Ablation of otolithic organs with argon laser.

Utricular maculae of guinea pigs were irradiated by argon laser through the oval window without touching the perilymph. The stapes was replaced in the oval window after irradiation. The inner ear was studied morphologically and physiologically. Argon laser beam caused detachment of the sensory epithelium from the basement membrane of the utricular macula. The lesion was round and localized at the site of irradiation. The epithelium changed to a layer of cuboidal cells after 2 to 3 weeks at the irradiated spot. Degeneration of the epithelium gradually spread to the periphery, and total loss of sensory epithelium was observed 10 weeks after irradiation. Hearing was preserved, and caloric test showed normal response.