Fistulotomy and primary sphincteroplasty for anal fistula: long-term data on continence and patient satisfaction.

Background: The aim of this study was to evaluate the safety and long-term efficacy of fistulotomy and primary sphincteroplasty (FIPS). Secondary endpoints were its impact on postoperative continence status and patients' satisfaction.

Methods: A retrospective study was conducted on patients with cryptoglandular anal fistula (AF) who had FIPS between June 2006 and May 2017. Patients were evaluated with standardized telephone interviews and clinical/instrumental assessment. Main outcome measures included fistula healing rate, continence status, and patient satisfaction. Incontinence was defined as an inability to hold either gas, liquid, or solid stools, as well as postdefecation soiling, and was measured by the Cleveland Clinic fecal incontinence score. Patient satisfaction was evaluated by an 11-point numeric rating scale.

Results: There were 203 patients (139 males; mean age: 48.7 years) who had FIPS. The overall healing rate was 93% (188 patients) with a mean follow-up period of 56 ± 31 months. Half of the total cohort (51%) had a complex fistula. Preoperatively, 8 (4%) patients complained of postdefecation soiling and 2 (1%) of gas incontinence. Postoperatively, 26 (13%) patients had continence impairment (de novo n = 24), mainly consisting of postdefecation soiling (10%). In univariate analysis, patients with recurrent (RR 6.153 95% CI 2.097-18.048; p = 0.002) or complex (RR 3.005 95% CI 1.203-7.506; p = 0.012) AF and those with secondary tracts (RR 8.190 95% CI 2.188-30.654; p = 0.004) or previous set on drainage (RR 5.286 95% CI 2.235-12.503; p = 0.0001) were at higher risk of incontinence. In multivariate analysis, no significant predictors were found, although fistula complexity approached statistical significance (RR 5.464 95% CI 0.944-31.623; p = 0.050). The mean patient satisfaction numeric rating scale was 9.3 ± 1.6. Lower satisfaction rates were found in patients with transphincteric (p = 0.011) or complex (p = 0.0001) AF, with secondary tracts (p = 0.041) or previous seton drainage (p = 0.008), and in those with postoperative continence impairment (p = 0.0001). Postoperative onset of incontinence was the only significant factor in multivariate analysis (p = 0.0001).

Conclusions: FIPS should be considered a valid therapeutic option for selected AF. However, the risk of postoperative minor fecal incontinence exists, and should be discussed during preoperative patient counselling.