The anal reflex in idiopathic faecal incontinence; an electrophysiological study

Abstract

Summary We have recorded the latency of the anal reflex, using a simple electrophysiological method, in 22 patients with anorectal incontinence and in 33 control subjects without anorectal disease. The mean latency in the control subjects was 8·3 ms (range 5–11·3 ms). In the patients with faecal incontinence the mean latency of the anal reflex was 13·0 ms (range 6·5–22·0 ms). The reflex latency was within the normal range in only three incontinent patients. These findings support our concept, based on histological examination of the external anal sphincter musculature, that a major cause of this syndrome is denervation of these muscles due to damage to the innervation of the external anal sphincter and puborectalis muscles.