The Stensen's duct line: A landmark in parotid duct and gland injury and surgery. A prospective anatomical, clinical and radiological study.

Introduction: The parotid duct (PD) is often involved in parotid gland diseases. A skin landmark could help the surgeon to locate its position. The parotid duct line (PDL) joins the tragus-antitragus point to the middle of the half upper lip. The aim of this study was to assess and scientifically validate this landmark.

Methods: A monocentric prospective anatomical, clinical and radiological study was conducted. Six fresh cadavers' PD were dissected. A subcutaneous flap was performed and the PD's position spotted by needle checking through the skin. 10 subjects with parotid obstructive symptoms were included for sialendoscopy, which light through the skin revealed the PDL's position. MRI was conducted on 20 PDs. The radiologist virtually drew the PDL and did a 3D reconstruction of the PD. The distance from the PDL to the PD was measured.

Results: Anatomical study: 2 PDs were on the PDL, 2 under and 2 over. Sialendoscopic study: 6 PDs were on the PDL (60%), 3 under and 1 over. MRI study: 13 over 20 PDs crossed the PDL (65%). Maximum mean distance from the PD was 10.44 mm [5.01-15.87] and minimum mean distance from the PD was 2.42 mm [0-5.75].

Discussion: This study sought to assess the relevance of the PDL, which is not parallel to the PD that runs a «S-Shape» curve when crossing the PDL. It could be used when evaluating a potential ductal injury in trauma management and when locating proximal parotid lithiasis during sialendoscopy.