What is the recommended treatment for a patient with fistula in ano?

Treatment of Fistula in Ano

The recommended treatment for fistula in ano depends on the type and complexity of the fistula, with surgical drainage being the primary approach for all anorectal abscesses, followed by appropriate fistula management based on anatomical classification.

Diagnostic Approach

Before determining treatment, proper diagnosis is essential:

• MRI is the gold standard imaging technique for assessing fistula anatomy and associated abscesses 1
• In cases of atypical presentation or suspected complex fistulas, imaging investigations (MRI, CT scan, or endosonography) should be performed 1
• Complete physical examination including digital rectal examination is necessary to identify the fistula tract and any secondary extensions

Treatment Algorithm Based on Fistula Classification

Simple Fistulas

• Intersphincteric fistulas: Fistulotomy is the procedure of choice with healing rates >95% 2
• Low transsphincteric fistulas: Fistulotomy can be performed if risk to sphincter function is minimal 2

Complex Fistulas

• High transsphincteric, suprasphincteric, and extrasphincteric fistulas: Only sphincter-preserving techniques should be used 2
• Recommended sphincter-preserving techniques:
  • Ligation of Intersphincteric Fistulous Tract (LIFT): 60-90% healing rate 2
  • Rectal advancement flaps: 60-90% healing rate 2
  • Loose seton placement: For staged approach or long-term drainage 3

Surgical Management Protocol

1. Initial management: Drainage of any associated abscess is mandatory

   • Immediate surgical incision and drainage for abscesses 1
   • Multiple counter incisions preferred for large abscesses 1

2. Fistula treatment based on complexity:

   • Simple fistulas: Primary fistulotomy with expected healing rate >95% 2, 4
   • Complex fistulas: Staged approach with initial seton placement followed by definitive repair 3
   • Recurrent or complex fistulas: Consider LIFT procedure or advancement flaps 2

3. Special considerations:

   • Crohn's disease-related fistulas: Long-term seton placement with medical therapy is preferred 3
   • Multiple or horseshoe fistulas: May require multiple procedures and imaging guidance 3

Antibiotic Therapy

• Antibiotics are not routinely recommended for uncomplicated fistulas with adequate drainage 1
• Indicated only when:
  • Systemic signs of infection are present
  • Patient is immunocompromised
  • Source control is incomplete
  • Significant cellulitis is present

Post-Operative Management

• Wound care: Cleaning with warm water/saline 2-3 times daily, sitz baths
• Packing removal within 24-48 hours
• Allow wound to heal by secondary intention
• For seton placement: Maintain for 1-2 months until resolution of induration and suppuration
• Follow-up within 48-72 hours after packing removal and every 1-2 weeks until complete healing

Outcomes and Complications

• Expected healing rates:
  • Simple fistulas: >95% with fistulotomy 2, 4
  • Complex fistulas: 60-90% with sphincter-preserving techniques 2
• Potential complications:
  • Recurrence: 2-5% for simple fistulas, higher for complex fistulas 4
  • Incontinence: 6.9% overall (4.0% to gas, 2.6% to liquid, 0.3% to solid feces) 4
  • Persistent fistula: 3.2% 4

Common Pitfalls to Avoid

• Failure to identify the internal opening of the fistula
• Inappropriate selection of surgical technique based on fistula anatomy
• Premature closure of external wound leading to recurrence
• Aggressive fistulotomy for complex fistulas risking sphincter damage and incontinence
• Inadequate drainage of associated abscesses

The treatment of fistula in ano requires careful assessment of the fistula anatomy and appropriate selection of surgical technique to balance the goals of fistula eradication and preservation of continence.