In order to determine the effects of freezing on the cochlear membranous labyrinth, a cryoprobe was
Applied tothe 2nd and/or 3rd turns of the cochleas of guinea pigs.Freezing was maintained for 1-5 minutes at-60°C. Animalswere killed immediately after freezing, 30 minutes, 12 hour 24 ours, 3 days after cryogurgery.
A light microscopic investigation was carried out on sectioned specimens stainedwithHematoxylinand Eosin or surface preparations.
Definite thologic changes were visible within frozen membranous tissues. However, the amount ofdamage depended upon the duration of freezing.
Initial histologic changes were the destruction of intermediate cells of the stria vascularis and anincrease in vascular permeability of small blood vessels of the lateral cochlearwalls (spiral ligament andstria vascularis).
Remarkable atrophy of the membranous labyrinth occurred withinthefrozen membranous areas ofthe animals which survived more than 12 hours after urgery.
The present investigation revealed that cryosurgery is most useful for destroying the inner earfunction without opening the bony labyrinthine walls.
