Management of Fistula-in-ano in Crohn's Disease

Initial Assessment and Management

The European Crohn's and Colitis Organisation recommends contrast-enhanced pelvic MRI as the initial imaging procedure for assessment of perianal fistulizing Crohn's disease, with endoscopic anorectal ultrasound as an alternative if rectal stenosis is excluded 3
Proctosigmoidoscopy should be performed to evaluate for concomitant rectal inflammation, which has significant prognostic and therapeutic implications, as recommended by the European Crohn's and Colitis Organisation 2
Examination under anesthesia (EUA) is considered the gold standard for assessment of perianal fistulas in the hands of an experienced surgeon, according to the European Crohn's and Colitis Organisation 3
More than two-thirds of patients with fistulas have an associated abscess that must be drained before considering definitive intervention, as stated by the European Crohn's and Colitis Organisation 4

Any perianal abscess must be surgically drained first, as recommended by the American Gastroenterological Association 5
Loose seton placement is necessary to establish drainage of the fistula tract, allowing inflammation to subside and preventing recurrence of abscesses, according to the European Crohn's and Colitis Organisation 1, 4
Active luminal Crohn's disease must be treated medically in conjunction with surgical management of fistulas, as recommended by the European Crohn's and Colitis Organisation 2

Antibiotics (metronidazole and/or ciprofloxacin) in combination with seton placement is the preferred initial strategy for symptomatic perianal fistulas, according to the European Crohn's and Colitis Organisation 2
For maintenance therapy, thiopurines, infliximab, adalimumab, or a combination of drainage and medical therapy should be used, as recommended by the European Crohn's and Colitis Organisation 1

For simple, low fistulas, fistulotomy may be considered only in carefully selected patients with subcutaneous, superficial, or low transsphincteric fistulas in the lower third of the anal sphincter, according to the European Crohn's and Colitis Organisation 1, 2
Contraindications to fistulotomy include active disease and evidence of perineal Crohn's disease involvement, as stated by the European Crohn's and Colitis Organisation 1
For complex fistulas, medical therapy to control disease-related inflammation is imperative before considering definitive surgical closure, according to the European Crohn's and Colitis Organisation 1, 4
Seton drainage should be maintained until inflammation is controlled, as recommended by the European Crohn's and Colitis Organisation 4
Surgical options after inflammation control include mucosal advancement flap, ligation of intersphincteric fistula tract (LIFT), fibrin glue, or fistula plug, according to the European Crohn's and Colitis Organisation 2

The presence of active proctitis significantly reduces the success rate of surgical interventions and increases the risk of complications, as stated by the European Crohn's and Colitis Organisation 6
The most conservative surgical approach should be adopted to avoid soft tissue damage and prevent extensive scarring, according to the European Crohn's and Colitis Organisation 1
Concomitant perianal skin tags should not be treated surgically as this can lead to chronic, non-healing ulcers, as recommended by the European Crohn's and Colitis Organisation 1

Performing fistulotomy without first controlling rectal inflammation can lead to poor healing and worsening of symptoms, according to the European Crohn's and Colitis Organisation 1
Failure to drain associated abscesses before definitive treatment increases the risk of recurrent sepsis, as stated by the European Crohn's and Colitis Organisation 4
Excision of perianal skin tags can lead to poor wound healing and complications, as recommended by the American Gastroenterological Association 5