What is the next step in managing a patient with Crohn's disease and a fistula-in-ano?

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

Medical treatment to control disease-related inflammation should be initiated before considering fistulotomy in a patient with Crohn's disease and fistula-in-ano. 1

Initial Assessment and Management

• Contrast-enhanced pelvic MRI is the recommended initial imaging procedure for assessment of perianal fistulizing Crohn's disease, with endoscopic anorectal ultrasound as an alternative if rectal stenosis is excluded 1
• Proctosigmoidoscopy should be performed to evaluate for concomitant rectal inflammation, which has significant prognostic and therapeutic implications 1
• Examination under anesthesia (EUA) is considered the gold standard for assessment of perianal fistulas in the hands of an experienced surgeon 1
• More than two-thirds of patients with fistulas have an associated abscess that must be drained before considering definitive intervention 1

Treatment Algorithm

Step 1: Control Sepsis and Inflammation

• Any perianal abscess must be surgically drained first 1
• Loose seton placement is necessary to establish drainage of the fistula tract, allowing inflammation to subside and preventing recurrence of abscesses 1
• Active luminal Crohn's disease must be treated medically in conjunction with surgical management of fistulas 1

Step 2: Medical Therapy

• Antibiotics (metronidazole and/or ciprofloxacin) in combination with seton placement is the preferred initial strategy for symptomatic perianal fistulas 1
• For maintenance therapy, thiopurines, infliximab, adalimumab, or a combination of drainage and medical therapy should be used 1
• Infliximab is FDA-approved for reducing the number of draining enterocutaneous and rectovaginal fistulas and maintaining fistula closure in adult patients with fistulizing Crohn's disease 2

Step 3: Definitive Management

• 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 1, 3
  • Contraindications to fistulotomy include active disease (CDAI >150) and evidence of perineal Crohn's disease involvement 1

• For complex fistulas:

  • Medical therapy to control disease-related inflammation is imperative before considering definitive surgical closure 1
  • Seton drainage should be maintained until inflammation is controlled 1
  • Surgical options after inflammation control include mucosal advancement flap, ligation of intersphincteric fistula tract (LIFT), fibrin glue, or fistula plug 1

Important Considerations

• The presence of active proctitis significantly reduces the success rate of surgical interventions and increases the risk of complications 1
• Fistulotomy should never be performed in patients with active rectal inflammation, as this can lead to poor healing and worsening of symptoms 4
• The most conservative surgical approach should be adopted to avoid soft tissue damage and prevent extensive scarring 1
• Concomitant perianal skin tags should not be treated surgically as this can lead to chronic, non-healing ulcers 1

Common Pitfalls to Avoid

• Performing fistulotomy without first controlling rectal inflammation can lead to poor healing and worsening of symptoms 1, 4
• Failure to drain associated abscesses before definitive treatment increases the risk of recurrent sepsis 1
• Aggressive surgical approaches in the presence of active disease can lead to sphincter damage and incontinence 3
• Excision of perianal skin tags can lead to poor wound healing and complications 1

Based on the evidence presented, the correct answer is c) Medical treatment before fistulotomy, as controlling disease-related inflammation is imperative to increase the likelihood of tract healing after surgery and reduce complications 1.