Comparison of post-operative vestibular function between vestibular schwannoma and non-vestibular schwannoma cerebellopontine angle tumors patients using video head impulse test

Abstract

Background

Cerebellopontine angle (CPA) tumors commonly cause audiovestibular symptoms due to eighth cranial nerve involvement. While vestibular schwannoma (VS) is the most frequently observed CPA tumor, vestibular outcomes following surgery for non-VS CPA tumors remain underreported.

Objectives

To compare post-operative vestibular function, as assessed by the video Head Impulse Test (vHIT), between patients with VS and non-VS CPA tumors.

Methods

A retrospective review was conducted on 37 patients (23 VS, 14 non-VS) who underwent CPA tumor resection and had vHIT evaluations pre- and post-operatively. Changes in vestibulo-ocular reflex (VOR) gain across the three semicircular canals were analyzed at 1 and 6 months after surgery.

Results

Although pre-operative VOR gains were comparable, the non-VS group demonstrated significantly better VOR gain recovery at 6 months in the horizontal and posterior semicircular canals (p = 0.0055, p = 0.0019, respectively). Notably, VOR gains in these canals improved beyond pre-operative levels in the non-VS group. No significant improvement was observed in the anterior semicircular canal.

Conclusions

vHIT outcomes indicate more favorable spontaneous vestibular recovery in non-VS CPA tumor than in VS tumor patients. These findings emphasize the importance of vestibular nerve preservation during non-VS tumor surgery and suggest differences in neural involvement between tumor types.