Abstract Background Crohn’s perianal fistulas are challenging to treat, with permanent closure rates around 30% despite various combined medical and surgical treatment options. Autologous platelet-rich stroma (PRS), combining stromal vascular fraction and platelet-rich plasma, has shown promising results in promoting tissue regeneration and reducing inflammation. This study aims to evaluate the efficacy of PRS injection as an adjunct to surgery on clinical and radiological closure rates in patients with therapy-refractory Crohn’s perianal fistulas. Methods In this prospective pilot study, conducted at a Dutch tertiary center from March 2025 to October 2025, adult patients with complex therapy-refractory Crohn’s perianal fistulas underwent fistula curettage and received autologous PRS injection derived from adipose tissue, and closure of the internal orifice. Calprotectin levels were measured in fistula scrapings to determine the inflammatory status using ELISA. Follow-up included physical examinations and MRI within 6 months to assess clinical and radiological fistula closure. The primary outcomes were complete clinical closure (defined as complete closure of the external opening(s) without discharge upon finger compression) and radiological closure (defined as MAGNIFI-CD ≤ 6 on MRI). Secondary outcomes included complications related to the procedure, as well as the correlation between fistula closure and fistula calprotectin levels. Results Nineteen patients were included (median age 40 years IQR 35–48; 71% female), with a median Crohn’s disease duration of 4 years IQR 2–14, and a median of 3 surgical interventions per patient. After a median follow-up of 5,5 months, clinical closure was achieved in 58% of patients. Postoperative MRI demonstrated complete radiological healing in 4/10 (40%) patients. No postoperative surgically related complications were observed. The median fistula calprotectin level was 1881µg/g. Although not significantly different, a lower calprotectin level was found in patients with clinical and radiological closure (1097µg/g) compared to those in the non-closure group (2726µg/g). Conclusion The addition of local PRS injection to the surgical closure of the internal orifice is safe and demonstrates promising early postoperative outcomes in patients with refractory Crohn’s perianal fistulas. However, clinical and radiological closure were more frequently observed in patients with a low scraping calprotectin level, suggesting that for more inflammatory fistulas, an alternative or additional approach may be necessary to achieve permanent closure. Conflict of interest: Mr. Bakar, Okan: No conflict of interest Wiggers, Jimme: No conflict of interest Wildenberg, Manon: Received research grant support from Hoffman-La Roche, Boehringer-Ingelheim Vlug, Malaika: No conflict of interest Buskens, Christianne J.: Grant: C. Buskens has received an unrestricted grant from Boehringer Ingelheim and Roche Personal Fees: C. Buskens has received consultancy fees and/or speaker’s honoraria from Tillotts, Takeda, MSD and Janssen
Bakar et al. (Thu,) studied this question.