Thermal variation in human temporal bone using rigid endoscope.

OBJECTIVE: Compare thermal variation in the region of the External Acoustic Canal (EAC) and the Round Window (RW) using different rigid endoscopes and light sources in human temporal bones. METHOD: This is an analytical experimental study using human temporal bones. Thermal variation was assessed during ten minutes, using a thermometer in the region of the EAC and the RW of two temporal bones, right and left. We used three different endoscopes (0° 4-mm, 0° 3-mm and 30° 4-mm) and five intensity/type light source (Halogen 100%, LED 50%, LED 100%, Xenon 50% and Xenon 100% with the same endoscope light fiber. RESULTS: We found temperature elevations in the EAC and RW in all measurements. Larger caliber endoscopes (4-mm) and light sources at 100% intensity generated higher temperatures, slightly higher in halogen and xenon. The 30° endoscopes tended to put more heat on structures, with little difference in most measurements. We identified greater temperature variations in the EAC of the right and left temporal bones compared to the RW overall. The highest temperature acquired in the present study was in the EAC of the temporal bone with a 4-mm and 30° endoscope, using xenon light source (intensity of 100%), with an increase of 4.51 °C. CONCLUSION: The type of endoscope and light source can influence the thermal variation and the risk of tissue injury during endoscopic ear surgery. Larger endoscopes with xenon and halogen light sources at maximum intensity generate more heat.

Effectiveness of endoscopy in cochlear implantation.

OBJECTIVE: Determine the effectiveness of endoscopy in cochlear implantation as compared to microscopy. METHOD: Study comparing microscopy and endoscopy in cochlear implant placement in 34 patients (23 endoscopic implants and 20 implants via microscopy), between 2014 and 2019, at the Centro Medico Naval, Mexico City. The study was performed under informed consent and according to the Council for International Organizations of Medical Sciences (CIOMS). RESULTS: Of the 34 patients, 12 were children or adolescents and 22 were adults. The visualization of the round window classified via microscopy per St. Thomas Hospital's classification showed that type IIB prevailed in 30.2% of patients, and type III in 41.9%, and when using the endoscope, the round window was observed in full in 82.6% of patients (type I), and type IIA was only observed in 17.4% (four patients). The number of attempts made to place the cochlear implant was greater with the microscope. The time to insertion of the electrode was 1.6 minutes. No differences were observed (p > 0.05) in the number of inpatient days. Cochleostomy was more frequent when using the microscope. CONCLUSIONS: Endoscopy is an effective resource in cochlear implantation for posterior tympanotomy, with no complications observed, offering greater safety in inserting the electrode through the round window.

OBJETIVO: Determinar la efectividad de la endoscopía en la implantación coclear en comparación con la técnica microscópica. MÉTODO: Se comparó la microscopía frente a la endoscopía en la colocación de implante coclear en 34 pacientes (23 endoscópicos y 20 microscópicos), del año 2014 al año 2019, en el Centro Médico Naval de la Ciudad de México. El estudio se realizó bajo consentimiento informado y apegado a las normas del Council for International Organizations of Medical Sciences. RESULTADOS: De los 34 pacientes, 12 eran niños o adolescentes y 22 eran adultos. La visualización de la ventana redonda fue clasificada con microscopio según la clasificación del St. Thomas Hospital, predominando la tipo IIB (30.2%) y la III (41.9%), y al utilizar el endoscopio se observó completa en el 82.6% (tipo I) y tipo IIA en tan solo el 17.4% (cuatro pacientes). El número de intentos en la colocación del implante coclear fue mayor con el microscopio. El tiempo en el que se insertó el electrodo fue de 1.6 minutos. No hubo diferencias (p > 0.05) en la estancia hospitalaria. Fue más frecuente la cocleostomía cuando se uso el microscopio. CONCLUSIONES: La endoscopía es un instrumento efectivo en la implantación coclear por timpanotomía posterior, sin presentarse complicaciones y dando mayor seguridad para insertar el electrodo por la ventana redonda.

