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Abstract Introduction Cervical vestibular-evoked myogenic potentials (cVEMPs) are biphasic, short latency potentials, which represent the inhibition of the contraction of the sternocleidomastoid muscle (SCM) mediated by the saccule, the inferior vestibular nerve, the vestibular nuclei and the medial vestibular spinal tract. Objective To evaluate the response of cVEMPs in individuals with profound prelingual bilateral cochlear hearing loss. Methods A prospective case-control study. A total of 64 volunteers, divided into a study group (31 patients with profound prelingual sensorineural hearing loss) and a control group (33 subjectsmatched for age and gender with psychoacoustic thresholds of ≤ 25 dB HL between 500 and 8,000 Hz) were submitted to the cVEMP exam. The causes of hearing loss were grouped by etiology and the involved period. Results The subjects of the study group aremore likely to present changes in cVEMPs compared to the control group (35.5% versus 6.1% respectively; p = 0.003), with an odds ratio (OR) of 8.52 (p = 0.009). Itmeans that they had 8.52-fold higher propensity of presenting altered cVEMP results. There were no statistically significant differences between the latencies, the interamplitude and the asymmetry index. Regarding the etiology, there was a statistically significant difference when the cause was infectious, with an OR of 15.50 (p = 0.005), and when the impairment occurred in the prenatal period, with an OR of 9.86 (p = 0.009). Conclusion The present study showed abnormalities in the sacculocolic pathway in a considerable portion of individuals with profound prelingual sensorineural hearing loss due to infectious and congenital causes, as revealed by the cVEMP results. (AU)

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La otitis media aguda es una infección del oído medio con alta prevalencia en población pediátrica, las complicaciones pueden generar desde hipoacusia neurosensorial de diverso grado hasta alteración vestibular y/o control postural, aunque de ello no existen mayores reportes ni investigaciones en Chile. Por lo anterior, el objetivo fue asociar la hipoacusia neurosensorial a alteraciones vestibulares y/o de control postural. Se evaluó a un sujeto de sexo femenino, 13 años de edad, quien presentó múltiples cuadros de Otitis Media Aguda y fue diagnosticada con hipoacusia neurosensorial bilateral grado moderado. Antes del estudio, reportó desequilibrio y aumento de riesgo de caída. Se aplicaron test auditivos (timpanometría y audiometría), vestibulares (evaluación del VIII par craneal) y de control postural (posturógrafo y tests "Time up and go", Romberg y Romberg en tándem). Se encontraron alteradas la prueba de integración sensorial, con predominancia del hemicuerpo derecho, igualmente predominancia a alteraciones auditivas en el oído derecho ante pruebas que valoraron oído medio. Se observó una relación directa entre las alteraciones posturales y de equilibrio con el tipo y grado de pérdida auditiva que presenta el sujeto de estudio.

The acute otitis media is a middle ear infection with high prevalence in pediatric population, the complications could generate from sensorineural hearing loss to vestibular alteration and/or postural control, although, there aren´t report or researches of it in Chile. Therefore, the objective was to associate sensorineural hearing loss with vestibular alterations and/or postural control. We evaluated a female subject presenting multiple events of acute otitis media and she was diagnosed with sensorineural hearing loss middle grade. Before this study, she reported imbalance and falling risk. Hearing (tympanometry and audiometry), vestibular (evaluation of the VIII cranial nerve) and postural control tests were applied (posturography and "Time up and go", Romberg and Romberg in tandem test). It was found altered the integration sensorial test, with predominance to half body right and predominance of hearing impairment in the right ear to the middle ear evaluated evidence. It was observed a direct relation between postural alterations and balance with the hearing loss type from the subject of study.

