High failure rates following ligation of the intersphincteric fistula tract for transsphincteric anal fistulas: are preoperative MRI measurements of the fistula tract predictive of outcome?

Abstract

Treatment of transsphincteric fistulas (TSFs) with fistulotomy after an indwelling seton is tempered by risks of incontinence and litigation. Thus, ligation of the TSF tract has been popularized as an alternative option. We previously reported on 107 patients who underwent ligation of the intersphincteric fistula tract (LIFT), with a 46% failure rate. Posterior fistula was the only predictor of recurrence. The aim of the present work was to investigate whether the length, width or depth of the fistula measured on preoperative MRI was correlated with recurrence. Following institutional review board approval, a retrospective analysis of our prospective Complex Anal Fistula Database from 1 January 2011 to 31 August 2019 was performed. Patients with TSF who underwent preoperative MRI and LIFT were included. Fistula location was classified as anterior, posterior or lateral. MRI measurements of fistula length, width and depth (in the intersphincteric groove) were performed. The type and rate of postoperative recurrence were analysed. 173 patients underwent MRI for an anal fistula; of these 40 underwent LIFT and 22/40 (55%) had preoperative MRI. There was no difference in the length, width or depth of anterior (n=9), posterior (n=7) or lateral (n=6) fistula tracts. The overall recurrence rate was 9/22 (41%). Posterior TSFs had the highest recurrence rate (5/7, 71%). The mean length, width, and depth of the fistula tract, measured at the preoperative site of LIFT in the intersphincteric groove, did not correlate with recurrence regardless of fistula location.