Anatomical Study of the Facial Recess with Implications in Round Window Visibility for Cochlear Implantation: Personal Observations and Review of the Literature

Abstract Introduction Posterior tympanotomy through facial recess (FR) is the conventional and most preferred approach to facilitate cochlear implantation, especially when the electrode is inserted through the round window. The complications of the FR approach can be minimized by proper understanding of the anatomy of the FR. Objective The present study was undertaken to assess the various parameters of FR and round window visibility, which may be of relevance for cochlear implant surgery. Methods Thirty-five normal wet human cadaveric temporal bones were studied by dissection for anatomy of FR and posterior tympanum. Photographs were taken with an 18megapixels digital camera, which were then imported to a computer to determine various parameters. Results The mean distance from the take-off point/crotch of the chorda tympani nerve (CTN) to the stylomastoid foramen was 4.08 ± 0.8 mm(range of 2.06 - 5.5mm). The variations in the course of the CTN included origin at the level of the lateral semicircular canal. Themean chorda-facial angle in our study was 26.91° ± 1.19°, with a range of 25° to 28.69°. The mean FR length ranged between 9.4 mm and 18.56 mm (mean of 12.41 ± 2.91mm) and varied with the origin of the CTN and pneumatization of temporal bone. The average maximum width of the FR was 2.93 ± 0.4 mm (range 2.24-3.45 mm) and the mean width of the FR at the level of the round window was 2.65 ± 0.41 mm. Conclusion The FR approach provides good access to the round windowmembrane in all cases. In some cases, table adjustment is required.

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.

Applied anatomy of round window and adjacent structures of tympanum related to cochlear implantation.

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 0.51-1.27mm (mean of 0.69±0.25mm). Maximum width of round window ranged from 0.51 to 2.04mm (mean of 1.16±0.47mm). Average minimum distance between round window and carotid canal was 3.71±0.88mm (range of 2.79-5.34mm) and that between round window and jugular fossa was 2.47±0.9mm (range of 1.24-4.3mm). 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.

Surgeon oriented preoperative radiologic evaluation in cochlear implantation - our experience with a proposed checklist

Introduction: Preoperative temporal bone imaging studies have been routinely performed prior to cochlear implantation. Radiologists need to report these examinations with special focus on the surgeon's expectations. Objectives: To provide a basic structured format, in the form of a checklist, for reporting preoperative computed tomography (CT) and to its clinical impact on operative findings. Methods: The preoperative temporal bone CT scans of 47 patients were analyzed and reported according to the proposed checklist. Intraoperative assessment of mastoidectomy, posterior tympanotomy and round window access was done by the surgeon in a blinded fashion and were correlated with the radiological findings to assess its significance. Results: The proposed radiological checklist was reliable in assessing operative difficulty during cochlear implantation. Contracted mastoid and lower tegmen position were associated with a greater difficulty of the cortical mastoidectomy. Presence of an air cell around the facial nerve (FN) was predictive of easier facial recess access exposure. Facial nerve location and posterior external auditory canal (EAC) wall inclination were predictive of difficult round window (RW) accessibility. Conclusion: Certain parameters on the preoperative temporal bone CT scan may be useful in predicting potential difficulties encountered during the key steps involved in cochlear implant surgery (AU)

The Crista Fenestra and Its Impact on the Surgical Approach to the Scala Tympani during Cochlear Implantation.

OBJECTIVE: The aim of this work was to describe the dimensions of the crista fenestra and determine its presence by means of high-resolution computed tomography (CT) for the purpose of cochlear implantation via the round window approach. METHODS: A series of 10 adult human temporal bones underwent high-resolution CT scanning and were further dissected for microscopic study of the round window niche. RESULTS: In all of the specimens, the round window membrane was fully visualized after the complete removal of bony overhangs. The crista fenestra was identified as a sharp bony crest located in the anterior and inferior borders of the niche; its area ranged from 0.28 to 0.80 mm2 (mean 0.51 ± 0.18). The proportion of the area occupied by the crista fenestra in the whole circumference of the round window ranged from 23 to 50% (mean 36%). We found a moderate positive correlation between the area of the niche and the dimensions of the crista fenestra (Spearman rho: 0.491). In every case, high-resolution CT scanning was unable to determine the presence of the crista fenestra. CONCLUSION: The crista fenestra occupies a variable but expressive area within the bony round window niche. Narrower round window niches tended to house smaller crests. The presence of the crista fenestra is an important obstacle to adequate access to the scala tympani. Nevertheless, a high-resolution CT scan provides no additional preoperative information with regard to its presence for the purpose of surgical access to the scala tympani via the round window niche.

