Joris van Dongen

184 Chapter 8 ABSTRACT Introduction The skin is the first physical barrier of the human body to pathogens. After skin defects occur, the wound starts to heal in consecutive and overlapping phases. Ideally, a wound heals without a scar, however multiple factors contribute to pathological scar formation e.g. chronic inflammation or large wound size. Till now, no evidence-based treatment is available to stimulate wound healing that regenerates damaged skin without a scar. Tissue stromal vascular fraction (tSVF) of adipose tissue is a heterogenous mixture of cell types embedded in an extracellular matrix loaded with a large number of growth factors and cytokines that stimulate and modulate all wound healing-related processes including parenchymal proliferation, angiogenesis, matrix remodeling and inflammation. In this study, we hypothesized that tSVF increases dermal wound healing of post-surgical wounds and thus suppress subsequent scar formation. Material & methods This prospective, double-blinded, placebo-controlled, randomized trial was conducted between 2016 and 2020. In total, 40 female mammoplasty patients were enrolled with 34 completing the follow-up. All patients received tSVF in the lateral 5 cm of the horizontal scar of one breast directly postoperative after a bilateral reduction mammaplasty. The other lateral 5 cm of the horizontal scar of the other breast received a placebo injection comprising 0.9% NaCl. tSVF was isolated by means of the fractionation of adipose tissue (FAT) procedure. Results were obtained using the patient and observer scar assessment scale (POSAS), photograph evaluation using a visual analogue scale (VAS) by blinded observers and number of complications up to 1 year postoperative. Results Injection of tSVF improved postoperative scar appearance as compared to a placebo injection evaluated using the POSAS questionnaire six months postoperative. This difference in scar appearance lost significance after twelve months. In both groups, postoperative scars were barely visible after twelve months. No improvement was seen based on the evaluation of photographs of postoperative scars between both groups. Conclusion Immediate postoperative injection of tSVF suppresses scar formation up to six months postoperative, although this effect seems to disappear after twelve months. This study indicates that tSVF accelerates early wound healing and coincides with barely visual scar formation.