping. We have observed a new density of charge at the graphene-substrate interface. The located capacitor effects at epitaxial graphene-substrate interfaces give rise to an unexpected mini gap in graphene band structure.

Sensitivity of the Inhomogeneous Magnetization Transfer Imaging Technique to Spinal Cord Damage in Multiple Sclerosis.

BACKGROUND AND PURPOSE: The inhomogeneous magnetization transfer technique has demonstrated high specificity for myelin, and has shown sensitivity to multiple sclerosis-related impairment in brain tissue. Our aim was to investigate its sensitivity to spinal cord impairment in MS relative to more established MR imaging techniques (volumetry, magnetization transfer, DTI). MATERIALS AND METHODS: Anatomic images covering the cervical spinal cord from the C1 to C6 levels and DTI, magnetization transfer/inhomogeneous magnetization transfer images at the C2/C5 levels were acquired in 19 patients with MS and 19 paired healthy controls. Anatomic images were segmented in spinal cord GM and WM, both manually and using the AMU40 atlases. MS lesions were manually delineated. MR metrics were analyzed within normal-appearing and lesion regions in anterolateral and posterolateral WM and compared using Wilcoxon rank tests and z scores. Correlations between MR metrics and clinical scores in patients with MS were evaluated using the Spearman rank correlation. RESULTS: AMU40-based C1-to-C6 GM/WM automatic segmentations in patients with MS were evaluated relative to manual delineation. Mean Dice coefficients were 0.75/0.89, respectively. All MR metrics (WM/GM cross-sectional areas, normal-appearing and lesion diffusivities, and magnetization transfer/inhomogeneous magnetization transfer ratios) were observed altered in patients compared with controls (P < .05). Additionally, the absolute inhomogeneous magnetization transfer ratio z scores were significantly higher than those of the other MR metrics (P < .0001), suggesting a higher inhomogeneous magnetization transfer sensitivity toward spinal cord impairment in MS. Significant correlations with the Expanded Disability Status Scale (ρ = -0.73/P = .02, ρ = -0.81/P = .004) and the total Medical Research Council scale (ρ = 0.80/P = .009, ρ = -0.74/P = .02) were observed for inhomogeneous magnetization transfer and magnetization transfer ratio z scores, respectively, in normal-appearing WM regions, while weaker and nonsignificant correlations were obtained for DTI metrics. CONCLUSIONS: With inhomogeneous magnetization transfer being highly sensitive to spinal cord damage in MS compared with conventional magnetization transfer and DTI, it could generate great clinical interest for longitudinal follow-up and potential remyelinating clinical trials. In line with other advanced myelin techniques with which it could be compared, it opens perspectives for multicentric investigations.

Morphological imperfections of epitaxial graphene: from a hindrance to the generation of new photo-responses in the visible domain.

We report the discovery of remarkable photo-physical phenomena with characteristics unique to epitaxial graphene grown on 6H-SiC (000-1). Surprisingly, the electrical resistance of graphene increases under light illumination in contrast to conventional materials where it normally decreases. The resistance shows logarithmic temperature dependences which may be attributed to an Altshuler-Aronov effect. We show that the photoresistance depends on the frequency of the irradiating light, with three lasers (red, green, and violet) used to demonstrate the phenomenon. The counterintuitive rise of the positive photoresistance may be attributed to a creation of trapped charges upon irradiation. We argue that the origin of the photoresistance is related to the texture formed by the graphene flakes. Photovoltage also exists and increases with light intensity. However, its value saturates quickly with irradiation and does not change with time. The saturation of the photovoltage may be associated with the formation of a quasi-equilibrium state of the excited electrons and holes associated with a charge redistribution between the graphene and SiC substrate. The obtained physical picture is in agreement with the photoresistance measurements: X-ray photoelectron spectrometry "XPS", atomic force microscopy "AFM", Raman spectroscopy and the magnetic dependence of photoresistance decay measurements. We also observed non-decaying photoresistance and linear magnetoresistance in magnetic fields up to 1 T. We argue that this is due to topological phases spontaneously induced by persistent current formation within the graphene flake edges by magnetic fields.

Impact and long-term protection of hepatitis B vaccination: 17 years after universal hepatitis B vaccination in Tunisia.