Evaluation of Intracochlear Trauma Caused by Insertion of Cochlear Implant Electrode Arrays through Different Quadrants of the Round Window.

HYPOTHESIS: This study aimed to evaluate whether there is a difference in the degree of intracochlear trauma when the cochlear implant electrode arrays is inserted through different quadrants of the round window membrane. BACKGROUND: The benefits of residual hearing preservation in cochlear implant recipients have promoted the development of atraumatic surgeries. Minimal trauma during electrode insertion is crucial for residual hearing preservation. METHODS: In total, 25 fresh human temporal bones were subjected to mastoidectomy and posterior tympanotomy. The cochlear implant electrode array was inserted through the anterosuperior quadrant of the round window membrane in 50% of the bones and through the anteroinferior quadrant in the remaining 50%. The temporal bones were dehydrated, embedded in epoxy, serially polished, stained, viewed through a stereomicroscope, and photographed with the electrode arrays in situ. The resulting images were analyzed for signs of intracochlear trauma. RESULTS: Histological examinations revealed varying degrees of damage to the intracochlear structures, although the incidence and severity of intracochlear trauma were not influenced by the quadrant of insertion. CONCLUSIONS: The incidence and severity of intracochlear trauma were similar in all samples, irrespective of electrode array insertion through the anterosuperior or anteroinferior quadrant of the round window membrane.

Ruido eléctrico de la ventana redonda / Round window electrical noise

Desde hace décadas se sabe que al colocar un electrodo cerca de la ventana redonda de la cóclea es posible registrar potenciales cocleares en respuesta a estímulos sonoros, tales como el potencial microfónico coclear o el potencial de acción compuesto del nervio auditivo. Sin embargo, hace algunos años, se ha descrito que al posicionar un electrodo en el nicho de la ventana redonda en animales de experimentación y en ausencia de estimulación acústica, se obtiene actividad eléctrica aparentemente aleatoria y no desencadenada por estímulo. Esta actividad eléctrica se ha denominado ruido eléctrico de ventana redonda (RWN, por su sigla en inglés Round Window Noise) y representaría la descarga espontánea de fibras del nervio auditivo. La técnica para su registro es similar a la utilizada en la electrococleografía para obtener potenciales cocleares en humanos. Esta señal se distingue del ruido eléctrico no biológico por tener un peak en su poder espectral centrado en torno a los 900 Hz. La amplitud de esta banda de frecuencia se correlaciona con la sensibilidad auditiva en la región basal de la cóclea, entre los 12 a 30 kHz en cobayos y gatos. El RWN se ha estudiado a través de estimulación acústica y bloqueo farmacológico, logrando caracterizar sus propiedades electrofisiológicas para desarrollar modelos de estudio con aplicación clínica.

For decades, it has been known that placing an electrode near the round window niche allows the recording of cochlear potentials in response to auditory stimuli, such as the cochlear microphonic potential and the compound action potential of the auditory nerve. However, some years ago, it was discovered, that by positioning an electrode in the round window niche of experimental animals, and in the absence of acoustic stimulation, apparently random electrical activity is obtained. This electrical activity is called round window electrical noise (RWN) and represents the spontaneous discharge of auditory nerve fibers. The recording technique is similar to that used in electrocochleography in humans. This bioelectrical signal is distinguished from that of non-biological electrical noise, as it has a power spectral peak centered around 900 Hz. The magnitude of this frequency peak is correlated with hearing sensitivity in the basal region of the cochlea, between 12 to 30 kHz in guinea pigs and cats. The RWN has been characterized using sound stimulation or pharmacologic suppression, and its electrophysiological properties could be used to develop models of auditory nerve function with possible clinical application.

