For severe otitis media with effusion, insertion of a ventilation tube is performed for the purpose of ventilation of the middle ear cavity and normalization of eustachian tube function and the middle ear mucosa. The ventilation tube is left in place for as long as several months or even a few years. However, the effect of insertion of a ventilation tube on vibration of the tympanic membrane is unknown. Therefore, we observed the effect by means of time-averaged holography using human tympanic membranes.
The following results were obtained. After insertion of a ventilation tube, the tympanic membrane vibratory pattern was not obviously changed, but the vibratory amplitude of the tympanic membrane was decreased, especially at 500Hz. Generally speaking, the change caused by insertion of a ventilation tube was very small.
