Reply: Topographic Analysis of the Supratrochlear Artery and the Supraorbital Artery: Implication for Improving the Safety of Forehead Augmentation.

Abstract

Sir: We are objectively addressing Dr. Hwang’s comments about our article.1 In our study, we sequentially dissected the upper face based on the conventional methods in the gross anatomy field. This is a fact. For our dissections, we injected red colored latex (Neoprene, lot no. 307L146; DuPont DeNemours, Puteaux, France) into the common carotid artery before detailed dissections.1 Among the preinjected specimens, we excluded specimens that were not injected into the ophthalmic arterial branches before the dissections. In classical anatomy textbooks, the superficial and deep branches of the supraorbital artery have been described. Nevertheless, there are no specific descriptions for their branching. Aside from some anatomical textbooks, few articles focus on the course of the supraorbital artery. It is described simply as follows: “passing through the supra-orbital foramen, supraorbital artery divides into a superficial and deep branch, which supply the integument... anastomosing with the frontal, anterior branch of the temporal, and the artery of the opposite side.” During our dissections, we recognized new branching patterns of the supraorbital artery, which did not correlate with descriptions in the textbook. The main arterial branches of the supraorbital artery ran beneath the orbicularis oculi and the frontalis after passing the supraorbital notch (or foramen). As for the layers at the eyebrow area, the retro-orbicularis oculi fat was located deep to the muscle layer and includes the supraorbital vessels and the nerve branches and the insertion of the corrugator. Clearly, the main trunk of the supraorbital artery is located within the retro-orbicularis oculi fat. Unlike the general anatomical knowledge with which one may be familiar, the extent of the retro-orbicularis oculi fat is wider within the subgaleal layer with a high upper margin from the eyebrow level. Within the retro-orbicularis oculi fat, the supraorbital artery runs singularly or divides into two branches accompanying the supraorbital nerve. We named this supraorbital artery branch within the retro-orbicularis oculi fat the deep branch of the supraorbital artery. After passing the retro-orbicularis oculi fat, the deep branch of the supraorbital artery pierces the frontalis 20.7 mm vertically from the horizontal plane passing through the superior orbital rim. From the piercing points of the frontalis, it runs superficially to the frontalis (superficial branch of the supraorbital artery), and the superficial branches anastomosed with the frontal branches of the superficial temporal artery.1 Based on our dissection experiences, we described the common and clear characteristics of the supraorbital artery courses and illustrated them in detail. In some specimens, we could observe the fine perforations supplying the skin at the upper eyebrow area. We focused on the main arterial branches in the forehead to provide clinical anatomical information. In addition, our article has shown an objective and novel supplement on the supraorbital artery course from a gross anatomy viewpoint. Regarding sample size, we dissected and collected vascular anatomy data from both Korean and Thai subjects (20 hemifaces). As mentioned in the Results section, the deep branch of the supraorbital artery was observed in every case. Simply put, the deep branch of the supraorbital artery is the constant course of the supraorbital artery within the retro-orbicularis oculi. There was no need to dissect more cadavers for clarification. I believe you have already witnessed the strongest form of evidence by means of anatomical dissections from my previous presentations at conferences. Regarding the query about the clinical technique of forehead augmentation, the recommended entry point should be lateral to the vertical plane of the supraorbital foramen to avoid vascular injury from the needle. The needle should first be inserted deep to the frontalis by bone touch to provide a proper opening and tract for the cannula. The entry point and the point where it reaches the periosteum are usually adjacent because of the thin skin and muscular layer. After that, the cannula should be guided along the supraperiosteal layer until it reaches the medial area of the forehead. At that point, the filling material should be released. We developed this technique to maximize forehead augmentation safety during vascular piercing in clinical procedures through our article. Because the needle touches the bone, it is unnecessary to take the thickness of the frontalis into consideration. DISCLOSURE None of the authors has financial or private relationships with commercial, academic, or political organizations or people that could have improperly influenced this research. All cadaveric objects in this study were legally donated to Yonsei Medical Center and Chulalongkorn University. Li-yao Cong, B.Sc.Division in Anatomy and Developmental BiologyDepartment of Oral BiologyHuman Identification Research InstituteBK21 PLUS ProjectYonsei University College of DentistrySeoul, Republic of Korea Weeranut Phothong, M.D.Department of DermatologyFaculty of MedicineSiriraj HospitalMahidol UniversityBangkok, Thailand Iksoo Koh, M.D., Ph.D.Koh Iksoo Aesthetic Clinic Hee-Jin Kim, D.D.S., Ph.D.Division in Anatomy and Developmental BiologyDepartment of Oral BiologyHuman Identification Research InstituteBK21 PLUS ProjectYonsei University College of DentistrySeoul, Republic of Korea