Discussion

Abstract

An accurate preoperative assessment of intraparotid tumor location, whether in the superficial or deep lobe with respect to the facial nerve, is essential before surgery. Because each surgeon must determine the method of surgical approach based on this information, precise and objective diagnostic imaging is required. Although attempts at direct visualization of the intraparotid facial nerve have been performed with magnetic resonance imaging (MRI), it is sometimes uncertain whether the curvilinear hypointense structure that can be seen in the parotid gland is actually the intraparotid facial nerve or a part of the ductal system. 1 Thibault F Halimi P Bely N et al. Internal architecture of the parotid gland at MR imaging: Facial nerve or ductal system?. Radiology. 1993; 188: 701 PubMed Google Scholar Hence, many surgeons use hypothetical lines or anatomic landmarks that can be drawn or visualized on cross-sectional images from computed tomography (CT) and MRI. 2 Ariyoshi Y Shimahara M Determining whether a parotid tumor is in the superficial or deep lobe using magnetic resonance imaging. J Oral Maxillofac Surg. 1998; 56: 23 Abstract Full Text PDF PubMed Scopus (55) Google Scholar , 3 Kurabayashi T Ida M Ohbayashi N et al. Criteria for differentiating superficial or deep lobe tumours of the parotid gland by computed tomography. Dentomaxillofac Radiol. 1993; 22: 81 PubMed Google Scholar Such hypothetical lines and anatomic landmarks must be relatively easy to detect and must run along the nerve as closely as possible. In addition, it is necessary that the hypothetical line can be drawn on in the same slice.