Tympanometric Changes in an Experimental Myringosclerosis Model After Myringotomy

Effect of Cochlear Implantation on Vestibular Evoked Myogenic Potentials and Wideband Acoustic Immittance

OBJECTIVES

The objective of this study was to determine if absent air conduction stimuli vestibular evoked myogenic potential (VEMP) responses found in ears after cochlear implantation can be the result of alterations in peripheral auditory mechanics rather than vestibular loss. Peripheral mechanical changes were investigated by comparing the response rates of air and bone conduction VEMPs as well as by measuring and evaluating wideband acoustic immittance (WAI) responses in ears with cochlear implants and normal-hearing control ears. The hypothesis was that the presence of a cochlear implant can lead to an air-bone gap, causing absent air conduction stimuli VEMP responses, but present bone conduction vibration VEMP responses (indicating normal vestibular function), with changes in WAI as compared with ears with normal hearing. Further hypotheses were that subsets of ears with cochlear implants would (a) have present VEMP responses to both stimuli, indicating normal vestibular function and either normal or near-normal WAI, or (b) have absent VEMP responses to both stimuli, regardless of WAI, due to true vestibular loss.

DESIGN

Twenty-seven ears with cochlear implants (age range 7 to 31) and 10 ears with normal hearing (age range 7 to 31) were included in the study. All ears completed otoscopy, audiometric testing, 226 Hz tympanometry, WAI measures (absorbance), air conduction stimuli cervical and ocular VEMP testing through insert earphones, and bone conduction vibration cervical and ocular VEMP testing with a mini-shaker. Comparisons of VEMP responses to air and bone conduction stimuli, as well as absorbance responses between ears with normal hearing and ears with cochlear implants, were completed.

RESULTS

All ears with normal hearing demonstrated 100% present VEMP response rates for both stimuli. Ears with cochlear implants had higher response rates to bone conduction vibration compared with air conduction stimuli for both cervical and ocular VEMPs; however, this was only significant for ocular VEMPs. Ears with cochlear implants demonstrated reduced low-frequency absorbance (500 to 1200 Hz) as compared with ears with normal hearing. To further analyze absorbance, ears with cochlear implants were placed into subgroups based on their cervical and ocular VEMP response patterns. These groups were (1) present air conduction stimuli response, present bone conduction vibration response, (2) absent air conduction stimuli response, present bone conduction vibration response, and (3) absent air conduction stimuli response, absent bone conduction vibration response. For both cervical and ocular VEMPs, the group with absent air conduction stimuli responses and present bone conduction vibration responses demonstrated the largest decrease in low-frequency absorbance as compared with the ears with normal hearing.

CONCLUSIONS

Bone conduction VEMP response rates were increased compared with air-conduction VEMP response rates in ears with cochlear implants. Ears with cochlear implants also demonstrate changes in low-frequency absorbance consistent with a stiffer system. This effect was largest for ears that had absent air conduction but present bone conduction VEMPs. These findings suggest that this group, in particular, has a mechanical change that could lead to an air-bone gap, thus, abolishing the air conduction VEMP response due to an alteration in mechanics and not a true vestibular loss. Clinical considerations include using bone conduction vibration VEMPs and WAI for preoperative and postoperative testing in patients undergoing cochlear implantation.

Diseño, modelado 3D y optimización del comportamiento mecanoacústico de un nuevo tubo de ventilación transtimpánico

Introducción y Objetivos: En este trabajo mostramos un nuevo tubo de ventilación transtimpánico cuyo diseño pretende solventar los efectos indeseables aparecidos durante la inserción de tubos de ventilación actualmente comercializados; analizamos su comportamiento mecánico en un modelo 3D del oído a fin de optimizar su comportamiento acústico. Métodos: Para el diseño del tubo se empleó un software autoCAD; El comportamiento mecánico se analizó en un modelo computadorizado dinámico 3D del oído humano basado en el método de los elementos finitos (FEM). Resultados: El nuevo tubo de ventilación posee un tamaño y una masa significativamente menores a los actualmente disponibles en el mercado lo que provoca un menor interferencia en la vibración del sistema tímpano-osicular; su diseño facilita que permanezca insertado mientras las condiciones del paciente así lo aconsejen evitando su caída hacia la caja o su precoz extrusión. Conclusiones: Las ventajas teóricas biológicas y acústicas del nuevo tubo desarrollado (con menor masa y cuyo diseño evita las complicaciones de los actuales) puede abrir una nueva posibilidad de tratamiento de la otitis media seromucosa crónica.

Application of Regenerative Treatment for Tympanic Membrane Perforation With Cholesteatoma, Tumor, or Severe Calcification

OBJECTIVE

To apply regenerative treatment for tympanic membrane (TM) perforation to patients with severe calcification of the TM, cholesteatomas, or tumors localized to the tympanic cavity.

STUDY DESIGN

Controlled clinical pilot study.

SETTING

General hospitals.

PATIENTS

Forty-five patients (age: 8-85; M = 19, F = 26) were selected from patients with or without TM perforation for the regenerative treatment. Twenty-five patients had cholesteatomas, 3 had tumors, and 17 had severe TM calcification. Patients were classified into three groups based on TM perforation size: less than 1/3 of the TM as Grade I (n = 5), 1/3 to 2/3 as Grade II (n = 19), and over 2/3 as Grade III (n = 21). Twenty patients who underwent standard tympanoplasty type I were selected as historical controls.

MATERIALS AND METHODS

Materials for the TM repair included gelatin sponge with basic fibroblast growth factor and fibrin glue. After lesions were removed through the TM perforation, gelatin sponge immersed in basic fibroblast growth factor was placed over the perforation. Fibrin glue was then dripped onto the sponge. Treatment efficacy was evaluated 6 months posttreatment.

RESULTS

Complete closure of the TM perforation was achieved in 91% (n = 41/45) of the patients in this regenerative treatment. Improvement in average hearing levels and air-bone gap were much better with this treatment than in the historical control group.

CONCLUSION

This new regenerative therapy is useful not only for patients with simple TM perforations but also for those with cholesteatomas, tumors, or severe calcification without requiring conventional surgical procedures. This regenerative therapy is an easy, safe, cost-effective, and minimally-invasive treatment.