Anatomic Variations of the Lateral Branch of the Supraorbital Nerve Observed in Endoscopic Forehead Surgery

Surgeons dissect carefully in the medial third of the supraorbital rim to preserve the supraorbital nerve (SON) during surgical forehead rejuvenation. However, the anatomic variations of SON exit from the frontal bone have been researched in cadaver or imaging studies. In this study, we report a variation in the lateral branch of SON observed in an endoscopic view during forehead lifts. A retrospective review of 462 patients who underwent endoscopy-assisted forehead lifts between January 2013 and April 2020 was performed. Data, including the location, number, and form of the exit point and thickness of SON and its lateral branch variant, were recorded and reviewed intraoperatively, utilizing high-definition endoscopic assistance. Thirty-nine patients and 51 sides were included, and all patients were female, with a mean age of 44.53 (18-75) years. This nerve exited a foramen in the frontal bone ~8.82 ± 2.79 mm lateral to SON and ~1.89 ± 1.34 mm from the supraorbital margin vertically. Observed thickness variations of the lateral branch of SON included 20 small, 25 medium, and 6 large nerves. This study revealed various positional and morphologic variations of the lateral branch of SON in an endoscopic view. Thus, surgeons can be alerted of the anatomic variations of SON and establish careful dissection during procedures. In addition, the findings of this study will be useful in planning nerve blocks, filler injections, and migraine treatments in the supraorbital region.