Efficacy and Safety of Resilient Hyaluronic Acid Fillers Injected with a Cannula: A Randomized, Evaluator-Blinded, Split-Face Controlled Study

Purpose: Cannulas are increasingly used for injecting hyaluronic acid fillers, as they are thought to improve patient comfort safety and treatment tolerability. This study aimed to demonstrate the non-inferiority of a Resilient Hyaluronic Acid 4 (RHA 4) filler injected with a cannula versus a needle for the treatment of moderate to severe nasolabial folds (NLF). Patients and Methods: A total of 50 subjects were included in a randomized, evaluator-blinded, split-face trial. The NLF were injected with RHA 4 using a cannula on one side of the face and using a needle on the other side on Day 0. A touch-up could be performed 4 weeks later. The subjects were followed up for 12 weeks after the last injection, ie, injection on Day 0 or touch-up. Efficacy was evaluated using a Wrinkle Severity Rating Scale (WSRS), the Global Aesthetic Improvement Scale (GAIS), and patient-reported outcomes. Safety assessments included the injection-site pain, common treatment reactions (CTRs), and adverse events (AEs). Results: Twelve weeks after the last injection, the efficacy of the cannula treatment was found to be non-inferior to that of the needle treatment, based on the WSRS score improvements. The other study endpoints showed the equivalent efficacy and safety of the two methods. No serious or unexpected AEs were reported. Conclusion: RHA 4 may be effectively and safely injected into the NLF using a cannula or a needle, provided it is administrated by a trained practitioner.