Hearing preservation and cochlear implants according to inner ear approach: multicentric evaluation / Preservação auditiva e implante coclear de acordo com a abordagem da orelha interna: avaliação multicêntrica

INTRODUCTION: Electroacoustic stimulation is an excellent option for people with residual hearing in the low frequencies, who obtain insufficient benefit with hearing aids. To be effective, the subject's residual hearing should be preserved during cochlear implant surgery. OBJECTIVES: To evaluate the hearing preservation in patients that underwent implant placement and to compare the results in accordance with the approach to the inner ear. METHODS: 19 subjects underwent a soft surgical technique, and the electrode MED-EL FLEX(tm) EAS, designed to be atraumatic, was used. We evaluated pre- and postoperative tonal audiometric tests with an average of 18.4 months after implantation, to measure the rate of hearing preservation. RESULTS: 17 patients had total or partial preservation of residual hearing; 5 had total hearing preservation and two individuals had no preservation of hearing. The insertion of the electrode occurred through a cochleostomy in 3 patients, and in 2 of these there was no hearing preservation; the other 16 patients experienced electrode insertion through a round window approach. All patients benefited from the cochlear implant, even those who are only using electrical stimulation. CONCLUSION: The hearing preservation occurred in 89.4% of cases. There was no significant difference between the forms of inner ear approach. .

INTRODUÇÃO: A estimulação eletroacústica é uma excelente opção para pessoas com audição residual nas baixas frequências, que obtêm benefício insuficiente com aparelhos auditivos. Para ser eficaz, a audição residual deve ser preservada durante a cirurgia de implante coclear. OBJETIVOS: Avaliar a preservação auditiva de pacientes implantados e comparar os resultados de acordo com a abordagem da orelha interna. MÉTODO: 19 indivíduos foram implantados com uma técnica cirúrgica para preservação auditiva, tendo sido utilizado o eletrodo MED-EL FLEXTM EAS, concebido para ser atraumático. Foram avaliados os exames audiométricos tonais no pré e pós-operatório, com uma média de 18,4 meses após o implante para medir a taxa de preservação da audição residual. RESULTADOS: 17 pacientes tiveram preservação total ou parcial da audição residual; cinco obtiveram preservação da audição total e dois indivíduos não tiveram preservação da audição. A inserção do eletrodo ocorreu por cocleostomia em 3 pacientes; em 2 destes pacientes não houve preservação da audição. Os outros 16 pacientes foram submetidos à abordagem pela janela redonda. Todos os pacientes foram beneficiados com o implante coclear, mesmo aqueles pacientes que utilizando apenas estimulação elétrica. CONCLUSÃO: A preservação auditiva ocorreu em 89,4% dos casos. Não houve diferença significativa entre as formas de abordagem da orelha interna. .

Hearing preservation and cochlear implants according to inner ear approach: multicentric evaluation.

INTRODUCTION: Electroacoustic stimulation is an excellent option for people with residual hearing in the low frequencies, who obtain insufficient benefit with hearing aids. To be effective, the subject's residual hearing should be preserved during cochlear implant surgery. OBJECTIVES: To evaluate the hearing preservation in patients that underwent implant placement and to compare the results in accordance with the approach to the inner ear. METHODS: 19 subjects underwent a soft surgical technique, and the electrode MED-EL FLEX™ EAS, designed to be atraumatic, was used. We evaluated pre- and postoperative tonal audiometric tests with an average of 18.4 months after implantation, to measure the rate of hearing preservation. RESULTS: 17 patients had total or partial preservation of residual hearing; 5 had total hearing preservation and two individuals had no preservation of hearing. The insertion of the electrode occurred through a cochleostomy in 3 patients, and in 2 of these there was no hearing preservation; the other 16 patients experienced electrode insertion through a round window approach. All patients benefited from the cochlear implant, even those who are only using electrical stimulation. CONCLUSION: The hearing preservation occurred in 89.4% of cases. There was no significant difference between the forms of inner ear approach.

Active middle ear implants in patients undergoing subtotal petrosectomy: long-term follow-up.

