L'atteinte du sinus caverneux dans le carcinome adenoïde systique

Introduction: Head and neck adenoid cystic carcinoma (ACC) is a malignant epithelial neoplasm, developing from salivary gland tissue. Cavernous sinus and skull base invasion by perinervous spread is a particular behavior of this tumor entity. We report two cases of cavernous sinus invasion.Cases report: The first one was originated in the parotid gland, invaded infratemporal fossa and extended to cavernous sinus through perineural infiltration along trigeminal nerve. Second case of ACC was developed in submandibular gland. An invasion of cavernous sinus was observed two years later despite a surgical resection with post operative  chemoradiotherapy.Discussion: ACC is characterized by locally aggressive invasion and a strong tendency to recur. Perineural spread extension is common in ACC, as a precursor of skull base invasion and cavernous sinus involvment along the mandibular, maxillary and facial nerves. Magnetic resonance imaging (MRI) has a higher sensitivity and specificity in detecting perineural spread. Surgical therapy is the choice treatment although complete resection is not possible in all cases due to the infiltration andperineural spread. So, radiation therapy is considered effective, and has been used successfully in ACC invading cavernous sinus. The place of chemotherapy has yet to be determinate. The prognosis of these extensive tumors is bad because high frequency of local recurrence and distant metastases.Key-words: adenoid cystic carcinoma, cavernous sinus, skull base, perineural invasion

Sensitivity of Melt Pool Size and Porosity Appearing to Base Plate Preheating in Laser Powder Bed Fusion Process

The base plate temperature ranks among the crucial building parameters whose effect on melt pool dimensions and porosity defects generation has not been sufficiently discussed in literature. In the current study, with the aim to explore the dependence between melt pool dimensions, porosity defects and base plate preheating, a 3-dimensional thermal finite element model is carried out to create IN718 single beads, at various base plate temperatures. The dimensions of the melt pool behave favourably with the base plate preheating. Indeed, the melt pool depth, width and length increase continuously with the heat of the base plate, from 20 °C to 500 °C. The melt pool width is more responsive to the base plate temperature than the melt pool depth. Numerical results also indicate that the melt dimensions become more responsive to the temperature of the base plate at a slower scan speed. The degree of porosity is predicted under multiple values of base plate temperature and the results show that porosity tends to disappear with further preheating of the base plate. A satisfying accordance between the numerical finding and the experimental results from literature is identified

Traitement des diplegies laryngees en fermeture: Apport du laser

Introduction: Les diplegies laryngees en fermeture sont rares et mal tolerees par les patients. Leur prise en charge therapeutique a connu de nombreuses avancees au cours des dernieres annees. Le but de ce travail est dfetudier la place du laser dans leur prise en charge.Malades et methodes : Notre etude est retrospective a propos de six patients porteurs de diplegie laryngee en fermeture. Lfage moyen etait de 46 ans (16 et 70 ans). Lfetiologie etait une intubation prolongee ou traumatique dans 3 cas, post thyroidectomie totale dans deux autres cas et idiopathique dans 1 cas. Le traitement a consiste en une tracheotomie en urgence dans 5 cas. Tous les patients ont beneficie dans un secondtemps dfun traitement au laser apres 9 mois de surveillance.Resultats : La cordectomie posterieure a ete realisee en premier temps dans 4 cas. Elle etait bilaterale en deux temps dans 2 cas et unilaterale dans 2 cas. Une aryteno.dectomie initiale a ete realisee pour les deux autres patients. Une revision chirurgicale a consiste en une arytenoidectomie dans 2 cas et une cordotomie partielle posterieure controlaterale dans un cas. La decanulation etait bien toleree pour 4 patients. Un seul malade a garde une gene respiratoire sans veritabledyspnee avec une canule parlante fermee et la decanulation a ete refusee. Une voix satisfaisante a ete obtenue pour tous les malades. Des fausses route transitoires ont ete note dans 2 cas.Discussion : Actuellement, le traitement endoscopique au laser constitue le traitement de choix dans la diplegie laryngee et doit etre propose en premiere intension. Deux techniques principales sont decrites :  lfaryteno.dectomie au laser type Ossof et la cordectomie posterieure transverse de kashima. plusieurs series ont defendu chacune des deux techniques. Notre serie a montre que les deux techniques peuvent etre associees pour donner de meilleurs resultats.Mots cles : diplegie laryngee, Laser, aryteno.dectomie, cordectomie posterieure

