A morphological features-based nomogram for predicting facial nerve function in the immediate postoperative period...

Tumor morphology critically influences facial nerve (FN) outcomes following vestibular schwannoma (VS) surgery. This study aimed to develop a nomogram based on preoperative features for preoperative prediction of FN outcomes after VS surgery.

A retrospective analysis included patients with sporadic VS who underwent surgical resection via the retrosigmoid approach. Tumor size was assessed using the Koos grade, the intrameatal components using the fundal fluid cap (FFC) sign, and the cerebellopontine angle cisternal components using our modified morphological subclassification. Logistic regression analysis was performed to construct a nomogram for predicting immediate postoperative FN function.

A total of 265 patients with VS met the inclusion criteria. Of these patients, 62 (23.4%) had poor FN function (House-Brackmann grade ≥ III) immediately after surgery. Univariate logistic regression analysis identified the Koos grade (p = 0.001), FFC sign (p = 0.023), and morphological subtype (p < 0.001) as significant predictors of poor FN function immediately after surgery. In multivariate logistic regression analysis, the FFC sign (OR 2.07, p = 0.042) and morphological subtype (OR 8.21, p < 0.001) remained statistically significant independent predictors of poor FN function. A nomogram constructed based on these indicators demonstrated good discrimination in the training cohort (area under the curve [AUC] 0.80), internal validation cohort (AUC 0.79), and external validation cohort (AUC 0.97).

A simple and reliable nomogram incorporating the Koos grade, FFC sign, and morphological subtype accurately predicts the risk of FN injury during surgery aimed at total resection of VS. This clinically straightforward tool can assist in patient counseling and development of more individualized surgical strategies to improve FN outcomes in patients with VS.