Anal stricture (also called anal stenosis) is a medical problem that is not common; it may be congenital (a baby is born with a medical problem), but usually if it does happen it is after anorectal surgery, which is surgery in the area of the rectum and anus. This may cause stricture (when a passage in the body becomes too narrow) of the anal canal, which leads to hard or painful bowel movements. When anal stenosis does occur it is usually after a hemorrhoidectomy, which is the surgical removal of hemorrhoids; this is the cause in 90% of cases of anal stenosis.
Mild stenosis can be treated with stool softeners or fiber (which come from plant foods) supplements (in pill or powder form). When the narrowing of the anal canal is not too much, an operation called a sphincterotomy can be done to correct the problem. This is an operation done on the internal anal sphincter muscle, a round muscle inside the anal canal. In cases where the anal canal becomes very narrow, an operation called an anoplasty is done. This is reconstructive surgery (also known as plastic surgery) of the anus.