Anal Fistula Surgery - Types, Symptoms, Risks & Complications

  1. What is an anal fistula?
  2. Types of anal fistula
  3. Symptoms of an anal fistula
  4. Why is anal fistula surgery required?
  5. Preoperative tests and diagnostics
  6. Methods of anal fistula surgery
  7. Post operative care and recovery
  8. Risks and Complications

What is an anal fistula? 

An anal fistula is a small tunnel with an internal opening inside the anal canal and an external opening on the skin surrounding the anus. Anal fistula is a common anorectal health condition which can lead to serious complications, if left untreated. Typically, when abscesses that form around the anal mucosal tissue are not treated, it continues to grow and worsen over time. Eventually, the abscesses punch out like a hole and make its way outside the skin. 

One of the most common reasons behind the formation of a fistula is an infection that didn’t heal properly. There are multiple glands present inside in a human anus that create mucus but when these glands get clogged, dirt and debris accumulates and causes an infection. This infection leads to formation of abscesses which turn into an anal fistula. 

Types of anal fistula

Fistulas are generally classified by their location. Primarily, there are 4 main types of anal fistulas: 

Intersphincteric fistula: Intersphincteric fistula is one of the most common types of anal fistulas. In this type, the tunnel starts in the space between the internal and external opening of the sphincter and opens up very close to the anal opening. 

Transsphincteric fistula: Often referred to as a horseshoe fistula, in a transsphincteric fistula, the tunnel starts in the space between the internal and external opening of the sphincter. The tunnel then crosses the external sphincter and opens up close to the anal opening. A transsphincteric fistula can wrap around the rectum in a U shape and may also have an opening on both sides of the anal opening. 

Suprasphincteric fistula: In a suprasphincteric fistula, the tunnel begins in the space between the internal and external sphincter but instead of going down, it turns upwards and crosses the puborectalis muscles before again changing its course and opening on the skin around the anus. 

Extrasphincteric fistula: This type of fistula is very rare. In case of an extrasphincteric fistula, the tract opens in the rectum and continues downward, passing through the levator ani muscle and opens around the anus. The chances of developing a extrasphincteric fistula is relatively higher if you suffer from Crohn's disease. 

Symptoms of an anal fistula

The signs are symptoms of an anal fistula include: 

  • Pain, swelling and redness around the anus
  • Pain with bowel movement
  • Bloody or foul smelling discharge from an opening around the anus
  • Skin irritation around the anus
  • Fever or chills
  • Difficulty controlling bowel movements

If you are experiencing any of the above mentioned symptoms, contact your health care provider as soon as possible.

Why is anal fistula surgery required?  

Surgeries are almost always necessary to treat an anal fistula as they do not heal on their own and if left untreated, can lead to severe complications. Some cases of fistula can cause bacterial infection which may result in sepsis, a serious condition which can cause tissue damage, organ failure and even death. 

If you suffer from an anal fistula, it is recommended to contact your healthcare provider and undergo anal fistula treatment as soon as possible. Delaying the surgery or allowing the fistula to persist can cause it to develop a secondary opening in which case, surgery becomes more complicated and can even cause damage to the sphincter.

Preoperative tests and diagnostics

Tests and diagnostics: Before a surgery, your healthcare provider will perform a series of tests to diagnose your fistula. Your doctor will look for an opening in the skin surrounding your anus. Once the opening is found, the doctor will try to determine how deep the tract goes and if it splits up into different directions. In some cases, fistulas are not visible on the skin surface and your doctor may need to perform additional imaging tests such as: 

  • MRI: If your doctor cannot locate the fistula opening on the skin around your anus, he or she may perform an MRI scan for a detailed image of the fistula tunnel and the sphincter muscles. 
  • Endoscopy: Using high frequency sound waves, your surgeon can get a detailed view of the fistula tunnel, sphincter muscles and its surrounding tissue.
  • Fistulography: A fistulography is an X-ray of the fistula primarily used to identify anal fistula tunnel.
  • Colonoscopy: Your surgeon may perform a colonoscopy to determine the location and depth of the fistula tunnel. 

Food and medications: You may be instructed not to eat or drink anything for 12 hours before the surgery. Your doctor may also advise you to temporarily stop taking any blood thinning medications that could increase the risk of excessive bleeding during surgery. 

Methods of anal fistula surgery 

The best method of treatment for anal fistula often depends on the position of your fistula or if it’s a single channel or branches off. Primarily, there are 2 methods of treating anal fistula: 

  • Fistulotomy: A fistulotomy procedure is one of the most commonly preferred and effective methods of anal fistula treatment. In a fistulotomy procedure, the surgeon will make a small incision at the site of the fistula and remove the infected area entirely alongside the gathered pus and fluids. Once the infected area has been removed, the incision is sutured and allowed to heal. The entire procedure is performed under general anaesthesia and takes about an hour to complete.
  • Laser surgery:  The laser surgery for an anal fistula is a medically advanced and minimally invasive procedure to treat a complex fistula without the use of any stitches. In laser surgery, a small laser beam is used to seal a fistula. It is a commonly used method for treating fistulas which branch off into different directions instead of a single channel. A laser surgery does not cause any major damage to the sphincter or the muscles around it so proctologists usually prefer it over a fistulotomy.

Post operative care and recovery

Post-operative care after an anal fistula surgery is one of the most important elements of your surgical journey. Depending on the method of your surgery, the recovery process can take anywhere between 1-3 months. It is advisable to strictly follow the medications and recovery tips prescribed by your doctor after surgery. Following are some tips to help with recovery after your anal fistula surgery. 

  • Avoid sexual intercourse or inserting anything into the rectum until the doctor says it's safe to do so. 
  • Drink plenty of water to avoid constipation and keep stools soft. 
  • Perform sitz bath 2-3 times a day for at least a month after surgery. 
  • Avoid any strenuous work or exercises which may put strain on your rectum or the tissue surrounding it. 
  • Contact your healthcare provider if you notice symptoms such as fever, nausea, increased pain, persistent bleeding from surgical site or smelly discharge from the wound. These can be signs of an infection and it is important to let your doctor know about it as soon as possible. 

Risks and complications

Anal fistula surgeries are completely safe procedures but like any other surgery, there are some risks of complications. It is important to keep a close eye on any symptoms after surgery and call your doctor if something seems off. 

  • Bowel incontinence: Bowel incontinence is one of the most common complications that occur after an anal fistula surgery. During an anal fistula surgery, the sphincter muscles around your anus can be damaged. These sphincter muscles are responsible for tightening around the anus and controlling bowel movement. Damage to these muscles can result in leaking of faeces through the rectum and  loss of some control over bowel movement. 
  • Recurrence of the anal fistula: While recurrence rate of anal fistulas are relatively low, they can still happen. The chances of recurrence often depends on the type, severity and method of surgery used to treat the fistula. Patients who have fistula recurrence, will have to undergo another anal fistula surgery. 
  • Infection: Surgeries that require an incision to be made on the skin have higher risk of an infection including fistulotomy procedures. Sometimes, the fistula tract may get infected and rapidly spread throughout the body. To reduce the chances of an infection, your surgeon may suggest you some antibiotics.  

An anal fistula can be scary and uncomfortable to talk about for some people. It is common for people to delay the surgery out of embarrassment and allow the condition to persist and worsen overtime. If you too suffer from an anal fistula, it is important to talk about it with your healthcare provider to stop the condition from worsening any further. 


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