Applied anatomy of round window and adjacent structures of tympanum related to cochlear implantation / Anatomia aplicada da janela redonda e estruturas adjacentes relacionadas ao implante coclear

Abstract Introduction: Various aspects of the round window anatomy and anatomy of posterior tympanum have relevant implications for designing cochlear implant electrodes and visualizing the round window through facial recess. Preoperative information about possible anatomical variations of the round window and its relationships to the adjacent neurovascular structures can help reduce complications in cochlear implant surgery. Objective: The present study was undertaken to assess the common variations in round window anatomy and the relationships to structures of the tympanum that may be relevant for cochlear implant surgery. Methods: Thirty-five normal wet human cadaveric temporal bones were studied by dissection for anatomy of round window and its relation to facial nerve, carotid canal, jugular fossa and other structures of posterior tympanum. The dissected bones were photographed by a digital camera of 18 megapixels, which were then imported to a computer to determine various parameters using ScopyDoc 8.0.0.22 version software, after proper calibration and at 1× magnification. Results: When the round window niche is placed posteriorly and inferiorly, the distance between round window and vertical facial nerve decreases, whereas that with horizontal facial nerve increases. In such cases, the distance between oval window and round window also increases. Maximum height of the round window in our study ranged from 0.51-1.27 mm (mean of 0.69 ± 0.25 mm). Maximum width of round window ranged from 0.51 to 2.04 mm (mean of 1.16 ± 0.47 mm). Average minimum distance between round window and carotid canal was 3.71 ± 0.88 mm (range of 2.79-5.34 mm) and that between round window and jugular fossa was 2.47 ± 0.9 mm (range of 1.24-4.3 mm). Conclusion: The distances from the round window to the oval window and facial nerve are important parameters in identifying a difficult round window niche. Modification of the electrode may be a better option than drilling off the round window margins for insertion of cochlear implant electrodes.

Resumo Introdução: Vários aspectos da anatomia da janela redonda e da anatomia da caixa timpânica posterior são relevantes, devido a suas implicações no desenho dos eletrodos para o implante coclear e na visibilidade da janela redonda através do recesso facial. Informações prévias sobre possíveis variações anatômicas da janela redonda e suas relações com as estruturas neurovasculares adjacentes podem ajudar a reduzir as complicações dessa cirurgia. Objetivo: O presente estudo foi realizado para avaliar as diversas variações da anatomia da janela redonda e sua relação com as estruturas adjacentes, o que pode ser relevante para a cirurgia de implante coclear. Método: Trinta e cinco ossos temporais normais de cadáveres humanos frescos foram dissecados para avaliação da anatomia da janela redonda e sua relação com o nervo facial, canal carotídeo, fossa jugular e outras estruturas da caixa timpânica posterior. Os ossos dissecados foram fotografados com uma câmera digital de 18 megapixels e as imagens importadas para um computador para determinar diversos parâmetros, utilizando-se o software ScopyDoc versão 8.0.0.22, após a calibração adequada e com ampliação de 1×. Resultados: Quando o nicho da janela redonda se encontra posicionado posteriormente e inferiormente, a distância entre a janela redonda e o nervo facial vertical diminui, enquanto aquela com o nervo facial horizontal aumenta. Em tais casos, a distância entre a janela oval e a janela redonda também aumenta. A altura máxima da janela redonda em nosso estudo variou de 0,51 a 1,27 mm (média de 0,69 ± 0,25 mm). A largura máxima da janela redonda variou de 0,51 a 2,04 mm (média de 1,16 a 0,47 mm). A distância mínima média entre a janela redonda e o canal carotídeo foi de 3,71 ± 0,88 mm (variação de 2,79 a 5,34 mm) e entre a janela redonda e a fossa jugular, em nosso estudo, foi de 2,47 ± 0,9 mm (variação de 1,24 ± 4,3 mm). Conclusão: A distância da janela redonda a partir da janela oval e do nervo facial são parâmetros importantes para a identificação do difícil nicho da janela redonda. A modificação do desenho do eletrodo pode ser uma opção melhor do que o broqueamento das margens da janela redonda para a inserção dos eletrodos no implante coclear.

Vestibulotomy in Congenital Stapes Fixation with Anomalous Facial Nerve / 대한이비인후과학회지

Conductive hearing loss is a condition that can be corrected surgically in most cases. Stapedotomy is usually performed for patients with congenital ossicular anomaly or fixation. However, otologic surgeons have often encountered difficulty due to the complexity of stapes surgery. Moreover, congenital stapes fixation with anomalous facial nerve and oval window absence is an uncommon and dangerous condition. In such cases, vestibulotomy can be a surgical option to prevent facial nerve damage and improve hearing. The etiology can be explained by the embryological development of the middle ear structures. To prevent facial nerve damage and maximize the efficacy of surgery, the surgeon should have knowledge about this disease and take a computed tomography for double check before stapes surgery. We describe a case of congenital stapes fixation with aberrant facial nerve courses, a 15-year-old female who was treated with vestibulotomy and piston wire insertion.