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Resumen El vértigo es un frecuente motivo de consulta cuyo origen puede ser periférico o central; causas poco frecuentes de este último son las asas vasculares que afectan el VIII par craneal llevando a acúfenos, pérdida de la audición y mareo. Se presenta una mujer de 47 años de edad, quien consulta por un cuadro de mareo, náuseas, pérdida del tono postural, cefalea y parestesia facial, cuyo examen físico revela signos de vértigo periférico, iniciándose tratamiento con antieméticos, anticinetósicos y vasodilatadores que llevan a empeoramiento del cuadro, por lo que se sospecha de patología a nivel de sistema nervioso central (SNC) que ejerce compresión con la vasodilatación. Se realiza una resonancia magnética que muestra un asa vascular en la arteria cerebelosa inferior anterior (AICA) que ingresa al conducto auditivo interno (CAI) explicando la sintomatología y cuyo efecto compresivo de los nervios centrales genera un efecto paradójico con la toma de vasodilatadores. (Acta Med Colomb 2018; 43: 226-229).

Abstract Vertigo is a frequent reason for consultation whose origin can be peripheral or central; infrequent causes of the latter are the vascular loops that affect the VIII cranial nerve leading to tinnitus, hearing loss and dizziness. The case of a 47-year-old woman who consulted for a picture of dizziness, nausea, loss of postural tone, headache and facial paraesthesia, and whose physical examination revealed signs of peripheral vertigo, is presented. Treatment was started with antiemetics, anticinetics and vasodilators that lead to worsening of the condition, for which pathology exerting compression due to vasodilation at the central nervous system (CNS) level, is suspected. An MRI is performed showing a vascular loop in the Anterior Lower Cerebellar Artery (AICA) that enters the Internal Auditory Canal (IAC) explaining the symptomatology and whose compressive effect of the central nerves generates a paradoxical effect with the taking of vasodilators. (Acta Med Colomb 2018; 43: 226-229).

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Nerve morphometry is known to produce relevant information for the evaluation of several phenomena, such as nerve repair, regeneration, implant, transplant, aging, and different human neuropathies. Manual morphometry is laborious, tedious, time consuming, and subject to many sources of error. Therefore, in this paper, we propose a new method for the automated morphometry of myelinated fibers in cross-section light microscopy images. Images from the recurrent laryngeal nerve of adult rats and the vestibulocochlear nerve of adult guinea pigs were used herein. The proposed pipeline for fiber segmentation is based on the techniques of competitive clustering and concavity analysis. The evaluation of the proposed method for segmentation of images was done by comparing the automatic segmentation with the manual segmentation. To further evaluate the proposed method considering morphometric features extracted from the segmented images, the distributions of these features were tested for statistical significant difference. The method achieved a high overall sensitivity and very low false-positive rates per image. We detect no statistical difference between the distribution of the features extracted from the manual and the pipeline segmentations. The method presented a good overall performance, showing widespread potential in experimental and clinical settings allowing large-scale image analysis and, thus, leading to more reliable results.

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Introduction: Acoustic nerve tumors have been recognized as a clinico-pathologic entity for at least 200 years, and they represent 90% of cerebellopontine angle diseases. Histologically, the tumors are derived from Schwann cells of the myelin sheath, with smaller tumors consisting of elongated palisade cells, while in large tumors, cystic degeneration can be found in the central areas, possibly due to deficient vascularization. We retrospectively reviewed 825 cases of vestibular schwannomas, reported between January 1984 and August 2006, in which the patients underwent surgery to remove the tumor. Objective: To evaluate signs, symptoms, aspects of clinical diagnosis, including the results of audiological and imaging studies, and surgical techniques and complications. Methods: A retrospective chart review. The medical records of all patients undergoing surgical treatment for schwannoma during the period indicated were reviewed. Results and Conclusion: Hearing loss was the first symptom reported in almost all cases, and tumor size was not proportional to the impairment of the auditory threshold. The surgical techniques allowed safe preservation of facial function. In particular, the retrolabyrinthine route proved useful in small tumors, with 50% preservation of hearing...

