Anal sphincter electromyography after colectomy, mucosal rectectomy, and ileoanal anastomosis.

Electromyography (EMG) was used to evaluate the external anal sphincter in 27 patients following colectomy, distal mucosal rectectomy, and ileoanal anastomosis. The studies were conducted four months to 58 months (mean, 20 months) following the restoration of intestinal continuity. Nine patients underwent endoanal rectal mucosal stripping, while in 18 patients the rectum was everted to facilitate the stripping. Postoperative continence varied widely, from perfect to frequent and severe mucous of fecal leak. Abnormal motor-unit potentials were identified by EMG in nine patients and this finding was usually associated with poor continence. The sex of the patient, technique of mucosal stripping, and type of anastomosis did not influence the EMG result, but patients at least 40 years old all had abnormal EMGs. We conclude that poor continence after ileoanal anastomosis correlates with an abnormal EMG of the external anal sphincter. The cause of the EMG abnormality is unclear.