Modelado y simulación de un capó automotriz

Tesis (Maestría en Ciencias en Ingeniería Mecánica), Instituto Politécnico Nacional, SEPI, ESIME Zacatenco, 2016, 1 archivo PDF, (158 páginas). tesis.ipn.m

Les voies d'abord transpétreuses conservatrices de l'audition

MONTPELLIER-BU Médecine UPM (341722108) / SudocPARIS-BIUM (751062103) / SudocMONTPELLIER-BU Médecine (341722104) / SudocSudocFranceF

Apport des techniques d'imagerie moderne dans la prise en charge du cholestéatome de l'oreille moyenne

MONTPELLIER-BU Médecine UPM (341722108) / SudocPARIS-BIUM (751062103) / SudocMONTPELLIER-BU Médecine (341722104) / SudocSudocFranceF

Comparison of echo-planar diffusion-weighted imaging and delayed postcontrast T1-weighted MR imaging for the detection of residual cholesteatoma.

International audienceBACKGROUND AND PURPOSE: Echo-planar diffusion-weighted imaging (DWI) and delayed postcontrast T1-weighted MR imaging (DPI) have been proposed in previous studies to detect residual middle ear cholesteatomas, with varying results. We assessed and compared these 2 techniques in patients with canal wall-up tympanoplasty. MATERIALS AND METHODS: This was a prospective cohort study. Patients who underwent surgery for middle ear cholesteatoma had CT scanning 9 months after the surgery. If opacity was observed (64%) on CT scans, DWI and DPI were performed before second-look surgery. CT, MR imaging, and surgical data were available for 31 patients. Charts were reviewed independently by 3 blinded examiners. Interobserver agreement for MR imaging was calculated (Cohen kappa). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for these techniques: 1) alone or in association, and 2) according to the residual cholesteatoma size measured during surgery. RESULTS: Interobserver agreement was better for DWI (kappa = 0.81) than for DPI (kappa = 0.51). Sensitivity, specificity, PPV, and NPV values were 60%, 72.73%, 80%, and 50%, respectively, with DWI; and 90%, 54.55%, 78.26%, and 75%, respectively, with DPI. With cholesteatomas >5 mm, the sensitivity and specificity of DWI reached 100% and 88%, respectively, with values for DPI reaching 100% and 80%, respectively. The association of both techniques only allowed improvements in the specificity for lesions >5 mm. CONCLUSIONS: Both techniques gave acceptable results for residual cholesteatoma detection. DWI is more specific but less sensitive than DPI. Their concurrent use may benefit patients by avoiding undue surgery

Refining the audiological assessment in children using narrow-band CE-Chirp-evoked auditory steady state responses

International audienceOBJECTIVE:To demonstrate the feasibility and reliability of simultaneous binaural recording of auditory steady-state responses (ASSR) in young children using narrow-band CE-Chirps as stimuli.DESIGN:Prospective cohort study comparing ASSR thresholds to four frequency stimuli (0.5, 1, 2, and 4 kHz), with click-evoked auditory brainstem responses (ABR) and behavioral response audiometry.STUDY SAMPLE:Thirty-two young children (mean age 7.4 ± 5.2 months) referred for auditory assessment were evaluated.RESULTS:The mean duration for ABR recordings was 13.3 ± 7.2 min versus 22.9 ± 15.8 min for ASSR (p < 0.01). ASSR (means of 2 and 4 kHz thresholds) were highly correlated with ABR thresholds (R2 = 0.935, p < 0.001), though significantly different (3 ± 10.7 dB, p = 0.02). ASSR (means of 0.5, 1, 2, and 4 kHz thresholds) were highly correlated with mean behavioral response audiometry thresholds (R2 = 0.968, p < 0.001). ASSRs were highly and significantly correlated with behavioral response audiometry at 0.5, 1, 2, and 4 kHz (R2 = 0.845, 0.907, 0.929, and 0.859 respectively, p < 0.001). 87.5% and 90.7% ASSR thresholds were within a ± 10 dB range around their corresponding ABR and mean behavioral response audiometry thresholds.CONCLUSIONS:Narrow-band CE-Chirps allow a fast and reliable assessment of auditory thresholds in children, especially in the low-frequency range, by comparison with other stimuli