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It is widely described in the literature that diabetic patients present hearing impairment. Despite the histological alterations of the internal ear structures in these patients as well as in experimental models of diabetes, to the best of our knowledge, an histological evaluation of the vestibulocochlear nerve have not been performed. In the present study, ultrastructural alterations are described and compared between a spinal nerves and a cranial nerve in rats with chronic induced diabetes. Male Wistar rats (n = 12), fed with standard diet from the animal care facility at 42 days of age were used. Induced diabetic animals (n=6) were fasted for 12 hours prior to being injected intraperitoneally with streptozotocin (STZ - 60mg/kg) in a single dose. Control animals (n=6) received (0.01 mol/l citrate buffer, pH 4.5) vehicle alone. Ten weeks after STZ injection the animals were perfused intracardially with Karnovsky solution. Right and left vestibulocochlear nerves were dissected and histologically processed for epoxy resin embedding. Samples were imaged with the transmission electron microscope. Large myelinated fibers with morphological signs of axonal atrophy in the vestibulocochlear nerves were readily observed. These results suggest that chronic STZ-induced diabetes in rats caused alterations in the myelinated fibers and Schwann cells, compatible to the classic diabetes signs and symptoms. Morphological alterations of the vestibulocochlear nerve in diabetes is described for the first time and contributes information for a better understanding of why there are changes in hearing observed in diabetic patients.

Se ha descrito ampliamente en la literatura que los pacientes diabéticos presentan discapacidad auditiva. En estos pacientes, a pesar de las alteraciones histológicas de las estructuras del oído interno, así como en modelos experimentales de diabetes, que mejoran nuestro conocimiento, la evaluación histológica del nervio vestibulococlear no ha sido realizada. Se describen y comparan las alteraciones ultraestructurales entre un nervio espinal y uno craneal en ratas con diabetes crónica inducida. Fueron utilizadas 12 ratas Wistar machos, de 42 días de edad, alimentadas con dieta estándar. Los animales diabéticos inducidos (n = 6) se mantuvieron en ayuno por 12 horas antes de ser inyectados por vía intraperitoneal con estreptozotocina (STZ - 60mg/kg) en una sola dosis. Los animales control (n = 6) sólo recibieron inyección de 0.01 mol/l buffer, citrato pH 4,5. Diez semanas después de la inyección de STZ, los animales fueron perfundidos intracardiacamente con solución de Karnovsky. Los nervios vestibulococlear derecho e izquierdo fueron disecados y procesados histológicamente para ser incluidos en resina epoxy. Las muestras fueron estudiadas con microscopio electrónico de transmisión. Fueron observadas fácilmente, grandes fibras mielinizadas con signos morfológicos de atrofia axonal en los nervios vestibulococlear. Estos resultados sugieren que la diabetes crónica inducida por STZ en ratas causó alteraciones en las fibras mielínicas y células del neurilema, compatible, con los signos y síntomas clásicos de la diabetes. Alteraciones morfológicas del nervio vestibulococlear en la diabetes son descritas por primera vez, lo que aporta información para una mejor comprensión de por qué hay cambios en la audición en los pacientes diabéticos.

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This paper reports 6 outbreaks of neurological disease associated with paralysis of the facial and vestibulocochlear nerves caused by intracranial space occupying lesions in feedlot cattle. The clinical signs observed were characterized by head tilt, uni or bilateral drooping and paralysis of the ears, eyelid ptosis, keratoconjunctivitis, and different degrees of ataxia. Morbidity and mortality rates ranged from 1.1 to 50 percent and 0 to 1 percent, respectively. Gross lesions observed included yellow, thickened leptomeninges, and marked enlargement of the roots of cranial nerves VII (facial) and VIII (vestibulocochlear). Histopathologically, there was severe, chronic, granulomatous meningitis and, in one case, chronic, granulomatous neuritis of the VII and VIII cranial nerves. Attempts to identify bacterial, viral, or parasitic agents were unsuccessful. Based on the morphologic lesions, the clinical condition was diagnosed as facial paralysis and vestibular syndrome associated with space occupying lesions in the meninges and the cranial nerves VII and VIII. Feedlot is a practice of growing diffusion in our country and this is a first report of outbreaks of facial paralysis and vestibular disease associated with space occupying lesions in Argentina.

