Influence of Intratympanic Low Concentration Gentamycin Injections on Hearing

Background: One of the challenges treating Meniere`s disease is helping patients who do not respond to conservative therapy. Intratympanic injections of Gentamicin, which is known as an ototoxic agent, have been proven to be effective in controlling Meniere`s disease, however their safety was questionable. There are several articles that prove that the hearing is only minimally deteriorated while using low dose Gentamicin whereas a few articles show a minor hearing improvement after such treatment.

Objectives: To check if low dose Intratympanic Gentamicin injections, in Meniere`s patients, who do not respond to conservative therapy, have an effect on hearing, in comparison to the same person`s other ear. Another goal is to check the effectiveness of the treatment.

Methods: A Comparative Retrospective Cohort Study comparing the change in hearing between the ear treated with the injections and the same person`s other ear. The study included 27 patients, all treated in the Otoneurologic clinic at Assaf Harofe medical center between 2003-2015.

Outcomes: In 74.1% of patients, treatment was successful after 1 course of Gntamycin injections. In the short term, there was improvement of earing in 1000 Hz frequency (P=0.014) and deterioration of hearing in 8000 Hz (P=0.039), both in comparison to the control ear. In the long term and after confounders adjustment, we found there is no difference in hearing between the treated ear and the same patient`s other ear.

Conclusions: In the short term, there may be slight changes in hearing, especially improvement of the hearing threshold, following Gentamicin intratympanic injections in Meniere patients who are resistant to conservative treatment, but in the long term, hearing threshold doesn`t change in comparison to the same patient`s other ear.