Fistulotomy: Everything You Need to Know

A fistulotomy is a surgical procedure used to treat a fistula, which occurs when two organs or tracts form an abnormal connection. The procedure is most commonly used to treat uncomplicated perianal fistulas (those occurring in and around the anus), which typically occur when an abscess develops in perianal tissues and breaks through the walls of adjacent structures as it grows. Fistulotomy can help open and drain the pocket so that the tissues can heal and close the abnormal passage.

Fistoltomy should not be confused with a fistulectomy, the latter of which involves the resection (removal) of a fistula.

What Is Fistulotomy?

Fistulas can develop in different parts of the body as the result of an infection, injury, surgery, or severe inflammation. Fistulotomy is one of several techniques that can be used to treat them, but it is typically reserved for cases involving the anus or rectum.

More specifically, fistulotomy is primarily used to treat simple fistulas—that is, those that are situated low (near the anal sphincters) that have a single opening between the adjacent structures.

Fistulotomy can be performed in a doctor's office, particularly when fistulas are small and shallow. Larger fistulas may need to be treated in the operating room of a hospital under general anesthesia.

Contraindications

Fistulotomy is contraindicated for the treatment of complex fistulas. Complex fistulas include those that lie above the anal sphincter (where there is more muscle), have multiple openings, or are the result of local radiation therapy or inflammatory bowel disease (IBD). Forward-lying (anterior) fistulas in women, typically involving vaginal tissues, are also considered complex.

Because vulnerable tissues are involved with these types of fistulas, there is a significant risk of recurrence and fecal incontinence (the inability to control bowel movements).

For these same reasons, fistulotomy is avoided in people with recurrent fistulas or those with pre-existing fecal incontinence.

According to the 2020 review in the Annals of Coloproctology, the recurrence rate of a complex fistula following fistulotomy is as high as 21%, while the risk of fecal incontinence (ranging from mild to severe) is as high as 82%.

Potential Risks

As with all surgical procedures, fistulotomy poses a risk of injury and complications. Some of these can occur immediately after the procedure, while others may develop within weeks or months.

Early complications of fistulotomy include:

Delayed complications occur less commonly but can include:

  • Fistula recurrence
  • Fecal incontinence
  • Anal stenosis (narrowing of the anus, making it more difficult to pass stools)
  • Delayed wound healing (a wound that remains unhealed after 12 weeks)

Purpose of the Surgery

The goal of a fistulotomy is to drain pus and fluids from fistulated tissues, allowing them to heal while closing the abnormal opening between the tracts. The intent of the surgery is to minimize injury to (or the cutting of) the anal sphincter in order to preserve sphincter function.

Fistulotomy can be used in over 50% of fistula cases. And when used appropriately, the surgery can offer a cure rate close to 100%, according to a 2018 analysis in the International Journal of Surgery.

Decision to Treat

Fistulotomy is generally the first procedure considered for superficial fistulas located between the internal and external anal sphincters. These types of fistulas can usually be treated quickly and effectively in an in-office procedure.

Large fistulas that have grown into deeper tissues can be treated in an operating room, but other options may be considered. This is because an additional procedure, called sphincteroplasty, may be needed to rebuild the sphincter following the fistulotomy. It is a technically complicated surgery that many surgical centers do not offer.

In its place, other staged procedures, such as a seton (a technique used to create a temporary drainage canal) followed by surgery to close the opening (with electrocautery, laser surgery, or biologic glues) may be preferred.

Fistulas should never be left untreated as they will not heal on their own. Untreated fistulas can lead to long-term or potentially life-threatening complications, such as sepsis and anal cancer.

Criteria for Selection

In order to determine if fistulotomy is appropriate, the doctor will perform a digital rectal exam using a gloved finger to estimate the size and location of the fistula. If performed by a gastroenterologist, the digital exam may be all that is needed to make the initial diagnosis.

Other tests would then be ordered to pinpoint the exact position and pathway of the fistula, including:

  • X-ray with barium contrast: During this test, a barium solution is either swallowed or given as an enema to help identify any abnormality on X-ray.
  • Magnetic resonance imaging (MRI): This imaging test uses powerful magnetic and radio waves to create highly detailed images of tissues. It is even more effective at imaging soft tissues that an X-ray or CT scan.
  • Endoscopic ultrasound: This involves the insertion of a narrow transducer into the anus and bowel to generate images of internal structures using high-frequency sound waves.
  • Fistulography: In this test, a contrast medium is introduced through the external opening of a fistula to visualize its size and pathway on X-ray.
  • Lower endoscopy: This involves the insertion of a flexible fiberoptic scope (called an endoscope) into the anus and bowel to image tissues.

