The Impact of Botulinum Toxin on Brow Height and Morphology: A Randomized Controlled Trial

Background: Previous reports have objectively demonstrated the efficacy of botulinum toxin for brow elevation. No clinical trial has compared the variation of the eyebrow shape and height when the lateral eyebrow depressors are injected alone or in combination with the medial eyebrow depressors. Methods: A prospective, randomized, controlled study was designed to evaluate and compare the effect of two different botulinum toxin injection techniques on brow shape and position. Patients were divided into two groups. Abobotu-linumtoxinA was injected in the lateral eyebrow depressors alone (group 1) or in both the lateral and medial eyebrow depressors (group 2). Objective eyebrow measurements were performed using standardized preinjection and postinjection photographs. Patient satisfaction was also evaluated. Results: Fifteen patients (30 eyebrows) were included in each group. The brow elevated by 0.6 to 2.1 mm at all positions in group 1. In group 2, the brow elevated from the medial limbus to the lateral edge of the brow (1 to 1.7 mm), with no changes at the level of the medial brow and canthus. When comparing the two injection techniques, the authors found a statistically significant difference in the change of eyebrow height at the level of the medial brow, medial canthus, and lateral brow edge. Ninety-seven percent of patients were satisfied with their results. Conclusion: Different eyebrow injection techniques yield different elevation patterns.