RESUMEN
BACKGROUND: Injection of hyaluronic acid fillers (HA) fillers for horizontal neck line correction and rejuvenation has gained popularity in recent years despite conflicting reports on its efficacy and safety. Most published reports are retrospective studies that commonly use the sharp needle technique. In this prospective study, we therefore aimed to determine the efficacy and safety of an HA filler (Belotero Balance®, Merz Aesthetics) on the treatment of horizontal neck lines by blunt cannula injection technique. MATERIALS AND METHODS: Thirty subjects were enrolled and treated with HA filler injections on the neck region using a blunt cannula injection technique into the deep dermis. Standardized photographic documentation was done at baseline, immediately after injection, and at 2-week, 1-, 3-, and 6-month follow-up after treatment. The rejuvenation effect was graded by the patients themselves and two blinded dermatologists using comparative photographs. Side effects were likewise recorded at each follow-up visit. RESULTS: All 30 subjects completed treatment and attended every follow-up visit. The study participants comprised both females and males aged 20-69 years with mild, moderate, and severe neck lines based on the Horizontal Neck Wrinkle Severity Scale (HNWS) (Plast Reconstr Surg Glob Open, 2019, 7, 2366). All patients received approximately 3 ml of HA fillers for the entire treatment area. Both patient and physician ratings revealed peak benefits at 1-month post-treatment, with a significant decline at 3 months, which was sustained until 6 months after the procedure. Only one patient developed bruising related to the treatment, which resolved spontaneously without any additional medication. CONCLUSION: The study demonstrated efficacy in improving the appearance of horizontal neck lines after one session of HA filler injection. The results showed peak improvement at 1 month, but with sustained rejuvenation effects up to 6 months after injection.