A Step-By-Step Surgical Protocol for the Treatment of Perianal Fistula with Adipose-Derived Mesenchymal Stem Cells.

Anal fistula is a challenging condition both for surgeons and patients. Recurrent fistula, Crohn's disease, or autoimmune disorders add further complexity to this situation. Numerous clinical trials have now demonstrated that cell-based therapy appears to be a good complement to fistulous surgery. As in any new treatment, especially that involving living cells, appropriate application is paramount to achieve optimal outcomes. As stem cell-based treatments are gaining a strong foothold in fistula management worldwide, we herein aim to share our mesenchymal stem cell surgical protocol. With the goal of optimizing results of this emerging therapy, we have improved and refined our protocol over the past 17 years of working with stem cells in clinical trials. The protocol consists of nine reproducible steps for mesenchymal stem cell application inside the fistulous tract, and has proven to be safe and effective in several studies, including international phase III clinical trials.