Role of Anorectal Manometry in Clinical Practice

Physiologic assessment of the anorectum and pelvic floor by anorectal manometry and balloon expulsion testing provides important insights into the pathologic processes underlying defecatory disorders and guides treatment, specifically the use of biofeedback for the treatment of dyssynergic defecation and the identification of possible structural abnormalities of the pelvic floor. While symptoms and digital rectal examination may suggest pelvic floor dysfunction to the clinician, only pelvic floor testing provides definitive diagnoses of these often treatable abnormalities. The use of anorectal manometry in clinical practice is currently limited by substantial variation in performance of the test and interpretation of the results, but anorectal manometry with the addition of balloon expulsion test to improve specificity provides the best current modality for the diagnosis of dyssynergic defecation. With the introduction of high-resolution and three-dimensional, high-definition probes, our ability to characterize the structure and function of the anorectum has never been better, though further research is still needed to improve our ability to diagnose pelvic floor dysfunction and refer appropriate patients to treatment. In areas where the availability of anorectal manometry (ARM) is limited, a thorough digital rectal exam performed by an experienced clinician plus the balloon expulsion test alone may identify appropriate patients to refer for additional testing. This review describes the appropriate indications for and appropriate performance of anorectal manometry in clinical practice with an eye toward the diagnosis of dyssynergic defecation in patients with chronic constipation, fecal incontinence, and chronic proctalgia.