A fissure is a tear in the skin of the anus, usually caused when a large, hard stool overstretches the anal opening and damages the fragile skin. It is often associated with constipation, and less frequently, with chronic diarrhea, inflammatory bowel disease or sexually transmitted diseases that involve the anus and rectum. Sometimes, the cause is unknown.
Anal fissures can be acute or chronic. An acute fissure is a superficial tear and a short-term condition. A chronic fissure is deeper and may expose underlying muscle. When lifestyle and diet changes and medication fail, and the condition becomes chronic, surgery is recommended. A lateral internal sphincterotomy is the surgical procedure most commonly used to repair a fissure.
Lateral internal sphincterotomy involves stretching or cutting the internal sphincter, the muscle that restricts and relaxes when stool passes from the body. Cutting the muscle prevents spasm and temporarily weakens the muscles, and this in turn helps the area to heal. The surgeon removes the fissure and any underlying scar tissue.
The surgery can be performed under local anesthesia, which involves injecting the immediate area with a numbing agent similar to that used at the dentist's office, or spinal anesthesia, which numbs the entire lower body. In some cases, general anesthesia may be used, which renders the patient unconscious. The choice of anesthesia depends on patient and physician preference, the patient's health, and the standard practice of the particular facility.
The patient is positioned on the table so that the anus and rectal area are exposed. This can be done face down, with the buttocks slightly elevated, or supine (on the back) with the legs held up in stirrups. After anesthesia is administered, the area is cleaned with an antiseptic solution.
The operation takes about 20 to 30 minutes. The wound is then sutured closed, usually with stitches that dissolve in time. Most patients can go home the same day.