Preoperative predictors for the extent of facial nerve sacrifice in parotid gland cancer: an ordinal logistic regression and nomogram analysis.

BACKGROUND

Anticipating facial nerve sacrifice in parotid gland cancer patients with normal preoperative function is clinically challenging.

METHODS

We retrospectively reviewed 89 patients with primary parotid gland cancer and normal preoperative facial nerve function. Resection extent was categorized as total preservation, partial, or total resection. Preoperative factors were analyzed using an ordinal logistic regression model. Based on the multivariable model, a nomogram was developed to predict the risk of facial nerve sacrifice, internally validated using bootstrapping, and evaluated for clinical utility via decision curve analysis (DCA). Sensitivity analysis was performed by excluding nondiagnostic cytological/histological cases.

RESULTS

Univariate analysis identified a preoperative malignant diagnosis, clinical T3-4, clinical nodal metastasis, pain, and deep lobe extension as significant predictors. Multivariable analysis revealed that a preoperative malignant diagnosis remained the strongest independent predictor for the extent of facial nerve resection (OR 3.16; 95% CI 1.14-9.20; p = 0.029), while the other variables lost significance. The developed nomogram demonstrated good discriminative ability (bootstrap-corrected C-index, 0.710) and adequate calibration. DCA revealed a superior net clinical benefit across a wide range of threshold probabilities (10% to 70%). Sensitivity analysis excluding nondiagnostic cases (n = 67) confirmed that the association for a preoperative malignant diagnosis remained statistically significant (OR 5.13; 95% CI 1.45-20.97; p = 0.015).

CONCLUSIONS

In patients with intact preoperative facial nerve function, the required extent of nerve sacrifice can be quantitatively estimated preoperatively. Our nomogram translates clinical factors into individualized probabilities of nerve sacrifice, facilitating reconstructive planning and preoperative patient counseling.