Radiographic Factors Predicting Postoperative Facial Nerve Deficit in Vestibular Schwannomas

Introduction: Vestibular schwannomas (VS) occur in 1 of 100,000 people in the United States. Given the nature and location of these tumors within the internal auditory canal (IAC), 12% of patients report facial paresthesia and 6% have facial nerve (FN) palsy. The FN is at a high risk of injury during surgeries, with 8 to 20% of patients reporting FN paralysis after surgery. The tumor diameter, volume, and location can predict FN damage.

Objective: To investigate if tumor filling of the IAC and tumor size predict postoperative FN function related to VS.

Method: We retrospectively reviewed 123 patients who underwent surgical resection of a VS from 2010 to 2021. Axial T2-weighted MRI at the level of the IAC was used for measuring the percentage of tumor filling the IAC and tumor size. The primary outcome was immediate post-operative FN deficits. Statistical analyses were done using multivariable logistic regression and Pearson correlation.

Results: There were 123 patients included in the study, and 88 patients with available MRIs for analysis. In the multivariable regression model, the percentage of tumor filling the IAC (p = 0.010) and tumor size (p = 0.013) were found to be an independent predictor of immediate post-operative FN deficits (n = 45, 51.13%). Spearman's rho correlation showed a moderately positive correlation between the percentage of tumor filling the IAC and immediate post-operative FN deficits r = 0.242 (p = 0.023).

Conclusion: The percentage of tumor filling the IAC and tumor size on pre-operative MRI can predict FN deficit in patients undergoing surgical resection of VS.

Publication History

Article published online:
01 February 2023