Long-term outcomes of a bioactive matrix enriched with an autologous platelet concentrate for the treatment of complex anal fistulae

Background: Treating complex anal fistulae (CAF) remains a clinical challenge. Regenerative fistula treatment (RFT) with a bioactive matrix enriched with autologous platelet concentrate (Obsidian RFT®) has shown potential in healing CAF while preserving continence, but its long-term efficacy is still debated. This study aims to report the outcomes of RFT in patients with CAF. Methods: A retrospective analysis of a prospective database of patients with CAF treated with RFT between February 2021 and November 2023 at a single center was conducted. Patients were included if they completed at least a 6-month follow-up. The primary outcome was fistula healing at last available follow-up. Secondary outcomes included unscheduled reoperation and anorectal function. Results: A total of 31 patients were treated with Obsidian RFT, 17 of whom completed the 6-month follow-up. Nine of the patients were women. The median age was 47 (24–63) years, and eight had inflammatory bowel disease. High transsphincteric fistulae were observed in 52.9% of patients. At a median follow-up of 21.8 (8–36) months, a 53% success rate was achieved. Approximately half of patients required at least one additional procedure owing to CAF persistence or recurrence. There were no reports of morbidity or mortality, and no worsening of continence was observed. Conclusions: This pilot study demonstrated that nearly half of the patients treated with RFT for CAF achieved long-term healing, with no adverse effects on continence and an excellent safety profile. Larger studies are needed to draw definitive conclusions.