Clinical significance and anatomical relationship between the inferior margin of oval window and the endosteum of basal cochlear turn / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate the safety range of drilling and fenestration on promontory inferior to the oval window in difficult stapedectomy via anatomical study of the relationship between the inferior margin of oval window and the endosteum of basal cochlear turn.</p><p><b>METHODS</b>By means of histological sections, the distances between the inferior margin of oval window and different locations of endosteum of basal cochlear turn, the corresponding height of the projecting endosteum and the thickness of promontory bone, on three vertical sections through the anterior, posterior and midpoint of the inferior edge of oval window were measured respectively.</p><p><b>RESULTS</b>The promontory bone inferior to the posterior point of the oval window was thickest, with an average thickness of about 1.1 mm. The endosteum of basal turn at this portion was lowest, with an average height of 0.2 mm. Furthermore, the shortest distance here between the inferior edge of oval window and the endosteum could be no more than 0.3 mm.</p><p><b>CONCLUSION</b>Relatively safe location of drilling on promontory should be selected on promontory inferior to the posterior point of the oval window, with the direction of drilling outward and downward.</p>

Patterns of cholesteatoma extension in chronic otitis media

To analyze the patterns of extension of cholesteatoma during surgery for chronic otitis media. A retrospective review was made of all cholesteatoma surgery in otology center within 6 years. Data included demographic data and the patterns of extension of cholesteatoma. One hundred sixty six patients, 86 [51.8%] males and 80 [48.2%] females, who were admitted with clinical diagnosis of chronic suppurative otitis media, with cholesteatoma. Analysis of the patterns of extension of cholesteatoma, showed that the tympanic cavity was involved in [91.6%], mastoid cavity in [74%] and Eustachian orifice in [42%] of our patients. In the Tympanic cavity, oval window [46%] and sinus tympani [40%] were involved. The most common patterns of extension included tympanic cavity. Attic and antrum involvement were greater than attic only. This study showed that despite decrease in chronic otitis media cases; still there is extensive extension of cholesteatoma in various part of temporal bone in different patients

Terceira janela da orelha interna: o que significa / Third window: what is it means

A deiscência do canal semicircular superior foi descrita por Minor e cols. em 1998 e tem como definição a ausência de cobertura óssea sobre o canal semicircular superior na zona próxima à duramáter na fossa craniana média, o que seria equivalente a uma terceira janela. Sabe-se que qualquer processo que crie uma comunicação adicional com o labirinto leva a sinais e sintomas clínicos semelhantes, sendo, portanto, denominado terceira janela. Os objetivos deste trabalho são apresentar o conceito de terceira janela, destacar a fisiopatologia, a clínica e os diagnósticos diferenciais, e discutir os achados de imagem, inclusive com casos de nosso serviço. As janelas redonda e oval são as duas aberturas fisiológicas do sistema hidráulico da orelha interna. Medianteuma terceira janela, este sistema é rompido e há alteração da fisiologia do labirinto, gerando sinais e sintomas auditivos e vestibulares. Terceira janela é um novo conceito no campo da otologia. O tratamento por parte do otorrinolaringologista depende da identificação desse distúrbio peloradiologista.

The superior semicircular canal dehiscence was described first time by Minor in 1998 and the definition is the absence of bone cover on superior semicircular canal in the zone adjacent duramater, equivalent third window. Any process that does a labyrinth additional communication produces similar signs and symptoms, denominated third window. The objective of this study was to introduce the third window conception, emphasizing physiology,pathology, clinical issues and different diagnostic, discussing imaging findings, together with cases of owner service. The oval and round windows are physiologies openings hydraulic system of the inner ear. Through a third window, this system is breaking and has a labyrinth physiology disorder, producing vestibular signs and symptoms and hearing loss. Third window is a new conception. Adequate treatment by specialist doctor depends on correct identification by radiologist.

Tomografía computada del oído con malformaciones congénitas: evaluación prequirúrgica / Computed tomography of the congenital anomalies of the ear: preoperatory evaluation

Se exploraron con tomografía computada de alta resolución 60 oídos de 44 pacientes con malformaciones congénitas de los oídos externo y medio, valorando las alteraciones anatómicas según un criterio pre-establecido. Se establecen algunos parámetros para dar mayor objetividad a este análisis. Se encontrtó alteración bilateral en 26 pacientes y unilateral en 28. De los 60 oídos, 39 (65 por ciento) tenían atresia del conducto auditivo externo y 21 (35 por ciento) estenosis. El oído medio era de tamaño adecuado en 43 (72 por ciento) oídos inadecuado en 17 (28 por ciento). El trayecto del nervio facial se encontró normal en 39 (65 por ciento) y alterado en 21 (35 por ciento) oídos. La proporción de anomalías en el curso del nervio facial fue mucho mayor en los oídos con atresia, 19 de 39 (49 por ciento) que presentaban estenosis del conducto. Se propone una escala de puntuación para seleccionar a los candidatos a la cirugía, según el pronóstico funcional y riesgo

Congenital anomalies of stapes and oval window

Ten cases of congenital abnormalies of stapes and oval window are seen between 1984 to 1992 among 1500 patients operated for middle ear pathology. Embryology and possible etiological factors are briefly described. Stapedectomy, vastibulotomy with Shea's fluroplastic cup piston prosthesis and vein grafting was done. In cases with mobile footplate, hearing improvement was not achieved by inserting the prosthesis between footplate and incus. Vestibulotomy certainly improved the hearing. Gelfoam was not used as vein graft acts as a good seal to the opening. None of these ten cases had anacusis and only one suffered from minor degree of sensorineural hearing loss in high frequencies

Estudo morfométrico da fóssula da janela oval / Morphometric study of oval window fossa

Os autores estudaram as dimensöes da fóssula da janela oval, com o intuito de constata a existência de variaçöes anatômicas, que podem geral dificuldades nas técnicas cirúrgicas de reconstruçäo funcional do ouvido médio