Botulinum Toxin Injection After Sternotomies to Improve Scar Aspect and Impact

Sternotomy scars, which are localized in a high-tension area are often dystrophic, hypertrophic or keloidal, and can be difficult to accept to patients who already endured a heavy intervention with high psychologic impact. The investigators wish to evaluate immediate post-surgical injection of botulinum toxin to improve scar aspect and impact. A randomized, placebo-controlled, split-scar clinical trial will determine the improvement of scar aspects assessed by standardized scores (SBSES, POSAS), patient satisfaction and tolerance.