Hearing after retrolabyrinthine vestibular neurectomy

Thirty-four patients underwent vestibular neurectomies between September 1984 and January 1989. The first 15 patients operated on through January 1987 (and followed for a minimum of 2 years) were evaluated separately for long-term hearing preservation and freedom from vertigo spells. Audiograms taken at 1 postoperative month revealed no change in the pure tone averages of 25 patients and showed improved hearing of 20 to 30 dB in 5 patients. Two patients sustained losses of 18.5 dB and 21 dB, respectively. The speech discrimination scores remained the same in 17 patients, improved in 9, and were reduced in 6. Audiograms performed 12 to 40 months postoperatively showed preservation of the pure tone averages and speech discrimination scores when compared with the earlier 1-month postoperative audiograms in 73% of the patients. The speech discrimination scores, however, tended to fluctuate with the symptomatic course of each disease. Two patients developed major vertigo spells 1 1/2 years following surgery. Postoperative ice-caloric testing revealed no responses in 25 patients and markedly reduced responses in 6. There were no major complications or facial paralysis. The retrolabyrinthine vestibular neurectomy is an effective way to control vertigo with preservation of hearing and an acceptably low incidence of complications and side effects.     

Middle fossa vestibular neurectomy in retrolabyrinthine neurectomy failures.

Retrolabyrinthine vestibular nerve section is an important treatment option in patients with refractory, incapacitating vertigo. However, an indistinct cleavage plane between the cochlear and vestibular portions of the eighth cranial nerve may result in incomplete sectioning of the superior and inferior vestibular nerve fibers. We describe 11 patients in whom middle fossa vestibular neurectomy was performed following failure of a retrolabyrinthine vestibular neurectomy. A successful postoperative outcome from this revision surgery was obtained in six of 11 patients on follow-up evaluation. Patients in whom infrared video electronystagmography showed persistent function of the inferior vestibular nerve following retrolabyrinthine vestibular nerve section had a better response to middle fossa vestibular neurectomy than those with no measurable residual vestibular function. Because it provides access to the vestibular nerves where there is separation from the cochlear nerves distal to the previous section, we feel that the middle fossa vestibular neurectomy is the procedure of choice in selected patients who fail retrolabyrinthine neurectomy.     

A comparison of retrosigmoid IAC, retrolabyrinthine, and middle fossa vestibular neurectomy for treatment of vertigo

A new procedure, the retrosigmoid internal auditory canal (IAC) vestibular neurectomy has been developed and presented. It involves a 3-cm retrosigmoid craniotomy removing the posterior wall of the IAC to the singular canal, with transection of the superior vestibular nerve and posterior ampullary nerve. This produces a complete denervation of the vestibular labyrinth and preserves the patient's hearing. All ten patients with Meniere's disease had their vertigo cured. Hearing was preserved to within 11 dB of the preoperative pure tone average in 9 of 10 cases. There were no serious complications, no cases of facial paralysis, and no cases of total hearing loss. These results compare favorably with the MFVN and the RVN. The retrosigmoid IAC vestibular neurectomy is an important improvement in the evolution of vestibular neurectomy for the treatment of vertigo.     

Hearing results in retrolabyrinthine vestibular neurectomy.

Patients having retrolabyrinthine vestibular neurectomy (RLVN) may have complications that compromise hearing. While most reviews have emphasized sensorineural loss, less attention has been given to conductive hearing loss, which may complicate RLVN. Hearing results of 25 consecutive cases of RLVN performed for Meniere's disease with incapacitating vertigo were tabulated according to 1985 American Academy of Otolaryngology (AAO) guidelines. Nine patients (36%) had improved hearing postoperatively, 5 (20%) had no change in hearing, and 11 (44%) had worse hearing postoperatively. The most commonly observed audiometric change was low-frequency conductive hearing loss, presumably secondary to partial ossicular fixation by bone dust or fat fibrosis in the attic and antrum. Five patients (20%) had low-frequency conductive hearing losses that increased by 10 dB or greater over preoperative levels. An additional 7 patients had lesser losses at low frequencies. One patient had a flat conductive hearing loss. Six (24%) of the patients had a decrease in bone levels of greater than 10 dB. Overall hearing results in this study are comparable to those of other series in the literature. Causes and prevention of conductive hearing loss in RLVN are discussed, and a format for presentation of hearing data that will highlight conductive hearing loss after surgery for Meniere's disease is presented.     

