Long-term results with the Rion E-type semi-implantable hearing aid.

Objective: The Rion implantable hearing aid (IHA) Ehime (E)-type was developed for ears with middle ear diseases. This study focused on the current status of the patients, device problems, postoperative difficulties, and preventive measures against them.

Study Design: Case series with chart review.

Setting: Tertiary referral hospital.

Subjects And Methods: Subjects were 30 patients who were implanted with the IHA E-type between 1984 and 1997 and followed up for more than 10 years. Current status of IHA implantees, incidents of device problems, and postoperative troubles and hearing outcomes were reviewed.

Results: Eleven patients (36.7%) still use the original device. The average period of use was 16.6 +/- 3.3 years (21 years at most). The incidence of problems was lower with the second version of the device compared to the first version. Frequencies of the troubles were related to the types of original ear diseases: seven of 17 cases with chronic otitis media (41.2%), two of seven cases with cholesteatoma (28.6%), and two of six cases with tympanosclerosis (33.3%). No cholesteatoma occurred after surgical procedures (i.e., external ear canal closure and tympanic membrane lateralized) (P = 0.06). The device was exposed through a retroauricular skin fistula where the internal coil had been implanted. Significantly fewer infections were observed when the two-stage operation was used (P < 0.01).

Conclusion: For long-term success in implantation of the IHA, careful control of middle ear inflammation and measures against eustachian tube dysfunction are required in addition to technological advancements.