Evaluation and treatment of constipation.

Constipation is a symptom that usually reflects the existence of associated diseases. The clinical history, physical examination, and barium enema or colonoscopy should permit the diagnosis of extracolonic and structural colonic causes of constipation. A comprehensive evaluation of colonic transit and pelvic floor function in patients with functional constipation should categorize the underlying pathophysiologic mechanism, and optimize the selection of candidates for surgical operations and their results.