Its ability to detect prolapse is similar to that of ﬂuoroscopy, but MRI can visualize pelvic ﬂoor musculature and soft tissue, thus giving it the advantage of detecting ballooning of the levator muscles and levator ani hernias. The supine position of the testing is a drawback; however, there are isolated reports of upright dynamic MRI using open scanners that show results comparable to ﬂuoroscopy for detection of anorectal pathology (92). Fluoroscopy and dynamic MRI can be used in situations involving severe multicompartmental prolapse or in which the severity of the symptoms is disproportionate to examination findings.
Anal Manometry Anal manometry is used to determine maximum resting pressure, maximum squeeze pressure, rectal sensation and compliance, as well as the presence of an intact rectoanal inhibitory reﬂex. With disordered defecation, it can be used to diagnose Hirschsprung disease and anismus. The addition of surface EMG to document relaxation helps exclude anismus as a cause of obstructed defecation. Failure of the anal sphincter to relax with defecation and increased electrical activity of the EAS and puborectalis are seen in patients with anismus. In contrast, there should be no increase in the electrical activity measured by surface electrodes for patients with Hirschsprung disease. A rectal balloon expulsion test can also be of assistance in the evaluation of rectal emptying and may be valuable during physiotherapy for diagnosing dyssynergic defecation.
Standard gastrointestinal evaluation for patients with symptoms of disordered defecation should include a barium enema or colonoscopy to eliminate the possibility of colorectal malignancy. Proctoscopy should be included as part of the routine examination because it may reveal anorectal pathology.
Therapeutic Approach to Fecal Incontinence
Treatment of fecal incontinence should first focus on nonsurgical options, including dietary modification, medical therapy, and biofeedback. Any underlying systemic conditions or gastrointestinal disorders should be treated before initiating an extensive evaluation for other causes of fecal incontinence. If symptoms persist, further investigation should be undertaken. If the evaluation discloses an underlying EAS defect and conservative therapy has been unsuccessful, it is reasonable to proceed with surgical treatment.
Following is an overview of treatment options and the efficacy of each approach. The lack of consistent outcome measures makes it difficult to compare efficacy among treatments. Some studies base success on strict conformity with criteria for continence, but the results vary for continence of ﬂatus, liquid, or solid stool. Other studies base success on more subjective criteria, such as improvement following treatment. Daily diaries can be maintained, but the results may be unreliable. Even if a validated symptom survey and quality-of-life scale are employed, few studies use the same outcome measure.
Nonsurgical Treatment Nonsurgical management focuses on maximizing the continence mechanism through alteration of stool characteristics or behavioral modification. Stool consistency and volume can be manipulated by dietary and pharmacologic means to achieve passage of one to two well-formed stools per day. The rationale for this approach is that formed stool is easier to control than liquid stool. Additionally, behavior modification can be employed using bowel regimens that focus on the predictable elimination of feces. Physical therapy and biofeedback can also be useful for strengthening the continence mechanism.