Descrevem-se 6 surtos de uma doença neurológica com paralisia dos nervos facial e vestibulo-coclear causada por lesões intracraniais que ocupam espaço em bovinos em confinamento. Os sinais clínicos foram desvio da cabeça, queda e paralisia das orelhas, ptose palpebral, ceratoconjuntivite e diferentes graus de ataxia. As taxas de morbidade e mortalidade foram de 1.1 por cento-50 por cento e de 0-1 por cento, respectivamente. As lesões macroscópicas incluíram engrossamento das meninges, que se apresentavam amareladas, e marcado engrossamento das raízes dos nervos cranianos VII (facial) e VIII (vestíbulo-coclear). Histologicamente observaram-se meningite crônica granulomatosa e, em um caso, neurite granulomatosa crônica do VII e VIII pares cranianos. Cultivos para bactérias ou vírus resultaram negativos. De acordo com as lesões observadas o quadro clínico foi diagnosticado como paralisia facial e síndrome vestibular associadas a lesões que ocupam espaço nas meninges e nervos cranianos VII e VIII. O confinamento é uma prática em expansão na Argentina e este é o primeiro relato, neste país, de surtos de paralisia facial e síndrome vestibular associados com lesões que ocupam espaço.

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This paper reports 6 outbreaks of neurological disease associated with paralysis of the facial and vestibulocochlear nerves caused by intracranial space occupying lesions in feedlot cattle. The clinical signs observed were characterized by head tilt, uni or bilateral drooping and paralysis of the ears, eyelid ptosis, keratoconjunctivitis, and different degrees of ataxia. Morbidity and mortality rates ranged from 1.1 to 50 percent and 0 to 1 percent, respectively. Gross lesions observed included yellow, thickened leptomeninges, and marked enlargement of the roots of cranial nerves VII (facial) and VIII (vestibulocochlear). Histopathologically, there was severe, chronic, granulomatous meningitis and, in one case, chronic, granulomatous neuritis of the VII and VIII cranial nerves. Attempts to identify bacterial, viral, or parasitic agents were unsuccessful. Based on the morphologic lesions, the clinical condition was diagnosed as facial paralysis and vestibular syndrome associated with space occupying lesions in the meninges and the cranial nerves VII and VIII. Feedlot is a practice of growing diffusion in our country and this is a first report of outbreaks of facial paralysis and vestibular disease associated with space occupying lesions in Argentina.(AU)

Descrevem-se 6 surtos de uma doença neurológica com paralisia dos nervos facial e vestibulo-coclear causada por lesões intracraniais que ocupam espaço em bovinos em confinamento. Os sinais clínicos foram desvio da cabeça, queda e paralisia das orelhas, ptose palpebral, ceratoconjuntivite e diferentes graus de ataxia. As taxas de morbidade e mortalidade foram de 1.1 por cento-50 por cento e de 0-1 por cento, respectivamente. As lesões macroscópicas incluíram engrossamento das meninges, que se apresentavam amareladas, e marcado engrossamento das raízes dos nervos cranianos VII (facial) e VIII (vestíbulo-coclear). Histologicamente observaram-se meningite crônica granulomatosa e, em um caso, neurite granulomatosa crônica do VII e VIII pares cranianos. Cultivos para bactérias ou vírus resultaram negativos. De acordo com as lesões observadas o quadro clínico foi diagnosticado como paralisia facial e síndrome vestibular associadas a lesões que ocupam espaço nas meninges e nervos cranianos VII e VIII. O confinamento é uma prática em expansão na Argentina e este é o primeiro relato, neste país, de surtos de paralisia facial e síndrome vestibular associados com lesões que ocupam espaço.(AU)

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Vestibular Shwannomas are responsible for 80-90% of the cerebelar-pontine angle tumors and their incidence is of 0.8 to 20.5% of all tumors. Unilateral and progressive hearing loss is the most frequent and premature symptom, and tinnitus is the second most common complaint. Only 5% of the patients have normal audiograms. In this case the patient complained of ipsilateral facial numbness and weak blink, posterior pinna hypoesthesia (Hitzelberger +), tear reduction and positive Romberg test. He also had mouth twisting but no other involvement of other cranial nerves. Hearing acuity was normal.

