Perception of and adaptation to rectal isobaric distension in patients with faecal incontinence

Abstract

Background-Perception of, and adaptation of the rectum to, distension probably play an important role in the maintenance of continence, but perception studies in faecal incontinence provide controversial conclusions possibly related to methodological biases. In order to better understand perception disorders, the aim of this study was to analyse anorectal adaptation to rectal isobaric distension in subjects with incontinence. Patients/Methods-Between June 95 and December 97, 97 consecutive patients (nine men and 88 women, mean (SEM) age 55 (1) years) suVering from incontinence were evaluated and compared with 15 healthy volunteers (four men and 11 women, mean age 48 (3) years). The patients were classified into three groups according to their perception status to rectal isobaric distensions (impaired, 22; normal, 61; enhanced, 14). Anal and rectal adaptations to increasing rectal pressure were analysed using a model of rectal isobaric distension. Results-The four groups did not diVer with respect to age, parity, or sex ratio. Magnitude of incontinence, prevalence of pelvic disorders, and sphincter defects were similar in the incontinent groups. When compared with healthy controls, anal pressure and rectal adaptation to distension were decreased in incontinent patients. When compared with incontinent patients with normal perception, patients with enhanced perception experienced similar rectal adaptation but had reduced anal pressure. In contrast, patients with impaired perception showed considerably decreased rectal adaptation but had similar anal pressure. Conclusion-Abnormal sensations during rectal distension are observed in one third of subjects suVering from incontinence. These abnormalities may reflect hyperreactivity or neuropathological damage of the rectal wall. (Gut 1999;44:687-692) Keywords: faecal; incontinence; rectum; barostat; perception; distension Anal dysfunction classically remains the main culprit in faecal incontinence. However, proximal sensation and adaptation of the rectum to distension probably play an important role in this disease for several reasons. Firstly, external anal sphincter responses to rectal stimulation are crucial in preserving continence and they are closely related to rectal sensory function.1 Secondly, patients with neurogenic incontinence have impaired perception of distension and electrical stimulation.2 Finally, biofeedback techniques modifying rectal balloon sensitivity have been shown to improve the condition of patients with faecal incontinence. Although some studies have shown impaired rectal sensation in faecal incontinence, 1 4-6 others have found either no abnormality 7 or enhanced perception 8 ; these apparent discrepancies may be related to methodological problems raised by isovolumic stimulation. Indeed, analysis of perception and compliance of the rectum by isovolumic distension models is inaccurate because these models hypothesise that (a) the rectum can be modelled as a closed cylinder, (b) the rectal size does not influence measured rectal com...

Accuracy of Anorectal Manometry in Patients with Fecal Incontinence

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