Combined Approach to Nasolabial Fold Rejuvenation: Hyaluronic Acid Fillers and DAO Botulinum Toxin Injection

(1) Background: The nasolabial fold is a key determinant of midfacial aging, influenced by both static volume loss and dynamic muscular activity. Botulinum toxin type A (BoNT-A) and hyaluronic acid (HA) fillers are widely used in aesthetic medicine, but limited evidence exists regarding the sequential use of these treatments to address both static and dynamic components of the nasolabial fold. (2) Methods: This prospective interventional case series included 23 patients with clinically evident nasolabial folds and depressor anguli oris (DAO) hyperactivity. All patients received BoNT-A injections into the DAO muscle, followed by HA filler augmentation in selected cases according to baseline severity. Patients were classified into three treatment groups in accordance with the treatment strategy selected at baseline: BoNT-A alone, BoNT-A plus 0.5 mL HA per side, and BoNT-A plus 1 mL HA per side. Outcomes were assessed using the Wrinkle Severity Rating Scale (WSRS) in both static and dynamic conditions and the Global Aesthetic Improvement Scale (GAIS), evaluated by two independent blinded physicians. (3) Results: All treatment groups demonstrated a reduction in dynamic WSRS scores following BoNT-A injection, reflecting decreased DAO activity and reduced dynamic accentuation of the nasolabial fold. Patients receiving combined BoNT-A and HA treatment showed additional improvement in static fold severity. Overall, GAIS scores indicated much to very much aesthetic improvement, with the highest outcomes observed in patients receiving 1 mL HA augmentation. Interobserver agreement was good across evaluations. (4) Conclusions: Botulinum toxin treatment of the DAO was linked to reduced dynamic accentuation of the nasolabial fold, while hyaluronic acid augmentation led to additional improvement in static fold severity. These preliminary findings indicate that sequential treatment might address both dynamic and static components of nasolabial fold appearance. However, larger randomized studies with longer follow-up are necessary to confirm these findings.