Hepatitis B virus (HBV) vaccination has been part of the Expanded Programme of Immunization (EPI) in Tunisia since 1995. The aim of this study was to evaluate, for the first time, the impact of mass vaccination in Tunisia 17 years after this programme was implemented, and in parallel, assess the long-term persistence of anti-HBs antibody in the vaccinated Tunisian population. A total of 1422 students were recruited (703 vaccinated, 719 non-vaccinated). HBV seromarkers were checked. None of the students from either group had positive HBsAg. The overall prevalence of anti-HBc was 0·8%. A Significantly higher prevalence of anti-HBc was noted in unvaccinated students than in vaccinated (1·4% vs. 0·3%, P = 0·02). The overall seroprotection rate (anti-HBs titre ⩾10 mIU/ml) was 68·9% in vaccinated subjects. Seroprotection rates and geometric mean titres decreased significantly with increasing age, reflecting waning anti-HBs titre over time. No significant difference was detected between seroprotection rates and gender or students' area of origin. Incomplete vaccination was the only factor associated with an anti-HBs titre <10 mIU/ml. This study demonstrates the excellent efficacy of the HBV vaccination programme in Tunisia 17 years after its launch. However, a significant decline of anti-HBs seroprotection has been observed in ⩾15-year-old adolescents which places them at risk of infection. Additional studies are needed in hyperendemic regions in Tunisia.

Epidemiology and medical cost of hospitalization due to rotavirus gastroenteritis among children under 5 years of age in the central-east of Tunisia.

Data on the economic burden of rotavirus infection in Tunisia are needed to inform the decision to include rotavirus in routine childhood immunizations. This study aimed to describe the epidemiological profile of rotavirus disease in central-east Tunisia and to estimate its hospital cost. In the first stage - the prospective collection of epidemiological data - we enrolled all patients < 5 years old who were hospitalized for acute diarrhoea at 5 university paediatric departments in central-east Tunisia during the period 2009-2011. Rotavirus was responsible for 65 (23.3%) of the 279 cases enrolled. In the second stage, cost data were collected retrospectively using an activity-based costing method from the medical records of the children who were positively diagnosed with rotavirus. The average cost of care per child was TD 433 (SD 134). This is a significant economic burden in Tunisia, where a safe and effective vaccine is available but not yet introduced to the immunization schedule.

Epidemiology and medical cost of hospitalization due to rotavirus gastroenteritis among children under 5 years of age in the central-east of Tunisia

Data on the economic burden of rotavirus infection in Tunisia are needed to inform the decision to include rotavirus in routine childhood immunizations. This study aimed to describe the epidemiological profile of rotavirus disease in central-east Tunisia and to estimate its hospital cost.In the first stage - the prospective collection of epidemiological data - we enrolled all patients < 5 years old who were hospitalized for acute diarrhoea at 5 university paediatric departments in central-east Tunisia during the period 2009-2011. Rotavirus was responsible for 65 [23.3%] of the 279 cases enrolled. In the second stage, cost data were collected retrospectively using an activity-based costing method from the medical records of the children who were positively diagnosed with rotavirus. The average cost of care per child was TD 433 [SD 134]. This is a significant economic burden in Tunisia, where a safe and effective vaccine is available but not yet introduced to the immunization schedule

Des données sur le fardeau économique de l'infection à rotavirus en Tunisie sont nécessaires pour décider ou non d'inclure le rotavirus dans les vaccinations infantiles systématiques. La présente étude visait à décrire le profil épidémiologique de l'infection à rotavirus dans le centre-est de la Tunisie et l'estimation de son coût hospitalier. Lors de la première phase, à savoir le recueil prospectif de données épidémiologiques, nous avons recruté tous les patients de moins de cinq ans ayant été hospitalisés pour une diarrhée aiguë dans cinq services pédiatriques universitaires du centre-est de la Tunisie entre 2009 et 2011. Le rotavirus était responsable de 65 cas sur 279 recrutés [23,3 %]. Lors de la deuxième phase, des données sur les coûts ont été recueillies rétrospectivement à partir des dossiers médicaux des enfants qui étaient positifs au rotavirus, en utilisant une méthodologie de gestion des coûts par activité.Le coût moyen des soins par enfant était de 433 dinars tunisiens [ET 134]. Ce montant représente un fardeau économique important en Tunisie, où un vaccin sûr et efficace existe mais n'est pas encore intégré dans le programme de vaccination

Sequence and structural analyses of NSP4 proteins from human group A rotavirus strains detected in Tunisia.

