INTRODUCTION
Facial aging is a multi-factorial process resulting in a range of physiologic and morphologic changes in both the hard and soft tissues of the face – the bones, ligaments, muscles, fasciae, subcutaneous fat, and skin.1,6 The use of soft-tissue filler injections to address the signs of facial aging has increased according to a statistical survey by the American Society of Plastic Surgeons. Between the years 2000 and 2017, the number of soft tissue filler procedures increased by 312%.7
Soft tissue fillers are frequently utilized to restore the age-related loss of soft tissue volume of the face.8-10 Recent studies have indicated that depending on the targeted layer, various aesthetic outcomes can be expected.11 Injections into the subdermal plane ie, into the superficial facial fat compartments, can result in better surface projection when compared to placing the product in the supraperiosteal plane ie, into the deep facial fat compartments and vice versa, depending on the targeted facial region. A measure for estimating this region-specific effect wasrecently introduced and termed the surface volume coefficient (SVC).11 The SVC is calculated by dividing the absolute change in scanned 3D surface projection (cc) by the amount of injected volume (cc) and provides information on the surface effect of a certain amount of injected volume, which could thus be considered the clinical effectiveness of an injected material.
Temporal volume loss can be treated via the injection of soft tissue filler into the subdermal or supraperiosteal plane while respecting regional danger zones. These danger zones are located in Layer 3 (location of the anterior branch of the superficial temporal artery), Layer 4 (intra-fascial plane; location of the motor branches of the facial nerve), Layer 6 (location of the medial zygomatico-temporal (sentinel) vein), and Layer 10 (location of the anterior and posterior deep temporal arteries). Positioning of the product thus needs to be carefully evaluated and balanced weighing safety primarily while considering aesthetic outcome. Injecting the material into the subdermal
Soft tissue fillers are frequently utilized to restore the age-related loss of soft tissue volume of the face.8-10 Recent studies have indicated that depending on the targeted layer, various aesthetic outcomes can be expected.11 Injections into the subdermal plane ie, into the superficial facial fat compartments, can result in better surface projection when compared to placing the product in the supraperiosteal plane ie, into the deep facial fat compartments and vice versa, depending on the targeted facial region. A measure for estimating this region-specific effect wasrecently introduced and termed the surface volume coefficient (SVC).11 The SVC is calculated by dividing the absolute change in scanned 3D surface projection (cc) by the amount of injected volume (cc) and provides information on the surface effect of a certain amount of injected volume, which could thus be considered the clinical effectiveness of an injected material.
Temporal volume loss can be treated via the injection of soft tissue filler into the subdermal or supraperiosteal plane while respecting regional danger zones. These danger zones are located in Layer 3 (location of the anterior branch of the superficial temporal artery), Layer 4 (intra-fascial plane; location of the motor branches of the facial nerve), Layer 6 (location of the medial zygomatico-temporal (sentinel) vein), and Layer 10 (location of the anterior and posterior deep temporal arteries). Positioning of the product thus needs to be carefully evaluated and balanced weighing safety primarily while considering aesthetic outcome. Injecting the material into the subdermal
