The problem of fecal incontinence has long been a “no mans land” falling between the cracks of different medical and surgical specialties.
Our ability to understand these disorders has improved considerably with increased research and co-ordination of the involved subspecialists. Diagnostic testing has also become more simplified producing improved understanding of the causes of the problem and improving our ability to treat these disorders.
Bowel control relies on muscles and nerves of the rectum and anus working together to hold and then release stool. The rectum (which is the lower end of the large bowel, also called the colon) stretches to hold stool. Stool is normally solid by the time it reaches the rectum. Circular muscles called sphincters close tightly like rubber bands around the opening at the end of the rectum, called the anus, until stool is ready to be released during a bowel movement. Pelvic floor muscles also help maintain bowel control by maintaining the correct angle between the colon,rectum and anus.
Damage to the pelvic floor from childbirth is the most common cause of fecal incontinence in women. The effect of the damage during childbirth often does not show up until many years later although there may have been temporary problems immediately after the delivery.
Damage to the nerves of the pelvic floor can impair the ability to sense stool in the rectum,decrease resting and squeeze pressures in the anal canal, decrease the ability to contract and relax muscles used during a bowel movement.
Damage to the muscles and fibrous layers can cause the rectum to drop down through the anus, a condition called rectal prolapse or cause the rectum to protrude through the vagina, a condition called rectocele or cause the pelvic floor to become weak and sag.
Anorectal ultrasonography very similar to a transvaginal ultrasound can be used to determine whether the anal sphincter muscles are torn and if so, where and to what extent. This information guides repair of the sphincter.
Anal electromyography measures electrical activity in the muscles of the pelvic floor using adhesive/ surface sensing pads to measure the electrical signals from muscle activity. This painless procedure tests for nerve damage of the pelvic floor and rectal muscle.
Successful treatment of fecal incontinence relies on correctly diagnosing the underlying problem. Treatment may include changing the diet or using medication to eliminate problems with loose stools. Treatment may include exercises to strengthen the muscles, surgery to repair torn structures.
Finally, sacral nerve stimulation is very effective at correcting abnormalities of the reflexes controlling relaxation and contraction of the rectum and anus. Sacral nerve stimulation or neuromodulation, involves placing thin wires (electrodes) near the nerves in the sacral area which then supply the anal canal and rectum and continuously stimulating these nerves with electrical pulses. This procedure requires a battery-operated stimulator placed beneath the skin and is similar in many respects to a pacemaker.