Rectal compliance, capacity, and rectoanal sensation in fecal incontinence

OBJECTIVE: Assessments of the pathophysiology of fecal incontinence are ske wed toward anal sphincter function; however, rectal compliance, rectoanal s ensation and capacity may also be relevant. The aim of this study was to ev aluate the usual and some novel diagnostic approaches in fecal incontinence . METHODS: In 22 unselected patients with fecal incontinence (21 F, 33-75 yr) , we quantified: 1) symptoms, anorectal manometry, and anal, ultrasound; 2) anal perception of temperature and light touch; 3) rectal sensitivity and compliance to distension; and 4) rectal reservoir function. Control values were obtained from two groups of 11 (seven F, 32-53 yr), and 32 (18 F, 19-4 4 yr) volunteers. RESULTS: Patients had urge (14), passive (four), or combined (four) fecal i ncontinence; symptoms were mild in three, moderate in nine, and severe in 1 0 patients. Most had low sphincteric pressures and ultrasonic abnormalities . Temperature perception was impaired (p < 0.05) in incontinent patients, t o a greater extent in the proximal anal canal and in patients with passive, as opposed to urge, incontinence. Intraluminal pressures for sensations of rectal distension were lower in incontinent patients (p = 0.02). Artificia l stools elicited sensations of rectal fining at lower volumes than did a b arostat bag, and in patients with urge, as opposed to passive, incontinence . In patients and controls, the sensation of urgency was associated (r(2) = 0.2, p < 0.01) with rectal compliance. CONCLUSIONS: We confirm that temperature sensation is impaired, and percept ion of rectal distension is not always reduced in fecal incontinence. Artif icial stool tended to induce sensations at lower volumes than did balloon i nflation. Altered sensory mechanisms may contribute to the pathophysiology of fecal incontinence. (C) 2001 by Am. Coll. of Gastroenterology.