Manometric tests of anorectal function in healthy adults

OBJECTIVE: Although tests of anorectal function are useful in the assessmen t of defecation disorders, there is inadequate and inconsistent information regarding normative data. Also, there are discrepancies in manometric tech niques and data interpretation. Our aim was to perform a comprehensive eval uation of anorectal function in healthy adults. METHODS: We used a 6-mm diameter probe containing six radially arrayed micr otransducers, and a 4-cm-long latex balloon for performing anorectal manome try in 45 healthy subjects who were controlled for gender and age. Sequenti ally, subjects were asked to squeeze, bear down, or blow up a party balloon . Subsequently, rectal sensation, rectal compliance, and rectoanal reflexes were assessed simultaneously by performing intermittent phasic balloon dis tentions. Additionally, balloon defecation, pudendal nerve latency, and sal ine continence tests were performed. RESULTS: In men, the anal sphincter was longer (p < 0.05) and squeeze sphin cter pressure and squeeze duration were higher (p < 0.01), but resting sphi ncter pressure was similar to that in women. When bearing down, although no t significant, the defecation index was higher in men. Distinct thresholds for rectal sensation were identified but there was no gender difference. Li kewise, rectal compliance and balloon expulsion time were similar. However, during saline infusion, the onset of first leak and total volume retained were higher (p < 0.001) and pudendal nerve latency was shorter (p < 0.05) i n men. Overall, parity or age did not influence anorectal function. CONCLUSIONS: This study represents the most comprehensive age- and gender-c ontrolled assessment of anorectal function using solid state technology. Ge nder influences some parameters of anorectal function. Our results could se rve as a valuable resource of normative data. (Am J Gastroenterol 1999;94:7 73-783. (C) 1999 by Am. Coll. of Gastroenterology).