Urethral stenosis (UrS) is a narrowing of the urethra's caliber. UrS results of ischemic fibrosis of the corpus spongiosum (spongiofibrosis). Fibrosis-induced retraction reduces the size of the urethral lumen. Spongiofibrosis may be due to infections, inflammation, trauma but remains mostly idiopathic.Endo-urethral treatment exposes to a high rate of recurrence (up to 60% depending on the site, length and etiology). The reconstruction treatment is more effective but more complex (use of oral mucosal flap or other substitution tissue, less mastered by the surgical community and more morbid.~The (ADSVF) is an easily accessible source of autologous mesenchymal stem cells. Obtention from lipoaspirates is safe, simple and standardized. Different animal models have demonstrated the pro-healing and anti-fibrotic properties of autologous ADSVF in the urethra corpus cavernous during erectile dysfunction, perineal fistulas during Crohn's disease and systemic sclerosis.~The main objective of this study is to assess the safety and tolerability of ADSVF, as add-on treatment to endoscopic urethrotomy for recurrent bulbar urethral stenosis during the follow-up.
SURF is a randomised controlled, parallel group, single blind phase II study designed to assess the safety and potential efficacy of an innovative therapeutic strategy for urethral stenosis based on adjuvant injection of autologous Adipose-Derived Stromal Vascular Fraction of Adipose Tissue (ADSVF) during endoscopic urethrotomy (standard care).