OBJECTIVE: In 2009, we had introduced the active middle ear implant (aMEI) round window coupling in patients undergoing a subtotal petrosectomy and reported our first results. In the current study, we evaluated the long-term firmness of the vibranting floating mass transducer (FMT) within the round window niche, the long-term audiologic results and the patient's perspective of wearing the speech processor over time. PATIENTS AND INTERVENTION: Of 10 patients, 6 female and 1 male patients (age range from 30 to 71 yr) had undergone subtotal petrosectomy with aMEI round window vibroplasty and were available for a long-term follow-up. Indications were recurrent or chronic ear infections with preserved inner ear function and inability for ossicular chain reconstruction. A thin piece of fascia was placed between the FMT and the round window membrane once the round window niche had been enlarged by drilling. The operative cavity was filled with fat and a muscle flap in all cases. MAIN OUTCOME MEASURES: Audiologic evaluations included pre- and postoperative pure-tone audiometry, Freiburger syllable and numeric tests. All patients underwent preoperative computed tomographic (CT) scans and magnetic resonance imaging (MRI) examination. Postoperative follow-up included CT scans at 1 and preferentially 3 to 5 years to confirm the correct positioning of the FMT and the complete removal of the underlaying pathology. Subjective benefit was rated by the Glasgow Hearing Aid Benefit Profile. RESULTS: There were no immediate postoperative complications. CT scans confirmed the correct and durable positioning of the FMT. Audiometric tests revealed a stable and adequate functional gain in all patients with limited adjustments over time. Subjective rating reached a high satisfaction score, and all patients remained long-term implant users. One patient developed a skin necrosis over the implant because of excessive pressure exerted by the retaining magnet of the headpiece. Revision was performed using local skin flaps with preservation of the functioning implant. CONCLUSION: Our radiologic, audiometric, and subjective data show stable long-term results of round window vibroplasty in patients undergoing subtotal petrosectomy, and we continue to recommend this treatment option instead of another mastoid revision procedure.

Avaliação do trauma intracoclear causado pela inserção do feixe de eletrodos do implante coclear via janela redonda em ossos temporais / Assessment of intracochlear trauma caused by insertion of cochlear implant electrode array via round window in temporal bones

INTRODUÇÃO: A ampliação dos critérios de indicação para cirurgia do implante coclear e os benefícios da preservação da audição residual no pósoperatório estimularam o desenvolvimento de técnicas cirúrgicas atraumáticas. Minimizar os traumas intracocleares durante a inserção do feixe de eletrodos do implante coclear é um passo fundamental para este intuito. O objetivo deste trabalho é avaliar se o trauma intracoclear é diferente quando o feixe de eletrodos do implante coclear é inserido através do quadrante anterossuperior ou anteroinferior da membrana da janela redonda. MÉTODOS: Vinte e cinco ossos temporais frescos de cadáveres humanos foram submetidos à timpanomastoidectomia padrão. Após exposição adequada da membrana da janela redonda, em metade dos ossos o feixe de eletrodos do implante coclear foi inserido via quadrante anterossuperior da membrana da janela redonda, e na outra metade via quadrante anteroinferior. Os ossos temporais foram desidratados e embebidos em epóxi, com o feixe de eletrodos in situ. As peças foram serialmente polidas, tingidas e visualizadas por meio de estereomicroscópio para avaliar o trauma intracoclear causado pela inserção do feixe de eletrodos. As imagens foram fotografadas. RESULTADOS: Em treze ossos temporais o feixe de eletrodos do implante coclear foi inserido via quadrante anterossuperior da membrana da janela redonda, e em doze ossos via quadrante anteroinferior. Obteve-se 372 superfícies. As análises histológicas revelaram diferentes graus de traumas às estruturas intracocleares. Os resultados mostraram que a inserção do feixe de eletrodos via quadrante anterossuperior ou anteroinferior acarretam a mesma frequência de trauma intracoclear. CONCLUSÕES: A presença de trauma intracoclear e a severidade dos traumas ocorridos no tocante à inserção do feixe de eletrodos de implante coclear pelo quadrante anterossuperior e anteroinferior da membrana da janela redonda não apresentou diferença estatisticamente significativa...

