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

Abstract

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. 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 < or =2 cm and >2 cm in diameter. 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 < or =2 cm in diameter, FN line (p = 0.022) and RV (p = 0.028) were significantly more accurate than U line and CA. 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.