[Noise pollution in the working environment]. / Pollution sonore dans le milieu professionnel.

NOISE POLLUTION IN THE WORKING ENVIRONMENT. Hearing damage due to exposure to noise in the workplace has been recognised as a professional disease since 1963. It first manifests itself as auditory fatigue, which can be assessed by Echoscan and which requires preventive measures, before bilateral hearing loss sets in, usually symmetrical, initially producing a very characteristic auditory scotoma centred on the 4000 Hz frequency. This irreversible hearing loss may be accompanied by tinnitus, more rarely by hyperacusis, as well as other extra-auditory manifestations: stress, high blood pressure or sleep disorders. The regulations aimed at protecting workers against noise trauma impose collective measures, the wearing of individual protectors and, above all, hearing monitoring every two years. Recognition as a professional disease of hearing damage resulting from professional exposure to noise damage enables the worker to be compensated and to be helped in the acquisition of hearing aids, if prescribed.

POLLUTION SONORE DANS LE MILIEU PROFESSIONNEL. L'atteinte auditive liée à une exposition aux bruits sur le lieu de travail est reconnue comme maladie professionnelle depuis 1963. Elle se manifeste d'abord par une fatigue auditive qu'il est possible d'objectiver par Echoscan et qui impose des mesures préventives avant que ne s'installe une surdité bilatérale, habituellement symétrique, réalisant au début un scotome auditif très caractéristique centré sur la fréquence de 4 000 Hz. Cette surdité irréversible peut s'accompagner d'acouphènes, plus rarement d'hyperacousie ainsi que d'autres manifestations extra-auditives : stress, hypertension artérielle ou encore troubles du sommeil. La réglementation visant à protéger les travailleurs contre les traumatismes sonores impose des mesures collectives, le port de protecteurs individuels mais surtout une surveillance de l'audition effectuée tous les deux ans. La reconnaissance comme maladie professionnelle de l'atteinte auditive consécutive à une exposition professionnelle aux bruits lésionnels permet d'indemniser le travailleur et de l'aider lors de l'acquisition de prothèses auditives éventuellement prescrites.

Is gelfoam sealing necessary in stapes surgery?

BACKGROUND: Sealing the oval window around the piston after fenestration with Gelfoam® is a common practice in stapes surgery for otosclerosis. OBJECTIVES: To analyse the effect of using or not using Gelfoam® as a sealing material. METHODS: A retrospective study was performed on 418 patients who underwent stapes surgery from 2013 until 2019. Data were collected from medical records in a tertiary centre. 215 cases in the Gelfoam group and 203 cases in the control group without sealing were included. The main comparisons were made between these two groups in terms of vestibular (primary outcome) and audiological outcomes and complications. RESULTS: The patients' mean age was 47 years with a mean follow up of 50 months and a female predominance (65.6%, p = .049). There was no significant difference in terms of postoperative vertigo (11.6% vs 8.4%) or audiological outcomes in between Gelfoam and control group respectively. The average postoperative air-bone gap in the Gelfoam group was 4.6 dB vs. 5.3 dB in the control group (p = .634). CONCLUSION AND SIGNIFICANCE: No difference were identified in vestibular or audiological outcomes during stapes surgery when using or not using Gelfoam® in the middle ear.

MRI Monitoring of Residual Vestibular Schwannomas: Modeling and Predictors of Growth.

OBJECTIVES: The aim was to model residual Vestibular Schwannoma (VS) over time to identify prognostic factors of postsurgical growth. STUDY DESIGN: Multicenter retrospective study. SETTING: Tertiary referral centers. PATIENTS: A group of 135 patients who underwent incomplete resection for VS between January 2010 and December 2018. On magnetic resonance imaging (MRI) examinations at baseline (1 year after surgery), patients included were divided into two groups: near-total resection (NTR, <25 mm × 2 mm) and subtotal resection (STR, greater volume). INTERVENTION: Monitoring of residual VS volume. MAIN OUTCOME MEASURES: 3D volumetric segmentation of residual tumors was performed on every MRI examination at baseline and during follow-up to model volume changes over time using the Lambda-Mu-Sigma method. RESULTS: The study followed-up 127 patients (median age: 56 yr) over a median follow-up of 39 months. Most VS residues (76.7%; 89/116) showed no growth at 5 years. Only 27 (23.3%) residues showed signs of regrowth (increase in volume >0.05 cm). The extent of resection is a predictor of tumor growth (odds ratio [OR] = 4.85; for STR over NTR; p = 0.003), but the growth rate was significantly different between STR and NTR residues (p < 0.001). At first, over 2 years after surgery, STR residues decreased (-1.0% volume per year), whereas NTR ones grew (+8% per year). Then, both residues showed sign of regrowth. CONCLUSION: Postoperative recommendations should now include the natural history of VS residue after resection: even though the growth rate differs between STR and NTR residues, most VS residues showed no growth.