BACKGROUND: The NSP4 protein of group A rotavirus (RVA) has been recognized as a viral enterotoxin and plays important roles in viral pathogenesis and morphogenesis. Domains involved in structural and functional interactions have been proposed mainly based on the simian SA11 strain. METHODS: NSP4 has been classified into 15 different genotypes (E1-E15), and the aim of this study was to analyze the sequences of 46 RVA strains in order to determine the aminoacid (aa) differences between E1 and E2 genotypes. Another aspect was to characterize the structural and physicochemical properties of these strains. RESULTS: Comparison of deduced aa sequences of the NSP4 protein showed that divergences between NSP4 genotypes E1 and E2 were mostly observed in the VP4-binding, the interspecies variable domain (ISVD) and the double-layered particle (DLP) binding domains. Interestingly, uncommon variations in residues 131 and 138, which are known to be important aa in pathogenesis, were found in one unusual animal derived strain belonging to the E2 genotype. Concerning the structural aspect, no significant differences were noted. CONCLUSION: The presence of punctual aa variations in the NSP4 genotypes may indicate that NSP4 mutates mainly via accumulation of point mutations.

Charged nano-domes and bubbles in epitaxial graphene.

For the first time, new epitaxial graphene nano-structures resembling charged 'bubbles' and 'domes' are reported. A strong influence, arising from the change in morphology, on the graphene layer's electronic, mechanical and optical properties has been shown. The morphological properties of these structures have been studied with atomic force microscopy (AFM), ultrasonic force microscopy (UFM) and Raman spectroscopy. After initial optical microscopy observation of the graphene, a detailed description of the surface morphology, via AFM and nanomechanical UFM measurements, was obtained. Here, graphene nano-structures, domes and bubbles, ranging from a few tens of nanometres (150­200 nm) to a few µm in size have been identified. The AFM topographical and UFM stiffness data implied the freestanding nature of the graphene layer within the domes and bubbles, with heights on the order of 5­12 nm. Raman spectroscopy mappings of G and 2D bands and their ratio confirm not only the graphene composition of these structures but also the existence of step bunching, defect variations and the carrier density distribution. In particular, inside the bubbles and substrate there arises complex charge redistribution; in fact, the graphene bubble­substrate interface forms a charged capacitance. We have determined the strength of the electric field inside the bubble­substrate interface, which may lead to a minigap of the order of 5 meV opening for epitaxial graphene grown on 4H-SiC face-terminated carbon.

Pyrolysis of waste animal fats in a fixed-bed reactor: production and characterization of bio-oil and bio-char.

Several animal (lamb, poultry and swine) fatty wastes were pyrolyzed under nitrogen, in a laboratory scale fixed-bed reactor and the main products (liquid bio-oil, solid bio-char and syngas) were obtained. The purpose of this study is to produce and characterize bio-oil and bio-char obtained from pyrolysis of animal fatty wastes. The maximum production of bio-oil was achieved at a pyrolysis temperature of 500 °C and a heating rate of 5 °C/min. The chemical (GC-MS analyses) and spectroscopic analyses (FTIR analyses) of bio-oil showed that it is a complex mixture consisting of different classes of organic compounds, i.e., hydrocarbons (alkanes, alkenes, cyclic compounds...etc.), carboxylic acids, aldehydes, ketones, esters,...etc. According to fuel properties, produced bio-oils showed good properties, suitable for its use as an engine fuel or as a potential source for synthetic fuels and chemical feedstock. Obtained bio-chars had low carbon content and high ash content which make them unattractive for as renewable source energy.

Neural network modelling of dose distribution and dose uniformity in the Tunisian Gamma Irradiator.

In this paper an approach to model dose distributions, isodose curves and dose uniformity in the Tunisian Gamma Irradiation Facility using artificial neural networks (ANNs) are described. For this purpose, measurements were carried out at different points in the irradiation cell using polymethyl methacrylate dosemeters. The calculated and experimental results are compared and good agreement is observed showing that ANNs can be used as an efficient tool for modelling dose distribution in the gamma irradiation facility. Monte Carlo (MC) photon-transport simulation techniques have been used to evaluate the spatial dose distribution for extensive benchmarking. ANN approach appears to be a significant advance over the time-consuming MC or the less accurate regression methods for dose mapping. As a second application, a detailed dose mapping using two different product densities was carried out. The minimum and maximum dose locations and dose uniformity as a function of the irradiated volume for each product density were determined. Good agreement between ANN modelling and experimental results was achieved.

