Anal fissures are painful tears in the lower end of the anal canal, most commonly caused by constipation and spasm of the internal sphincter of the anus. When initial treatment (high fiber diet, stool softener, laxative) fails surgery becomes necessary to relieve the spasm of the sphincter by cutting part of the sphincter which allows it to relax. Instead of surgical treatment, Botox injection into the sphincter can achieve the same result without the possible complications of surgery -- which is mainly incontinence.
The Botox injection lasts for three to four months which causes the sphincter to relax and allows the tear to heal. It is important to maintain regular, soft bowel movements with a high-fiber diet, a stool softener and, if necessary, laxative to avoid recurrence of the anal fissure.