INTRODUCTION: The expansion of the indication criteria for cochlear implant surgery and the benefits of preserving residual hearing postoperatively have stimulated the development of atraumatic surgeries. Minimizing the intracochlear traumas during the electrodes insertion is a critical step for this aim. The objective of this study is to assess whether there is a difference in intracochlear trauma when the cochlear implant electrode array is inserted through the anterior-superior or anterior-inferior quadrants of the round window membrane. METHODS: Twenty-five fresh human temporal bones were submitted to standard tympanomastoidectomy. After adequate exposure of the round window membrane, in half of the bones the cochlear implant electrode array was inserted via anterior-superior quadrant of round window membrane and in the other half via anterior-inferior quadrant. The temporal bones were dehydrated and embedded in epoxy with the electrodes array in situ. The specimens were serially polished, stained and viewed through a stereomicroscope to assess the intracochlear trauma caused by insertion of the electrode array. Resulting images were documented. RESULTS: In thirteen temporal bones the cochlear implant electrode array was inserted via anterior-superior quadrant of round window membrane and in twelve bones via anterior-inferior quadrant. Three hundred and seventy two surfaces were obtained. Histological examinations revealed varying degrees of damage to the intracohlear structures. The results showed that the insertion of the electrode array via anterior-superior or anterior-inferior quadrant lead to the same frequency of intracochlear trauma. CONCLUSIONS: The presence of intracochlear trauma and severity of traumas regarding the insertion of cochlear implant electrode array via anterior-superior and via anterior-inferior quadrant of the round window membrane showed no statistically significant difference. However, it was observed that surgical exposure...

A comparison between neural response telemetry via cochleostomy or the round window approach in cochlear implantation.

UNLABELLED: There are two techniques for cochlear implant (CI) electrode placement: cochleostomy and the round window (RW) approach. OBJECTIVE: This study aims to compare neural response telemetry (NRT) results immediately after surgery to check for possible differences on auditory nerve stimulation between these two techniques. MATERIALS AND METHODS: This is a prospective cross-sectional study. Twenty-three patients were enrolled. Six patients underwent surgery by cochleostomy and 17 had it through the RW approach. RESULTS: Mean charge units (MCU) for high frequency sounds: patients submitted to the RW approach had a mean value of 190.4 (± 29.2) while cochleostomy patients averaged 187.8 (± 32.7); p = 0.71. MCU for mid frequency sounds: patients submitted to the RW approach had a mean value of 192.5 (± 22) while cochleostomy patients averaged 178.5 (± 18.5); p = 0.23. MCU for low frequency sounds: patients submitted to the RW approach had a mean value of 183.3 (± 25) while cochleostomy patients averaged 163.8 (± 19.3); p = 0.19. CONCLUSION: This study showed no differences in the action potential of the distal portion of the auditory nerve in patients with multichannel cochlear implants submitted to surgery by cochleostomy or through the RW approach, using the implant itself to generate stimuli and record responses. Both techniques equally stimulate the cochlear nerve. Therefore, the choice of approach can be made based on the surgeon's own preference and experience.

Comparação da telemetria de resposta neural via cocleostomia ou via janela redonda no implante coclear / A comparison between neural response telemetry via cochleostomy or the round window approach in cochlear implantation