Teratome mature de la parotide : a propos d’une observation

Le tératome de la parotide est une malformation tumorale vestigiale rare contenant des dérivés plus ou moins différenciés, des trois feuillets embryonnaires. A la lumière d’une nouvelle observation et des données de la littérature, on se propose de mettre l’accent sur les aspects cliniques, histologiques et thérapeutiques de cette affection exceptionnelle dans cette localisation.Mots-clés : tératome, glande parotide, chirurgie, matureTeratoma of the parotid is a rare remnant malformation tumor containing undifferenciated derivatives of three germ layers. Through a new observation and literature review, authors proposed to focus on the clinical, histological and treatment of this lesion in this exceptionallocation.Key-words : teratoma, parotid gland, sugery, matur

Facteurs predictifs de survenue de pharyngostome après laryngectomie totale

Objectif : Déterminer l’incidence de survenue de la fistule pharyngo-cutanée ou pharyngostome après laryngectomie totale ainsi que les facteurs prédisposants.Matériel et méthodes: C’est une étude rétrospective qui a porté sur 187 malades ayant eu une laryngectomie totale à notre département (Janvier 1985-Décembre 2007). Nous avons étudié les facteurs cliniques, histologiques, les modalités thérapeutiques ainsi que évolutives à la recherche de corrélation avec la survenue de pharyngostome après laryngectomie totale. -Résultats : Les pharyngostomes ont été observé dans14,4% des cas. La chimioradiothérapie préopératoire était significativement corrélée à l’apparition de pharyngostome (p=0,008). L’infection postopératoire est un facteur hautement significatif de survenue de pharyngostome (p=0,000). De même que l’hémorragie postopératoire (p=0,016), les troubles de ladéglutition (p=0,037), et les bronchopneumopathies (p=0,032). La rupture capsulaire lors d’un envahissement ganglionnaire était très  significativement corrélée à la survenue d’un pharyngostome (p = 0,001).Conclusion : en présence de facteurs de risque significatifs de  pharyngostome, cette complication peut ainsi être prévue même si sa prévention demeure encore difficile.Mots-clés : Pharyngostome, Laryngectomie totale, Incidence, facteurs prédisposants

Sensitivity of Melt Pool Dimensions and Keyhole to Laser Beam Diameter

The laser powder bed fusion process has witnessed a huge interest in recent years since it has the potential to produce challenging shapes in a broad range of applications. The process parameters have a considerable effect on melt pool size and on the development of defect porosity. This paper predicts numerically the effect of a large range of laser beam diameters on melt pool dimensions and on the occurrence of porosity defects such as keyhole. A series of single beads of Inconel IN625 was made using various combinations of beam diameters, scan speeds, and laser powers. The use of a large diameter was more suitable rather than a small diameter as it ensures a large and shallow heat affected zone, thus decreasing the development of the keyhole defect. Our numerical results correlate satisfactorily with experimental finding from literature

Quel bilan d’extension faut-il faire pour les carcinomes indifferencies du nasopharynx ?

