Surgical management of complex perianal fistula revisited in a systematic review: a critical view of available scientific evidence

Background Treating complex perianal fstulas in Crohn's disease patients remains a challenge. Classical surgical treatments for Crohn's disease fstulas have been extrapolated from cryptoglandular fstulas treatment, which have diferent etiology, and this might interfere with its efectiveness, in addition, they increase fecal incontinence risk. Recently, new surgical techniques with support from biological approaches, like stem cells, have been developed to preserve the function of the sphincter. We have performed a systematic literature review to compare the results of these diferent techniques in the treatment of Crohn's or Cryptoglandular fstula. Methods PubMed, EMBASE, Database of Abstracts of Reviews of Efectiveness, Cochrane Central Register of Con‑ trolled Trials were searched systematically for relevant articles. We included randomized controlled trials and obser‑ vational studies that referred to humans, were written in English, included adults 18+ years old, and were published during the 10-year period from 2/01/2010 to 2/29/2020. Evidence level was assigned as designated by the Scottish Intercollegiate Guidelines Network. Results Of the 577 citations screened, a total of 79 were ultimately included in our review. In Crohn's disease patients, classical techniques such as primarily seton, Ligation of Intersphincteric Fistula Tracks, or lay open, healing rates were approximately 50–60%, while in cryptoglandular fstula were around, 70–80% for setons or faps. In Crohn's disease patients, new surgical techniques using derivatives of adipose tissue reported healing rates exceeding 70%, stem cells-treated patients achieved higher combined remission versus controls (56.3% vs 38.6%, p=0.010), mesenchymal cells reported a healing rate of 80% at week 12. In patients with cryptoglandular fstulas, a healing rate of 70% using derivatives of adipose tissue or platelets was achieved, and a healing rate of 80% was achieved using laser technology. Fecal incontinence was improved after the use of autologous platelet growth factors and Nitinol Clips. Conclusion New surgical techniques showed better healing rates in Crohn's disease patients than classical tech‑ niques, which have better results in cryptoglandular fstula than in Crohn's disease. Healing rates for complex cryp‑ toglandular fstulas were similar between the classic and new techniques, being the new techniques less invasive; the incontinence rate improved with the current techniques.