Definition and Overview

Sphincterotomy is a surgical procedure to repair anal fissure, which is a tear in the anterior or posterior midline of the anus. Although this is the main surgery performed for anal fissure repair, it is normally done only when other non-surgical treatments including laxatives and dietary changes have failed to correct the condition.

The surgery may be either lateral internal, which involves making a small incision in the inner sphincter muscle to decrease the tension and pressure on the anal canal, or advancement anal flap, which uses a graft material from the patient’s own body to provide more blood supply into the tear so it will heal.

Who Should Undergo and Expected Results

Sphincterotomy is performed on patients diagnosed with anal fissure or tear in the anus. This tear may be obvious because of a crack in the skin or due to the presence of a lump next to the fissure. Other common signs and symptoms include bleeding during bowel movements, burning sensation in the anus and its surrounding area, or pain when passing stool.

Although the condition can affect people of all ages, it is commonly diagnosed among pregnant women because of childbirth, children since they tend to strain when they have bowel movements, and those who suffer from constipation. Underlying viral conditions such as HIV or syphilis, which can prevent the fissure from healing, can also cause the condition.

Anal fissures have the ability to heal on their own, so often, doctors treat them with non-surgical options such as stool softeners, laxatives, rest, high-fiber diet, Botox to relax the muscles, pain relievers, and nitroglycerin treatment. However, if the tear does not heal or worsens, especially over the course of six weeks when it is already considered as chronic, the doctor typically recommends surgery.

How Does the Procedure Work?

Anal fissure repair, which is performed by a colorectal surgeon, can be either lateral internal sphincterotomy or advancement anal flap.

In the lateral internal sphincterotomy, the internal sphincter muscle, one of the two muscles that are responsible for controlling the passing of stool, is either stretched or cut to keep the anal canal more relaxed and increase the chances of healing.

The surgery begins by positioning the patient on the operating table in a supine position (face down) while the legs are raised in stirrups or the buttocks placed in a higher position. Local anaesthesia is applied directly to the anal area, although many surgeons prefer general anaesthesia to prevent tear recurrence. The area is also given antiseptic before the surgeon makes a small incision to access the internal sphincter muscle. Using surgical instruments like a scalpel or scissor, the muscle is divided or cut into two or simply stretched. If there is a scar tissue, which indicates a previous fissure, it will also be removed. The incision is then closed up and bandaged.

The advancement anal flap or the dermal flap is often done on patients with chronic fissures by giving the area, which may no longer be healing on its own, with a healthy source of blood supply.

During the surgery, the patient is administered with general anaesthesia. The surgeon then removes a graft material with a healthy blood supply, usually the skin tissue next to the anus, to close the fissure.

Possible Risks and Complications

It is expected that there will be discomfort and pain around an hour or two after the surgery, so the patient is typically given pain relievers and is advised to remain in a supine position to prevent anaesthesia-induced headaches. Infection can also occur, which can be treated with antibiotics, as well as bleeding, which is usually minor and goes away over time.

One of the more serious complications is fecal incontinence or the loss of voluntary control of bowel movement. It is also possible for the fissure to recur even after these surgeries.


  • Johnlin FC, Tucker RD, Ferguson S. The effect of guidewires during electrosurgical sphincterotomy.Gastrointest Endosc. 1992. 38:536.

  • O’Brien JW, Chen SL, Connolly R, Libby ED. Current induction in a fiberglass guidewire compared to conventional wires during simulated papillotomy. Gastrointest Endosc. 1997. 45:493.

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