Comparison of longitudinal and radial characteristics of intra-anal pressures using 3D high-definition anorectal manometry between children with anoretal malformations and functional constipation.

Background: Pathophysiology of fecal incontinence (FI) in children with anorectal malformations (AM) is not well understood. Standard or high-resolution anorectal manometry (ARM) does not identify radial asymmetry or localize abnormal sphincter function. 3D high-definition anorectal manometry (HDARM) provides detailed topographic and 3D pressure gradient representation of anal canal.

Aims: To compare intra-anal pressure profiles between children with AM and controls using HDARM and to determine the association between manometric properties and reported predictors of fecal continence (AM type, spinal anomaly, and sacral integrity).

Methods: HDARM tracings of 30 children with AM and FI referred for ARM were compared with 30 age and sex-matched children with constipation. 2D pressure profiles were used to measure length of high-pressure zone (HPZ). Longitudinal and radial measurements of sphincter pressure at rest and squeeze were taken along each segment in 3D topographic views and compared between groups.

Key Results: 3D measurements demonstrated longitudinal and radial differences between groups along all quadrants of HPZ. At rest, intra-anal pressures were lower along the four segments longitudinally across the anal canal and radially along the quadrants in AM group (P < .01). At squeeze, all quadrant pressures were lower in segments 1-4 in AM group (P < .01). Sensation was abnormal in AM group (P < .01). Intra-anal pressures longitudinally and radially were not associated with predictors of fecal continence.

Conclusions And Inferences: Children with AM had abnormal sensation and lower pressures longitudinally and radially along all quadrants of anal canal. Manometric properties at rest were not associated with reported predictors of fecal continence.