Computed Tomography-Measured Minimum Fascia-Tumor Distance for Parotid Tumor Location and Facial Palsy Prediction.

OBJECTIVE: To assess the diagnostic performance of CT-measured minimum fascia-tumor distance (MFTD) for predicting parotid tumor location and its association with postoperative facial nerve function. STUDY DESIGN: Retrospective cohort. SETTING: Referral hospital. METHODS: This retrospective cohort study included 323 patients with benign parotid tumors treated at referral centers. CT-measured MFTD values were compared between superficial and deep lobe tumors. Diagnostic accuracy for identifying deep lobe tumors was evaluated using a receiver operating characteristic (ROC) curve. Univariable and multivariable logistic regression analyses were performed to identify predictive factors for tumor location and postoperative facial palsy. RESULTS: MFTD significantly differed between superficial and deep lobe tumors (1.59 ± 2.14 mm vs. 3.90 ± 3.40 mm, p < .001). ROC analysis yielded an area under the curve of 0.70 (95% confidence interval [CI], 0.60-0.79; p < .001), with 3.0 mm identified as the optimal threshold. Independent predictors of deep lobe tumors included MFTD (odds ratio [OR], 1.34; 95% CI, 1.19-1.49; p < .001) and maximal tumor diameter (OR, 1.03; 95% CI, 1.00-1.06; p = .043). Predictors of postoperative temporary facial palsy were MFTD (OR, 1.26; 95% CI, 1.11-1.42; p < .001), female sex (OR, 3.17; 95% CI, 1.49-6.73; p = .003), and anterior tumor location (OR, 2.69; 95% CI, 1.21-6.00; p = .016). CONCLUSION: CT-based MFTD provides reliable diagnostic performance for distinguishing deep lobe parotid tumors. Beyond tumor localization, MFTD also predicts the risk of postoperative temporary facial palsy. Incorporating MFTD into preoperative planning and patient counseling may enhance surgical decision-making and outcomes.