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Os Schwannomas vestibulares são responsáveis por 80 a 90 por cento dos tumores do ângulo ponto-cerebelar. A atual incidência é estimada em 0,8 por cento a 2,5 por cento da população mundial. A hipoacusia unilateral e progressiva é o sintoma mais precoce e freqüente, sendo o tinido a segunda queixa mais comum. Estudos demonstram que apenas 5 por cento dos pacientes com schwannoma vestibular têm exames audiométricos normais. No caso em foco é relatado hipoestesia da hemiface com diminuição do reflexo córneo palpebral ipsilateral, hipoestesia da porção póstero-superior do pavilhão auditivo (sinal de Hitzelberger positivo), diminuição do lacrimejamento, Romberg sensibilizado positivo. Observava-se discreto desvio da rima labial para a esquerda, não apresentando outras alterações nos demais pares cranianos. À acumetria, não havia alteração da sensibilidade auditiva em ambas as vias aéreas.

Vestibular Shwannomas are responsible for 80-90 percent of the cerebelar-pontine angle tumors and their incidence is of 0.8 to 20.5 percent of all tumors. Unilateral and progressive hearing loss is the most frequent and premature symptom, and tinnitus is the second most common complaint. Only 5 percent of the patients have normal audiograms. In this case the patient complained of ipsilateral facial numbness and weak blink, posterior pinna hypoesthesia (Hitzelberger +), tear reduction and positive Romberg test. He also had mouth twisting but no other involvement of other cranial nerves. Hearing acuity was normal.

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OBJECTIVE: To evaluate the result of the surgical treatment of vestibular schwannoma (VS) operated in dorsal decubitus (mastoid position). METHOD: 240 patients with a VS underwent a retrosigmoid craniotomy for tumor resection in dorsal decubitus (mastoid position). The function of 7th and 8th cranial nerves was monitored during surgery and the opened internal auditory canal (IAC) was reconstructed using a vascularized dura flap, muscle and fibrin glue. RESULTS: Complete tumor removal was achieved in 99% of the cases, with a mortality of 1.6%. The facial nerve function was preserved in 85% of cases and hearing in 40% of the patients (with preoperative hearing) with tumors of up 1.5 cm in diameter. The incidence of cerebrospinal fluid leak was 5.8% and meningitis 2.9%. Venous air embolism was registered in 3% of cases; it was not associated to mortality. CONCLUSION: Surgical removal of VS in dorsal position has several advantages; the morbidity and mortality are very low.

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OBJECTIVE: To evaluate the result of the surgical treatment of vestibular schwannoma (VS) operated in dorsal decubitus (mastoid position). METHOD: 240 patients with a VS underwent a retrosigmoid craniotomy for tumor resection in dorsal decubitus (mastoid position). The function of 7th and 8th cranial nerves was monitored during surgery and the opened internal auditory canal (IAC) was reconstructed using a vascularized dura flap, muscle and fibrin glue. RESULTS: Complete tumor removal was achieved in 99 percent of the cases, with a mortality of 1.6 percent. The facial nerve function was preserved in 85 percent of cases and hearing in 40 percent of the patients (with preoperative hearing) with tumors of up 1.5 cm in diameter. The incidence of cerebrospinal fluid leak was 5.8 percent and meningitis 2.9 percent. Venous air embolism was registered in 3 percent of cases; it was not associated to mortality. CONCLUSION: Surgical removal of VS in dorsal position has several advantages; the morbidity and mortality are very low.

OBJETIVO: Avaliar o resultado do tratamento cirúrgico de pacientes portadores de schwannoma do vestibular (SV) operados em decúbito dorsal (posição de mastóide). MÉTODO: 240 pacientes foram submetidos a craniotomia retrosigmóide na posição de mastóide. A função do VII e VIII nervos cranianos foi monitorizada durante a cirurgia e a reconstrução da abertura do conduto auditivo interno foi realizada com retalho vascularizado de dura-mater, músculo e cola de fibrina. RESULTADOS: A exérese foi completa em 99 por cento dos casos, com mortalidade de 1,6 por cento. Houve preservação da função do nervo facial em 85 por cento dos casos e da audição em 40 por cento dos pacientes com audição prévia e tumores menores de 1,5 cm. A incidência de fístula liquórica foi 5,8 por cento e meningite 2,9 por cento. Embolia gasosa foi registrada em 3 por cento dos casos, não associada à mortalidade. CONCLUSÃO: O tratamento cirúrgico dos SV utilizando-se a posição de mastóide tem várias vantagens, com baixa morbidade e mortalidade.