Medium-term assessment of Eustachian tube function after balloon dilation

International audienceThere is at present no consensus on the treatment of obstructive Eustachian tube dysfunction. In case of failure of well-conducted drug and pressure therapy, some authors recommend balloon dilation; the present study aimed to assess the efficacy and safety of Eustachian tube balloon dilation

Benefit of Preoperative Temporal Bone CT for Atraumatic Cochlear Implantation

International audienceHYPOTHESIS: Evaluate the benefit of preoperative surgical planning using computed tomography (CT) for atraumatic cochlear implantation. BACKGROUND: The surgical technique has a direct impact on hearing and structure preservation. Much interest has been given to depth of electrode insertion. We focused on electrode diameter depending on exposure of round window membrane (RWM) as calculated on preoperative CT. METHODS: Measurements were calculated radiologically and anatomically on 10 temporal bones. Results were compared with CT scans of a control population. Thereafter, preoperative CT scan measurements were applied to seven additional temporal bones that underwent cochlear implantation with the insertion of two electrodes of different diameters (14 implantations) to validate radiological analysis. RESULTS: RWM size was 1.5?\textpm?0.2?mm on CT and 1.2?\textpm?0.2?mm during dissection; posterosuperior bony overhang of round window niche was 1.1?\textpm?0.1?mm on CT and 1.3?\textpm?0.2?mm during dissection. There was no statistically significant difference between radiological and anatomical measurements and between radiological measurements of cadaveric temporal bones and control population (p?\textgreater?0.05 for both). Also, preoperative surgical planning was reliable in the seven temporal bones implanted with two electrode types (accuracy 93%, sensitivity 85.7%, specificity 100%) yielding no damage to intracochlear structures. CONCLUSION: Difficulties to access RWM could be predicted on preoperative CT of temporal bones and control population, which correlated well with anatomical dissections and surgical findings during cochlear implantation. According to CT planning, electrode insertion through RWM was feasible in most patients, with or without drilling posterosuperior bony overhang of round window niche. Promontory cochleostomy could be recommended when electrode apical diameter exceeded maximal RWM exposure. There was no case of intracochlear trauma on microdissections

Outcomes after cochlear reimplantation in children

International audienceOBJECTIVES:With cochlear implantation now a routine procedure, reimplantation is becoming more commonplace for medical/surgical complications or device malfunctions. This study investigated the indications for reimplantation and the auditory outcomes following reimplantation surgery in prelingually-deafened children.METHODS:Of the 539 prelingually deafened children implanted between 1990 and 2013, 45 were reimplanted (8.3% of implantations). Causes of reimplantation, type of device and angle of insertion at initial implantation were recorded, as well as type of implant reinserted, number of electrodes inserted and angle of insertion (calculated on cone beam computed tomography) on reimplantation, and finally any surgical findings. Speech perception test scores (phonetically balanced kindergarten (PBK) words, open-set sentence testing in quiet and in noise (S/N+ 10 dB SNR), and speech tracking scores) were obtained 1, 2 and 3 years after reimplantation, and compared against the best speech recognition score obtained with the first implant before failure.RESULTS:Medical reasons for reimplantation were found in 10 cases (22.2%). A malfunctioning device had occurred in 35 cases (77.7%) including hard failure in 24 and soft failure in 11. Complete insertion was achieved in the scala tympani in 42 cases and in the scala vestibuli in one case; partial insertion occurred in the remaining two cases. In two cases, one or two electrode rings snatched off from the electrode array during removal. The mean insertion angle was 330.5° before surgery and 311.8° after reimplantation (no statistical difference p=0.48). The postoperative speech perception outcome measures showed no significant difference to the best score before reimplantation. Angle of insertion, type of device and etiology of deafness did not influence the results. The PBK performance improved over 10% in 43.2% of children, was similar in 40.5%, and showed a more than 10% decrease in 16.2% of children after reimplantation. The latter decline in performance was explained for some children by a partial insertion.CONCLUSIONS:Reimplantation has no negative effect on auditory outcome. In rare cases, speech perception outcome may not improve, requiring a specific rehabilitation program