Comparison of VEMPs, VHIT and caloric test outcomes after vestibular neurectomy in Menière's disease

Objective: Selective unilateral vestibular neurectomy (VN) is considered a reliable surgical treatment in case of recurrent vertigo in Menière's disease (MD) because of hearing preservation and a minimally invasive posterior fossa retrosigmoid approach. The present study aimed to assess the quality of life and the long-term vestibular function in patients submitted to yearly follow-up after VN because of intractable MD. Methods: Retrospective series of 15 MD patients undergoing retrosigmoid VN for recurrent vertigo. Outcome measures included cVEMPs and oVEMPs (cervical and ocular vestibular evoked myogenic potentials), VHIT (Video Head Impulse Test) and caloric test, besides to DHI (Dizziness Handicap Inventory) and PTA (Pure Tone Audiometry). Results: Mean DHI score resulted within normal values in 74% of patients, significantly correlated to the duration of the follow-up. In the operated side, cVEMPs and oVEMPs have not been elicited respectively in 11 patients (73%) and 13 patients (87%), whereas it was not possible to evoke any response at bithermal caloric test in 4 cases. The gain of VOR from VHIT resulted always below normal values after VN except in one patient, who has also undergone an episode of posterior BBPV. The difference between average PTA threshold before and after VN resulted not significant. Conclusion: The vestibular outcomes prove VN to be an effective and safe surgery in MD; furthermore, the unexpected occurrence of BPPV after VN can justify the presence of neural anastomosis between the inferior vestibular nerve and the cochlear nerve, allowing to still perceive vestibular symptomatology despite of a proper neurectomy.