A lateral internal sphincterotomy is an outpatient surgery during which the sphincter is cut or stretched to help anal fissures heal. Some practices may help support recovery.

The sphincter is the circular group of muscles surrounding the anus that are responsible for controlling bowel movements. A sphincterotomy is performed on the innermost layer of muscle in the sphincter.

A lateral internal sphincterotomy is used to treat severe anal fissures if other treatments have not helped.

The incision made during surgery can ease the pressure inside the sphincter that prevents healing and increase blood flow to the area to speed up the healing process. The procedure typically cures the anal fissure but may also cause complications.

Several other procedures are often performed alongside a sphincterotomy as needed. These include:

  • hemorrhoidectomy, which removes hemorrhoids
  • fissurectomy, which repairs tears in the anal canal
  • fistulotomy, which treats an anal fistula

Before recommending a sphincterotomy, a doctor may first recommend less invasive treatment, such as:

  • a high fiber diet
  • stool softeners
  • injections of onabotulinumtoxinA (Botox)
  • frequent sitz baths
  • drinking more fluids
  • topical analgesics

Anal fissures are breaks or tears in the skin of the anal canal.

They can occur due to:

  • frequent constipation and straining during bowel movements
  • frequent hard stools
  • tearing during childbirth or sexual activity that involves anal penetration

Some underlying health conditions, such as inflammatory bowel disease and prior anal surgery, can increase the risk.

Though they may heal on their own, some anal fissures may require medical intervention, particularly if painful symptoms persist.

Anal fissures can also become chronic and may not respond to other treatments. If that’s the case, a doctor may recommend a lateral internal sphincterotomy.


A doctor may provide instructions ahead of your surgery. Bowel prep is not typically required for a lateral internal sphincterotomy. A bowel prep involves cleaning out your digestive tract using laxatives or enemas. It’s best to follow whatever directions the doctor provides.

The doctor may want you to receive a local anesthetic and remain awake during the surgery, or they may prefer full sedation. If you have any preference or concerns about different anesthesia methods, speak to the doctor beforehand.

Depending on whether or not your procedure will be performed under anesthesia, you may need to arrange transportation after the procedure.


During the procedure, the surgeon makes a small incision in the internal anal sphincter, sometimes with the assistance of a small insertable camera. There are multiple effective ways to perform this surgery, and your doctor can tell you which method they prefer.

The surgery typically takes around 30 minutes.


You can typically return home on the same day as your surgery. Be sure to have a ride home planned before the procedure, particularly if you’ll be under general anesthesia.

You may feel soreness or have small amounts of bleeding or drainage for a few days following the procedure. A doctor may recommend soaking in a warm bath.

It will likely take about 6 weeks for your anus to heal fully, but most people can resume their daily activities, including going to work and driving, within 1 to 2 weeks after the procedure.

You may also experience some pain during bowel movements directly following surgery. A doctor may recommend taking a fiber supplement to reduce straining and constipation. It’s also normal to have some blood when wiping after a bowel movement for the first few weeks.

Most people find that their anal fissure has been cured within 3 to 4 weeks of their sphincterotomy.

Recovery at home

Some things you can do to help aid in your recovery:

  • Get plenty of rest.
  • Try to walk a little each day.
  • Refrain from driving for the recommended amount of time.
  • Shower or bathe as usual, but pat your anal area dry afterward to avoid irritation.
  • Drink plenty of fluids.
  • Eat a high fiber diet or take fiber supplements.
  • If you experience constipation, a doctor may recommend a mild laxative or stool softener.
  • Take your pain medications exactly as instructed.
  • Sit in around 10 centimeters of warm water (sitz bath) three times daily and after bowel movements until the pain in your anal area subsides.
  • When attempting to move your bowels, use a small step to support your feet. This will flex your hips and place your pelvis in a squatting position, which can help you to pass a stool more easily.
  • Using baby wipes instead of toilet paper is often more comfortable and doesn’t irritate the anus.
  • Avoid using fragranced soaps.

A lateral internal sphincterotomy is a simple and widely performed procedure that is highly effective in the treatment of anal fissures. Side effects and complications are rare but can occur.

It’s typical for people to experience minor fecal incontinence and difficulty controlling flatulence in the immediate weeks after the surgery. This side effect usually resolves on its own as your anus heals, but if you experience persistent incontinence, consider following up with the doctor.

Hemorrhaging, or bleeding, during surgery is rare. If it does occur, the surgeon will put in extra stitches while operating.

A lateral internal sphincterotomy is a procedure that can successfully treat severe or chronic anal fissures. Recovery from this procedure is relatively quick.

Many careful comfort measures can be taken to assist in the recovery process. Side effects are extremely rare and can be treated if they occur.