These tests can help direct how a fistulotomy is approached and determine if other surgical procedures should be considered instead.

How to Prepare

Upon determination that a fistulotomy is appropriate, an appointment would be scheduled to perform the surgery. Less-complicated cases may be handled by a gastroenterologist, a general internist who has undergone additional training in the gastrointestinal tract.

If you are referred to a surgeon for the procedure, a separate appointment would be scheduled to review the findings and discuss the surgery from preparation to recovery. A fistulotomy can be performed by a colorectal surgeon, also known as a proctologist, who is board-certified in general surgery and has undergone additional training in colon and rectal surgery.

Location

Depending on the size and location of the fistula, a fistulotomy can be performed in a hospital, surgical center, or a gastroenterologist's office.

What to Wear

As you will need to change into a hospital gown, wear something loose-fitting and comfortable that you can easily remove and put back on. Leave any valuables at home, including watches and jewelry. Note that you will be asked to remove contact lenses, dentures, hearing aids, and piercings before the surgery.

After the procedure is performed, the nurse will provide sanitary pads to place in your underwear if there is any bleeding.

Food and Drink

You should stop eating at midnight on the night before the surgery. Up to four hours before the procedure, you can drink a small amount of water to take any morning pills (if approved by your surgeon). Within four hours, you cannot drink or eat anything, including gum or ice chips.

Though bowel preparation is not required for fistulotomy, some doctors recommend using a single enema the morning of the procedure to help clear the bowel of any fecal residue.

Medications

Your doctor will advise you to stop taking certain medications that can promote bleeding and slow wound healing. Some may need to be stopped one or several days in advance of the procedure, while others may need to be temporarily stopped during recovery.

The drugs of concern typically include:

Your doctor may also recommend that you stop smoking for a week or two following surgery. Smoking causes the narrowing of blood vessels and can slow healing by reducing the amount of oxygen that reaches the wound.

What to Bring

Be sure to bring your driver's license (or other form of government ID), insurance card, and an approved form of payment if the facility requires upfront payment of your copay or coinsurance.

You will also need to bring someone with you to drive you home. Even if general anesthesia is not used, you will almost invariably be too groggy and uncomfortable to drive yourself safely.

What to Expect on the Day of Surgery

Regardless of whether your procedure is being performed by a gastroenterologist or colorectal surgeon, your doctor will be accompanied by an operating nurse and, in most cases, an anesthesiologist.

Before the Surgery

Once you are checked in and have signed the necessary consent forms, you will be escorted to the back to change into a hospital gown. After vital signs are checked, an intravenous (IV) line will be inserted into a vein in your arm to deliver medications and fluids.

The anesthesiologist will also meet with you to discuss any drug allergies you have and whether you have had adverse reactions to anesthesia in the past. The anesthesiologist should also advise you about which type of anesthesia is being used and why.

During the Surgery

Once you have been prepped for surgery, you will likely be given either a general anesthetic to put you completely to sleep or a form of sedation called monitored anesthesia care (MAC) that induces "twilight sleep." This will be pushed through your IV.

However, if the fistula is small and situated near the surface of the skin, a local anesthetic delivered by injection to help numb the site may be all that is needed. In such cases, an anesthesiologist may not be necessary.

Pre-operative antibiotics will be delivered through the IV line to aid with healing and help prevent infection.

Depending on the location and position of the fistula, you may be placed in one of three positions:

  • Prone position: Facing down on a flat table
  • Kraske position: Facing down on an inverted V-shape table in a "jackknife" position
  • Lithotomy position: Lying on your back with your knees and calves in raised stirrups in a 90-degree position

During the fistulotomy, the doctor will make an incision to open the abnormal opening between the two structures. An anal retractor gently opens the anus, while the fistula itself is cut with a scalpel. Every effort will be made to avoid or limit damage to the anal sphincters.

