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

OBJECTIVE: 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.

STUDY DESIGN: Prospective case series.

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

MAIN OUTCOME MEASURES: 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.

RESULTS: 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).

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