Existem duas técnicas para inserção dos eletrodos do implante coclear (IC): Via cocleostomia ou via janela redonda (JR). OBJETIVO: Comparar a telemetria de resposta neural (NRT) no pós-operatório imediato, verificando se há diferenças na estimulação do nervo auditivo entre estas duas técnicas. MÉTODOS: Prospectivo e transversal. Foram avaliados 23 pacientes. Seis submetidos à cirurgia via cocleostomia e 17 via JR. RESULTADOS: Comparação das unidades de corrente médias (UCM) para sons agudos: via JR com média de 190,4 (± 29,2) e via cocleostomia 187,8 (± 32,7), p = 0,71. Comparação das UCM para sons intermediários: via JR, média de 192,5 (± 22) e via cocleostomia 178,5 (± 18.5), p = 0,23. Comparação das UCM para sons graves: via JR, média de 183,3 (± 25) e via cocleostomia 163,8 (± 19,3), p = 0,19. CONCLUSÃO: Este estudo não mostrou diferença na captação do potencial de ação da porção distal do nervo auditivo em pacientes usuários do implante coclear multicanal submetidos à cirurgia via cocleostomia ou via JR, utilizando o próprio implante para eliciar o estímulo e gravar as respostas. Portanto, ambas as técnicas estimulam de maneira igual o nervo coclear, e baseado nisto conclui-se, também, que realizar o implante coclear via cocleostomia ou RW é uma escolha que depende da experiência cirúrgica e opção do cirurgião.

There are two techniques for cochlear implant (CI) electrode placement: cochleostomy and the round window (RW) approach. OBJECTIVE: This study aims to compare neural response telemetry (NRT) results immediately after surgery to check for possible differences on auditory nerve stimulation between these two techniques. MATERIALS AND METHODS: This is a prospective cross-sectional study. Twenty-three patients were enrolled. Six patients underwent surgery by cochleostomy and 17 had it through the RW approach. RESULTS: Mean charge units (MCU) for high frequency sounds: patients submitted to the RW approach had a mean value of 190.4 (± 29.2) while cochleostomy patients averaged 187.8 (± 32.7); p = 0.71. MCU for mid frequency sounds: patients submitted to the RW approach had a mean value of 192.5 (± 22) while cochleostomy patients averaged 178.5 (± 18.5); p = 0.23. MCU for low frequency sounds: patients submitted to the RW approach had a mean value of 183.3 (± 25) while cochleostomy patients averaged 163.8 (± 19.3); p = 0.19. CONCLUSION: This study showed no differences in the action potential of the distal portion of the auditory nerve in patients with multichannel cochlear implants submitted to surgery by cochleostomy or through the RW approach, using the implant itself to generate stimuli and record responses. Both techniques equally stimulate the cochlear nerve. Therefore, the choice of approach can be made based on the surgeon's own preference and experience.

Perilymphatic fistula in guinea pigs: natural evolution versus surgical treatment.

UNLABELLED: Perilymphatic fistulas still represent a major treatment challenge. In some cases, its surgical closure can reduce auditory and vestibular sequelae. AIM: To compare the behavior of cochlear window perilymphatic fistulas in guinea pigs as to their natural evolution and immediate surgical closure. MATERIALS AND METHODS: Experimental study. Forty guinea pigs were submitted to cochlear window membrane lesion and randomly broken down into two groups: open fistula (OF) and surgically closed fistula (SCF). We found the summation potential (SP) and action potential (AP) latencies and amplitudes and the SP/AP ratio at three times: pre-fistula (PRE), immediate post-fistula (IPF) and late post-fistula (LPF). RESULTS: There was a significant drop in amplitudes and raise in SP and AP latencies among the times studied. As to the SP/AP ratios, there was a reduction between PRE and IPF, both were significant. There was no behavior difference between the OF and SCF. CONCLUSIONS: Within the time frame considered, guinea pigs submitted to cochlear window membrane lesions evolved with a worsening in potentials and latencies. Despite the partial improvement in electrophysiological parameters, surgical closure did not prove statistically more effective than natural evolution.

Fístula perilinfática em cobaias: comparação entre evolução natural e correção cirúrgica / Perilymphatic fistula in guinea pigs: natural evolution versus surgical treatment

