P359 Platelet-rich stroma injection (PRS) as a novel surgical treatment of refractory perianal fistulas in Crohn’s disease: A pilot study

J. Arkenbosch1, O. van Ruler2, R.S. Dwarkasing3, W.R. Schouten2, A.C. de Vries1, E.J.R. de Graaf2, C.J. van der Woude1

1Department of Gastroenterology, Erasmus MC, Rotterdam, The Netherlands, 2Department of Surgery, IJsselland Hospital, Capelle a/d IJssel, The Netherlands, 3Department of Radiology, Erasmus MC, Rotterdam, The Netherlands

Background

Perianal fistulizing Crohn’s disease (FCD) comes with significant morbidity and severe reduced quality of life. Treatment of FCD is challenging and includes immunosuppressive drugs, antibiotics and surgery. All therapies are associated with high recurrence rates. Platelet-rich stroma (PRS) is a combination of platelet-rich plasma (PRP) and stromal vascular fraction (SVF). Autologous PRS includes stromal cells in their matrix with stimulating factors, plays an essential role in wound repair and defence mechanisms against infection and is easy to obtain and inject. Because of its operating mechanism, PRS could be of additional value in patients with refractory FCD. This study aims to assess the feasibility, safety and efficacy of local injection of PRS in patients with refractory FCD.

Methods

After informed consent, 10 patients (age ≥16 years) with refractory FCD were included between March 2018 and July 2019. Exclusion criteria were rectovaginal fistulas, persistent proctitis and pelvic abscesses. All patients underwent surgery with harvesting of subcutaneous fat and venous blood sampling to obtain 6 ml of PRS (1 ml of SVF resp. 5 ml of PRP), excision of the external opening(s), fistula curettage, and injection of PRS in the fistula wall and closure of the internal opening. A pre- and postoperative MRI was performed. Endpoints were clinical outcome, both closure and absence of discharge at physical examination, patient-reported outcome (no effect/moderate effect/major effect), as well as radiological outcome (van Assche score). From 3 months postoperative, re-injection of PRS was considered in patients with unfavourable clinical and/or radiological outcome.

Results

All patients (4:6 female:male; median age 33 (IQR 22.9–38.7) had infralevatoric fistulas with a median van Assche score of 17 [range 14–20] without rectal involvement and abscesses. Median follow-up was 6 months [4–12]. The median duration of FCD was 4 years (IQR 2–5). The median number of drugs given were 4 [1–7] and number of operations 3 [2–3], including stoma formation in 2 patients. Crohn’s disease activity outside the anorectum was present in all patients. 7 patients underwent 1 PRS injection and 3 patients 2 injections. There were no complications of the PRS injection. Fistula closure was present in 5 patients and open in 5 patients, of which 2 patients had no signs of discharge. One patient underwent restoration of bowel continuity. Of 7 postoperative MRIs available to date, median decrease of van Assche score was 4 (17 vs. 13)[0–15]. Patient-reported outcome was major effect in 4, moderate effect in 3, and no effect in 3 patients.

Conclusion

Autologous PRS appears to be feasible, safe and promising in the treatment of refractory perianal fistulizing Crohn’s disease.