A fistula in ano is an abnormal tunnel (tract) that forms between the anal canal/rectum and the perianal skin. It usually develops after an anal abscess that has drained but left a persistent tract.

Causes

• Perianal abscess (most common)
• Infections (tuberculosis, HIV, actinomycosis)
• Inflammatory bowel disease (Crohn’s disease)
• Trauma or surgery around the anus
• Malignancy (rare)

Symptoms

• Persistent or recurrent pus or serous discharge from an opening near the anus
• Pain and swelling around the anus (especially before discharge appears)
• Itching, irritation, foul smell
• Sometimes fever, if abscess recurs
• A visible external opening near the anus, often with induration

Classification

1. According to Parks classification (based on relation to sphincters):

• Intersphincteric – most common
• Trans-sphincteric
• Suprasphincteric
• Extrasphincteric

Treatment

Fistula does not heal spontaneously – surgery is required.

Surgical

• Kshar sutra Ligation
• Laser Ablation
• Sclerotherapy
• Cryotherapy (Thandi Machine)
• Fistulotomy (laying open the tract) – for simple, low fistulas
• Seton placement – for high/complex fistulas, to preserve sphincter
• LIFT procedure (Ligation of Intersphincteric Fistula Tract) – sphincter-saving method
• Advancement flap surgery – used in recurrent/complex cases
• Fibrin glue or plugs – minimally invasive, but higher recurrence rates