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Vestibular paroxysmia is a syndrome of cross-compression of the VIII cranial nerve and was first described by Jannetta who used the term "disabling positional vertigo". This syndrome is characterized by brief attacks of vertigo, tinnitus, vestibular and auditory deficits. MRI may show the VIII nerve compression from vessels in the posterior fossa, such as the basilar, vertebral, anterior-inferior cerebellar or the posterior-inferior cerebellar arteries. Vestibular paroxysmia may be treated either with medical therapy, such as carbamazepine, phenytoin or gabapentin or with the microvascular decompression of the VIII nerve. This study describes eight patients with vestibular paroxysmia. Four of them showed also clinical signs suggesting cross-compression of the V and/or VII nerve. Seven patients treated with carbamazepine had significant improvement of vertigo and tinnitus.

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A paroxismia vestibular é uma síndrome de compressão do VIII nervo craniano e foi denominada inicialmente por Janetta "vertigem posicional incapacitante". Esta síndrome é caracterizada por episódios curtos de vertigem, zumbido, déficit vestibular e auditivo. A RM pode mostrar compressão do VIII nervo por vasos da fossa posterior, como a artéria basilar, artéria vertebral, artéria cerebelar inferior anterior, artéria cerebelar inferior posterior. A paroxismia vestibular pode ser tratada com terapia medicamentosa tais como carbamazepina, fenitoína ou gabapentina, ou com descompressão microvascular do VIII nervo. Este estudo descreve oito pacientes com paroxismia vestibular. Quatro deles mostraram também sinais clínicos sugerindo compressão do V e/ou VII nervos. Sete pacientes tratados com carbamazepina tiveram melhora significativa da vertigem e zumbido.

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A surdez súbita é um sintoma cuja etiologia nem sempre é elucidada mesmo dispondo-se de toda propedêutica atual. Neste estudo avaliaremos as alterações encontradas em ressonância magnética de pacientes portadores de surdez súbita. FORMA DE ESTUDO: coorte transversal. MATERIAL E MÉTODO: Estudo prospectivo com realização de RM em 49 dos 61 pacientes com surdez súbita atendidos no pronto socorro de Otorrinolaringologia do Hospital São Paulo, no período de abril de 2001 a maio de 2003. Doze pacientes abandonaram ou não foram submetidos à ressonância magnética por outros motivos. RESULTADOS: 23 (46,9 por cento) pacientes apresentaram alterações à ressonância magnética. Foram encontrados dois tumores sugestivos de meningioma e três schwannomas do oitavo par craniano. Lesões subcorticais e periventriculares esparsas e hiperintensas em FLAIR foram encontradas em 13 pacientes. Cinco (21,7 por cento) pacientes apresentaram alterações periféricas. CONCLUSÃO: A surdez súbita deve ser abordada como um sintoma comum a diferentes doenças. A presença de tumores do ângulo pontocerebelar em 10,2 por cento dos nossos casos, entre outras causas tratáveis, justifica o uso da ressonância magnética com contraste tanto para o estudo do sistema auditivo periférico quanto para o estudo das vias auditivas centrais, incluindo o cérebro.

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O implante auditivo de tronco cerebral é uma opção os pacientes surdos que não têm a integridade das vias auditivas preservada. A cirurgia, por sua complexidade anatômica e funcional, requer treinamento específico em laboratório de anatomia por parte do cirurgião. OBJETIVOS: Estudar a anatomia cirúrgica da cirurgia do implante auditivo de tronco cerebral. FORMA DE ESTUDO: Estudo anatômico. MATERIAL E MÉTODO: Neste estudo dissecamos cadáver fresco preparado com solução corante injetada nas artérias e veias intra-cranianas. O local de inserção do eletrodo do implante auditivo de tronco cerebral foi estudado através do acesso translabiríntico. RESULTADOS: A técnica cirúrgica utilizada para a implantação do eletrodo de tronco cerebral é semelhante à utilizada na remoção do shwannoma vestibular. O complexo de núcleo coclear, composto pelo núcleo coclear ventral e dorsal, é o local para a colocação do eletrodo. O núcleo coclear ventral é o principal núcleo de transmissão de impulsos neurais do VIII par e seus axônios formam a principal via ascendente do nervo coclear. Tanto o núcleo ventral como o dorsal não são visíveis durante a cirurgia e sua localização depende de identificação de estruturas anatômicas adjacentes. CONCLUSÃO: A região de implantação do eletrodo do implante auditivo de tronco cerebral apresenta referências anatômicas que permitem sua fácil identificação durante a cirurgia.

