Anal fistula is the medical term for an infected tunnel that develops between the skin and anus. Most anal fistulas are the result of an infection that starts in an anal gland located midway in the anus. This infection results in formation of an abscess that drains spontaneously or is drained surgically through the skin next to the anus. The opening then forms a tunnel under the skin and connects with the infected gland forming a fistula.
Diagnosis of anal fistula: The opening of the channel at the skin (external) generally appears as a red, inflamed area that may ooze pus and blood. This external opening is usually easily detected. Finding the fistula opening in the anus is more complicated.
Most simple fistula are diagnosed by symptoms and signs and is confirmed by examination under anaesthesia. Complex and recurrent fistula use the latest technology, including Magnetic Resonance Imaging (MRI) for mapping the fistula tract and providing detailed images of the sphincter muscles, endoscopic ultrasound and fistulogram.
Treatment: Treatment of low anal fistula is relatively straight forward; cutting the fistula’s tract called fistulotomy. However, that of high variety and complex fistulas are difficult to treat and should be attempted only by a skilled colorectal surgeon to avoid incontinence of stool.
Interventions include insertion of seton, fibrin glue, ligation of the intersphincteric fistula tract (LIFT) advancement flaps, diversion colostomy etc. and requires the help of experienced and skilled surgeons expert in anal fistula management.
The writer is a Colorectal Surgeon at the Rahetid-RA Hospital.