Lateral internal sphincterotomy to heal anal fissures

Surgery may be necessary if medicine fails to heal a tear (fissure) in the anus. The preferred procedure is lateral internal sphincterotomy. A doctor makes a small incision in the internal anal sphincter, one of two muscles that control the anus. This can be done as outpatient surgery under local anesthesia or general anesthesia.

The internal anal sphincter is always under tension, also known as resting pressure. If that pressure becomes too high, a fissure may form or an existing one may not heal. The incision reduces the resting pressure, allowing the fissure to heal.

Lateral internal sphincterotomy has a better success rate than any medicine that is used to treat long-term anal fissures. The results last longer, and fewer people have anal fissures come back after surgery than after treatment with medicine.¹

In some studies, a greater number of people who had lateral internal sphincterotomy had some inability to control gas or stool (incontinence) after surgery compared to people treated with medicine. Despite these results, satisfaction with this surgery is high. And a review of many studies showed that the risk of incontinence was 8%. This means that about 8 out of 100 people who had the surgery had some problem with incontinence. But this rate was not very different from the rates seen in people who were treated with medicine for their chronic anal fissures.² If you are deciding whether to have this surgery, it is important that you consider the chance of incontinence.

Citations

1. Nelson R (2007). Anal fissure (chronic), search date January 2007. Online version of BMJ Clinical Evidence. Also available online: http://www.clinicalevidence.com.
2. Nelson R (2006, amended 2006). Non-surgical therapy for anal fissure. Cochrane Database of Systematic Reviews (4). Oxford: Update Software.