Comparison between application of platelet rich plasma and mucosal advancement flap in patients with high transsphincteric anal fistulas: a randomized control trial.

Background: There is still a search for a standard method of therapy for high anal fistulas. The aim of this trial was a comparison between a modified two stage minimally invasive procedure, consisting of loose-seton placement with the subsequent application of platelet rich plasma with mucosal advancement flap for the treatment of high transsphincteric anal fistulas of crypto-glandular origin.

Methods: The study was designed as a prospective, randomized trial including 96 patients. Curettage of fistulous tracts, and loose-seton placement was performed in those patients with active inflammation, and if the diameter of a fistulous tract exceeded 3 mm. Afterwards, the patients were randomly assigned to either the PRP group or MAF group, consisting of 49 patients, and 47 patients, respectively.

Results: There was no significant statistical difference (p = 0.152) between both investigated groups of patients regarding closure of fistulas since it was achieved in 35 (71.43%) patients from group I, compared to 27 (57.45%) patients from group II. The diameter of fistulous tracts below 4 mm exerted a significant impact (p < 0.001) on the healing process after PRP application because fistulas with the narrow tracts were closed in 34 (87.18%) patients, whereas a wider fistula was healed in 1 (10%) patient.

Conclusion: The local application of PRP in high, unbranched, and with narrow tracts trans-sphincteric anal fistulas of crypto-glandular origin, following loose-seton drainage is an effective, simple, and a safe method of therapy with a low rate of morbidity.