Fistula in Ano - Fistula in Ano is abnormal communication between anal canal and perianal skin lined by granulation tissue, secondary tracks may be multiple. Etiology - Crypto Glandular Hypothesis -Most of the fistulas originate from anal gland infections. Anal cryptic glands lie between the internal and external anal sphincter and drain into the anal canal.

The Cryptoglandular hypothesis states that an infection begins in the anal canal glands and progresses into the muscular wall of the anal sphincters to cause an anorectal abscess.Fistula in Ano can also develop secondary to trauma, malignancy, radiation, tuberculosis, inflammatory bowel disease etc.

Classification of Fistula

Park’s Classification

• Intersphincteric - 45%
• Transsphincteric- 30%
• Suprasphincteric – 20%
• Extrasphincteric - 5%

Signs and Symptoms

• Perianal discharge
• Swelling
• Skin excoriation
• External opening
• Diagnosis is made on the basis of Digital Rectal Examination and Proctoscopy.

Imaging (MRI)

• Not required for routine fistula evaluation
• Primary opening is difficult to identify
• Recurrent or multiple fistulae to identify secondary tracts or missed primary openings

Treatment

• Fistulotomy/Fistulectomy – are commonly used surgical techniques
• Seton - Material inserted into fistula tract to encircle the sphincter muscles.There are two types of Seton’s – Draining or Cutting. Another type of Seton is Chemical seton( Ayurvedic ) k/aKsharsutra.Seton’s are used in treatment of High Fistula
• Lift Procedure
• Anorectal Advancement Flap
• Other Procedures like VAAFT and Biodegradable material-Fibrin glue, Collagen plug have been used with variable success rates.
• Laser Surgery.