Lateral internal sphincterotomy, the most common treatment for chronic anal fissure, may cause permanent injury to the anal sphincter, which can lead to fecal incontinence. We compared two nonsurgical treatments that avert the risk of fecal incontinence.treatment with either topical nitroglycerin or botulinum toxin is effective as an alternative to surgery
Patients will be randomized to receive treatment with either a total of 20 U of botulinum toxin(diluted in saline to a concentration of 50 U per milliliter.