Partial Labyrinthectomy with Argon Laser

Abstract

Ablation of the saccule and the utricle using an argon laser was carried out in monkeys. After stapedectomy, the saccular macula and the utricular macula were irradiated through the oval window. Animals were sacrificed on 0 day, 10 days, 14 days, and 10 weeks after irradiation. The sensory cells of the saccular macula were detached from the supporting cells at the impact point. The otolith, the saccular wall, and the connective tissue of the saccular macula just beneath the supporting cells were intact. Two weeks after irradiation, sensory cells had disappeared, and the number of nerve fibers was reduced. Ten weeks after the irradiation (1.0 w × 0.5 s × 3 spots), two-thirds of the saccular macula had degenerated, and its surface was covered by a cuboidal cell layer. The number of nerve fibers was reduced. The ganglion cells of the inferior vestibular nerve had degenerated and the cells were smaller than the superior vestibular nerve. Two weeks after irradiation of the utricle, not only sensory cells and supporting cells but also the basement membrane of the utricular macula, connective tissue, and nerve fibers had degenerated and disappeared. Degeneration was extremely localized.

Key Words:

• argon laser
• saccule
• utricle
• labyrinthectomy