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.
Fecal incontinence
Surgery may be carried out if conservative measures alone are not sufficient to control incontinence. There are many surgical options, and their relative effectiveness is debated due to a lack of good quality evidence. The optimal treatment regime may be a both surgical and non-surgical treatments. The surgical options can be considered in four categories: restoration and improvement of residual sphincter function (sphincteroplasty, sacral nerve stimulation, tibial nerve stimulation, correction of anorectal deformity), replacement / imitation of the sphincter or its function (anal encirclement, SECCA procedure, non-dynamic graciloplasty, perianal injectable bulking agents), dynamic sphincter replacement (artificial bowel sphincter, dynamic graciloplasty), antegrade continence enema (Malone procedure), and finally fecal diversion (e.g. colostomy). A surgical treatment algorithm has been proposed. Isolated sphincter defects (IAS/EAS) may be initially treated with sphincteroplasty and if this fails, the person can be assessed for sacral nerve stimulation. Functional deficits of the EAS and/or IAS (i.e. where there is no structural defect, or only limited EAS structural defect, or with neurogenic incontinence) may be assessed for sacral nerve stimulation. If this fails, neosphincter with either dynamic graciloplasty or artificial anal sphincter may be indicated. Substantial muscular and/or neural defects may be treated with neosphincter initially.