Anal Fistula

An anal fistula is an abnormal tract that forms between the anal canal and the skin surface, usually in the perianal region. It may be simple, with a single tract, or complex, with multiple secondary tracts. Anal fistulas do not heal spontaneously and usually require medical or surgical intervention. They are more common in adult men around the age of 40, while in children they are more often congenital.

In most cases, anal fistulas arise from obstruction of the anal glands, leading to inflammation and fistula formation. Other possible causes include perirectal or anal trauma, fissures, Crohn’s disease, diverticulitis, malignancy or infections such as tuberculosis.

Common symptoms include recurrent abscesses, discharge of pus or blood, anal itching, swelling and local pain. In severe infections, systemic symptoms may occur. Diagnosis is based on clinical history, physical examination and, when necessary, complementary investigations such as fistula probing, anoscopy, fistulography, endoanal ultrasound or magnetic resonance imaging (MRI). Colonoscopy or sigmoidoscopy may be performed to exclude underlying conditions.

Treatment is always surgical, as fistulas do not heal spontaneously. The approach depends on the location, complexity and relationship with the anal sphincter. Techniques include:

• Laser techniques (laser energy applied along the fistula tract);
• Fistulectomy: complete excision of the fistula with closure of the area;
• Fistulotomy: opening of the tract to allow gradual healing;
• Seton placement: surgical thread used for drainage and controlled healing;
• Closure of the internal opening with biodegradable material.

The goal of treatment is to eliminate the fistula while preserving anal sphincter function, ensuring continence for stool and gas. With appropriate follow-up by gastroenterologists or general surgeons, the prognosis is favourable and most patients recover without significant complications.