Colonic transit studies and colonic manometry in pediatric constipation.

Objectives: In a subgroup of children with refractory constipation, colonic function investigations, such as colonic transit scintigraphy (CS) and colonic manometry (CM), are used to define the underlying pathophysiologic mechanisms. There are limited studies comparing colonic transit and contractile function. We aimed to correlate CS and CM and assess whether specific manometric patterns might predict the luminal transit findings.

Methods: Children with refractory constipation undergoing both CS and CM between 2012 and 2022 at two Tertiary Pediatric Gastroenterology Services were retrospectively reviewed. For CS, the geometric center (GC) was used to quantify the transit across the different colonic segments and studies were categorized into normal transit, recto-sigmoid hold-up, and slow transit. Contractile patterns from CM were classified into equivalent regional subtypes as normal, distal colonic dysmotility and pan-colonic dysmotility, respectively.

Results: Twenty-two patients (59% male, median age: 10.94 years) were included. No significant agreement in the subtype of constipation was found between CS and CM (K = 0.224, p = 0.070). However, a strong correlation was observed between the numeric score of the GC at 6 h and the amplitude of bisacodyl-induced high amplitude propagating contractions (HAPCs) in the rectosigmoid (r = 0.761, p = 0.007). Moreover, a higher percentage of radiotracers in the ascending colon at 24 h was related to a higher number of bisacodyl-induced HAPCs.

Conclusions: Scintigraphic GC at 6 h showed a substantial correlation with parameters from CM in the rectosigmoid colon, implicating the potential role of this colonic region as a gatekeeper for colonic luminal transit.