Ambulatory seton placement followed by fistulotomy: efficacy and safety for perianal fistula treatment.

Purpose: To evaluate the efficacy and safety of ambulatory seton placement followed by superficial fistulotomy as treatment of perianal fistula.

Methods: Retrospective observational analysis of patients with cryptogenic perianal fistula aged 18-90 years, followed in a central hospital proctology consultation between 2006 and 2017. Data were obtained through clinical record's analysis. Fistula was characterized, using Parks Classification. A probe was passed through the fistula tract, followed by a seton, which remained in situ until superficial fistulotomy was possible.

Results: Ninety-six patients were included (66.67% males, mean age 56 ± 15 years old). Nineteen patients (19.89%) had previous history of perianal fistula and 14 (14.58%) previous anorectal surgery. Seventy-four patients (78.72%) were submitted to fistulotomy, three (3.19%) had seton fistulotomy and one had no seton progression. Intention-to-treat and per-protocol efficacy analyses were 80.2 and 98.7%, respectively. Among the 74 patients who completed the procedure, type of fistula and time with seton were distributed as followed: 47 (63.51%) intersphincteric fistula (15 ± 31 weeks), 26 (35.14%) transsphincteric fistula (32 ± 47 weeks), one (1.35%) suprasphincteric fistula (11 weeks). Previous fistula was associated with a longer time with seton (P = 0.018). Incontinence was reported in two (2.7%) patients, who had previous perianal fistula or anorectal surgery. Two patients (2.7%) had recurrence after fistulotomy.

Conclusion: Placement of seton followed by superficial fistulotomy in an ambulatory setting is a safe and effective method for simple low perianal fistula treatment. Incontinence rate may be higher in patients with previous perianal fistula or anorectal surgery.