Is constipation a disorder of defecation or impaired motility?: distinction based on defecography and colonic transit studies.

Abstract

The purpose of this study was to determine whether constipation is a disorder of defecation or of impaired motility by using defecography and transit studies. Thirty-five patients (34 women, one man) with severe constipation underwent defecography and colonic transit studies in a 2-month period. Transit studies included the use of orally administered radiopaque markers and plain abdominal radiographs obtained up to 4 days later. Fluoroscopically guided defecography was performed with barium paste introduced into the rectum. Normal colonic transit time was observed in seven (20%) of the 35 patients. Abnormal findings included colonic inertia in six (17%) patients, hindgut dysfunction in 10 (29%) patients, and outlet obstruction in 12 (34%) patients. Rectocele, enterocele, descending perineum syndrome, and dyskinetic puborectalis were found equally in both groups of patients. Rectal prolapse was more commonly found in patients with hindgut dysfunction and outlet obstruction (p < .05). Surgical or medical management of severely constipated patients relies on objectively identifying the underlying pathophysiology. Our findings suggest that constipation is often a disorder of defecation rather than an impairment of colonic motility.