Lateral Internal Sphincterotomy (LIS) is a surgical treatment for a chronic anal fissure, particularly when symptoms continue despite appropriate non-surgical treatment. An anal fissure is a small tear in the lining of the anus that can cause sharp pain, burning after bowel movements, and bright-red bleeding.
How Does Lateral Internal Sphincterotomy Work?
During LIS surgery, a surgeon carefully divides a small portion of the internal anal sphincter muscle. This reduces excessive muscle spasm and pressure, helping improve conditions for the fissure to heal. The fissure itself generally does not need to be surgically removed.
When Is LIS Recommended?
Anal fissure surgery may be considered when a fissure becomes chronic or does not respond adequately to dietary changes, stool-softening measures, topical medicines, or other treatments. Your colorectal or general surgeon will assess your symptoms and medical history before recommending surgery.
Benefits and Recovery
LIS can relieve fissure-related pain and help the wound heal. It is commonly performed as a same-day procedure, although the exact recovery period varies. Maintaining soft stools, adequate fibre and good bowel habits is important during recovery.
As with any surgery, LIS carries potential risks, including temporary or persistent difficulty controlling gas or stool in some patients. Your surgeon should discuss individual risks, alternatives, and expected recovery before treatment.