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.

Effect of Probe-Tone Frequency on Ipsilateral and Contralateral Electrical Stapedius Reflex Measurement in Children With Cochlear Implants.

OBJECTIVES: The upper loudness limit of electrical stimulation in cochlear implant patients is sometimes set using electrically elicited stapedius reflex thresholds (eSRTs), especially in children for whom reporting skills may be limited. In unilateral cochlear implant patients, eSRT levels are measured typically in the contralateral unimplanted ear because the ability to measure eSRTs in the implanted ear is likely to be limited due to the cochlear implant surgery and consequential changes in middle ear dynamics. This practice is particularly limiting in the case of fitting bilaterally implanted pediatric cases because there is no unimplanted ear option to choose for eSRT measurement. The goal of this study was to identify an improved measurement protocol to increase the success of eSRT measurement in ipsilateral or contralateral or both implanted ears of pediatric cochlear implant recipients. This work hypothesizes that use of a higher probe frequency (e.g., 1000 Hz compared with the 226 Hz standard), which is closer to the mechanical middle ear resonant frequency, may be more effective in measuring middle ear muscle contraction in either ear. DESIGN: In the present study, eSRTs were measured using multiple probe frequencies (226, 678, and 1000 Hz) in the ipsilateral and contralateral ears of 19 children with unilateral Advanced Bionics (AB) cochlear implants (mean age = 8.6 years, SD = 2.29). An integrated middle ear analyzer designed by AB was used to elicit and detect stapedius reflexes and assign eSRT levels. In the integrated middle ear analyzer system, an Interacoustics Titan middle ear analyzer was used to perform middle ear measurements in synchrony with research software running on an AB Neptune speech processor, which controlled the delivery of electrical pulse trains at varying levels to the test subject. Changes in middle ear acoustic admittance following an electrical pulse train stimulus indicated the occurrence of an electrically elicited stapedius reflex. RESULTS: Of the 19 ears tested, ipsilateral eSRTs were successfully measured in 3 (16%), 4 (21%), and 7 (37%) ears using probe tones of 226, 678, and 1000 Hz, respectively. Contralateral eSRT levels were measured in 11 (58%), 13 (68%), and 13 (68%) ears using the three different probe frequencies, respectively. A significant difference was found in the incidence of successful eSRT measurement as a function of probe frequency in the ipsilateral ears with the greatest pair-wise difference between the 226 and 1000 Hz probe. A significant increase in contralateral eSRT measurement success as a function of probe frequency was not found. These findings are consistent with the idea that changes in middle ear mechanics, secondary to cochlear implant surgery, may interfere with the detection of stapedius muscle contraction in the ipsilateral middle ear. The best logistic, mixed-effects model of the occurrence of successful eSRT measures included ear of measurement and probe frequency as significant fixed effects. No significant differences in average eSRT levels were observed across ipsilateral and contralateral measurements or as a function of probe frequency. CONCLUSION: Typically, measurement of stapedius reflexes is less successful in the implanted ears of cochlear implant recipients compared with measurements in the contralateral, unimplanted ear. The ability to measure eSRT levels ipsilaterally can be improved by using a higher probe frequency.