As fístulas perilinfáticas ainda constituem um grande desafio quanto ao seu tratamento. Em alguns casos, seu fechamento cirúrgico pode reduzir as sequelas auditivas e vestibulares. OBJETIVO: Comparar o comportamento de fístulas perilinfáticas de janela coclear em cobaias quanto à evolução natural e fechamento cirúrgico imediato. MATERIAL E MÉTODOS: Estudo experimental. Quarenta cobaias foram submetidas à lesão da membrana da janela coclear e divididas em dois grupos aleatoriamente: fístula aberta (FA) e fístula fechada cirurgicamente (FF). Foram determinadas as amplitudes e latências do potencial de somação (PS) e do potencial de ação (PA) e da relação PS/PA em três momentos: pré-fístula (PRÉ), pós-fístula imediato (PFI) e pós-fístula tardio (PFT). RESULTADOS: Observou-se significativa queda das amplitudes e aumento das latências do PS e PA entre os momentos considerados. Quanto à relação PS/PA, houve diminuição entre PRÉ e PFI mas aumento entre PFI e PFT, ambos significantes. Não houve diferença de comportamento entre os grupos FA e FF. CONCLUSÕES: No período considerado, cobaias submetidas a lesões da membrana da janela coclear evoluíram com piora dos potenciais e latências. Apesar da melhora parcial dos parâmetros eletrofisiológicos o fechamento cirúrgico não se mostrou estatisticamente mais efetivo que a evolução natural das mesmas.

Perilymphatic fistulas still represent a major treatment challenge. In some cases, its surgical closure can reduce auditory and vestibular sequelae. AIM: to compare the behavior of cochlear window perilymphatic fistulas in guinea pigs as to their natural evolution and immediate surgical closure. MATERIALS AND METHODS: Experimental study. Forty guinea pigs were submitted to cochlear window membrane lesion and randomly broken down into two groups: open fistula (OF) and surgically closed fistula (SCF). We found the summation potential (SP) and action potential (AP) latencies and amplitudes and the SP/AP ratio at three times: pre-fistula (PRE), immediate post-fistula (IPF) and late post-fistula (LPF). RESULTS: There was a significant drop in amplitudes and raise in SP and AP latencies among the times studied. As to the SP/AP ratios, there was a reduction between PRE and IPF, both were significant. There was no behavior difference between the OF and SCF. CONCLUSIONS: Within the time frame considered, guinea pigs submitted to cochlear window membrane lesions evolved with a worsening in potentials and latencies. Despite the partial improvement in electrophysiological parameters, surgical closure did not prove statistically more effective than natural evolution.

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.

Gotas óticas y su ototoxicidad / Otic drops and their ototoxicity

A pesar del frecuente uso de medicamentos óticos tópicos en el tratamiento de otitis media crónica activa, otorreas en presencia de tubos de ventilación o profilaxis tras la colocación de tubos, la controversia respecto al potencial rol ototóxico de estos agentes tópicos está lejos de resolverse. Si bien en animales se ha demostrado ototoxicidad coclear para la mayoría de los medicamentos, en humanos esto no parece se frecuente. En la presente revisión, referiré brevemente a la estructura de la membrana de la ventana redonda (MVR) y a los factores que influyen en su permeabilidad. Posteriormente, se comentarán los agentes tópicos más frecuentemente utilizados y su potencial ototoxicidad basado en estudios realizados tanto en animales como en humanos

Clinical aspects of round window membrane permeability under normal and pathological conditions.

Current research and an overall review of 25 years of round window membrane studies are presented. The approach, rationale and concepts that have evolved from these studies are described. Ultrastructural studies of the round window membrane of humans, monkeys, felines and rodents have disclosed three basic layers: an outer epithelium, a middle core of connective tissue and an inner epithelium. Interspecies variations are mainly in terms of thickness, being thinnest in rodents and thickest in humans. Morphologic evidence suggests that the layers of the round window participate in resorption and secretion of substances to and from the inner ear, and that the membrane could play a role in the defense system of the ear. Different substances, including antibiotics and tracers, when placed in the middle ear side traverse the membrane. Tracers placed in perilymph become incorporated into the membrane by the inner epithelial cells. Permeability is selective and factors affecting permeability include size, concentration, electrical charge, thickness of the membrane and tacilitating agents. Passage of substances through the membrane is by different pathways, the nature of which is seemingly decided at the outer epithelium of the membrane. Round window membrane studies have provided increased knowledge of the anatomy and function of this structure, as well as new insights into pathology and pathogenesis. The concepts that have evolved from these studies are potentially useful for understanding middle and inner ear interactions, and for eventual drug delivery (based on permeability) to the inner ear.