Preoperative prediction of the location of parotid gland tumors using anatomical landmarks

Background: The location of the parotid gland tumor can affect the duration and difficulty of operation. Therefore, accurate preoperative evaluation of tumor location can affect surgical outcomes. Methods: Results in 100 patients with parotid gland tumors who underwent parotidectomy between January 2000 and October 2005 were retrospectively reviewed. Tumor location was determined relative to four landmarks-facial nerve (FN) line, Utrecht (U) line, Conn's arc (CA), and retromandibular vein (RV)-on computerized tomography (CT) scans, and confirmed by intraoperative findings. The accuracy of each landmark was evaluated. Correlations between accuracy and tumor size were determined for tumors ≤2 cm and >2 cm in diameter. Results: Of the four landmarks, the U line was the most accurate (94%), sensitive (89.3%), and specific (97.7%) in predicting tumor location. However, for tumors ≤2 cm in diameter, FN line (p = 0.022) and RV (p = 0.028) were significantly more accurate than U line and CA. Conclusion: Although the U line was the most accurate in predicting the location of parotid gland tumors, landmarks predicting accurate tumor location should be selected according to tumor size.