EXTERNAL ANAL-SPHINCTER DYSFUNCTION AND POSTOPERATIVE BOWEL HABITS OFPATIENTS WITH HIRSCHSPRUNGS-DISEASE

An electromyogram (EMG) of the external anal sphincter (EAS) was obtai ned both before and after surgery in five patients with Hirschsprung's disease and eight normal control patients. The EMG, evoked by the tra nsrectal stimulation of the pudendal nerve, was recorded at both the s acral and anal regions to investigate the deep and superficial EAS, re spectively. In eight control patients, the EMG at the sacral region co nsisted of a polyphasic wave with apparently two or three major peaks. and the simple monophasic wave with one or two peaks was found at the anal region. its peak corresponded to the early peaks in the sacral r egion. The mean onset latency of the EMG in the sacral region was 2.8 ms. Four patients with Hirschsprung's disease also exhibited responses that were similar to the controls, and their postoperative bowel habi ts were satisfactory. However, the remaining one patient, who still re quired a daily enema after surgery, exhibited an apparently different response, which was monophasic at both the sacral and anal regions wit h a long onset latency of 5.0 ms before and after surgery. It is postu lated that some cases with Hirschsprung's disease might be associated with an EAS dysfunction before surgery, which possibly led to the deve lopment of postoperative bowel dysmotility. Copyright (C) 1997 by W.B. Saunders Company