: An anal fistula is an inflammatory tunnel under the skin, connecting the anal canal and the surface of the surrounding skin. 80% occur as a result of an anorectal infection, wherein the anal crypts are infected and cysts containing pus form near the anal canal. If the abscess breaks or is opened a fistula is often formed.
Symptoms of an anal fistula can be similar to those of hemorrhoids, manifesting as drainage from the anus, itchiness, and constant, throbbing pain, and is exacerbated by bowel movement. An anal fistula is commonly mistaken for a hemorrhoid upon first notice; however it eventually has episodes of recurrent infection. They are two very different issues that are important to distinguish. The patients with anal fistula usually have the history of anal abscess and recurrent fistula infection.
In the complex cases advanced diagnostic methods may be necessary.
1. Fistula probe, a thin metal instrument specially designed to be inserted through a fistula.
2. Anoscope, a small tube used to view the anal canal
3. Flexible sigmoidoscopy
4. An injected dye solution into fistula.
5. Imagine tests with endoscopic ultrasound and MRI
6. Fistulography with X-ray of the fistula after a contrast solution is injected.
Treatment varies depending on the severity and location of the fistula. Antibiotics, antipyretics and, pain medication is prescribed if there is drainage (indicating abscess). For simple rectal abscesses, antibiotics are usually not needed. The surgical procedure for simple fistulas are called a fistulotomy, where the fistula tract is cleared out surgically and allowed to heal properly. For simple fistulas, success rate with fistulotomy is over 90%. More complex fistulas may be to twisted or branching for a fistulotomy so fibrin glue or fibrin plug may be used instead. Fibrin glue is largely out of favor now due to its low success rates. The fistula is filled with this glue, which hardens and then dissolves, allowing scar tissue to form and the fistula to heal. Fibrin plug is a similar concept, but it is not a liquid. Like the glue, it dissolves, allowing growth of scarr tissue. Fibrin treatment has the advantage of not causing incontinence, which can be a risk of fistulotomy. Though in common, staged surgery may be needed.
With this condition, it is better to seek help sooner than later. Advanced abscesses that become complex are much more difficult to treat. For most however, it seems procrastination is not much of a problem- pain is a very effective motivator.
Dr. Shu manages the simple or superficial anal fistula with fistulotomy or fistulectomy, and he usually refers the patients with complex anal fistula to the colorectal specialist for further evaluation and treatment.
