An anal fistula commonly known as fistula in ano is a narrow tunnel with its internal opening in the anal canal and its external opening in the skin near the anus. They're usually the result of an infection near the anus causing a collection of pus (abscess) in the nearby tissue. When the pus drains away, it can leave a channel behind. The biggest challenge is to prevent recurrence of fistula.
The risk factors for recurrence can be broadly classified into four categories: 1) The fundamental anatomy of the fistula and presence of comorbid diseases like Tuberculosis, Diabetes, Chronic Disease, Malignancy 2) lack of proper preoperative assessment of the fistula, which includes failure to recognize the internal opening and overall structure of the fistula, 3) intraoperative loopholes that include improper procedure selection, inexperience of the surgeon, and failure to get rid of the entire tract along with its ramifications, and 4) lack of proper postoperative care in the early and late periods following the surgery. Fistulas are classified by their relationship to parts of the anal sphincter complex ( that allow us to control our stool). They are classified as intersphincteric, transsphincteric, suprasphincteric and extrasphincteric. The intersphincteric is the most common and the extrasphincteric is the least common. These classifications are important in helping the surgeon make treatment decisions.