Randomised controlled trial comparing ligation of the intersphicteric fistula tract vs advancement flap for complex anorectal fistulas requiring intial seton drainage

INTERVENTION: A probe was inserted into the tract an incision then made in the intersphincteric groove and the fistula tract identified in this space. Once the tract is dissected free it is encircled and the probe removed. The fistula tract is then divided and transfixed both sides with 3/0 PDS. The external opening is left open the internal opening is curetted and closed with a vicryl suture. This is a single intervention. Operation duration is approximately 10 minutes. CONDITION: Complex anorectal fistulas where setons were previously inserted because fistulotomy was deemed to risk significant incontinence PRIMARY OUTCOME: To determine if ligation of the intersphicteric fistula tract provides at least a 40% improvement in recurrence rate over anorectal advancement flap for complex anorectal fistulas after initial seton drainage. This outcome will be assessed by clinical examination, history and if required MRI and ultrasound. SECONDARY OUTCOME: Bowel function: return to normal healthy bowel function Complications Incontinence Pain Satisfaction Time taken to resume normal activities INCLUSION CRITERIA: Patients with transsphincteric or complex fistulas were entered into the study. Fistulas were classified as complex if any of the following were present: tract crossing more than 30% to 50% of the external sphincter, anterior fistula in a woman, multiple tracts, recurrent fistula, pre‐existing incontinence or Crohns disease.