Once open, the base of the wound is curetted (scraped). The wound is then left open to heal on its own. If needed, marsupialization (in which the cut edges of the wound are stitched) may be used to promote drainage, reduced bleeding, and provide better pain control.

Finally, the wound is either packed or covered with gauze and bandaged to help keep it clean.

A fistulotomy can take anywhere from 30 minutes to an hour to perform, depending on the size and location of the fistula.

After the Surgery

After surgery, you are taken to a recovery room and monitored until you are fully awake. Food and drink may be given as well as anti-nausea medication if you feel nauseous. It is not uncommon to experience rectal pain and discomfort immediately after a fistulotomy, even if a local anesthetic was used.

Once you are stable enough to walk and change into your clothes, the nurse will send you home with pain medications, antibiotics, sanitary pads or diapers, and wound care instructions. A friend or family member will need to drive you home and ideally stay with you overnight to monitor for complications.

Aftercare instructions
Verywell / Brianna Gilmartin  

Recovery

Irrespective of the type of anesthesia used, you should relax for the rest of the day once you return home. Do not bathe or shower for the first day. To reduce discomfort, lie on your side when relaxing or sleeping, wear loose-fitting clothes and underwear, and limit the amount of walking you do.

Thereafter, expect to spend a week or two recovering, which involves wound management, pain control, changes in diet, and the restriction of physical activity.

With proper care, most people can return to work and normal activity within one to two weeks of a fistulotomy.

Healing

Your doctor will provide you instructions as to how often you need to change the dressing on your wound. In the early days, you may need to do so up to four times a day, packing the wound gently with sterile gauze to absorb any fluids or blood. After that, the dressing can usually be changed daily.

You may be provided a topical antibiotic to use during the initial stages of healing as well as oral antibiotics that you should take as directed and to completion.

During recovery, it is important to avoid strenuous physical activity, heavy lifting, or positions like deep squatting that can open a wound. It also helps to sit on soft pillows or a donut-shaped pillow (available online or in many drugstores) to reduce pressure on the wound.

It is important to note that, even with proper care, complications of fistula surgery can sometimes occur.

When to Call a Doctor

Call your surgeon immediately if you experience any of the following after undergoing a fistulotomy:

  • Heavy, uncontrollable bleeding
  • Increasing pain, redness, swelling or discharge at the surgical site
  • A high temperature (over 100.5 F) with chills
  • Difficulty or inability to urinate
  • Constipation for more than three days
  • Nausea and vomiting

Bowel Movements

People often worry about bowel movements during recovery from fistula surgery, which may not only be painful but difficult to clean. To help ease pain during bowel movements, eat a fiber-rich diet and use a laxative or stool softener prescribed by your surgeon.

After a bowel movement, you can clean the wound by rinsing it with warm water squirted from a peri bottle. Once thoroughly rinsed, you can either dab the area clean with a baby wipe or gently cleanse the skin with cotton gauze while sitting in a sitz bath. (Avoid adding hydrogen peroxide, fragrances, homeopathic remedies, or any alcohol-based products to the water, as doing so could slow healing.)

Avoid using terrycloth towels or sponges to clean the wound. After washing, pat rather than rub the skin dry. Alternately, you can use a hairdryer set to the lowest settings (both temperature and strength) to gently dry the skin.

Pain Control

Pain can be usually be controlled with an over-the-counter pain reliever like Tylenol (acetaminophen) and/or a topical anesthetic like lidocaine. Fifteen-minute sitz baths can also help.

If the pain is especially severe, your doctor may prescribe an opioid painkiller like Vicodin (hydrocodone) but usually for only a few days to avoid opioid dependence.

Long-Term Care

Follow-up care is key to recovery and long-term health. In some cases, your surgeon may schedule a follow-up visit in a day or two after surgery if the wound is large or the procedure was extensive. If the fistula was relatively uncomplicated, you may only need to see the surgeon in three to four weeks.

Fistulotomy is extremely effective in resolving simple perianal fistulas. If the fistula heals with no complications, it usually won't return or require ongoing medical care.

A Word From Verywell

If you think you have a fistula but are not sure, it is important to have it checked out by a gastroenterologist. Signs include throbbing pain while sitting down or having a bowel movement, swelling and redness around the anus, and passing blood or pus when you defecate. Only an investigation by a doctor can confirm if you have a fistula and direct you to the appropriate treatment.

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