Non-Crohn's complex and multirelapsed perianal fistulas treated with sphincter sparing surgical procedures and adjuvant adipose tissue injection

Purpose: The purpose of this study was to evaluate the results obtained by the treatment of non-Crohn’s-related complex and multirelapsed perianal fistulas using a surgical sphincter-sparing technique with adjuvant adipose tissue injection, a rich source of progenitor and immunomodulatory cells. Methods: A prospective, non-randomized, interventional, single-center, open-label clinical trial was conducted from January 2020 to December 2022. Nine patients were enrolled and assessed after a minimum of twelve months of follow-up. All patients underwent removal of the setons, excision, or curettage of the fistula tract and mucosal flap or internal opening suture. The collection and processing of adipose tissue to be injected was performed using a commercially available system. Results: Selected cases included six men and three women with a mean age of 42. All patients had an extended disease course period, ranging from 3 to 13 years (mean 6.6 years), and a history of multiple previous surgeries, including two to eight interventions (an average of 4.4 per case). All fistulas were high transsphincteric, in four cases in horseshoe and two cases with secondary suprasphincteric or peri-elevator tract fistulas. At a mean follow-up of 18 months (range 12–36), a complete healing rate was documented in six cases (66%) and a remarkable improvement in three cases (33,3%). Conclusions: In the group of patients described with complex fistulas with multiple recurrences, many from palliative treatments with setons, the adjuvant injection of adipose tissue associated with a sphincter-sparing surgical procedure might help to achieve closure or improvement in a significant percentage of cases. The study protocol was prospectively registered on Clinicaltrials.gov (NCT 04750499) .