Tolerance and safety of 45S5 bioactive glass used in obliteration procedures during middle ear surgery: Preliminary results.

OBJECTIVE: Otologists face many disadvantages after extensive mastoid drilling and canal wall down technique in cholesteatoma surgery. Mastoid and epitympanic cavity obliterations or reconstructions after canal wall down procedure using bioactive glass seem to be an interesting solution to overcome some of these disadvantages. Bioactive glass offers many benefits including the availability when there are no sufficient autologous materials for obliteration, its antibacterial activity in chronic infected ear and decreasing the recidivism of cholesteatoma. The objective of this study is to evaluate the tolerance and safety of 45S5 bioactive glass as a filing bone-synthetic material by clinical, audiological and radiological examinations. METHODOLOGY: A retrospective study of 42 patients who had undergone obliteration of mastoid or/and epitympanic cavity with 45S5 bioactive glass between, November 2017 to January 2019. Data from clinical follow-ups, audiological assessment, CT-scan and MRI were analyzed. RESULT: The patients' mean age was 49.8 years old. Microscopic examinations showed dry well-healed tympanic membranes and external auditory canals for 95.2% of the patients after 1 year. Inner ear injuries after obliteration were not observed by comparing pre and post-operative bone conduction audiometry (p value 0.457). No facial palsy was reported post-operatively. One-year postoperative radiological assessments did not reveal any silent implantation of cholesteatoma or residual disease. CONCLUSION: Mastoid and epitympanic obliterations with 45S5 bioactive glass seem to be a tolerable and safe option in cholesteatoma surgery with favorable outcomes similar to other member of bioactive glass especially the S53P4.

MRI monitoring of small and medium-sized vestibular schwannomas: predictors of growth.

Background: Vestibular schwannomas are among the most common intracranial tumours. Their growth is difficult to predict.Objectives: To study the evolution of small and medium-sized vestibular schwannomas (VSs) and identify factors predictive of growth.Material and methods: This was a retrospective longitudinal study at a tertiary referral centre from January 2011 to January 2018. The inclusion criteria were radiological diagnosis of sporadic unilateral VS of stage I or II. Radiological and clinical data were analysed descriptively and by multivariate logistic regression to identify factors predictive of growth.Results: A total of 1105 cases were discussed in multidisciplinary meetings and 336 patients were included with a mean age of 57.8 years and a mean follow-up time of 24 months. Around two thirds of these patients (62.8%) had non-progressive tumours. Factors identified as predictive of VS growth were the size at diagnosis (OR = 2.622, 95% CI, 1.50-4.66; p = .001) and internal auditory canal filling (OR = 7.672; 95% CI, 4.52-13.43; p < .001).Conclusions and significance: Monitoring is the primary treatment modality for small or medium-sized VSs. As reported here for the first time, internal auditory canal filling is significantly associated with VS growth.

Is one of these two techniques: CO2 laser versus microdrill assisted stapedotomy results in better post-operative hearing outcome?

OBJECTIVE: To evaluate hearing results and outcome using two different surgical techniques (microdrill and CO2 Laser fenestration) in the treatment of conductive hearing loss in patients with otosclerosis. STUDY DESIGN: Retrospective audiometric database and chart review from January 2005 until December 2016. SETTING: Two tertiary referral hospitals MATERIALS AND METHODS: Seven-hundred forty-two primary stapedotomy have been reviewed retrospectively in two referral hospitals. This multicenter study compared 424 patients operated for otosclerosis with microdrill technique and 318 patients operated with CO2 laser assisted stapedotomy. Preoperative and postoperative audiological assessment (following the recommendations of the Committee on Hearing and Equilibrium) were compared between the two groups at least 6 weeks and at 1 year or more. Measure of overclosure and hearing damage have been analyzed and compared between the groups. RESULTS: There were no statistically significant differences in demographic data between the two groups and no statistically significant difference in hearing outcome between the two groups. CO2 Laser with 0.4 piston showed slightly better results to close the air-bone gap postoperatively to ≤ 10 dB (84% as compared with the 80% of patients operated with microdrill technique). Patients operated with microdrill technique and 0.6 piston have less damage to hearing at 4 kHz. CONCLUSION: The use of CO2 laser seems associated with better postoperative air-bone gap closure. However, it carries more risk of hearing damage at 4 kHz at it is the case for the microdrill at 1 kHz. In general, postoperative hearing outcome using these two surgical techniques is comparable.

