Post-operative Hearing Changes In Patients With Ménière's Disease Receiving Vestibular Neurectomy Via Retrosigmoid Approach And Pathological Observation Of Vestibular Nerve

Objective:To study the post-operative hearing changes in patients with Ménière's disease receiving vestibular neurectomy via retrosigmoid approach.Methods : A retrospective study was carried out. Data of six patients receiving retrosigmoid approach vestibular neurectomy from July 2006 to July 2008 were collected. The results including vertigo attack frequency, pure tone hearing threshold and vestibular function test before and after the surgery were analysised respectively.Results:There was no significant differcnce in pure tone hearing threshold before and after the surgery (p>0.05). After the surgery, 5 cases were found complete vertigo control while 1 basical control. Vestibular function of 2 cases was completely compensated, while the other 4 cases partly compensated.Conclusion: Selective vestibular neurectomy via retrosigmoid approach is one of the most effective methods for the control of vertigo in Ménière's disease while preserving or improving the residual hearing. Objective: Inner ear pathological changes are the major basis of Meniere's disease (MD), but whether the vestibular nerve fibers are involved is still undetermined. In this paper, we studied the biopsy specimens of vestibular nerves of MD patients and discussed the possible correlation between pathological changes of the vestibular nerve and the clinical manifestations.Methods: In 1 patients, a translabyrinthine vestibular nerve transection was done; in 4 patients, a retrosigmiod vestibular neurectomy was done. All 5 biopsy specimens of vestibular nerves were underwent HE stained histopathological examination.Results: HE stained histopathological examination can be a good indication of nerve fiber structure. Under the light microscope, all the five cases of vestibular nerve fibers showed different degrees of pathological changes. Nerve fibers loose and edema were the most common pathological abnormalities, in addition to the performance of a variety of characteristic degeneration of nerve fibers, such as the nerve fiber amyloidosis and calcified body mainly distributed in the sheath region. Patients with significant abnormality in vestibular nerve fibers showed heavier vertiginous symptoms and abnormal vestibular tests but minor cochlear dysfunction, suggesting the possible correlation between pathological changes of nerve fibers and vestibular dysfunction.Conclusion: This study found that MD can present degenerative changes in nerve fibers, suggesting that the pathological basis of Meniere's disease with vestibular nerve fibers in lesions. Nerve fiber degeneration can lead to the vestibular end-organ vestibular signals generated by the former Court of abnormal central conduction, thus affecting the vestibular function and clinical manifestations, vestibular nerve fiber degeneration in the pathogenesis of Meniere's disease significance worthy of further study.