Management of Fistula-in-Ano
Indications and Contraindications for Definitive Fistula Surgery
- The American Gastroenterological Association recommends operating on fistula-in-ano only when the patient is symptomatic, has no active abscess, has medically controlled proctitis (if Crohn's disease), and the fistula anatomy is clearly defined—otherwise, defer definitive surgery and focus on drainage alone 1
- Active abscess present is an absolute contraindication to definitive fistula repair—drain the abscess first with loose seton placement 2, 1, 3
- Active proctitis in Crohn's disease is an absolute contraindication to definitive fistula surgery, as active inflammation dramatically reduces healing rates 1, 3
- Asymptomatic low anal-introital fistulae require no surgical intervention at all 1, 3
- The European Crohn’s and Colitis Organisation recommends avoiding fistulotomy when Crohn's Disease Activity Index (CDAI) is greater than 150, indicating poorly controlled systemic disease 1, 3
- Evidence of perineal Crohn's disease involvement is a relative contraindication to definitive fistula surgery, as extensive perianal disease increases failure risk 1, 3
Surgical Approach Based on Fistula Anatomy
- For low/subcutaneous fistulas not involving sphincter muscle, perform fistulotomy at the time of abscess drainage, as recommended by the World Journal of Emergency Surgery 2, 7
- For fistulas involving any sphincter muscle, place a loose draining seton only—do not lay open the tract, as recommended by the World Journal of Emergency Surgery 2, 4, 5, 6, 8
Special Considerations for Crohn's Disease
- Control luminal Crohn's disease with thiopurines, infliximab, or adalimumab before and after surgery, as recommended by the Journal of Crohn's and Colitis 1, 3
- Assess the rectum for proctitis at the time of any drainage procedure, as recommended by the World Journal of Emergency Surgery 4, 5, 6
- Consider diverting ostomy for refractory cases, as recommended by the Journal of Crohn's and Colitis 1, 3