Hearing results and control of vertigo after retrolabyrinthine vestibular nerve section

To determine the effect of retrolabyrinthine vestibular nerve section (RVNS) on hearing, vertigo, and associated symptoms, we reviewed our experience in 48 patients. Of the 48, 39 responded to a questionnaire. Although RVNS appeared to have little effect on hearing in Meniere's patients, 91% of non-Meniere's patients had significant and often delayed postoperative sensorineural hearing loss. Our results for vertigo control compared favorably to previous reports with 96% of Meniere's patients and 69% of non-Meniere's patients reporting improvement. Presently, we more frequently recommend RVNS as the primary procedure for the control of severe vertigo in Meniere's patients. Patients with vertigo from other causes must be carefully selected.     

Results of vestibular neurectomy in the treatment of vertigo. Apropos of 38 cases

We present a series of 38 patients, operated by vestibular neurectomy, during 1968-1987, for peripheral vertigo intractable to medical therapy of different origin. This study includes a retrospective analysis of the results on vertigo, hearing, tinnitus and postoperative complications. Then, the operative indications and surgical approaches are discussed.     

迷路后径路前庭神经切断术治疗难治性梅尼埃病75例

目的 探讨迷路后径路前庭神经切断术治疗难治性梅尼埃病的手术安全性、可靠性、术后疗效。 方法 回顾性分析75例单侧难治性梅尼埃病患者行经迷路后径路前庭神经切断术的临床资料。 结果 75例患者平均病程(53.11±43.87)个月,术前500 Hz、1 000 Hz、2 000 Hz、4 000 Hz平均听阈(63.71±16.85)dB HL。听力分期Ⅱ期2例,Ⅲ期34例,Ⅳ期39例。Ⅱ期2例患者为内淋巴囊减压术后复发患者。术后颅内感染1例(1.3%)、脑脊液漏4例(5.3%)、暂时性面瘫1例(1.3%)、切口感染2例(2.6%)、切口脂肪液化3例(3.9%)。无颅内出血及术后即刻全聋的病例。术后眩晕疗效评定73例患者为A级,2例患者为B级。 结论 经迷路后前庭神经切断术疗效确切,风险与并发症可控,可显著改善患者生活质量。     

Endoscope-assisted vestibular neurectomy

Objective/Hypothesis: In some instances endoscopes offer better visualization than the microscope and frequently allow less invasive surgery. This study was undertaken to determine whether endoscopy is safe and effective during neurectomy of the vestibular nerve. Method: Ten patients with intractable unilateral Meniere's disease underwent a retrosigmoid craniotomy for neurectomy of the vestibular nerve. Endoscopy with a Hopkins telescope was used during each procedure to study posterior fossa anatomic relationships and to assist the neurectomy. Preoperative and postoperative audiometric evaluation was performed in all patients undergoing vestibular neurectomy. Nine of these patients had preoperative electronystagmography, and four patients completed postoperative electronystagmography. The 1995 American Academy of Otolaryngology—Head and Neck Surgery's Committee on Hearing and Equilibrium guidelines for the diagnosis and evaluation of therapy in Meniere's disease were used. Results: Complete neurectomy was achieved in all 10 patients. Endoscopy allowed improved identification of the nervus intermedius and the facial, cochlear, and vestibular nerves and adjacent neurovascular relationships without the need for significant retraction of the cerebellum or brainstem. In addition, endoscopic identification of the cleavage plane between the cochlear and vestibular nerves medial to or within the internal auditory canal (n = 3) was not made with the 0-degree endoscope; however, identification was made with the 30- or 70-degree endoscope in all cases. In all patients with Meniere's disease, elimination of the recurrent episodes of vertigo (n = 10) or otolithic crisis of Tumarkin (n = 1) was achieved. Conclusions: Posterior fossa endoscopy can be performed safely. Endoscope-assisted neurectomy of the vestibular nerve may offer some advantages over standard microsurgery including increased visualization, more complete neurectomy, minimal cerebellar retraction, and a lowered risk of cerebrospinal fluid leakage.     

