Evaluation of preoperative Ultrasonography in the Differentiation between Superficial and Deep Parotid Gland Tumors.

Imaging of the intraparotid course of the facial nerve remains a challenge and is not an established routine procedure. The aim of this study was to evaluate ultrasound in localizing a parotid tumor in relation to the facial nerve. The ultrasound findings and operative reports of all patients treated for parotid gland tumors were studied retrospectively. Eight hundred sixty-eight parotid lesions formed our study sample. The unit of measurement was the minimal distance between the parotideomasseteric fascia and the superficial capsule of the tumor, measured in millimeters by means of ultrasound. The mean value for this parameter was 1.3 mm for superficial and 4.6 mm for deep lobe tumors (p < 0.001). When the cutoff value was set at 2.6 mm, the sensitivity and specificity of ultrasound were 89.6 and 88.4%, respectively. Our study revealed that ultrasound can help in the pre-operative differentiation between tumors of the superficial and deep lobes of the parotid gland.