Vestibular nerve pathology in cases of intractable vertigo: an electronmicroscopic study.

OBJECTIVE

This study aimed to determine the absence or presence and the nature of pathology of the vestibular nerve in case of intractable vertigo.

STUDY DESIGN

This was a prospective study.

SETTING

The study was performed at a private practice tertiary referral center.

PATIENTS

There-were 42 patients with intractable vertigo in the study.

INTERVENTIONS

All patients received thorough diagnostic examinations and surgical excision of the vestibular nerves.

MAIN OUTCOME MEASURES

Segments of the superior and inferior vestibular nerves were surgically removed, preserved in glutaraldehyde, examined by electronmicroscopy, and the findings were correlated with the clinical diagnosis.

RESULTS

A variety of different types of pathologic lesions were identified, including axon and supporting cell degeneration, herpes zoster virus, other viruses, results of bacterial infection, and regrowth of nerve after surgical resection.

CONCLUSION

The vestibular nerves were found to be histologically normal in lesions primarily involving the end organ such as most early Meniere's disease cases, benign paroxysmal postural vertigo (BPPV), and mild labyrinthine concussion. Vestibular nerve degeneration was seen with advanced Meniere's disease, severe labyrinthine concussion, and with vascular loops in the internal auditory canal. Herpes zoster involves Scarpa ganglion in herpes zoster oticus. Viruses were found in the nuclei of vestibular nerve cells in a patient with delayed hydrops. Regrowth of the vestibular nerve after surgical resection was confirmed in three cases.