Anal Fistula/Abscess
What is an anal abscess?
An anal abscess is a painful collection of pus that develops in the tissues around the anus
Causes of anal abscess
A number of small glands are normally present between the inner and outer layers of the anal sphincter muscle. Bacteria may lodge in these glands, resulting in blockage and subsequent infection. This may extend to various areas around the anal canal to involve the anal sphincter muscle and surrounding tissues.
Symptoms of anal abscess
The most common symptom is pain over the abscess area due to increasing pressure from the pus collection. There may be an associated red and swollen lump. The abscess may burst through the overlying skin. Other symptoms are fever, chills and shakes.
What is an anal fistula?
An anal fistula is a tunnel that connects an infected gland inside the anus to an opening on the skin around the anus.
Is fistula related to any other disease?
Most fistulae are the result of infections in the anal gland (cyrptoglandular theory). However, patients with underlying inflammatory bowel disease (Ulcerative colitis and Crohn’s disease), sexually transmitted disease, radiation, tuberculosis, trauma and malignancies may also be prone to develop anal abscesses and fistulae.
How is an abscess treated?
Do not attempt to drain an anal abscess on your own
Referral to a colorectal specialist is required especially in complex cases
How is a fistula treated?
Surgery is needed to cure anal fistula, sometimes this is performed over several stages. An examination under anaesthetic is necessary to identify the course of tract between the anus and the skin. The amount of anal sphincter involvement is also assessed at the same surgery.
The fistula tract may be treated in one of three ways according to its complexity and underlying cause. It is very important that your surgeon is familiar with all aspects of the disease and is skilled in the full range of available surgical techniques. Members of CSSANZ have these skills, and they are trained in the long term support and follow-up of patients who have surgery for complex abscesses or anal fistulae.
Fistulotomy: opens the length of the tract to the skin, allowing the open wound to heal slowly. Small amount of sphincter muscle is divided. This is an effective treatment for fistulas with minimal muscle involvement. Division of larger amount of sphincter muscle may result in some weakness of the muscle. Continence of a patient will depend on the anatomy of the fistula and the amount of intact sphincter after fistulotomy.
Seton insertion and exchange: A seton is a loop of flexible material placed along the tract to maintain adequate drainage for a period of time. In patients with underlying inflammatory bowel disease (IBD), seton(s) may be needed for a longer period or exchanged at 4-8 weeks intervals, until the underlying IBD is under controlled
Fistula repair: This is a more complex operation where fistulotomy is not possible. Several techniques with variable success rates may be considered. These procedures are definitive in nature.
MAF: an advancement flap is created from the rectum locally, like a trap door to close over the internal opening of the tract.
LIFT: the skin above the fistula is opened up between the inner and the outer layers of the sphincter muscle and the fistula is tied off and divided.
Laser closure: is a sphincter saving technique using a radial emitting laser fibre to obliterate the fistula, with closure of the internal opening.
Anal plug: a plug made of collagen is inserted into the tract and secured in position. Tissue surrounding the plug grows into the collagen, thereby closing the defect permanently.
Anal fistula can be a difficult and frustrating condition, as healing rates are variable. As a patient, it is important that you receive a clear description of the likelihood of healing from your surgeon.