Cochleovestibular nerve sections in labyrinthectomized patients.

Labyrinthectomy is indicated for a patient who has unilateral peripheral labyrinthine disease with unserviceable hearing loss. For most patients, labyrinthectomy provides complete relief from intractable vertigo. Some patients continue to have persistent vertigo, however, even after a complete destructive labyrinthectomy. Only after cochleovestibular nerve sections were these patients relieved of intractable vertigo. Representative cases of cochleovestibular nerve sections in labyrinthectomized patients are presented. The reason why the cochleovestibular nerve section relieves the symptom of vertigo in labyrinthectomized patients is not clear. Labyrinthectomy destroys vestibular sense organs, while cochleovestibular nerve section eliminates spontaneous activity and prevents the possibility of nerve regeneration by excision of the ganglion. For those patients who required vestibular nerve sections, there may have been abnormal excitation of vestibular nerve fibers. This might be explained by incomplete labyrinthectomy, regeneration of vestibular nerve fibers, contribution from vestibular ganglia or nonfunctioning cochlea, and vascular loop syndrome.