Anal Abscess and Fistula

Endoanal ultrasonography with 3D reconstruction

As with any other form of ultrasound examination, the endoanal ultrasound examination is performed using special probes inserted into the anus. This has the advantage of examining the tissues around the anus more closely. This 2D examination is now supplanted by a sophisticated machine which combines 200 or more serial 2D images into a 3D volume image, allowing more precise visualization of the anus and any disease around it, e.g. fistula tract. When we can see better, we can plan and treat it better!


An anal fistula is a small tunnel (tract) from the anal canal to a hole in the skin near the anus. Anal fistulas can cause unpleasant symptoms, such as discomfort, discharge and skin irritation, and will not usually get better on their own.

Surgery is recommended in most cases. An anal fistulotomy is surgery to open and drain an anal fistula, helping the fistula to heal. 

Ligation of Intersphincteric Fistula Tract (LIFT procedure)

This is another newer sphincter preserving technique aimed at curing the fistula without the risk of incontinence. It is simpler to perform as the dissection starts from the outside, in between the internal and external sphincter rings. The part of the fistula tract lying in between the two sphincters is removed and the openings on the sphincters sutured closed. The incisional wound outside is also closed, making post-operative wound care simpler, and associated with less pain and a faster recovery. Most practitioners find this easier to perform when compared to the Endorectal Advancement Flap. Long term success rate in our hands is 83%.

Endorectal advancement flap

As mentioned, a fistula tract has an internal opening within the anus. Sometimes, this opening lies higher up in the anal canal, increasing the risk of conventional surgery of cutting open the fistula tract and the risk of incontinence. One method of avoiding incontinence and yet closing the internal fistula opening is the endorectal advancement flap. This involves creating a tongue of anal tissue lining which is pulled downwards from above to cover the internal opening. This is a highly technical method with a good success rate of 85% in our experience.

Fibrin glue injection

This is another technique available and it involves a special glue injected into the fistula tract from the outside. This is akin to pouring “cement” into the fistula tract so as to occlude it completely. The body would replace the glue with scar tissue over time. Although theoretically simple to perform and minimally invasive, this technique has not been very successful. Success rates average around 20%.