Joris van Dongen

187 tSVF as a treatment for scar remodeling Table 1. In- and exclusion criteria of subjects participating in this study. Inclusion criteria Exclusion criteria Females Breast surgical intervention 1 year prior start of the study Age 18-60 Any oncological event in history Known psychiatric condition Known systemic disease that will impair wound healing Smoking Pregnancy or active child wish Frequent exposure to known carcinogenic substances ( e.g. work related) Active or previous use of hormone replacement therapy Harvesting, preparation and injection of tissue-stromal vascular fraction Fortyml of adipose tissue was harvested from abdominal regionwith very fine Tonnard harvesting cannulas (Tulip, Medical Products, San Diego, CA) to obtain two times 1 ml of tSVF by means of the fractionation of adipose tissue procedure (FAT). 20 Briefly, harvested lipoaspirate was decanted and centrifuged at 3,000 rpm with a radius fixed angle rotor (Medilite, Thermo Fisher Scientific, Waltham, MA) for 2.5 min. at room temperature (RT). Then, two times 10 ml of centrifuged lipoaspirate was mechanical dissociated using a fractionator (a luer to luer connector hub with three holes of 1.4mm inside) by pushing lipoaspirate 30 times forward and backwards. After fractionation, lipoaspirate was centrifuged again using identical settings. One ml of tSVFwas injected into the lateral 5 cm of the horizontal scar of one breast, while the lateral 5 cm of the other breast received 1 ml of saline. Injection was performed into the wound edges using a 18G needle after suturing intracutaneously with monocryl 4.0. Patient and observer scar assessment scale Scar appearance was assessed with the use of the patient and observer scar assessment scale (POSAS) by both the patient and plastic surgeon 6 months and 12 months postoperative. As primary outcome, the total average score of the patient part of the POSAS questionnaire was used, while the observer part served as secondary outcome. Each scar characteristics of both the patient and observer part of the POSAS questionnaire was analysed separately. A lower score represents an aesthetically better scar than a higher score. Only the lateral 5 cm of the horizontal scar was assessed.