Treatment of transsphincteric fistula-in-ano with growth factors from autologous platelets: results of a phase II clinical trial

Purpose The aim of this paper is to evaluate to the safety, feasibility and efficacy of a novel treatment for transsphincteric cryptoglandular fistula: injection of autologous plasma rich in growth factors (PRGF) into the fistula tract accompanied by sealing using a fibrin plug created from the activated platelet-poor fraction of the same plasma. Method This article is a prospective, phase II clinical trial. The procedure was externally audited. Thirty-six patients diagnosed with transsphincteric fistula-in-ano were included. All patients underwent follow-up examinations at 1 week and again at 3, 6 and 12 months after discharge. Main outcome measures safety (number of adverse events), feasibility and effectiveness of the treatment. Results A total of 36 patients received the study treatment, with the procedure found to be feasible in all patients. A total of seven adverse events (AE) related to the injected product or surgical procedure were identified in 4 of 36 patients. At the end of the follow-up period (12 months), 33.3% of patients (12/36) had achieved complete fistula healing and 11.1% of patients (4/36) had achieved partial healing. In total, this amounted to 44.4% of patients (16/36) being asymptomatic at final follow-up. In successfully healed patients, a gradual reduction in pain was observed, as measured using a Visual Analog Scale (VAS) (p = 0.0278). Compared to baseline, a significant improvement in Wexner score was seen in patients achieving total or partial healing of the fistula (p = 0.0195). Conclusions The study treatment was safe and feasible, with apparently modest efficacy rates. Continence and pain improvement following treatment may be considered predictive factors for healing.