Description

A fistula-in-ano is an abnormal communication (tract) between the anal canal and the perianal skin. It often arises as a complication of a perianal abscess, especially when the abscess fails to heal completely. --- 🧠 Pathophysiology Originates from infected anal glands (located in the intersphincteric space) When the abscess drains or bursts, an epithelialized tract may persist between the anal canal and the skin --- 🔍 Causes Perianal abscess (most common) Crohn’s disease Tuberculosis Radiation or surgery Malignancy (rare) Trauma or foreign body --- ⚠️ Symptoms Persistent or intermittent discharge of pus or stool from a small external opening Pain, especially during defecation Perianal swelling, redness, or irritation May be asymptomatic between episodes if chronic --- 🔬 Diagnosis 🧑‍⚕️ Clinical Inspection reveals external opening near the anal verge Gentle probing may help trace the tract Goodsall’s Rule helps predict internal opening location: Posterior external opening → curved tract to posterior midline Anterior external opening → straight tract to nearest crypt 🖥️ Imaging (for complex or recurrent fistulas) MRI pelvis – gold standard for complex or multiple tracts Endoanal ultrasound Fistulography (rarely used now) --- 🧭 Classification (Parks Classification) Type Description Intersphincteric Between internal and external sphincter (most common) Transsphincteric Crosses both sphincters into ischiorectal fossa Suprasphincteric Arches above puborectalis muscle Extrasphincteric From rectum to perianal skin without involving sphincters --- 💉 Treatment 🧑‍⚕️ Goals: Eliminate the tract Preserve continence Minimize recurrence 🔧 Surgical Options: Procedure Indication Notes Fistulotomy Simple, superficial tracts Tract is laid open to heal; risk of incontinence in high tracts Seton Placement High fistulas or Crohn’s disease Draining or cutting setons used LIFT Procedure Inter-sphincteric/trans-sphincteric fistulas Ligation of intersphincteric fistula tract Advancement Flap Recurrent or high fistulas Flap used to cover internal opening VAAFT/EPSiT Minimally invasive Video-assisted/Endoscopic techniques --- ⚠️ Complications Recurrence Fecal incontinence Chronic infection Abscess reformation --- 📌 Postoperative Care Sitz baths Stool softeners Analgesics Antibiotics only if infected Long-term follow-up for Crohn’s patients