Anal Fistula (Fistulotomy / Seton Placement)

Procedure Snapshot

• Indication: Chronic fistula-in-ano; post-abscess.
• Expected duration: ___
• Special instruments: Probe, cautery, seton, anoscope.

Step Workflow

1. Identify external opening; inject peroxide/dye.
2. Probe tract to internal opening.
3. Low tract: lay open.
4. High tract: place loose or cutting seton.
5. Curette granulation; hemostasis.
6. Leave open for secondary healing.

Key Pimp Questions

• Q: Definition of “high”?
  A: Involvement of > 30–50% external sphincter (PMID 29503456).
• Q: Etiology? Cryptoglandular > 90%.
• Q: Purpose of seton?
  A: Maintain drainage and fibrosis while protecting sphincter.

Critical Anatomy

• Landmarks: Internal/external sphincter, dentate line.
• Danger zones: External sphincter (continence), anterior tract in females (vagina).

Informed Consent Highlights

• Benefits: Drainage, healing.
• Alternatives: Fibrin plug, advancement flap.
• Risks:
  • Incontinence ___ (PMID 31282128)
  • Recurrence ___ (PMID 31142527)
  • Infection/bleeding ___

Post-op Considerations

• Sitz baths, stool softeners.
• Loose seton removal in ___ weeks.

References

• Chassin’s, Anorectal section.
• Clinical Scenarios, Anorectal chapter.
• Hall 2021 (PMID 34192677).