Study on 3D High-Resolution Anorectal Manometry Interrater Agreement in the Evaluation of Dyssynergic Defecation Disorders

Abstract

Anorectal manometry measurements exhibit significant interrater variability. Newer techniques like 3D high-resolution anorectal manometry (3D-HRAM) have the potential to enhance diagnostic accuracy and our understanding of defecation disorders. However, the extent of interrater variability in 3D-HRAM is still unknown. Between January 2020 to April 2022, patients referred for pelvic floor physical therapy (PFPT) due to functional defecation complaints underwent 3D-HRAM testing. In a retrospective analysis, three expert raters independently evaluated the 3D-HRAM results in a blinded matter to assess interrater agreement. The evaluation also determined the level of agreement concerning dyssynergic patterns during simulated defecation. The 3D-HRAM results of 50 patients (37 females) were included. Twenty-nine patients had complaints of fecal incontinence, eleven patients had chronic constipation, and ten patients had several other complaints. There was a substantial agreement (kappa 0.612) between the raters concerning the 3D images on dyssynergic patterns during simulated defecation. Our study emphasizes the need for standardized guidelines in evaluating 3D-HRAM test results to reduce subjectivity and further improve agreement among raters. Implementing these guidelines could improve diagnostic consistency and enhance personalized treatment strategies, increasing the reliability and usefulness of 3D-HRAM testing in clinical practice.

Keywords: 3D-HRAM; chronic constipation; defecation disorders; dyssynergia; fecal incontinence; interrater agreement; three-dimensional high-resolution anorectal manometry.

Figure 1

Example of the pressure profile in 2D and 3D using ManoView software of a 70-year-old female with chronic constipation: (a) elevated anal resting pressure and (b) a dyssynergic pattern during simulated defecation characterized by paradoxical contraction of the pelvic floor muscles. Legend: The puborectal muscle (PR) is seen in the middle of the 2D profile. ATN = anterior, POST = posterior, L = left, R = right. The white line in the cylinder is ‘cut’ and unrolled to obtain the 2D image, so that the anterior is on both sides (ANT) of the 2D image.

Figure 2

Example of the pressure profile in 2D and 3D using ManoView software of a 45-year-old male with fecal incontinence. (a) Low anal resting pressure and (b) signs of reduced contractility, particularly on the anterior side (shown in blue), characterized by a diminished ability of the IAS muscles to generate a coordinated contraction. Legend: The puborectal muscle (PR) is seen in the middle of the 2D profile. ATN = anterior, POST = posterior, L = left, R = right. The white line in the cylinder is ‘cut’ and unrolled to obtain the 2D image, so that the anterior is on both sides (ANT) of the 2D image.