[Epidemiology of rotavirus gastroenteritis among children under 5 years of age in Tunisia - results of sentinel hospital surveillance 2009 to 2011]. / Épidémiologie des gastroentérites à rotavirus chez les enfants âgés de moins de cinq ans en Tunisie - Résultats de la surveillance sentinelle hospitalière 2009 à 2011.

BACKGROUND: Rotavirus is the major cause of severe acute gastroenteritis among young children. The objectives of this study were to assess the epidemiology, clinical and virological features of community-acquired rotavirus acute gastroenteritis, in children under 5 years of age, hospitalized in Tunisia. METHODS: A multicenter prospective observational study was conducted from April 2009 to March 2011, in 11 sentinel pediatric departments. Clinical data and stool samples were collected for all children under 5 years, admitted for acute gastroenteritis. Rotavirus was detected by Elisa immunoassay test and genotyped for G and P by semi-nested multiplex RT-PCR. RESULT: A total of 621 children were enrolled in this study. Rotavirus was detected in 30.3% of cases (95% CI [26.7-33.9]). The estimated incidence rate of rotavirus acute gastroenteritis was 11 cases/100,000 child-years (95% CI [9.43-12.57]). This infection affected predominantly children aged under 24 months, and occurred mainly in winter (55.3%). Vomiting, fever and dehydration were observed in 79.6%, 69.5% and 57% respectively. Genotype analysis identified four G types (G1, G2, G3 and G4) and 4 P types (P[4], P[6], P[8] and P[9]). The most common G/P combination was G3P[8] (24.4%), followed by G4P[8] (13.3%) and G1P[8] (6.5%). CONCLUSION: These results highlight the frequency and potential severity of rotavirus acute gastroenteritis in pediatric hospital settings. The present study could provide a sufficient database to make a decision related to the introduction of rotavirus vaccine in Tunisian national immunization program.

Application of the Monte Carlo method for the efficiency calibration of CsI and NaI detectors for gamma-ray measurements from terrestrial samples.

Gamma-ray measurements in terrestrial/environmental samples require the use of high efficient detectors because of the low level of the radionuclide activity concentrations in the samples; thus scintillators are suitable for this purpose. Two scintillation detectors were studied in this work; CsI(Tl) and NaI(Tl) with identical size for measurement of terrestrial samples for performance study. This work describes a Monte Carlo method for making the full-energy efficiency calibration curves for both detectors using gamma-ray energies associated with the decay of naturally occurring radionuclides (137)Cs (661keV), (40)K (1460keV), (238)U ((214)Bi, 1764keV) and (232)Th ((208)Tl, 2614keV), which are found in terrestrial samples. The magnitude of the coincidence summing effect occurring for the 2614keV emission of (208)Tl is assessed by simulation. The method provides an efficient tool to make the full-energy efficiency calibration curve for scintillation detectors for any samples geometry and volume in order to determine accurate activity concentrations in terrestrial samples.

[Acute occlusion with fever in a Tunisian woman]. / Syndrome occlusif fébrite aigu chez une tunisienne.

The purpose of this report is to describe a case of idiopathic segmental infarction of the great omentum, in a Tunisian woman, who presented with acute right hypchondrial pain simulating cholecystitis. Abdominal CT scan is the modality of choice. If symptoms resist medical treatment or complications occur, laparoscopic excision is the best therapeutic technique.

[Evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007)]. / Évolution des souches de Rotavirus du groupe A en circulation en Tunisie sur une période de trois ans (2005-2007).

