Assessment of anorectal motility measurements in the management of adult megacolon.

Anorectal motility was studied in 23 patients with adult megacolon. A balloon was used for rectal distension, and electrical signals from the anal canal or rectal mucosa were monitored with a silver/silver chloride electrode. Intraluminal pressure was measured by a pressure transducer linked to the vicinity of the electrode via a polythene tube. Responses to rectal distension provided a means of distinguishing patients with adult Hirschprung's disease from ones with idiopathic megacolon. Some patients with the latter condition showed an elevation of mean anal canal pressure relative to that in normal subjects. There was no statistically significant difference in slow-wave frequency in the anal canal between patients and adult megacolon and normal subjects. The fall in anal canal pressure associated with rectal distension was correlated with a decline in the amplitude of slow-wave electrical activity. The measurement of anorectal motor parameters was of value in the management of adult megacolon.