الفهرس 
Anatomy of the Rectum, Anal Canal and the Pelvic FloorOnly 14 pages are availabe for public view
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Abstract
A
nal incontinence is the inability to control feces and to expel it at a proper place and at a proper time. The consistency of the feces, the rectal capacity, the pelvic floor muscles are important factors affecting continence. IAS is consistently contracted and gives a watertight closure of the anal canal with the help of the hemorrhoidal tissue that fills the opening of the anal canal. The sensibility of rectum and anus gives awareness of stool in the distal rectum and activates the contraction of EAS as additional help for IAS. The central nervous system has to be intact to govern the sensory input and the motor output.
Anal incontinence is not a diagnosis but a symptom of different causes, which affects at least 2.2% of community-dwelling adults and 45% of nursing home residents. Many suffer from social isolation and loss of self-esteem. The psychological impact is devastating. They often conceal their problems by complaining of chronic diarrhea, defecation problems, or rectal urgency. A thorough history is therefore essential in assessing patients with AI. An assessment of bowel habit is essential and IBS should be excluded.
The diagnosis is based on characteristic clinical findings and the exclusion of other disorders. Incontinence often occurs as a consequence of diarrhea. Urgency refers to patients with a need to defecate immediately at the risk of incontinence when facilities are absent. Assessment of the severity of incontinence is important. Details of frequency, stool consistency, and frequency of defecation should be evaluated. A history of neurologic disorders is essential. The presence of central nervous system disorders, peripheral neuropathy, low back injury, and diabetes mellitus should be established. A history of large or small bowel resection, pelvic irradiation, or inflammatory bowel disease should be recorded.
Causes of Incontinence include, congenital, pelvic floor denervation, obstetric, iatrogenic, traumatic and irradiation.
Clinical examination is of paramount importance in the evaluation and management of incontinent patients. Neurologic assessment should be done.
Digital rectal examination (DRE) should assess the degree of anal resting tone, anal tone during squeezing. Digital examination of the vagina should be performed to check for vaginal prolapse, rectoceles, cystoceles, or enteroceles. The sphincter complex and perineal body can be assessed by bidigital anovaginal examination. The puborectalis muscle can be palpated bilaterally and posteriorly.
Anorectal manometry (ARM) includes resting anal pressure, anal squeeze pressure, the rectoanal inhibitory reflex, compliance of the rectum in response to balloon distension, and sensory thresholds in response to balloon distension. It gives an objective assessment of anal sphincter function.
Defecography provides an impression of pelvic floor activity. It demonstrates the anorectal angle and diagnoses the presence of internal rectal intussusceptions.
Endoanal ultrasound (EAUS) investigates the anal sphincters for atrophy, scar tissue and defects in the sphincters. For visualization of defects in the perineum of a woman, vaginal endosonography can be helpful.
Magnetic resonance imaging (MRI) can visualize the anal canal, lower rectum, and the surrounding tissue of prostate, bladder, and uterus. MRI reveals lesions and atrophy of the sphincters.
Endoscopy can exclude some diseases that give diarrhea and mucus production; proctitis, colitis, solitary rectal ulcer and villous adenoma.
Conservative Treatment is the initial approach to the incontinent patient. It improves continence, quality of life, psychologic well-being, and anal sphincter function. The aim of pharmacologic treatment of AI is to try to achieve passage of one or two well-formed stools a day by constipating agents. Bulking agents may improve the consistency of a liquid stool. Laxative abuse should be stopped.
Biofeedback (BFB) Treatment, the rationale underlying BFB assumes that the physiologic activity that is monitored is causally related to a clinical problem and that alteration of that activity can lead to resolution of the problem. It may be most appropriate when there is neurologic injury (i.e., partial denervation), but it has been reported to also benefit incontinent patients with minor structural defects.
Anal Encirclement Procedures, different materials have been used including nylon, silk, fascia strips, silver wire, and silastic bands. The complication rate is high.
Overlapping Sphincteroplasty, patients with incontinence secondary to an obstetric or iatrogenic anterior defect are best suited for surgical correction of AI. Poor result after adequate sphincteric repair is attributed to coexistent pelvic floor denervation. Primary sphincteric repair is inadequate in most women with obstetric ruptures after vaginal delivery because most have residual sphincter defects and about 50% still experience incontinence. Outcome after end-to-end repair is somewhat inferior to overlapping repair whereas overlapping repair might be associated with more evacuation difficulties. Good functional results are usually obtained in 50%–80% but seem to deteriorate with time. Poor outcome is usually associated with pelvic floor denervation or a residual sphincter defect.
Postanal Repair improves anal incontinence by restoring the anorectal angle and lengthens the anal canal. The principal indication is denervation damage of the pelvic floor. The initial results are good. Long-term benefits, however, are only reported by 30%–40% of patients; 30% are not improved at all. Total pelvic floor repair, a combination of postanal and anterior repair, does not produce consistent changes in anatomy or physiology either. It rarely renders patients completely continent but substantially improves continence and lifestyle in approximately half of them. The main indication is incontinence in conjunction with severe pelvic floor descent syndrome. Posterior reconstruction may be replaced by SNS.
Sacral nerve stimulation (SNS) offers the opportunity to test the stimulation before the decision for a permanent implant is made. An average success rate of approximately 80% is given. The best indication for sacral nerve stimulation is AI in patients with intact anal sphincters or for patients who had an unsuccessful anal repair in the past. It seems to work well in patients with neurogenic incontinence.
Dynamic Graciloplasty (DGP), patients with a completely destroyed anal sphincter or a large gap between both ends of the sphincters cannot be helped anymore with anal repair. The success rate varies between 40% and 80%.
Artificial bowel sphincter (ABS), the anus is encircled with an implantable fluid-filled cuff, compresses the anus all the time. Continence is excellent.
Magnetic Anal Sphincter, a new approach to an ABS is to use small magnets inserted surgically around the anal canal creating high pressure zones of different amplitude with good promising results.
When conservative and operative treatment has failed to create an acceptable level of continence, the patient is left with a colostomy.
Today, measuring the quality of life an8d taking the patient’s perspective into account are indispensable for judging the outcome of surgical treatments. Adequate tools to measure quality of life have been developed in recent years. Unspecific quality of life measures do not adequately reflect the influence of specific diseases on the quality of life. Therefore, disease-specific quality of life measures had to be validated. For AI, Fecal Incontinence Severity Index (FISI) and Fecal Incontinence Quality of Life Scale (FIQoL).