The diagnostic efficacy of ultrasonographically-based measurements of minimum and maximum fascia-tumor distance in differentiating superficial from deep lobe benign parotid tumors

Abstract

The objective was to calculate the efficacy of ultrasonographically-based measurements of minimum and maximum fascia-tumor distance (MiFTD and MaFTD) of benign salivary gland tumors to identify tumor location in the superficial or deep lobe of the parotid gland. MiFTDs and MaFTDs were measured on pre-operative ultrasonographic images of 102 tumors. Tumor location was classified at surgery as superficial or deep based on relation to the facial nerve, with 74 tumors in the superficial lobe and 28 in the deep lobe. The diagnostic efficacy of differences in MiFTD and MaFTD between locations was calculated with the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity. Statistical significance was established at P < .05. Mean MiFTD and MaFTD values were significantly smaller in the superficial lobe tumors than in the deep lobe lesions (P < .001). Tumors with cutoff values of MiFTD >2.7 mm or MaFTD >21.1 mm were considered deep lobe lesions. When using the cutoff values for both MiFTD and MaFTD, the AUC was 0.893, whereas sensitivity and specificity were .821 and .919, respectively. Ultrasonography can help in the preoperative localization of tumors in the superficial and deep lobes of the parotid gland. This can facilitate proper surgical treatment selection and minimize the risk of adverse consequences of facial nerve damage while improving cosmetic outcomes.