What You Need to Know About Complex Perianal Fistula If You Have Crohn’s Disease

What You Need to Know About Complex Perianal Fistula If You Have Crohn’s Disease

December 3, 2020
Anne M. Sydor

There are multiple causes of perianal fistulas, including Crohn’s disease. Here we take a look at complex perianal fistulas in people who also have Crohn’s disease.

What Is a Complex Perianal Fistula?

In Crohn’s disease — one of the two main types of inflammatory bowel disease (IBD) — the area around the anus (the perianal region) is affected frequently. About 1 of every 3 people with Crohn’s disease will have perianal symptoms at some point, including pain, bleeding, swelling, seepage of feces, discharge, constipation, and incontinence.

Perianal symptoms and problems can be caused by Crohn’s disease itself, a disease which causes open sores (called ulcers) in the lining of any part of the digestive tract. The symptoms of Crohn’s disease, including frequent, urgent bowel movements and chronic diarrhea, and some medications used to treat those symptoms can also stress and injure the perianal area and the sphincter muscle that opens and closes the anus so waste can be pushed out of the body.

When an ulcer extends through the lining of the intestine into the perianal area, an abnormal connection like a tunnel (or tract) can sometimes form between the intestine and the other tissue, such as skin or the sphincter muscle or both. It is these tracts that are the fistulas, which are painful, easily infected, and usually require treatment.

A perianal fistula is considered “complex” if:

  • A certain area or amount of sphincter muscle is involved
  • A fistula branches (has more than one place where it opens into muscle or skin)
  • The tract is infected or has formed a pus-filled sac inside called an abscess
  • The rectum or vagina are involved

Some guidelines also suggest that fistula in anyone with IBD, fecal incontinence, chronic diarrhea, or anorectal cancer should also be considered complex.

How Are Complex Fistulas Treated?

Today, there is no proven best-practice standard-of-care treatment for complex perianal fistulas, especially for people with Crohn’s disease. It is clear that care is improved when a stomach and intestine specialist (gastroenterologist) and a surgeon who specializes in surgery of the perianal area, colon, and rectum (colorectal surgeon) work as a team.

Choosing the treatment that is best for you can be done in a way that focuses on what you would like to achieve. It may be helpful to ask your health care team to explain what could happen in the best and worst cases for each of the treatments they suggest you consider. Knowing that the reality is likely to be somewhere in between best and worst, you can then compare treatments.


Perianal fistulas can be treated with antibiotics, immunosuppressants, and a newer class of drugs called TNF suppressors, which are considered biologic agents. The antibiotics metronidazole and ciprofloxacin have both been used to treat fistulas, and about 1 of 4 people who use these have some fistulas close after 6 to 8 weeks of using the antibiotics. Unfortunately, the fistulas often come back when a person stops taking the antibiotics. This is a problem because using antibiotics long-term can worsen Crohn’s disease.

Immunosuppressants are often used to treat Crohn’s disease and can also promote fistula closure. The immunosuppressant drugs azathioprine, methotrexate, cyclosporine A, and mycophenolate mofetil have been tested in very small numbers of patients for the treatment of fistulas. The TNF suppressors, including infliximab, adalimumab, or certolizumab reduced drainage from fistula in most people and closed fistula in about half of those who were treated.

More recent studies suggest that combining antibiotics with immunosuppressants or TNF suppressors may be more successful than any singular drug type alone. In these studies, fistulas closed in about 3 out of 4 people.


Although the medications discussed can reduce symptoms and close fistula for some people, these do not work in everyone and do not repair the tissue damage. That is, the fistula is closed, but the tract is still there. For complete repair and full control of any infections, surgical treatments are needed.

There is no one type of surgery that is considered best for all complex fistula cases, and choosing a type of surgery depends on whether infection is present, where the fistula is, individual factors, and the surgeon’s experience.

The risks of surgical procedures are infection, fecal incontinence, and recurrence of the fistula. These risks are higher for people with Crohn’s disease because of the ongoing disease process that makes it more difficult for the perianal region to heal. Before any procedure, the exact path of the fistula is determined with MRI, ultrasound, or a physical examination (often under anesthesia to control pain).

seton is a piece of surgical thread that’s left in the fistula for several weeks to keep it open (a technique first described by Hippocrates in ancient Greece). Leaving the thread in the fistula keeps it open, allowing it to drain and heal. Sometimes the thread is tied tightly or gradually tightened, making the tract smaller and smaller, eventually leading to full healing. A loose seton can be used as a long-term remedy as well. Using a loose seton with one of the biologic medications described in this article is more effective as a form of treatment and results in lower risk of recurrence than using the seton alone. This is one of the reasons why it is important to have a team approach to medical care that includes the gastroenterologist, surgeon, and you as essential team members.

In flap surgery, the fistula is cleaned out by the surgeon, and a piece of tissue from the rectum (the lowest part of the large intestine just above the anus) is used to cover the opening to the fistula. About 2 of every 3 people will have successful treatment with this method, although Crohn’s disease is considered a factor for a lower chance of success.

Fistulas can be filled with a “glue” made from proteins that tend to stick together. Success with the glue alone is uncommon, and often an additional plug made up of collagen and other biologic tissue can be used to plug the fistula. This tissue is then gradually absorbed, permanently closing the fistula. Approximately 1 of every 2 people have success with this method. Laser surgery has also been used to create scar tissue within the fistula and plug the opening. This has been successful in about 2 of every 3 people who had the surgery.