BACKGROUND: Rotaviruses are the most frequent agents associated with diarrhoea in children worldwide. Analysis of mobility of the 11 segments of genomic RNA by polyacrylamide gel electrophoresis (PAGE) yields a pattern which is characteristic for a particular rotavirus isolate. The group A rotaviruses can be further characterized by analysis of VP7 and VP4 genes specificities, responsible for rotavirus classification into G and P genotypes, respectively. The aim of the present study was to determine the evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007). MATERIAL AND METHODS: A total of 1503 stool samples collected from children less than five years old, consulting or hospitalised in Tunisia for diarrhoea between 2005 and 2007, were screened for the presence of group A Rotaviruses. Rotavirus-positive specimens were further analyzed by PAGE and G/P-genotyped by multiplex semi-nested RT-PCR. RESULTS: Rotaviruses were detected in 323 stool samples over 1503 (21 %). Long electropherotypes predominated in Tunisia during the whole period of study (N=158 vs N=82 short electropherotypes). VP7 genotyping showed the cocirculation of five different genotypes: G1, G2, G3, G4 and G9. VP4 typing detected four different P-genotypes: P[8], P[4], P[6] and P[11]. Rotavirus strains with G3P[8] specificity were predominating in Tunisia in 2005 and 2006, replaced by G2P[4] strains in 2007.

Relationship between electropherotypes and VP7/VP4 genotypes of group A rotaviruses detected between 2000 and 2007 in Tunisian children.

BACKGROUND: Rotaviruses are the most frequent agents associated with diarrhoea in children worldwide. Analysis of mobility of the 11 segments of genomic RNA by polyacrylamide gel electrophoresis (PAGE) yields a pattern which is characteristic for a particular rotavirus isolate. The group A rotaviruses can be further characterized by analysis of VP7 and VP4 genes specificities, responsible for rotavirus classification into G and P genotypes, respectively. The aim of the present study was to detect a relationship between electropherotype pattern and molecular characteristics of the rotavirus strains. MATERIAL AND METHODS: Were analyzed 278 rotavirus-positive specimens by PAGE and G/P-genotyped by multiplex semi-nested RT-PCR. Pearson's correlation tests were used for statistical analysis. RESULTS: Twelve different electropherotypes were visualized, eight with a long profile (186 cases) and four with a short one (87 cases). Concerning VP7 types, G2 viral strains were found to be predominant and were detected in 91 specimens (32.7%). Strains with G1, G3, G4, G8 and G9 specificities were detected in 62 (22.3%), 82 (29.5%), 13 (4.7%), two (0.7%) and seven cases (2.5%), respectively. The results of VP4 genotyping showed a predominance of P[8] genotype which comprised half of the strains identified (139 cases, 50%). VP4 P[4], P[6] and P[11] were found in 83 (29.9%), 31 (11.1%) and 11 (4.0%) specimens, respectively. A high rate of mixed strains was also found (1.8% mixed electropherotypes, 7.6% G-mixed and 5% P-mixed strains). Electropherotype pattern of rotavirus strains was significantly correlated with VP7 genotype (p=0.018) and with VP4 genotype specificities (p<0.001).

Clinical Features of Rotavirus Infections : Influence of Child Age on Clinical Manifestations

Objectifs : Decrire les caracteristiques cliniques des infections a Rotavirus et comparer les symptomes observes en fonction de l'age des enfants. Malades et methodes : Les dossiers cliniques de 278 enfants de moins de 5 ans infectes par le Rotavirus ont ete consultes retrospectivement. La presence d'antigenes de Rotavirus du groupe A dans les selles a ete detectee par la technique immunoenzymatique. Une correlation statistique entre les signes cliniques et l'age des enfants a ete recherchee au moyen des tests de correlation de Pearson. Resultats : Parmi les 278 enfants positifs a Rotavirus; 93;9ont presente une diarrhee; 79;1des vomissements; 71;6de la fievre; 37;4des signes respiratoires et 33;1des troubles neurologiques. Une rehydratation intraveineuse requise pour 59;7des enfants. D'une facon generale; la diarrhee (p = 0;001); les vomissements (p = 0;007); la fievre (p=0;045); les troubles respiratoires (p = 0;01) et la deshydratation (p 0;001) etaient significativement plus frequents chez les nourrissons de 1-24 mois par rapport aux autres enfants infectes. Conclusion : La severite du syndrome clinique induit par les infections a Rotavirus semble etre directement influencee par l'age de l'enfant. Il etait interessant de noter que les nourrissons de 1 a 5 mois ont presente des formes cliniques souvent aussi severes que ceux de 6 a 24 mois

The Canaletto®™ implant for reconstructing transverse carpal ligament in carpal tunnel surgery. Surgical technique and cohort prospective study about 400 Canaletto cases versus 400 cases with open carpal tunnel surgery.

