Dyssynergic defecation.

Dyssynergic defecation is a common clinical problem that affects half of patients with chronic constipation. In many patients, there is a significant overlap with slow transit constipation. The chief underlying pathophysiologic mechanism is a failure of rectoanal coordination. By using a combination of history, prospective stool diaries, detailed clinical evaluation, and anorectal physiologic tests, it is possible to diagnose this problem. Controlled trials are under way to evaluate the efficacy of biofeedback therapy. Meanwhile, it is possible to treat most patients by using neuromuscular conditioning and biofeedback therapy. Further refinements in diagnostic criteria and in rehabilitation therapy programs should facilitate better diagnosis and treatment of patients with dyssynergic defecation.