Anal fistulas are tunnels that form between the inside of the anus and the outside skin around the anus. A muscular opening at the end of the digestive tract through which stool exits the body is called the anus. Anal fistulas can cause pain, swelling, discharge, and infection. In this blog post, we will describe the causes, symptoms, diagnosis, treatment, and prevention of anal fistulas.
As a result of an infection in the anal gland, most anal fistulas result in an abscess that drains naturally or surgically through the skin next to the anus. This drainage tract forms a tunnel under the skin that connects the anal gland or anal canal to a hole in the skin around the anus, which is the fistula.
Some other possible causes of anal fistulas include:
Crohn’s disease or other inflammatory bowel disease
Trauma to the anal area
Infections of the anal area
Surgery or radiation for treatment of anal cancer
Symptoms of an anal fistula can include:
An opening on the skin around the anus
A red, inflamed area around the tunnel opening
Oozing of pus, blood or stool from the tunnel opening
Pain in the rectum and anus, especially when sitting or passing stool
Fever
Your health care provider will discuss your symptoms with you and perform a physical exam to diagnose an anal fistula. An external opening of an anal fistula is usually visible on the skin around the anus. It is more difficult to locate the fistula's internal opening within the anal canal. It is important to understand the path of an anal fistula for effective treatment.
One or more of the following imaging tests may be used to identify the fistula tunnel:
MRI can map the fistula tunnel and provide detailed images of the sphincter muscle and other structures of the pelvic floor.
Endoscopic ultrasound, which uses high-frequency sound waves, can identify the fistula, the sphincter muscles and surrounding tissues.
Fistulography is an X-ray of the fistula that uses an injected contrast to identify the anal fistula tunnel.
Examination under anesthesia. A colon and rectal surgeon may recommend anesthesia during an examination of the fistula. This allows for a thorough look at the fistula tunnel and can identify any possible complications.
Other options to identify the fistula’s internal opening include:
Fistula probe. An instrument specially designed to be inserted through a fistula is used to identify the fistula tunnel.
Anoscope. A small endoscope is used to view the anal canal.
Endoscopes are used to examine the large intestine (colon) during flexible sigmoidoscopy or colonoscopy. Sigmoidoscopy can assess the lower part of the colon (sigmoid colon). A colonoscopy can be helpful in identifying other disorders, particularly ulcerative colitis or Crohn’s disease. It examines the entire length of the colon.
An injected dye solution. This may help locate the fistula opening.
The treatment of anal fistulas varies depending on their location, complexity, and cause. It is important to repair the anal fistula completely to prevent recurrence and protect the sphincter muscles. When these muscles are damaged, fecal incontinence can occur. However, nonsurgical treatments may be available in some cases.
Surgical options include:
As part of the fistulotomy procedure, the surgeon cuts the internal opening, scrapes and flushes out infected tissue, flattens the tunnel, and stitches it together. A more complicated fistula may need some of its tunnel removed by the surgeon. In cases where significant amounts of sphincter muscle must be cut or where the entire tunnel cannot be found, fistulotomies may be performed in two stages.
This procedure involves creating a flap from the rectal wall and then using it to cover the fistula's internal opening. This procedure can reduce the amount of sphincter muscle that is cut.
As part of the seton procedure, surgical thread is placed in the fistula for several weeks to help it heal before other procedures are performed to treat it. Over time, the seton is tightened to gradually cut through the sphincter muscle, preventing incontinence and preserving muscle function.
Fibrin glue or collagen plugs are materials injected into the fistula to seal it. They can be used for simple fistulas involving little sphincter muscle. However, the success rate of these methods is low.
A newer technique called LIFT involves cutting the fistula between the sphincter muscles and closing both ends to prevent cutting the sphincter muscle. Although the long-term effects of this method are unclear, it can avoid cutting the sphincter muscle and reduce the risk of incontinence.
Nonsurgical options include:
An inflammatory bowel disease or other inflammatory bowel disease may benefit from biologic therapy, a type of medication that can reduce inflammation and help heal the fistula. Nevertheless, biologic therapy is not a cure for fistulas and can have serious side effects.
An experimental treatment that involves injecting stem cells into a fistula to stimulate tissue regeneration is stem cell therapy. Despite the fact that stem cell therapy is not widely available and has not been proven safe or effective, it may be used for people with complex or recurrent fistulas that do not respond to other treatments.
Generally, there is not much one can do to prevent anal fistulas, but actions should be taken to prevent anal abscesses, which are the main cause. Some preventive measures include:
Maintaining good hygiene and cleanliness in the anal region
Avoiding excessive cleansing of the anal region
Eating foods rich in fiber such as wheat germ, brown rice, barley, fruits, and vegetables
Drinking plenty of fluids to prevent constipation
Seeking medical attention if you have symptoms of an anal abscess or fistula
In an anal fistulas, a tunnel forms between the inside of the anus and the outside skin around the anus, causing pain, swelling, discharge, and infection. Anal abscesses can result from an infection that begins in the anal gland. It can be diagnosed by a physical exam and imaging tests. It can be treated surgically or non-surgically. By avoiding anal abscesses and maintaining good hygiene and diet, it can be prevented. Consult your health care provider if you have any questions or concerns about anal fistulas.
