Fistula is nothing but a hollow tube or sinus or a track (generally defined as an abnormal passage between two epithelium). Fistula in ano is more common in males to females, the ratio is believed to be 7:2.
* History of Anorectal abscess
* perianal discharge ( purulent / bloody discharge )
* Swelling / Lump
* Skin excoriation
Fistula in Ano is classified (Park’s Classification) in to four, based on the location of the track.
* Inter Sphincteric Anal Fistula (Most common)
* Trans Sphincteric Anal Fistula (Most common)
* Supra Sphincteric Anal Fistula (Rare)
* Extra Sphincteric Anal Fistula (Rare)
Another classification is based on the location of internal opening of the Fistula Track.
* Low Level Anal Fistula - They open into the anal canal below the Anorectal ring.
* High Level Anal Fistula - They open into the anal canal at or above the Anorectal ring.