Probabilistic Tractography to Predict the Position of Cranial Nerves Displaced by Skull Base Tumors: Value for Surgical Strategy Through a Case Series of 62 Patients.

BACKGROUND: Predicting the displacement of cranial nerves by tumors could make surgery safer and the outcome better. Recent advances in imaging and processing have overcome some of the limits associated with cranial nerve tractography, such as spatial resolution and fiber crossing. Among others, probabilistic algorithms yield to a more accurate depiction of cranial nerve trajectories. OBJECTIVE: To report how cranial nerve probabilistic tractography can help the surgical strategy in a series of various skull base tumors. METHODS: After distortion correction and region of interest seeding, a probabilistic tractography algorithm used the constrained spherical deconvolution model and attempted the reconstruction of cranial nerve trajectories in both healthy and displaced conditions. RESULTS: Sixty-two patients were included and presented: vestibular schwannomas (n = 33); cerebellopontine angle meningiomas (n = 15); arachnoid or epidermoid cysts (n = 6); cavernous sinus and lower nerves schwannomas (n = 4); and other tumors (n = 4). For each patient, at least one 'displaced' cranial nerve was not clearly identified on classical anatomical MRI images. All 372 cranial nerves were successfully tracked on each healthy side; among the 175 cranial nerves considered 'displaced' by tumors, 152 (87%) were successfully tracked. Among the 127 displaced nerves of operated patients (n = 51), their position was confirmed intraoperatively for 118 (93%) of them. Conditions that led to tractography failure were detailed. On the basis of tractography, the surgical strategy was adjusted for 44 patients (71%). CONCLUSION: This study reports a cranial nerve probabilistic tractography pipeline that can: predict the position of most cranial nerves displaced by skull base tumors, help the surgical strategy, and thus be a pertinent tool for future routine clinical application.

A comparative retrospective study: hypoglossofacial versus masseterofacial nerve anastomosis using Sunnybrook facial grading system.

INTRODUCTION: The aim of our study is to compare the functional results between two surgical techniques for reanimation of facial paralysis: hypoglossal-to-facial versus masseteric-to-facial nerve anastomosis. METHODS: This is a retrospective study of 13 patients treated for complete facial paralysis in two medical tertiary centers. The patients were classified into two groups. First group: masseteric-to-facial nerve anastomosis. Second group: hypoglossofacial nerve anastomosis. Sunnybrook facial grading system was used to evaluate the functional results. The mean scores were compared using Mann-Whitney test. The correlation between the age at surgery, the delay in time from the onset of the facial paralysis to the time of surgery and the results of Sunnybrook scores was studied using correlation and linear regression. RESULTS: No significant statistical difference was found between the mean of total score of the two groups (first group = 38 ± 4.898, second group = 37.83 ± 4.956). All the patients treated by hypoglossofacial nerve anastomosis presented with hemiglossal atrophy. We found slight superiority for the masseterofacial nerve anastomosis in dynamic movements, whereas at rest the hypoglossofacial anastomosis is slightly better. All the differences were not statistically significant. No correlation was found between the age at surgery (age range included 32-73 years) and post-operative results. No correlation was found between the delays up to 24 months from the onset of the facial paralysis and post-operative results. CONCLUSION: Our study showed that both types of anastomosis are effective with comparable results. The masseterofacial nerve anastomosis is preferred when possible to avoid the hemiglossal atrophy and its complications.

Effect of corticosteroids on facial function after cerebellopontine angle tumor removal: a double-blind study versus placebo.