The LIFT procedure (ligation of the intersphincteric fistula tract) is used when a fistula passed through the sphincter muscle around the anus. The procedure is a treatment for fistulas that pass through the anal sphincter muscles, where a fistulotomy would be too risky. A cut is made above the fistula and a stitch is used to close each end. The fistula is then opened and washed out and can heal. For people with Crohn’s disease, the procedure is successful about 2 of 3 times that it is done. The risk of incontinence is much lower with the LIFT procedure than flap surgery.

Even with the best medical and surgical treatments, fistulas may not fully heal or may continue to recur. Sometimes an ostomy-and stoma-procedure is needed to divert feces from the anus. In this procedure, an opening is created in the abdomen and the large intestine is connected to it. Waste flows into a bag that must be emptied regularly. Every effort is made to make this a temporary solution, and the intestine can be reconnected after the anus has healed for most people. Some people, however, will need to use this as a permanent solution.

Using This Information

For many people, this information can be difficult to take in even after hearing or reading about it more than once and can cause stress, worry, and and fear. Remember that you are not alone. Support groups for people with Crohn’s disease and other resources are available. It is important to learn what you can and ask questions. Whenever possible, it is good to have health care from a team from different areas of medicine (multidisciplinary) who work together and may include a primary care provider, a gastroenterologist, a colorectal surgeon, and a social worker or psychologist. This model of care may make it possible for you to talk with and get to know a surgeon before you need to make decisions about surgery and also means that if and when surgery is needed, someone will be there for you.

If there is not a multidisciplinary care team available where you are, consider talking to your doctors and nurses about how likely it is that you will eventually need a surgery of one kind or another. Ask if there are surgeons who they typically send their patients to and when they do refer them out for surgery. Also, find out if you can meet and consult with some of these surgeons when you don’t need surgery so that you can have someone in place if surgery is ever needed in the future.

Except in cases of life-threatening emergencies, the choice of when to be referred for surgery is individual and can be made in consultation with your health care team. When symptoms are not well-controlled with medicine or are only partially controlled, you may decide that surgery is worth it for you. This can be an ongoing conversation with your team and is ultimately about what levels of pain and discomfort you are willing to tolerate and what quality of life means to you personally.

Relying on Experience

When choosing your health care team members — multidisciplinary or not — it is best to find people who have experience treating Crohn’s disease. This is especially true for surgeons. Whenever possible, choose a surgeon who has performed the surgery you are going to have multiple times. You should be able to get an answer easily to the question of how many times a surgeon has done the procedure each year to get a sense of their experience (more is better).

You can also rely on the experience of other people with Crohn’s disease by seeking out in-person and online support groups. Some helpful things that people have said about their surgeries include:

  • “Coming to terms with needing surgery is a process. Take time to find out what your needs are and to adjust physically and emotionally.”
  • “Learning from other people’s experiences was empowering for me even when their experiences were different from my own.”
  • “Hang in there, it is okay to not be okay some of the time.”
  • “Find a surgeon willing to adjust the plans according to what is most important to you.”
  • “Over time, surgery gave me a much better quality of life.”

Fistulas are a common complication of Crohn’s disease that are best treated with a combination of medication and surgery by a multidisciplinary team. Whenever possible, finding a team of people who will work with you as the most important team member and adapt treatment to your life goals is helpful.

Learning from other people with Crohn’s disease who are considering or have experienced surgery can be an empowering way to come to terms with your needs and improve your quality of life.

Anal Fistula. Mayo Clinic. Published January 18, 2018. Accessed August 9, 2020. https://www.mayoclinic.org/diseases-conditions/anal-fistula/care-at-mayo-clinic/mac-20352874

Bolshinsky V, Church J. Management of Complex Anorectal and Perianal Crohn’s Disease. Clin Colon Rectal Surg. 2019;32(4):255-260. doi:10.1055/s-0039-1683907

Gold SL, Cohen-Mekelburg S, Schneider Y, Steinlauf A. Perianal fistulas in patients with Crohn’s disease, part 1: current medical management. Gastroenterol Hepatol (N Y). 2018;14(8):470-481.

Gold SL, Cohen-Mekelburg S, Schneider Y, Steinlauf A. Perianal fistulas in patients with Crohn’s disease, part 2: surgical, endoscopic, and future therapies. Gastroenterol Hepatol (NY). 2018;14(9):521-528.

Surgery for Crohn’s Disease. Crohn’s and Colitis Foundation. Accessed August 9, 2020. https://www.crohnscolitisfoundation.org/what-is-crohns-disease/treatment/surgery

Panes J, Reinisch W, Rupniewska E, et al. Burden and outcomes for complex perianal fistulas in Crohn’s disease: Systematic review. World J Gastroenterol. 2018;24(42):4821-4834. https://doi.org/10.3748/wjg.v24.i42.4821

Vogel JD, Johnson EK, Morris AM, et al. Clinical practice guideline for the management of anorectal abscess, fistula-in-ano, and rectovaginal fistula. Colon Rectum. 2016;59:1117-1133. https://doi.org/10.1097/DCR.0000000000000733





Back To Top