The anatomical variations of the emergence routes of supraorbital nerve: A cadaveric study and systematic review

Background: Knowledge of the location of supraorbital nerve is essential to perform supraorbital endoscopic surgery, regional nerve block, and nerve decompression in the treatment of migraine. This study discusses the emergence routes of supraorbital nerve as well as a systematic literature review on previous anatomical studies. This comparative analysis will be beneficial for surgeons worldwide. Methods: The study sample consisted of 19 cadavers with bilateral supraorbital nerve dissections. The emergence route of the nerve through either a notch or foramen was recorded. Additionally, the distance from midline, nerve branching patterns, and diameter of emergence routes were measured. Results: Our findings showed an equal number of supraorbital emergence route between notch and foramen (42%) and demonstrated average distance from emergence route and facial midline 22.34 (3.05) mm in male and 23.58 +/- 2.42 mm in female. Diameter of notch type is 3.97 (0.99) mm and 3.39 (1.09) mm in foramen type. Data from systematic review showed range of distance from emergence route to facial midline from 22.2 to 33.7 mm. East Asia population had significant shorter distance of supraorbital emergence route to facial midline than Middle Asia and Caucasian population. Conclusion: This study provides greater insight into the anatomic variations and supraorbital never course in an understudied minority population. Surgeons should be aware of this critical area and strive to minimize dissection to prevent iatrogenic nerve injury. (c) 2021 Asian Surgical Association and Taiwan Robotic Surgery Association. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).