Double-blind, randomized, controlled clinical trial to compare safety and efficacy of a metallic cannula with that of a standard needle for soft tissue augmentation of the nasolabial folds.

Background: Injection-related side effects and complications are likely to occur during or after filler injections; they are mainly caused by the injection technique.

Objective: To assess safety and efficacy of a metallic cannula to inject hyaluronic acid (HA) filler in the nasolabial folds and to compare the safety of this cannula with that of a standard needle.

Methods: This was a prospective, randomized, phase II, double-blinded study that included 25 participants with Grade 2 to 3 for bilateral nasolabial folds according to the Modified Fitzpatrick Wrinkle Scale (MFWS). The side of the injection was randomized (cannula or needle), and 0.5 mL of HA was injected into each nasolabial fold.

Results: At day 3, mean MFWS score fell from 2.40 ± 0.40 to 1.46 ± 0.52 (p < .001) on the cannula-injected side and from 2.40 ± 0.40 to 1.48 ± 0.60 (p < .001) on the regular needle-injected side. Participants reported fewer side effects on the side injected with the new tool on the day of the injections: pain (p = .03), edema (p < .001), redness (p = .01) and hematoma (p < .001) than on the needle side.

Conclusion: The new cannula is a safe and useful tool to inject HA fillers in the nasolabial folds, producing less pain, edema, hematoma, and redness than regular needles.