Fecal incontinence
FI is a sign or a symptom, not a diagnosis, and represents an extensive list of causes. Usually, it is the result of a complex interplay of several coexisting factors, many of which may be simple to correct. Up to 80% of people may have more than one abnormality that is contributing. Deficits of individual functional components of the continence mechanism can be partially compensated for a certain period of time, until the compensating components themselves fail. For example, obstetric injury may precede onset by decades, but postmenopausal changes in the tissue strength reduce in turn the competence of the compensatory mechanisms. The most common factors in the development are thought to be obstetric injury and after effects of anorectal surgery, especially those involving the anal sphincters and hemorrhoidal vascular cushions. The majority of incontinent persons over the age of 18 fall into one of several groups: those with structural anorectal abnormalities (sphincter trauma, sphincter degeneration, perianal fistula, rectal prolapse), neurological disorders (multiple sclerosis, spinal cord injury, spina bifida, stroke, etc.), constipation/fecal loading (presence of a large amount of feces in the rectum with stool of any consistency), cognitive and/or behavioral dysfunction (dementia, learning disabilities), diarrhea, inflammatory bowel diseases (e.g. ulcerative colitis, Crohn's disease), irritable bowel syndrome, disability related (people who are frail, acutely unwell, or have chronic/acute disabilities), and those cases which are idiopathic (of unknown cause). Diabetes mellitus is also known to be a cause, but the mechanism of this relationship is not well understood.
Surgical management of fecal incontinence
This is also termed artificial anal sphincter or neosphincter. The usual surgical approach is through the perineum or alternatively via the vagina. The artificial bowel sphincter involves the implantation of 3 components: (i) A fluid filled silicone elastomer cuff placed around the anus, (ii) a liquid filled, pressure-regulating balloon positioned in the peritoneal fat, and (iii) a manual pump connecting these components (placed in either the labia majora or the scrotum). When the cuff is inflated, the anal canal sealed. The fluid is transferred to the balloon by the manual pump, resulting in deflation of the cuff, opening of the anal canal and allowing for defecation. This procedure improves FI scores and quality of life, and continence is excellent when the procedure works (successful outcome in 85% patients with a functioning device). The procedure is less technically demanding than the graciloplasty, but there is the disadvantage of using foreign material, which can erode through the anal canal. As with graciloplasty, obstructed defecation may develop with a working device, and may be treated with enemas. Complications include infection, which may warrant temporary removal of the device. Graciloplasty and artificial anal sphincter both significantly improve continence, with artificial anal sphincter being superior, however both methods have high rates of complications.