Midface Multilayering Filler Injection Technique: Understanding of the Dynamic Facial Anatomy Through a "Smiling Cadavers" Anatomical Study

Background: Understanding age-related changes in compartmentalized facial fat and their role in facial dynamics and aesthetics is essential to target filler injections for midface rejuvenation. Methods: A novel anatomical approach ("smiling cadavers") was used to identify the main midface fat compartments involved during muscular contraction when smiling and their motion and behavior with and without filler injections. Based on these insights and the literature, a multilayering filler injection approach was developed to optimize midface rejuvenation by restoring fat volumes using rheologically different products injected into different fat compartments. Results: Twenty-four hemifacial dissections confirmed the presence of two fat compartment layers, separated by the orbicularis oculi muscle in the horizontal plane and by the septa in the vertical plane, and revealed the anatomical effects of facial movement. The midface is composed of deep static fat compartments and a superficial dynamic adipose layer that follows the facial movements, creating a natural dynamic appearance. A proof-of-concept study involved 130 White patients (36 to 56 years; 91 percent women). After the procedure, 95 percent of patients and 98 percent of practitioners rated facial appearance as "improved" or "much/very much improved." No major complications were reported. Conclusions: The smiling cadavers method enhances understanding of dynamic facial anatomy by showing the superficial and deep fat compartments of the midface at rest and their motion during a procedure to represent a smile. The multilayered injection technique takes into account these anatomical findings to rejuvenate the midface, achieving a natural appearance at rest and during motion.