Physiologic investigation of primary chronic constipation in children: comparison with the barium enema study.

Rectoanal manometry and a rectometrographic study were carried out on 31 control subjects and 63 constipated children. A single contrast barium enema was performed on all constipated children and on 20 children for whom this x-ray study (made for a reason other than constipation) was considered normal. This study allowed the determining of four manometric parameters (rectoanal inhibitory reflex threshold, rectorectal reflex threshold, conscious rectal sensitivity threshold, maximal anal resting closure pressure), of three rectometrographic parameters (maximal rectal tolerable pressure, maximal rectal tolerable volume, maximal rectal compliance), and of one radiologic parameter (rectopelvic ratio). It appeared that the barium enema study was not meaningful. The threshold of the inhibitory reflex and of the rectoanal reflex did not allow for a specific definition of abnormality in constipation. Anal closure pressure was higher in 38% of the constipated patients. The sensitivity threshold was significantly higher in the constipated group. In 79% of the patients an increase in rectal compliance was observed. Finally, in this series of constipated patients who did not have Hirschsprung's disease, organic abnormalities were demonstrated in 97% of the children.