Abstract Background An injection with autologous platelet-rich stroma (PRS) as add-on to surgery for treatment-refractory perianal fistulizing Crohn’s disease (pCD) showed promising results on both short- and long-term in a pilot study conducted in our tertiary referral center. This prospective cohort study evaluated perpetuation of short-term outcomes following PRS injection compared to the results in an earlier pilot study. Methods Subsequent to a pilot study with the same methods and inclusion criteria, consecutive adults with therapy refractory pCD undergoing surgery and PRS injection were included. All surgeries were performed by already trained (pilot study) surgeons in a tertiary referral center. Primary outcome was complete clinical closure at 3 and 12 months. Secondary outcomes included combined clinical and radiologic healing at time of first postoperative MRI, recurrence, and the need for unplanned re-interventions. Outcomes were assessed and compared between the pilot A and post-pilot B cohorts. A potential learning curve was explored for the primary outcome at 12 months using multivariable logistic regression with backward elimination comparing both cohorts. Results The total cohort comprised fifty-nine patients (A n = 25; B n = 34). Comparison of patients treated in A with B revealed no significant differences in baseline or fistula characteristics (Table 1). Non-significant higher closure rates were observed in the post-pilot cohort (3m: 50% B vs. 32% A, p = 0.167 95% CI 0.64–6.26; p = 0.235). Numerically lower combined clinical and radiologic closure rates at the first postoperative MRI were observed in the cohort B (26% vs. 38% A, p = 0.352). The median interval to imaging differed (3.4 months B vs. 5.7 months A). Overall (n = 55), the mean (m)vanAssche index decreased from 10.7 points (SD 3.8) to 5.9 points (SD 4.5)(p 0.001). No recurrences were observed in cohort A whereas 3 (12%) patients in cohort B experienced recurrence (p = 0.202; overall 8%). Unplanned re-interventions aimed at source control were comparable between the A and B (both 24%, p = 0.967). Although at 12m higher rates of reinterventions aimed at closure plus additional PRS were observed in cohort A, this difference did not reach statistical significance (44% vs. 27%, p = 0.160). Conclusion Autologous PRS injection appears to be a promising add-on to the surgical treatment of therapy-refractory pCD, with sustained encouraging closure and low recurrence rates at one-year follow-up. There was no evidence of a learning curve significantly impacting clinical outcomes at one year postoperatively. References: Schouten WR, Arkenbosch JHC, van der Woude CJ, et al. Efficacy and safety of autologous adipose-derived stromal vascular fraction enriched with platelet-rich plasma in flap repair of transsphincteric cryptoglandular fistulas. Tech Coloproctol 2021;25:1301-1309. Bak MTJ, de Vries AC, Witjes CDM, et al. Intraoperative Autologous Platelet-Rich Stroma Injection as Add-On to Fistula Curettage and Closure of the Internal Orifice Demonstrates a Favorable Outcome in Long-Term in Patients Suffering from Therapy-Refractory Perianal Fistulizing Crohn’s Disease. Inflammatory Bowel Diseases 2025. Conflict of interest: Bak, Michiel: Grant: Unrestricted research grant from Falk Pharma Benelux Other: Speaker fees from AbbVie Verweij, Merel: No conflict of interest Dwarkasing, Roy S.: No conflict of interest Witjes, Caroline: No conflict of interest Molendijk, Ilse: No conflict of interest De Vries, Annemarie C.: No conflict of interest Dr. Van Ruler, Oddeke: No conflict of interest
Bak et al. (Thu,) studied this question.