A lateral internal sphincterotomy (LIS) is a short outpatient surgery for a chronic anal fissure that has not healed with creams, fiber, and other home care. The surgeon makes a small, controlled cut in part of the internal anal sphincter muscle so it relaxes, blood flow improves, and the fissure can heal. It is one of the most effective treatments for a chronic fissure, and most people heal within a few weeks.

If you have been living with sharp, tearing pain every time you have a bowel movement, you are not alone. Below, Houston Community Surgical explains who needs this surgery, what recovery looks like, and the honest facts about risks.

What is an anal fissure, and why do some not heal?

An anal fissure is a small tear in the lining of the anal canal. Many heal on their own, but some become chronic because a tight sphincter muscle keeps squeezing the area and limits blood flow.

Common signs of a fissure include:

• Sharp pain during a bowel movement, often called "passing glass"
• Burning or aching that can last minutes to hours afterward
• Bright red blood on the toilet paper
• A small skin tag near the tear (a "sentinel tag") in long-standing fissures

A fissure is usually called chronic when it has lasted more than about 6 to 8 weeks. Not sure whether your pain is a fissure or a hemorrhoid? Read how doctors tell the difference between hemorrhoids and a fissure.

Who needs a lateral internal sphincterotomy?

LIS is usually considered for people with a chronic fissure that has not healed with non-surgical treatment. Guidelines from the American Society of Colon and Rectal Surgeons (ASCRS) say it may also be offered to carefully selected patients without first trying medicine.

Most people start with simpler steps. These include:

• Fiber and plenty of water to keep stools soft
• Warm sitz baths
• Prescription ointments that relax the sphincter, such as nitroglycerin or diltiazem
• Botulinum toxin (Botox) injections into the sphincter for some patients. Houston Community Surgical offers Botox injections for anal fissures.

Surgery is usually discussed when these steps have not worked, when pain keeps coming back, or when the fissure has lasted many months.

A fissure in an unusual spot, or more than one fissure, may need extra testing for other causes such as Crohn's disease or infection before any surgery.

What happens during the procedure?

LIS is a short outpatient procedure, and most people go home the same day. It is usually done under anesthesia, and the cut is made in the internal sphincter only, not the outer muscle you squeeze on purpose.

Dr. Belizaire performs lateral internal sphincterotomy for chronic anal fissures at hospitals and surgery centers across Houston.

Here is the basic idea:

• The internal sphincter is a ring of muscle you do not control. In many chronic fissures it stays too tight.
• The surgeon divides a small, measured portion of this muscle on the side of the anal canal.
• This lowers the pressure, improves blood flow, and gives the tear a chance to heal.

What is recovery like after a sphincterotomy?

Many people notice that the sharp fissure pain improves within days, even though the area is still sore from surgery. Full healing of the fissure usually takes a few weeks.

What to expect during recovery:

• First few days: Soreness that is usually managed with over-the-counter pain medicine, sitz baths, and stool softeners.
• First bowel movement: It may be uncomfortable, but many people say it is less painful than before surgery.
• Light bleeding or drainage: A small amount is common for the first week or two.
• Back to work: Many people with desk jobs return to work within about a week.
• Full healing: Usually within about 2 to 4 weeks. Most fissures are healed by the follow-up visit.

Keep stools soft with fiber and water during recovery. Straining and hard stools are the main things that can slow healing.

Can a sphincterotomy cause bowel leakage?

Yes, it can, but lasting leakage is uncommon. Some people notice minor changes, like less control of gas or slight soiling, in the first weeks after surgery. For most people this is mild and goes away.

A small number of people have changes that last longer. This is why the decision is personal. The risk may be higher for people who:

• Already have some leakage or weak control before surgery
• Have had a tear or injury during vaginal childbirth
• Have had prior anal surgery

For people with these risk factors, other options may be a better fit. These can include continued medicine, Botox, or a procedure that removes the fissure and covers it with healthy tissue without cutting the sphincter. Dr. Belizaire also performs anal advancement flap procedures for fissures in patients at higher risk of leakage.

How well does lateral internal sphincterotomy work?

LIS has one of the highest healing rates of any fissure treatment. ASCRS guidelines describe it as the treatment of choice for selected patients with a chronic fissure who do not have leakage problems to begin with.

Fissures can come back after any treatment, but this is less common after LIS than after creams or Botox alone. Healthy bowel habits help lower that risk.

When should you see a colorectal surgeon about a fissure?

See a specialist if your fissure pain has lasted more than 6 to 8 weeks, keeps coming back, or is affecting your daily life. You should also be seen if you have heavy bleeding, a fever, a lump, or changes in your bowel habits.

A colorectal surgeon can confirm the diagnosis, rule out other causes, and talk through every option, from medicine to surgery. Learn more about anal fissure symptoms and common misconceptions.

Frequently Asked Questions

Is a lateral internal sphincterotomy painful?

There is some soreness after surgery, but many people find it less painful than living with the fissure. Pain usually improves a lot within the first week.

How long does it take to heal after a sphincterotomy?

Most fissures heal within about 2 to 4 weeks. Many people feel much better well before that.

Will I lose control of my bowels after sphincterotomy?

Most people do not. Mild, short-term changes with gas or slight soiling can happen, and lasting problems are uncommon. Your surgeon will review your personal risk first.

Can an anal fissure come back after surgery?

It can, but it is less common after LIS than after other treatments. Soft, regular stools help prevent a new tear.

Do I have to try creams before surgery?

Most people do. Guidelines say surgery may be offered without trying medicine first in some carefully selected patients.

Talk with a Houston colorectal surgeon

A chronic fissure can wear you down, but it is very treatable. If you live in the Houston area and your fissure is not healing, you can request a consultation with Dr. Belizaire at houstoncommunitysurgical.com to talk through your options.

Sources

• Davids JS, Hawkins AT, Bhama AR, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Anal Fissures. Dis Colon Rectum. 2023;66(2):190-199. PubMed
• Wald A, Bharucha AE, Limketkai B, et al. ACG Clinical Guidelines: Management of Benign Anorectal Disorders. Am J Gastroenterol. 2021. PubMed
• Nyam DC, Pemberton JH. Long-term results of lateral internal sphincterotomy for chronic anal fissure with particular reference to incidence of fecal incontinence. Dis Colon Rectum. 1999;42(10):1306-1310. PubMed