Poly D,L Lactic Acid Injection for Subzygomatic Arch Depression (Lateral Sunken Cheek)

BACKGROUND: Subzygomatic arch depression (lateral sunken cheek) is a frequent midface contour concern associated with age‑related soft‑tissue redistribution and retaining ligament laxity. It can be difficult to correct with conventional hyaluronic acid (HA) filler because taut ligamentous boundaries may limit smooth volumization and predispose to contour irregularity or an "overfilled" appearance. OBJECTIVES: To describe a cannula‑based superficial fat injection technique using a highly diluted poly‑D,L‑lactic acid (PDLLA) hybrid injectable (Juvelook Volume; VAIM, Seoul, Korea) for subzygomatic arch depression and to report clinical outcomes from a consecutive case series. METHODS: Adults with lateral sunken cheeks underwent 3 treatment sessions at 3‑week intervals. PDLLA hybrid injectable was reconstituted with 8 mL normal saline and injected 4 mL per side per session into the superficial fat layer using a 25‑gauge, 50‑mm cannula. A single entry point just inferior to the zygomatic ligament proper was used for 3‑vector fanning with retrograde linear threading. Outcomes were assessed at 3 months after the final session using investigator‑rated Global Aesthetic Improvement Scale (GAIS) and patient satisfaction. Safety events were recorded. RESULTS: Twenty‑four patients completed the protocol. At 3 months, GAIS was rated very much improved in 7 (29.2%), much improved in 11 (45.8%), improved in 5 (20.8%), and no change in 1 (4.2%). Median GAIS score was 2 (much improved) and differed significantly from the no‑change score (Wilcoxon test versus 4; P<0.001). Twenty‑one patients (87.5%) were satisfied or very satisfied. Transient ecchymosis occurred in 3 patients (12.5%) and resolved within 10 days; no nodules, infections, granulomas, or vascular events were observed. CONCLUSIONS: A superficial fat, cannula‑based, highly diluted PDLLA hybrid protocol may provide predictable improvement of subzygomatic arch depression with low downtime. The approach leverages gradual biostimulation rather than immediate bolus volume and may be useful in areas constrained by retaining ligaments. Controlled comparative studies with objective volumetric endpoints are warranted.