Obstructed defecation

Lore & Background

Obstructed defecation syndrome is recognized as a major cause of primary constipation, though its definition and terminology remain disputed. Some sources inappropriately treat ODS as a synonym for anismus, but anismus is only one possible cause. Other authors use ODS to refer to defecatory dysfunction without pathological findings. The 2018 consensus statement from the American Society of Colon and Rectal Surgeons defines ODS as 'a subset of functional constipation in which patients report symptoms of incomplete rectal emptying with or without an actual reduction in the number of bowel movements per week.'

Reader's Guide

Obstructed defecation syndrome is significant because it represents a distinct pathophysiological entity within functional constipation, often requiring different diagnostic and therapeutic approaches than slow transit constipation. Its symptoms—such as straining, self-digitation, and sensation of incomplete evacuation—can severely impair quality of life.

The term's absence from ICD-11 and Rome-IV classifications, which instead use 'functional defecation disorders,' reflects ongoing confusion in terminology. One publication criticized these classifications as ambiguous and symptom-based rather than etiopathological. Understanding ODS is crucial for clinicians to avoid misdiagnosis and to address the overlap with other constipation subtypes, such as dyssynergic defecation and slow transit constipation.

Did You Know?

• Self-digitation is recognized as a symptom of ODS, not a treatment, and is not generally recommended by medical professionals.
• Approximately 60% of patients with dyssynergic defecation also have slow transit constipation.