Lateral internal sphincterotomy (original) (raw)

Lateral internal sphincterotomy is an operation performed on the internal anal sphincter muscle for the treatment of chronic anal fissure. The internal anal sphincter is one of two muscles that comprise the anal sphincter which controls the passage of feces. The procedure helps by lowering the resting pressure of the internal anal sphincter, which improves blood supply to the fissure and allows faster healing. The procedure has been shown to be very effective, with 96% of fissures healing at a median of 3 weeks in one trial.