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UNLABELLED: The auditory brainstem implant (ABI) is an option for deaf patients who do not have the whole of their auditory pathways preserved. The surgery, because of its anatomical and functional complexity, requires specific training of the surgeon in an anatomy lab. AIM: To study the surgical anatomy of the surgery for auditory brainstem implant. STUDY DESIGN: Anatomic study. MATERIAL AND METHOD: In this exercise we dissected a fresh cadaver prepared with a dye solution injected into the arteries and intra-cranial veins. The location for the insertion of the electrode for the ABI has been studied through the translabyrinthine access. RESULTS: The surgical technique used for implanting the electrode of the brainstem is similar to that used in the removal of the schwannoma vestibular. The cochlear nucleus complex, composed of the ventral and dorsal cochlear nuclei is the location for placing the electrode. The ventral cochlear nucleus is the principal nucleus for transmission of neural impulses from the VIII par and form the main ascendant route of the cochlear nerve. Neither the ventral nor the dorsal nuclei are visible during surgery and their location depends on the identification of adjacent anatomical structures. CONCLUSION: The region for the implantation of the electrode in the auditory brainstem implant presents anatomical references that allow its easy identification during surgery.

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UNLABELLED: The etiology of sudden deafness can remain undetermined despite extensive investigation. This study addresses the value of magnetic resonance imaging in the analysis of sudden deafness patients. STUDY DESIGN: Transversal cohort. MATERIAL AND METHOD: In a prospective study, 49 patients attended at otolaryngology emergency room of Federal University of Sao Paulo--Escola Paulista de Medicina, from April 2001 to May 2003, were submitted to magnetic resonance imaging. RESULTS: Magnetic Resonance abnormalities were seen in 23 (46.9%) patients and revealed two tumors suggestive of meningioma, three vestibular schwannomas, thirteen microangiopathic changes of the brain and five (21.7%) pathological conditions of the labyrinth. CONCLUSION: Sudden deafness should be approached as a symptom common to different diseases. The presence of cerebellopontine angle tumors in 10.2% of our cases, among other treatable causes, justifies the recommendation of gadolinium-enhanced magnetic resonance use, not only to study the auditory peripheral pathway, but to study the whole auditory pathway including the brain.

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El síndrome de Ramsay Hunt, es una causa infecciosa de parálisis del nervio facial, teniendo actualmente una incidencia de 15 a 40 casos por 100000 habitantes. El objetivo del presente trabajo, es dar a conocer esta patología así como establecer pautas de tratamiento. Realizamos una revisión bibliográfica, efectuando una actualización del mismo. La mayor incidencia esta en los 40 y 60 años, no encontrando distinción en la incidencia entre hombre y mujeres, generalmente existe remisión total de la enfermedad, este síndrome es el principal responsable de la parálisis de Bell. El tratamiento debe consistir en antivirales. Todo paciente portador de parálisis de Bell deberá ser revisado en busca de lesiones herpeticas que comprometan el trayecto inervado por el octavo y séptimo par craneal, así como esta indicado se le practiquen, pruebas inmunológicas, tales como la reacción de cadena de polimerasas para virus de la varicela-zoster, Debe ser tratado con antivirales, a dosis similares a las empleadas en la primo infección por virus del herpes, así como se incluirán esteroides para su tratamiento ya que la fisiopatología es debida al proceso inflamatorio. Siendo esta patología poco conocida por el personal de salud, nos proponemos a difundir nuestra actualización y resultados encontrados

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