Retrolabyrinthine Vestibular Nerve Section Research Articles

Vestibular Neurectomy for Intractable Vertigo: Case Series and Evaluation of Role of Endoscopic Assistance in Retrolabyrinthine Craniotomy

Objective This study evaluates the utility of endoscopy for retrolabyrinthine vestibular nerve section (RLVNS). Design/Setting This is a retrospective review for RLVNSs by the senior author. The endoscope's utility was assessed and assigned a grade based on operative findings. Participants/Main Outcome Measures Fifteen patients (eight males and seven females; 53 and 47%, respectively) were identified with mean age 56.7 years. Indications included Ménière's disease (MD) in 12 of 15 patients (80%), uncompensated vestibular neuritis in 2 patients (13%), and other vestibular neuropathy in 1 patient (7%). Vertigo resolved in 14 of 15 patients (93%). Complications included decreased hearing in two patients (13%) and deep venous thrombosis in one patient (7%). There were no facial nerve complications or mortalities. Results Sectioning vestibular division of the vestibular-cochlear nerve was achieved without perceived benefit of endoscopy in the 80% of cases (grade 0, n = 12). Endoscopy was helpful in patients with a small mastoid (grade 1, n = 2, 13.3%), and deemed necessary where the flocculus of the cerebellum was adherent to the eighth nerve arachnoid at the porus acusticus (grade 2, n = 1, 6.7%). Conclusion RLVNS is a safe and efficacious procedure for the treatment of vertigo; the surgical endoscope may be a useful adjunct in selected cases. Patients with MD may expect the greatest benefit from surgery.

Combined retrosigmoid retrolabyrinthine vestibular nerve section: Results of our experience over 10 years. Otol Neurotol 2005;26:481-483

Combined retrosigmoid retrolabyrinthine vestibular nerve section: Results of our experience over 10 years. Otol Neurotol 2005;26:481-483

Combined retrosigmoid retrolabyrinthine vestibular nerve section: Results of our experience over 10 years. Otol Neurotol 2005;26:481-483

Combined retrosigmoid retrolabyrinthine vestibular nerve section: Results of our experience over 10 years. Otol Neurotol 2005;26:481-483

Retrolabyrinthine Vestibular Nerve Section: A Current Appraisal

We report our experience (1987-1993) with Meniere's disease patients treated with a retrolabyrinthine vestibular neurectomy. The current literature was reviewed and our results have been compared with those of previous reports. The overall success rate for vertigo relief was 96.7%, with no serious or permanent complications resulting from the procedure. The technical elements of the operation, as they apply to our approach and those of others, have been analyzed, with special attention given to the anatomical features of the region and their influence on success or failure. We conclude that the retrolabyrinthine approach for vestibular nerve section remains a safe and highly successful technique which merits continued use.

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.

Prognostic significance of hearing loss as a lateralizing indicator in the surgical treatment of vertigo

In patients with peripheral vertigo the presence of an asymmetrical hearing loss is an important lateralizing sign, having both diagnostic and prognostic significance. In a consecutive series of 83 patients undergoing retro-labyrinthine vestibular nerve section for uncontrolled vertigo, asymmetrical hearing loss was associated with an 83 per cent incidence of complete control of vertigo and a 49 per cent incidence of complete relief from dysequilibrium. In the absence of a lateralizing hearing loss, the figures were 50 per cent and 24 per cent respectively (p less than 0.01 and p less than 0.05). The explanation for this finding may be that the presence of a hearing loss is more often associated with an exclusively peripheral disorder (controllable by peripheral surgical ablation), whereas in patients with symmetrical hearing there may be an unrecognized central or contralateral pathology resulting in less effective results from a unilateral peripheral surgical approach. The bithermal caloric test did not give such useful diagnostic or prognostic information.

Retrolabyrinthine vestibular nerve section: Efficacy in disorders other than meniere's disease

The retrolabyrinthine vestibular nerve section has evolved as an effective treatment for intractable vertigo of peripheral vestibular origin when hearing preservation is desired. This report studies the efficacy of retrolabyrinthine vestibular nerve section for control of vertigo due to causes other than Meniere's disease. This report details our experience with 42 patients with a wide variety of diagnoses. The reduced success rate of retrolabyrinthine vestibular nerve section in these patients is difficult to evaluate, as very few patients have been analyzed with respect to their specific diagnoses. Of patients who underwent retrolabyrinthine vestibular nerve section for control of vertigo, 23 patients had uncompensated vestibular neuritis and 19 others had a wide range of other diagnoses. For patients with uncompensated vestibular neuritis (n = 23), the physician record noted that 39% of patients were cured and 30% improved. This compares to our series of patients with Meniere's disease (n = 48), where 94% were cured and 2% improved. The true vestibular abnormality may be less reliably identified in patients with uncompensated vestibular neuritis, contributing to the less effective results. Since the development of a vestibular rehabilitation program, retrolabyrinthine vestibular nerve section for uncompensated vestibular neuritis has been all but abandoned. Retrolabyrinthine vestibular nerve section appears to achieve a high cure rate in patients with sensorineural hearing loss associated with their vestibular abnormalities. While retrolabyrinthine vestibular nerve section is helpful for control of vertigo in some diagnoses, a substantial incidence of persistent postoperative dysequilibrium was noted.

