How to Perform and Interpret a High-resolution Anorectal Manometry Test

Abstract

High-resolution anorectal manometry (HR-ARM) and high-definition anorectal manometry (HD-ARM) catheters have closely spaced water-perfused or solid state circumferentially-oriented pressure sensors that provide much better spatiotemporal pressurization than non-high resolution catheters. This is a comprehensive review of HR-ARM and HD-ARM anorectal manometry catheter systems, the methods for conducting, analyzing, and interpreting HR-ARM and HD-ARM, and a comparison of HR-ARM with non-high resolution anorectal manometry. Compared to non-high resolution techniques, HR-ARM and HD-ARM studies take less time and are easier to interpret. However, HR-ARM and HD-ARM catheters are more expensive and fragile and have a shorter lifespan. Further studies are needed to refine our understanding of normal values and to rigorously evaluate the incremental clinical utility of HR-ARM or HD-ARM compared to non-high resolution manometry.

Keywords: Anal canal; Constipation; Fecal incontinence; Manometry; Physiology.

Figure 1

Catheter design. High-resolution anorectal manometry catheters manufactured by (A) Given Imaging, (B) Sandhill Scientific, and (C) Medical Measurement Systems. (D) shows a high definition manometry catheter made by Given Imaging.

Figure 2

Types of pelvic floor dyssynergia seen with high-resolution anorectal manometry. (A) Type I dyssynergia: an adequate increase in rectal pressure (≥ 40 mmHg) accompanied by a paradoxical simultaneous increase in anal pressure. (B) Type II dyssynergia: an inadequate increase in rectal pressure (< 40 mmHg; poor propulsive force) accompanied by a paradoxical simultaneous increase in anal pressure. (C) Type III dyssynergia: an adequate increase in rectal pressure (≥ 40 mmHg) accompanied by a failed reduction in anal pressure (≤ 20% baseline pressure). (D) Type IV dyssynergia: an inadequate increase in rectal pressure of (< 40 mmHg; poor propulsive force) accompanied by a failed reduction in anal pressure (≤ 20% baseline pressure).

Figure 3

Three anorectal pressure phenotypes identified by high-resolution anorectal manometry in patients with dyssynergic defecation.

Figure 4

High definition anorectal manometry in a healthy individual. (A) Rest frame shows the high-pressure band is seen in the middle of the image. (B) Squeeze frame shows an “λ” shape on 2-D mapping indicating normal functioning of the EAS muscle. (C) Bear-down frame shows a green low-pressure zones appearing in the end (ie, a low-pressure area in the distal posterior wall of the anorectum).

Figure 5

Defecogram and high-resolution anorectal manometry in the same individual. (A) Defecography shows rectocele and intussusception. (B) An increase in rectal pressure and a localized high-pressure band at the level of the anal sphincter during bearing down are seen on manometry.