The aim of this study was to assess the effect of corticosteroids administered intra- and postoperatively on the occurrence of facial palsy after a cerebellopontine angle (CPA) tumor resection, and to investigate pre- and intraoperative prognostic factors. A multicenter, prospective, randomized, double-blind and versus-placebo study was conducted between 2006 and 2010. Three hundred and ten patients operated on for a CPA tumor (96% vestibular schwannomas, 4% miscellaneous) were included by five participating centers. The population was stratified into patients with small (≤15 mm CPA on axial MRI views) and large tumors. In each group, patients were randomized to receive corticosteroid (1 mg/kg/day i.v. methylprednisolone intraoperatively and at postoperative days 1-5) or placebo. Steroids did not affect the facial function at postoperative days 1, 8 and 30 in patients with small or large tumors as evaluated by House and Brackmann grading.

Experience of multidisciplinary team meetings in vestibular schwannoma: a preliminary report.

To assess the contribution of multidisciplinary team meetings (MTM) on vestibular schwannoma management as well as to (1) compare professional compliance to national guidelines and (2) study the percentage of loss to follow-up in cases of conservative management by radiologic observation. A retrospective descriptive study of MTMs held between January 2011 and May 2013 in a tertiary referral center. Patients were classified in three groups according to the MTM decision (observation, surgery or radiotherapy). A total of 363 cases were discussed during the study period (29 months). One hundred and ninety-four decisions (53.4%) were for conservative management with radiologic observation, 130 (35.8%) for surgery, and 39 (10.7%) for radiation therapy. The sex ratio was 0.94, and the patients had a median age of 59 years (range 18-86 years). Most of the vestibular schwannomas (74.2%) were small (stages I and II). Global concordance between the MTM decision and International Radiosurgery Association guidelines was 88.7%. Twenty-three percent of the 104 files that were discussed in MTMs between January 2011 and July 2012, for which conservative management was decided, were lost to follow-up by 18 months. Management of vestibular schwannoma remains controversial, but it usually depends on the evolutive status. MTMs improve practice and facilitate the creation and maintenance of local registries. Future studies in MTMs are warranted to evaluate the benefit and evaluated if MTM could optimize long-term follow-up, limiting loss to follow-up in the observation of vestibular schwannomas that may be evolutive.

Hearing preservation in retrosigmoid approach of small vestibular schwannomas: prognostic value of the degree of internal auditory canal filling.

OBJECTIVES: To assess the contribution of preoperative radiologic appearance of vestibular schwannoma (VS) on the magnetic resonance imaging in constructive interference in steady-state sequences and demonstrate if the degree of the internal auditory canal (IAC) filling is correlated with hearing and facial preservation. PATIENTS: A group of 278 patients who underwent VS surgery in a tertiary referral center. INTERVENTION: Retrosigmoid approach surgery. MAIN OUTCOME MEASURES: Patients were classified in 4 groups according to the percentage of IAC filling on the preoperative magnetic resonance imaging as Group IAC 1(IAC empty or filled <25% and with free fundus), Group IAC 2 (IAC filled from 25% to 50% with free fundus), Group IAC 3 (IAC filled from 50% to 75% with free fundus), and Group IAC 4 (complete filling of the IAC without fundus obliteration). RESULTS: A good correlation was observed between the IAC classification and the rate of hearing and facial preservation. The global rate of postoperative facial palsy was 10.4%. The global rate of hearing preservation in 213 patients with preoperative hearing class A and B was 40.8%. Regression analysis showed that the degree of lateral extension of the VS in the IAC was a strong predictor of hearing preservation ( p < 0.04). CONCLUSION: The retrosigmoid approach yields good facial outcomes in selected patients with possible hearing preservation. In case of patient with small tumor and IAC empty or filled less than 75% and with free fundus, surgery is the treatment of choice for patients with serviceable hearing and the desire to retain it.

Perioperative complications after translabyrinthine removal of large or giant vestibular schwannoma: Outcomes for 123 patients.

CONCLUSION: Large vestibular schwannomas are benign but dangerous tumors. The translabyrinthine approach allows the surgeon to limit vital and functional complications due to the disease itself or to its surgical removal. OBJECTIVE: Morbi-mortality study focused on large vestibular schwannoma surgically treated by translabyrinthine removal. METHODS: This was a retrospective review of prospectively collected data in a series of 123 patients who underwent translabyrinthine removal of a large vestibular schwannoma (>4 cm in the cerebellopontine angle, stage IV). All surgical and medical complications and facial function were reviewed, with a 1-year follow-up. RESULTS: Mortality during the first year was 0.8% (one case of infarct of the anterior inferior cerebellar artery, fatal after 8 months). In all, 4.9% of patients underwent a second surgery (for delayed hemorrhage or cerebrospinal fluid leak) during the first months after removal of a large vestibular schwannoma; 3.2% of patients experienced definitive neurologic complications (one death, one cerebellar disturbance, and two cases of 10th cranial nerve palsy).