Consequences of Middle Ear Bone Dust during Neurotologic Surgery

Most otologists are cautioned at some point in their training that if bone dust is allowed to enter the middle ear while the mastoid is being drilled, there may be adverse consequences. Two cases of ossicular fixation and conductive hearing loss after retrolabyrinthine vestibular nerve section prompted us to examine the issue of bone dust in the middle ear. In a study of 13 temporal bones that had undergone neurotologic surgery, we found 11 that showed evidence of viable bone dust in the middle ear, and three that had ossicular fixation. Viable bone dust was always encased in a mucous membrane lining. These findings suggest that bone dust that enters the middle ear may indeed remain viable and cause ossicular fixation. The surgeon should therefore take every precaution to prevent bone dust from entering the middle ear during neurotologic procedures in which conservation of hearing is attempted.

Cochlear Nerve Action Potentials during Cerebellopontine Angle Surgery

The cochlear nerve action potential (AP) was monitored during two types of hearing preservation surgery: (1) removal of small cerebellopontine angle tumors and (2) retrolabyrinthine vestibular nerve section. The purpose of this investigation was to study the relationship between changes in intraoperative AP latency, amplitude, and threshold, and changes in audiometric hearing subsequent to surgery. The presence or absence of a cochlear nerve AP toward the end of surgery accurately predicted the presence or absence of postoperative hearing (93%). Regression analyses were performed to explore the relationship between audiometric pre- and postoperative thresholds and intraoperative AP threshold changes. Statistically significant relationships were found for (1) pre-operative audiometric thresholds and initial AP click thresholds (p = 0.0068); (2) final AP click thresholds and postoperative audiometric thresholds (p = 0.0003); (3) AP click (p = 0.0001) and 1 kHz (p = 0.0006) threshold shifts and pre- to postoperative audiometric threshold shifts. No relationship was found between either AP latency or amplitude values and postoperative hearing. Intraoperative threshold measurements can be used as an indicator of hearing change. If amplitude or latency indices are also monitored it may be better to use stimulus levels close to the evoked potential threshold.

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.

Infrared/video ENG recording of eye movements to evaluate the inferior vestibular nerve using the minimal caloric test.

The technique was originally developed to test the inferior vestibular nerve in tumor suspects whose high-frequency hearing loss exceeded the capabilities of the auditory brainstem response tests and whose electronystagmographic results showed no significantly reduced vestibular response. The test has subsequently been found effective to demonstrate persistent singular nerve fiber function in patients with persistent vertigo after retrolabyrinthine vestibular nerve section.

Retrolabyrinthine Vestibular Nerve Section: Limitations and Clinical Experience

Finding the correct surgical approach for the vertiginous patient continues to be a challenge. At the Western Section Meeting of the Triological Society, Carol A. Bowman, MD, and Charles A. Mangham, Jr, MD, of the Virginia Mason Clinic, Seattle, reviewed their experience with the retrolabyrinthine vestibular nerve section. It was pointed out that even though the control rate for vertigo is reportedly high with this procedure, many patients still have postsurgical vestibular symptoms. Bowman and Mangham reviewed 36 cases and reported control of the rotatory vertigo in 94% of the patients involved. In questioning their patients, they found that the majority continued to have symptoms of vestibular disturbance and balance disturbance even though the rotatory vertigo was controlled. In spite of the limitations of the procedure, the authors still feel that it is efficacious for the vertiginous patient.—James L. Parkin, MD, MS, Salt Lake City

Retrolabyrinthine vestibular nerve section: analysis of results.

The retrolabyrinthine section of the vestibular nerve is an effective procedure for the ablation of unilateral vestibular function while preserving hearing. Although this procedure has been most frequently used for the control of unilateral Meniere's disease, it may also be effective in the control of unilateral vestibular dysfunction of other etiologies. A 2-year experience with the indications for and the surgical results in a series of patients who underwent this procedure is presented. Brief case histories of a variety of etiologies of unilateral vestibular dysfunction are discussed.