Introduction: Nasopharyngeal carcinoma prognosis is often correlated with its local extension but especially lymphatic node and metastatic.The aimof our work was to study sensitivity and the specificity of clinical and paraclinic explorations in the initial assessmentPatients and methods : It .s about a retrospective study of 366 patients having nasopharyngeal carcinoma, diagnosed over eleven years period between 1993 and 2003 in Sfax hospital. Into pretherapeutic, all the patients had a complementary assessment including:- Nasopharyngeal tomodensitometry (TDM), in all the cases, extended to the cervical area in 112 cases and a magnetic resonnance Imagery (MRI) of the nasopharynx and cerebral in 18 cases.- Metastatic assessment: comprising systematically a chest radiography, an abdominal ultrasonography and an osseous scintiscanning. The statistical study comprised a descriptive study and an analytical study.Results : The metastasis diagnosis was retained in 39 cases (10,7%): osseous in 82%, hepatic in 23% and pulmonary in 12,8% of the cases. The tumour was associated to lymph node N3 in 25 cases (64%). At univariate study, we retained the presence of significant difference between the groups of the metastatic and lack metastatic patients for : the male sex, reason for consultation (cervical node, rhinologic signs and otologic signs) and cervical node at the examination.The multivariate analysis for all the factors was without interest. We choose the parameters according to the result of the univariate study, the literature and parameters' found among all patients with discovered CNP. It comes out from this study that the following elements are providers of metastases: age between 40 and 45years, male sex and cervical node N3a stage.Discussion : The assessment of extension is not standardized for all the authors. Indeed, for the study of the pulmonary extension (AJCC)/ (UICC) recommends the systematic practice of the chest radiography. For (NCCN), the practice of chest radiography is only for patients classified at the stage 2 and 3 in WHO classification. For KUMAR, LEUNG and our results, it is recommended systematically to practice the chest radiography . This radiography would be supplemented by a thoracic tomodensitometry with the least suspect lesion. For the hepatic assessment, some recommend the systematic practice of abdominal echography for the advanced nodestages (N3). For others, it will be indicated only for the symptomatic patients. For (AJCC)/ (UICC) abdominal echography is systematic.For the osseous assessment, KRAIPHIBUL recommends the practice of the osseous scintiscanning only for patients having signs of osseous call but LEUNG and SHAM recommend the practice of the osseous scintiscanning only for the patients having cervical node N3.Key words: Nasopharyngeal carcinoma/ extension assessment/ metastasis

CFD Investigation on the Steady Interaction between an Offset Jet and an Oblique Wall Jet

In this paper a CFD investigation on the interaction between an offset jet and an oblique wall jet using two-dimensional steady RANS equations is performed. This combination is denoted WOJ (Wall Offset jets). Several turbulence models such as the standard k-ω, SST k-ω, standard k-ε, RNG k-ε and realizable k-ε models are tested in the present study. A parametric study is performed to highlight the wall inclination effect on the WOJ flow maximum velocity decay as well as the shear layers spreading. Comparison between combined wall and offset jet (WOJ) and single offset jet (SOJ) flows is also established. Results show that increasing the wall inclination improves the combined wall and offset jets flow spreading. Furthermore, the outer shear layers spreading, is better than the inner shear layers one. Comparing to the combined wall and offset jet flow (WOJ), a better spreading is found in the case of single offset jet flow (SOJ)

Observer Based Robust Position Control of a Hydraulic Servo System Using Variable Structure Control

This paper deals with the position control of a hydraulic servo system rod. Our approach considers the surface design as a case of virtual controller design using the backstepping method. We first prove that a linear surface does not yield to a robust controller with respect to the unmatched uncertainty and perturbation. Next, to remedy this deficiency, a sliding controller based on the second-order sliding mode is proposed which outperforms the first controller in terms of chattering attenuation and robustness with respect to parameter uncertainty only. Next, based on backstepping a nested variable structure design method is proposed which ensures the robustness with respect to both unmatched uncertainty and perturbation. Finally, a robust sliding mode observer is appended to the closed loop control system to achieve output feedback control. The stability and convergence to reference position with zero steady state error are proven when the controller is constructed using the estimated states. To illustrate the efficiency of the proposed methods, numerical simulation results are shown