Enhancing the Lateral Orbital “C-Angle” With Calcium Hydroxylapatite: An Anatomic and Clinical Study

Abstract

Abstract Background Deliberate injection of specific facial subunits may improve aesthetic outcomes in facial rejuvenation. We contend that the lateral orbital area (LOA) is a key anatomic subunit in the perception of eye attractiveness, with a C-shaped distribution of fat contributing to the formation of a distinct angle in the lateral orbit. Objectives The aim of this study was to describe the anatomy of the LOA that constitutes the C-shaped angle and to investigate the safety and cosmetic outcomes of nonsurgical enhancement of that area with calcium hydroxylapatite (CaHA). Methods Four injected fresh-frozen cadaver heads were dissected. Twenty patients were enrolled in a prospective clinical study. Participants were seen on the day of injection, and at 2 weeks and 3 months postinjection. Two-dimensional and 3D photographs were analyzed to quantify the volumetric changes between pretreatment and postinjection time points. Secondary outcomes included Global Aesthetic Improvement Scale score and subject satisfaction at 3 months. Results Cadaver dissections revealed distinct fat compartments and a zone of adhesion forming the C-shaped area around the lateral orbit. In the clinical study, a mean of 1.88 mL of CaHA was injected into each lateral periorbital region. There was 97% and 76% volume retention at 2 weeks and 3 months, respectively, with 70% of patients being “very satisfied” at 3 months. The average Global Aesthetic Improvement Scale rating at 3 months was 3.95. There were no complications. Conclusions The LOA is a distinct facial subunit that can be enhanced safely by CaHA injection with good cosmetic outcomes. Focusing on the C-angle can improve periorbital aesthetics. Level of Evidence: 4