[Meningiomas of the posterior petrous bone: diagnostic and therapeutic aspects]. / Méningiomes de la face postérieure du rocher: aspects diagnostiques et therapeutiques.

OBJECTIVE: To compare the clinical and paraclinical picture and the postoperative results of meningiomas of the posterior petrous bone and to compare them with those of vestibular schwannomas (VSs) operated on by the same surgical team. MATERIAL AND METHOD: A retrospective study of 27 patients (23 females) operated on for meningioma of the posterior petrous bone between 1994 and 2004. These were compared with 424 patients with VS operated on between October 1994 and January 2001. All patients had a full audiovestibular workup before and after surgery. Tumours were classified according to the Desgeorges classification for meningiomas and Koss for the VS. RESULTS-DISCUSSION: For smaller tumours, facial function is better for the VS, whereas other cranial nerves are more frequently affected in the meningiomas. For larger tumours, facial function results are better for meningiomas, but other cranial nerve complications are more frequent, with a 33.3% cranial nerve V complication rate and a mortality rate of 6.6%. CONCLUSION: Meningiomas of the posterior temporal bone may present clinically and radiologically like a VS, especially for intracanalar tumour and stage IV tumours. For smaller meningiomas, hearing preservation is similar to VS and could be proposed even for stage III meningiomas. On the other hand, trigeminal nerve, facial nerve, and other cranial nerve complications are more common after excision of stage I and II meningiomas.

Are stage IV vestibular schwannomas preoperatively different from other stages?

OBJECTIVE: The aim of this study was to focus on the clinical and paraclinical symptoms of patients suffering from Stage IV vestibular schwannomas (VSs). PATIENTS: In this prospective study, we included 734 patients who have VS and candidates for operation. MAIN OUTCOME MEASURES: Patients were classified as having Stage I, II, III, or IV tumors according to Tos criteria as evaluated by magnetic resonance imaging. PREOPERATIVE CLINICAL EVALUATION: We recorded the occurrence of complaints (%) and duration (yr) of hearing loss, tinnitus, and balance disorder. Preoperative paraclinical evaluation included pure-tone (PTA) and speech audiometry, auditory brainstem response (ABR) patterns, and vestibular deficit at videonystamography (VNG). Continuous variables were compared between Stage IV and other stages using analysis of variance. Qualitative variables expressed as a percentage of presence were compared between Stage IV and other stages using percentage comparison. RESULTS: Quantitative Parameters. Patients with Stage IV VS were significantly younger as compared with patients with other stages. Stage IV hearing loss was greater compared with other stages at 250 and 500 Hz but smaller at 2,000 and 8,000 Hz. We found no difference in the loss of PTA between Stage IV and the other stages. Speech discriminancy score was smaller in Stage IV. The durations of hearing loss, tinnitus, and balance disorders were similar whatever the tumor stage. Auditory brainstem response patterns showed no difference in Wave III latency between Stage IV VS and other stages, whereas Wave V latency and V-I interval were higher in Stage IV. Both ABR threshold and VNG caloric deficit were higher in Stage IV VS compared with other stages. Qualitative Parameters. The percentage of patients with Stage IV was lower than that with Stages II and III. The percentage of men and women was similar in all stages. The occurrence of hearing loss was similar in all stages, whereas that of tinnitus was lower in Stage IV compared with Stages I and II. In contrast, the occurrence of balance disorder was higher in Stage IV compared with all other stages. CONCLUSION: In clinical and paraclinical manifestation, Stage IV VS is different from the other stages. The PTA differences may be attributed to the younger age. Occurrence of clinical symptoms, ABR, and VNG pattern can be explained by the fact that Stage IV develops rapidly in the vestibular, rather than the cochlear nerve and by the fact that larger tumors can be cerebellar compression. This has been confirmed by the higher occurrence of balance disorders in Stage IV and the lower occurrence of tinnitus with similar hearing loss in all stages.