Anorectal electromyography in the diagnosis of Hirschsprung's disease.

Anorectal electromyography using intraluminal electrodes was done in nine patients with Hirschsprung's disease and in nine control patients with chronic constipation. In chronic constipation, many bursts of spikes were seen in both the anal canal and the rectum corresponding to contractions of the external sphincter muscle. These were propagated from the anal canal to the rectum. In contrast, in Hirschsprung's disease few bursts of spikes were seen in the rectum, and they were not propagated from the anal canal to the rectum, even if they corresponded to contractions of the external sphincter muscle. Thus anorectal electromyography proved to be a useful screening test for Hirschsprung's disease. The bursts of spikes were analysed by a signal processor that provided more precise details for the diagnosis of Hirschsprung's disease.