The techniques used for carpal tunnel release are open surgery, endoscopy and retinaculum repair. Postoperative outcome, however, is often altered by pain, weakness, insufficient sensory or motor recovery and recurrences. We propose, since March 2001, a new surgical technique based on the reconstruction of the flexor retinaculum using the Canaletto®™ implant. The present study consists in a comparative prospective analysis of 400 patients with a Canaletto®™ implant versus 400 patients having undergone open surgery without Canaletto. The average follow-up was 31 months (1-72 months). The rate of carpal tunnel syndrome recovery (suppression of diurnal and nocturnal paraesthesia) was 97.25% in the Canaletto group and 96.11% in the group without Canaletto. The quality of healing was better in the Canaletto group, with a reduced rate of postoperative oedema. Strength recovery defined as a postoperative strength between 80 and 100% of preoperative strength, as assessed by Jamar, was obtained in 67% of patients in the Canaletto group vs. 33% in the group without Canaletto at 1 month of follow-up. There were still some early strength failures in 226 patients (56.5%) of the group without Canaletto and 31 patients (7.75%) of the Canaletto group. In the long term, patients of the Canaletto group displayed strength between 120 and 200% of preoperative strength. Sensory recovery measured by visual analogic scale in patients with preoperative loss of sensitivity was better in the Canaletto group with an average of 8.9/10 vs. 5.8/10 in the group without Canaletto. No recurrence of carpal tunnel was observed in the Canaletto group whereas four recurrences occurred in the group without Canaletto. Mean duration of sick leave decreased from 5 weeks in the group without Canaletto to 3 weeks in the Canaletto group. Such mechanical and biological properties made this implant becoming part of our surgical armamentum; we use it in about 25% of our surgical procedures for carpal tunnel syndromes. There is some limitations regarding the results of this study due to: (1) a potential selection bias between the two cohorts related to Canaletto indication, and (2) one of the authors is also the designer of the implant (the other one has no conflict of interest).

Liposarcoma of the extremities: MR imaging features and their correlation with pathologic data.

OBJECTIVE: To describe the MRI features of liposarcomas of the extremities and correlate them with data from the histologic subtypes. MATERIAL AND METHODS: Retrospective study of 20 cases of liposarcoma of the extremities identified on MRI, surgically removed and confirmed at pathology. On MRI examination, T1- and T2-weighted fat-suppressed and non-fat-suppressed images were acquired then gadolinium-enhanced fat-suppressed T1-weighted images were obtained in at least two orthogonal planes. RESULTS: Sixteen female and four male patients aged 12 to 77 years old at presentation, in 16 cases, with a slowly enlarging painless mass (demonstrating no associated local or general inflammatory components), located in the lower extremity (16 cases) and predominantly located in the thigh (13 cases). Pathologic examination revealed three cases of well-differentiated liposarcoma, 12 cases of myxoid liposarcoma one of which with round cells, three cases of pleomorphic liposarcoma, one case of dedifferentiated liposarcoma and one case of mixed-type liposarcoma. MR images mostly showed well-circumscribed tumors (19 cases) . Well-differentiated liposarcomas typically demonstrated a very specific diagnostic appearance as a predominantly adipose mass containing nonlipomatous components seen as thick septa that may show nodularity. Other subtypes of liposarcoma demonstrated a small amount of adipose tissue thus producing a marbled textural pattern on T1-weighted images particularly in myxoid liposarcomas (9 cases), or even nonlipomatous elements in high-grade liposarcomas (in round cell liposarcoma and in two out of three pleomorphic liposarcomas). The myxoid subtype has also a relatively characteristic appearance as a low signal intensity noted on T1-weighted images and a marked high signal intensity on T2. The dedifferentiated liposarcoma has a very specific radiologic appearance as a nonlipomatous component within a predominantly adipose mass, simulating that of well-differentiated liposarcomas. CONCLUSION: MRI of extremity liposarcomas is a highly reliable and sensitive method to characterize liposarcomas. Besides its value in the diagnosis of liposarcoma and locoregional extension control, it allows proper identification of the specific histologic subtypes of liposarcoma. LEVEL OF EVIDENCE: Level IV. Rétrospective diagnostic study.