[Pathophysiology of defecatory disturbance in the patient with Hirschsprung's disease and chronically constipated patients with simple megarectum].

The disturbance of defecation in the patient with Hirschsprung's disease and the pathophysiology of constipation in the constipated patient with simple megarectum were investigated. In Hirschsprung's disease, an existence of aganglionosis and the sphincter achalasia are two main factors which cause clinical symptoms such as chronic constipation and megacolon. As a surgical treatment, we have routinely performed our modified Duhamel's operation. Postoperative followup study indicated that the most cases in our series have gained a satisfactory defecatory function 1 to 3 years after operation. In chronically constipated patient with simple megarectum, on the other hand, it was found manometrically that the most of them had significantly high anal canal pressure and incomplete anal relaxation after rectal stimulation. These findings indicate that those patients have hypertonic and achalasic sphincter. Therefore, the authors propose "high anal pressure syndrome (HAPS)" for such constipated patient with simple megarectum. As to the surgical treatment, 6 patients with simple megarectum had a complete posterior internal sphincterotomy and the postoperative results were excellent or good in our series.