Cochlear effects of cryosurgery.

A total of 21 cochleas in 13 chinchillas were treated with cryosurgery and the damage to the organ of Corti was evaluated with the scanning electron microscope. The apical half-turn was treated in 11 of the cochleas and the basal half-turn in 10. Apical exposure to the cryoprobe generally resulted in severe damage to sensory cells in the apical turn whereas basal turn exposure generally resulted in mild damage to sensory cells in the basal turn. On occasion severe damage from apical turn exposure resulted in severe damage that extended to the basal turn. First row outer hair cells were the most susceptible to damage and inner hair cells least susceptible.