Abstract
The cochleas of 25 guinea pigs were exposed to carbon dioxide laser irradiation for.the duration of 0.4 to 1 second at 4 to 32 watts.
Animals were killed immediately or 30 minutes after the irradiation. The damages were examined histopathologically.
When 7 males were applied there was considerable damage to both the bony and the membraneous labyrinth. The bony capsule of the cochlea was found scorched and perforated. The underlying cochlear lateral wall around the perforation was destroyed. The cells composing the stria vascularis and spiral ligament were swollen and partially vacuolated. Reissner's membrane and the organ of Corti had disappeared completely. With increased laser intensities the lesions were found extending deep into the modiolus of the cochlea. The cochlear lateral wall, organ of Corti, Reissner's membrane and spiral limbus were severely destroyed. The spiral ganglion cells were also involved. An increase in vascular permeability was also noted in the areas of the irradiated labyrinth. In order to abolish the functionof the labyrinth by laser it was found necessary to expose the membranous labyrinth, which may induce local infection.
More experimental studies must be done before laser can be safely used in human ear surgery.
