Local irrigation with silver nitrate, a non-surgical approach for persistent anal fistula

Abstract

Purpose: Treatment of persistent anal fistula implies a major challenge for surgeons, with risk of additional recurrence and potential continence impairment. We present a non-surgical treatment based on irrigation with silver nitrate 1% solution. Methods: This is a prospective study including patients with persistent anal fistula after surgery, who were treated with silver nitrate 1% solution irrigation from May 2015 to March 2017. Patients with evidence of abscess, presence of >1 external opening and those with bowel inflammatory disease were excluded. 3–5 cc of silver nitrate 1% solution were instilled through a catheter. The procedure was repeated on a weekly basis, conducting a maximum of 7 sessions per patient. Results: 18 patients (13 male, 72.2%) with a median age of 48 years old (IQR 41–55) were treated using silver nitrate 1% solution. A median of 5 sessions per patient was performed (IQR 3–6). The median follow-up period was 18 months (IQR 9–25). After the described period 8 patients’ (44.4%) presented complete resolution of the fistula, 2 patients’ (11.2%) were classified as partial healing and in 8 patients’ (44.4%) the treatment was considered to fail. 6 patients’ experienced self-limited pain during instillation, with persistence up to 24 h in 2 of them. Conclusions: Treatment with silver nitrate 1% solution is a minimally invasive procedure, with a favourable safety profile, that can be performed in an outpatients’ basis achieving a complete healing rate of 44.4%. Therefore, this method should be considered for the treatment of recurrent or persistent anal fistula.