Intratympanic gentamicin treatment 'as needed' for Meniere's disease. Long-term analysis using the Kaplan-Meier method.

In recent years, several titration or on-demand protocols using low-dose repeated intratympanic (IT) gentamicin injections have been adopted for the vertigo control in unilateral medical refractory Menière's disease (MD). Because of the frequent recurrence and the need to treat the patients several times, it is difficult to strictly follow the 1995 AAO-HNS criteria to classify the results. The Kaplan-Meier analysis provides an effective and simpler method to address these concerns. We report the results of a long-term study (7 years) on a large population of MD patients (174) treated with on-request low-dose delayed IT gentamicin injections analysed using the Kaplan-Meier survival method. Effective vertigo control was obtained with a single injection in 40.2 \% of the patients (excellent responders) and with repeated injections (2-9) in 43.7 \% of the patients (moderate responders). Only six patients (3.5 \%) needed to be submitted to vestibular neurectomy because of the persistence of vertigo attacks (non-responders). A subgroup of 22 patients (12.6 \%) reporting a late recurrence of vertigo attacks after an initial vertigo-free interval lasting more than 2 years (short-term responders) were successfully treated with a further cycle of injections. In no cases, we observed significant signs of cochlear or vestibular toxicity. Kaplan-Meier survival analysis provided an excellent method for reporting treatment success or failure in patients followed for variable length of time with our kind of protocol.