CLINICAL PATHOPHYSIOLOGY OF VESTIBULAR NEURECTOMY

This study attempts to characterize the residual vestibular function r emaining after incomplete supralabyrinthine vestibular neurectomy perf ormed for disabling vertigo. Patients with bilateral vestibular neurec tomy had preserved horizontal vestibule-ocular reflexes in response to high angular accelerations with gain enhancement over time. A torsion al down-beating spontaneous nystagmus and an important tilt of the sub jective vertical were observed when the remaining eighth nerve was sec tioned after homolateral incomplete supralabyrinthine vestibular neure ctomy. These findings suggest that a reorganization of vestibular refl exes may occur after incomplete supralabyrinthine vestibular neurectom y if efferents of the inferior vestibular branch are partially spared. The vestibular function after incomplete supralabyrinthine vestibular neurectomy does not affect the postoperative control of vertiginous a ttacks and may have positive effects in case of deterioration of the c ontralateral inner ear.