Methods of Evaluation of Anorectal Causes of Obstructed Defecation

Obstructed defecation is a complex disorder that results in impaired propagation of stool from the rectum. It is one of the major subtypes of functional constipation and can be secondary to either functional or anatomic etiologies. Patients with obstructed defecation typically present with symptoms of abdominal discomfort, a sensation of incomplete evacuation and rectal obstruction, passage of hard stools, the need for rectal or vaginal digitation, excessive straining, and reduced stool frequency. Evaluation of obstructed defecation is multimodal, starting with a thorough history and physical examination with focus on the abdominal, perineal, and rectal examination. Additional modalities to elicit the diagnosis of obstructed defecation include proctoscopy, colonic transit time studies, anorectal manometry, a rectal balloon expulsion test, defecography, electromyography, and ultrasound. The results from these studies should be taken in the context of each patient's clinical situation, as there is no single criterion standard for the diagnosis of obstructed defecation. Surgery is typically a last resort for these patients and the majority of patients will have good symptomatic management with diet and lifestyle changes. Patients who are found to have functional mechanisms behind their obstructed defecation also benefit from pelvic floor exercises and biofeedback therapy.