Diagnostic Strategy and Tools for Identifying Defecatory Disorders

Abstract

This article reviews the indications, techniques, interpretation, strengths, and weaknesses of tests (anal manometry, anal surface electromyography, rectal balloon expulsion test, barium and MRI defecography, assessment of rectal compliance and sensation, and colonic transit) that are used diagnose defecatory disorders in constipated patients. The selection of tests and the sequence in which they are performed should be individualized to and interpreted in the context of the clinical features. Because anorectal functions are affected by age, results should be interpreted with reference to age- and sex-matched normal values for the same technique.

Keywords: Anal sphincter; Biofeedback therapy; Constipation; High-resolution anorectal manometry; MRI.

Figure 1.

Anorectal Manometry Catheters.

Figure 2.. Representative images and summary data (median and inter-quartile values) of rectoanal pressures at rest and during evacuation in the seated position in the four patterns.

Rectoanal pressures were measured by a 12-sensor catheter depicted in the cartoon on the top right. Observe the caudal transmission of pressure from the rectal balloon throughout the anal canal in the transmission pattern. ^a P < 0.05, ^b P ≤ 0.01, ^c P ≤ 0.001 for comparison of rectal or anal pressure during evacuation in patients with normal versus prolonged BET in the same pattern. (From Sharma M, Muthyala A, Feuerhak K, Puthanmadhom Narayanan S, Bailey KR, Bharucha AE. Improving the utility of high-resolution manometry for the diagnosis of defecatory disorders in women with chronic constipation. Neurogastroenterology & Motility. 2020;e13910; with permission)

Figure 3.. Normal and Abnormal Anorectal Evacuation

Evacuation was recorded by magnetic resonance imaging (top row) and high-resolution manometry (bottom row). Magnetic resonance imaging shows increased puborectalis indentation during squeeze (B, arrow) and normal relaxation of the puborectalis, perineal descent, opening of the anal canal, and evacuation of ultrasound gel during evacuation (C). In patients with constipation, during evacuation, there is paradoxical contraction of the puborectalis (D, arrow) and exaggerated perineal descent with an enterocele (E, arrow). High-resolution manometry shows anal pressure at rest (F) and increased anal pressure during squeeze (G) compared to rest (F). The white rectangle demarcates the duration of squeeze (G) and evacuation (H–K). Note the increased rectal pressure with anal relaxation during evacuation in a healthy person (H). By contrast during evacuation in constipated patients, note increased rectal pressure with paradoxical anal contraction (I), no change in rectal pressure vs rest (J), and no change in rectal pressure with paradoxical anal contraction (K). (From Bharucha A, Wald A. Chronic Constipation. Mayo Clin Proc. 2019;94(11):2340-2357. doi:10.1016/j.mayocp.2019.01.031; with permission)

Figure 4.. Representative examples of a wireless motility capsule in patients with normal (Panel A) and slow colon transit (Panel B).

Pressures, temperature, and pH values are respectively shown in red, blue, and green. measures gastric emptying, small bowel transit time and colonic transit time. Panel A shows a wireless motility capsule recording with normal colonic transit time (4:15 h). In contrast, panel B shows a patient with delayed colonic transit time (64:12 h).