Direct round window membrane application of gentamicin in the treatment of Meniere's disease. 
To evaluate the effectiveness of the round window membrane (RWM) Gelfoam gentamicin technique in patients with Meniere's disease who were unresponsive to medical management or in whom surgical therapy failed.  Protocol 1, single intratympanic gentamicin infusion; protocol 2 (the best method), 2 infusions, 5 days apart with reevaluation at 1 month; and protocol 3, multiple infusions 1 to 4 weeks apart.  In total, 32 patients (19 male, 13 female) were enrolled in the study.  The mean age was 65 years (range 34 to 94 years).  Seven of these patients were surgical salvage cases.  Laser-assisted otoendoscopy with a 1.7-mm otoendoscope (Smith-Nephew Richards, Memphis, TN) was performed first.  If the RWM was obscured by mucosa or adhesions, these were cleared before placing a 2 x 3 mm piece of dry Gelfoam against the RWM.  Buffered gentamicin (26.7 mg/mL) was then injected into the middle ear (0.2 to 0.3 mL).  Overall, vertigo was controlled in 75% of the patients after the completion of the treatment, with subtotal vestibular ablation in two thirds of patients.  Hearing was preserved in 90% of the patients (within 15 dB pure-tone average or 15% speech discrimination score), tinnitus improved in 48%, and aural pressure improved in 62.5%.