Clinical role of a modified seton technique for the treatment of trans-sphincteric and supra-sphincteric anal fistulas

We have devised a modified seton technique that resects the external fistula tract while preserving the anal sphincter muscle. This study assessed the technique when used for the management of complex anal fistulas. Between January 2006 and December 2007, 239 patients (208 males and 31 females, median age: 41 years) underwent surgery for complex anal fistulas using the technique. Of the 239 patients, 198 patients had trans-sphincteric fistula and 41 patients had supra-sphincteric fistula. The durations of the surgeries were 17 min (47, 13) [median (range, interquartile range)] for trans-sphincteric fistulas and 38 (44, 16) for supra-sphincteric fistulas. The durations of the surgeries were significantly (P < 0.05) longer for supra-sphincteric fistula than trans-sphincteric fistula. The hospital stays were 4 (13, 2) days and 5 (14, 3) days, respectively, for trans- and supra-sphincteric fistulas. The durations of seton placement until the spontaneous dropping of the seton were 42 (121, 48) and 141 (171, 55) days respectively. The recurrence rate was 0 % in patients with trans-sphincteric fistulas and 4.9 % (2 of 41) in patients with supra-sphincteric fistulas (P < 0.01). Serious incontinence was not observed. The technique provided favorable results for the treatment of complex anal fistulas and could be safely applied while preserving the sphincter function and conserving fecal continence.