前庭神经切断术后的前庭代偿观察

目的观察前庭神经切断术后的前庭代偿过程。方法对1998-2005年10例前庭神经切断术后患者．观察自发性眼震和平衡失调的持续时间，并对4例术前、后眼震电图进行对比观察。结果患者术后均出现快相向健侧的水平性眼震，持续4～7天消失，平衡失调恢复时间为一月至一年不等，年龄越大持续时间越长。4例进行眼震电图检查的患者，3例前庭功能均丧失，1例热水试验出现反向眼震。结论前庭代偿是前庭神经切断术后患者康复的必然过程，前庭康复训练可缩短前庭代偿的时间。     

Hearing preservation in vestibular neurectomy

The goal of vestibular neurectomy is to control disabling vertigo while preserving hearing in patients with nonhydropic intractable peripheral vertigo or in patients with Meniere's disease in which an endolymphatic sac procedure has failed. Labyrinthectomy continues to be used to treat patients with intractable vertigo and serviceable hearing. We feel that a labyrinthectomy is contraindicated when any useful hearing remains. Vestibular neurectomy affords the surgeon a means to eliminate the abnormal vestibular input without sacrificing hearing. Two approaches have been used to section the vestibular nerves: the middle fossa approach since 1961 and the retrolabyrinthine approach more recently. Both approaches are effective in relieving vertigo while preserving hearing. This paper presents a statistical analysis of these two approaches. Although differences did exist, both were found to be highly successful in alleviating incapacitating vertigo and preserving hearing in a large percentage of patients.     

Posterior fossa vestibular neurectomy.

Many procedures have been devised to deal with intractable vertigo and conserve hearing, but despite this selective vestibular nerve section remains by far the most effective treatment. A series of 14 patients who underwent posterior fossa vestibular neurectomy is reported. The results are reported for vertigo control, hearing and tinnitus. All of the patients achieved vertigo control according to the AAOO (1972) reporting system. A simple and reliable system for the classification of the disability in these patients has yet to be devised. This problem is addressed and a disability grading system proposed, and discussed.     

MRI of the vestibular nerve after selective vestibular neurectomy

Conclusion. In patients with Ménière's disease and persisting vertigo attacks after vestibular neurectomy (VNx) MRI of the vestibulocochlear nerve can identify residual vestibular nerve fibres that could be responsible for the vertigo attacks. Objective. To test if MRI of the vestibulocochlear nerve can corroborate the presence of residual vestibular nerve fibres in patients with persisting vertigo attacks and residual vestibular function after VNx. Materials and methods. Vestibulocochlear nerve bundles of seven post-VNx unilateral Ménière's patients were imaged using 1.5 Tesla MRI with steady state free precession (SSFP) sequences. Reformatted MR images orthogonal to the vestibulocochlear nerve axis in internal auditory canal were compared on the VNx and intact sides. Vestibular function was assessed with caloric tests, three-dimensional head impulse tests and vestibular evoked myogenic potentials. Of the seven patients only one was asymptomatic (totally free of vertigo); six had continued to experience vertigo attacks, albeit not as long or as severe as before VNx. Results. On the VNx side, MRI showed intact facial and cochlear nerves in all seven patients. In the six symptomatic patients, although superior and inferior vestibular nerve bulk and signal were reduced, residual bulk suggestive of inferior vestibular nerve was evident, correlating with evidence of residual posterior canal function on impulsive testing in all six symptomatic patients. In the asymptomatic patient, superior and inferior vestibular nerves were absent on MRI and impulsive testing revealed no residual posterior canal function.