Is Vibration Anesthesia Effective and Safe for Pain Reduction in Botulinum Toxin Injection? A Randomized Split-Face Controlled Trial and Cadaver Experiment

Abstract Background Pain is an important issue in botulinum toxin injection. Vibration anesthesia is a noninvasive method for pain alleviation, but few studies have reported its use during botulinum toxin injection. Objectives The aim of this study was to investigate whether vibration anesthesia was effective and safe for pain reduction during botulinum toxin injection for masseter reduction. Methods A randomized split-face controlled trial was performed in patients who required masseter reduction. Vibration anesthesia was randomly administered on either side. Study outcomes were pain scores on a visual analog scale, duration of effect, satisfaction, and complications. Intergroup comparison and linear regression analyses were performed. Results In a total of 216 patients, the pain score on the vibration side (2.97 ± 1.44) was significantly lower than that on the nonvibration side (4.72 ± 2.13) (P < .0001), with a higher proportion of mild pain. Linear regression showed that a history of injection and more injection points and doses increased the pain, whereas a 2-mL syringe reduced the pain compared to a 1-mL syringe. Side effects were found in 19 patients and 21 sides (7%), but were not associated with vibration. High satisfaction was reported. A cadaver experiment confirmed that vibration did not alter the diffusion radius and depth of injection. Conclusions Vibration anesthesia significantly relieved pain during botulinum toxin injection for masseter reduction, and it did not cause adverse effects and or affect duration of effect. Therefore, we recommend vibration anesthesia, a larger syringe size, and fewer injection points to improve patient experience and satisfaction. Level of Evidence: 3 (Therapeutic)