Pain and Bruising Levels after Lip Augmentation: A Comparison of Anterograde and Retrograde Techniques Using an Automated Motorized Injection Device. A Blinded, Prospective, Randomized, Parallel WithinSubject Trial

BACKGROUND Dermal fillers for lip augmentation can be injected using various techniques. Although all seem to provide acceptable results, it is not clear which technique is safer, less painful, and provides greater patient comfort. OBJECTIVE To compare patients' self-reported pain intensity during the injection of hyaluronic acid dermal filler for lip augmentation, with 2 different techniques, anterograde versus retrograde. METHODS AND MATERIALS Prospective, single-center, within-subject, single-blinded, randomized controlled trial. All subjects received injections in the lip with hyaluronic acid-based filler, each side using the anterograde or retrograde injection technique. An automated motorized injection device was used to ensure a homogeneous deposition flow of the product injected and reduce operator bias. Pain intensity was selfassessed using a 100-mm visual analog scale. Presence and severity of bruising were recorded. RESULTS Forty-four women (mean age 30.3 years) were randomized. Mean self-reported pain score was 53.1% lower with the anterograde technique than with the retrograde (p < .0001). The anterograde technique had lower rates of site reactions, showed a faster recovery time, and 68.2% of patients favored this technique. CONCLUSION This study demonstrated that the anterograde technique was less painful, and led to fewer bruising and site reactions than the retrograde technique when using an automated device.