Anal Fistula Surgery: Seton Removal & Laying Open Procedure

An anal fistula is an abnormal tunnel connecting the inside of the anal canal to the skin around the anus. Most fistulas develop after an anal abscess and require surgery to heal permanently.

What Is a Seton?

A seton is a thread or suture material that is passed through the fistula track. It works by:

• Cutting seton: Gradually tightening over weeks to divide the sphincter slowly, preserving continence
• Draining seton: Keeps the fistula open and draining while allowing tissue to build up before definitive surgery

The seton is tightened (or replaced) at regular intervals during clinic visits until it cuts through the muscle slowly.

Laying Open (Fistulotomy)

Fistulotomy is the most common surgery for simple, low fistulas. The surgeon:

1. Opens the entire fistula track from inside out
2. The wound heals by "secondary intention" (from the inside out)
3. Takes 4–8 weeks for complete healing

Success rate: >90% for simple fistulas with low recurrence.

Which Procedure Is Right for You?

Type of Fistula	Preferred Surgery
Low, simple fistula	Fistulotomy (laying open)
High, complex fistula	Seton (staged procedure)
Crohn's-related fistula	Seton + medical management
Recurrent fistula	Advanced flap procedures

Recovery After Surgery

• Hospital stay: 1–2 days (for fistulotomy)
• Wound care: Daily sitz baths, dressing changes for 4–8 weeks
• Diet: High fibre, plenty of fluids
• Activity: Light activities in 1 week; avoid heavy lifting for 4 weeks
• Pain: Managed with analgesics; most significant in first 3–5 days

Possible Complications

• Wound infection (uncommon with proper care)
• Recurrence (more likely with complex fistulas)
• Incontinence (rare with low fistulas; seton minimises this risk for high fistulas)

When to Seek Immediate Help

• Increasing pain, swelling, or fever after surgery
• Heavy bleeding from the wound
• No improvement after 10 days

Iswarya Hospital's Colorectal Surgery team has extensive experience in the management of complex anal fistulas with sphincter-preserving techniques.