Introduction

Vestibular schwannomas (VS) are rare, benign tumors originating from the eighth cranial nerve in the cerebellopontine angle. Surgery for VS can damage the adjacent facial nerve (FN), leading to significant functional and aesthetic issues. Postoperative treatments like Botox, physical therapy, and surgical interventions are often used to enhance facial nerve function. This study investigates the relationship between tumor size, postoperative rehabilitation strategies, and long-term facial nerve function outcomes in patients with surgically treated vestibular schwannomas.

Methods

This retrospective chart review was conducted at a single tertiary institution. Facial nerve function was scored using the House-Brackmann (HB) system. Spearman's rank correlation coefficient and analysis of variance (ANOVA) were employed to analyze the data.

Results

Among 267 patients who underwent VS resection, 238 (89.2%) did not receive postoperative rehabilitation (Group 1) and 29 (10.8%) received rehabilitation treatment. 17 (6.5%) pursued only Botox and/or physical therapy (Group 2) and 12 (4.5%) underwent surgical management

(Group 3). Spearman’s rank correlation analysis revealed a strong positive correlation between tumor size and HB score (Spearman’s rho=0.71, p<0.0001). ANOVA revealed a significant difference between pre- and post-operative HB scores between Group 1 and Group 2 (p<0.0001), as well as between Group 1 and Group 3 (p<0.0001). There was no significant difference in pre and post-operative HB score between Group 2 and Group 3 (p=0.13).

Conclusions

This study indicates a significant positive correlation between tumor size and HB score, suggesting that larger tumors are associated with worse facial nerve outcomes, consistent with existing literature. Furthermore, adjuvant treatments, including Botox and surgical management,

significantly improved facial nerve outcomes compared to observation alone. These findings underscore the importance of implementing facial nerve rehabilitation strategies, particularly in patients with larger tumors who are at higher risk for FN injury. Our study raises critical questions about the standard of care after vestibular schwannoma resection.

Figure

Figure 1. Correlation chart of the Spearman’s rank correlation coefficient. Tumors were divided into bins based on size: 0-4.9 mm, 5-9.9 mm, 10-14.9 mm, 15-19.9 mm, 20-24.9 mm, 25-29.9 mm and 30+ mm for the analysis. Rho = 0.71, Fisher’s transformation CI 99% 0.63 - 0.78, p<0.0001.