Intratympanic gentamicin for control of vertigo in Meniere's disease: vestibular signs that specify completion of therapy.

OBJECTIVE: To determine if a protocol of weekly intratympanic gentamicin injections administered until development of signs of unilateral vestibular hypofunction can alleviate vertigo while preserving hearing in patients with intractable vertigo caused by unilateral Meniere's disease.

STUDY DESIGN: The study design was a prospective investigational protocol.

SETTING: The study was performed in outpatients at a tertiary referral center.

PATIENTS: Entry criteria included a diagnosis of "definite" Meniere's disease according to the 1995 report of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS), intractable vertigo despite optimal medical therapy, no symptoms suggestive of Meniere's disease in the contralateral ear and serviceable hearing in the contralateral ear. The outcomes of the first 34 patients who entered the protocol are reported.

INTERVENTION: A buffered gentamicin solution was injected into the middle ear at weekly intervals until development of spontaneous nystagmus, head-shaking-induced nystagmus, or head-thrust sign indicative of vestibular hypofunction in the treated ear.

MAIN OUTCOME MEASURE: The 1995 AAO-HNS criteria for reporting treatment outcome in Meniere's disease were used. The effects of treatment were assessed in terms of control of vertigo, disability status, hearing level, and quantitative measurement of vestibular function with caloric and rotatory chair tests.

RESULTS: Vertigo was controlled in 91% of the patients. Profound hearing loss occurred as a result of gentamicin injection in one patient (3%). Intratympanic gentamicin was significantly less effective in controlling vertigo in patients who had previous otologic surgery on the affected ear. Recurrence of vertigo > or = 6 months after initially complete control was noted in seven patients (22%). Vertigo in six of these patients was eliminated by additional intratympanic gentamicin injections.

CONCLUSIONS: Ending weekly intratympanic gentamicin injections when clinical signs of unilateral vestibular hypofunction appear can control vertigo in most patients. Hearing loss directly attributable to gentamicin is uncommon. Treatment outcome is best in patients who have not had previous otologic surgery.