Does intratympanic gentamicin treatment for Meniere's disease cause complete vestibular ablation?

To determine changes in vestibular function following intratympanic gentamicin (ITG) treatment for Meniere's disease and to correlate changes with the need for further treatment.

Prospective case series.

One hundred and three patients with disabling unilateral Meniere's disease who had failed a minimum of 6 months medical treatment.

Vestibular function was measured by electronystagmography (ENG) caloric testing before and serially following treatment. Caloric responses were classified as normal (excitability difference [ED] < 25%), bithermal response (ED > or = 25%), positive response to ice water only, and absent ice water response.

Twenty-one percent of patients had a bithermal caloric response, 62% had an absent ice water response, and 17% had an ice water response only 1 month following treatment. Mean follow-up was 27.3 months (range = 1-106 months). Eighty-four patients had one treatment course only. Fourteen patients required a further course of treatment due to recurrence of vertigo; 38% of these had recovery of caloric function. Significantly more patients with normal caloric function prior to initial treatment required further treatment compared to those with initial reduced caloric function (p < .05). Patients rendered absent ice water responsive were significantly less likely to require further treatment than those with a persistent caloric response (p < .0001).

An absent ice water response is highly predictive of adequate vertigo control. Regimens of ITG that aim to completely ablate vestibular function are recommended.