Intratympanic therapy for Ménière's disease. High-concentration gentamicin with round-window protection

Abstract

Many therapeutic options exist for the management of patients with Ménière's disease. In the last few years, the use of intratympanic gentamicin has been investigated as an alternative treatment to vestibular nerve section or labyrinthectomy. In humans, the concentration of gentamicin used for intratympanic treatment of vertigo ranges from 10 mg/mL to 40 mg/mL, and the number of doses from 2 to 14, with a total administered amount between 6 and 2.400 mg. Here lower doses of gentamicin were used, usually had the lowest incidence of hearing loss, but more injections were needed to ablate vestibular function. The purpose of this study was to evaluate the acute and chronic ototoxic effects of intratympanic high-concentration gentamicin after having obliterated the round-window niche with connective tissue in 11 subjects' ears with Ménière's disease. Intratympanic gentamicin was administered according to a predetermined and fixed schedule consisting of two doses of 0.5 mL gentamicin solution, injected once a week with a drug concentration of 80 mg/mL. The total dose of gentamicin was < or = 80 mg. The charts of the patients were surveyed in accordance with the 1995 AAO-HNS guidelines. Three patients had recurrence of vertigo between 3 and 6 months after the second injection and went on to one additional dose of gentamicin. At 2 years follow-up, 10 patients (91%) had complete and 1 (9%) substantial control of vertigo; 3 subjects (27%) had hearing decreased. Tinnitus disappeared or decreased in 3 patients (27%); eight subjects (73%) reported their aural pressure abolished or decreased. The present study demonstrates that in patients with Ménière's disease, 0.5 mL gentamicin solution, with a concentration of 80 mg/mL (total dose < or = 80 mg), injected intratympanically once a week after having obliterated the round-window niche, permits complete or substantial control of vertigo in two-thirds of cases after two doses and in all subjects after three doses. This vertigo control rate is compared to that observed after vestibular nerve section. Hearing results are not different from those with natural control, with endolymphatic sac surgery, and with vestibular nerve section.