High-resolution anorectal manometry in children with functional constipation with or without fecal incontinence

Background: High-resolution anorectal manometry (HR-ARM) is expected to be better than conventional manometry. Our aim was to characterize HR-ARM pressures in children with functional constipation (FC), with or without fecal incontinence (FI). Methods: Children with diagnosis of FC, with or without FI, according to Rome-IV criteria, were enrolled. All patients underwent HR-ARM using 24-channel water-perfused catheter. Results: Twenty-nine consecutive children (M/F: 21/8; mean age ± SD: 9.5 ± 3.1 years; range 4-15), of whom 21 affected by FC without FI (mean age ± SD: 9.3 ± 3.23 years) and 8 affected by FC with FI (mean age ± SD: 10.2 ± 3.08 years), were enrolled. No significant differences were found regard to gender and age. The analysis of HR-ARM 3D plots demonstrated asymmetry of the anal canal, with higher pressures in distal halves. Comparing pressures between the two groups, we found lower values in FC with FI than in FC without FI group, with a statistically significance for maximum and mean resting pressures (P =.032 and P =.008, respectively). When evaluating our study population respect to asymptomatic children, we found lower resting pressures, lower maximum squeeze pressure, and higher rectoanal inhibitory reflex (RAIR) values. Conclusions: Our data demonstrate that HR-ARM pressures at rest and during squeezing in FC with FI children are lower than FC without FI subjects, particularly in anteroposterior quadrants. Compared to children without lower gastrointestinal symptoms, children with FC with or without FI show lower pressures and higher values of RAIR.