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151 Water-perfused colonic manometry 7 INTRODUCTION Functional constipation is a common pediatric healthcare problem with a worldwide prevalence ranging from 0.7% to 29.6%. 1 It is estimated to account for 3% of general pediatrician visits and up to 25% of visits to a pediatric gastroenterologist in the United States. 2 A subtype of children with delayed colonic transit can suffer from severe and long- lasting symptoms, which usually respond poorly to conventional therapeutic strategies 3 and result in a significant impact on the child’s quality of life. 4–7 When symptoms are irresponsive to optimal conventional treatment for at least three months, this is referred to as intractable. 8 In severe cases, children with chronic intractable constipation may require surgical interventions such as an ileostomy or a (sub)total colectomy. 9,10 Although the pathophysiology of constipation is incompletely understood, abnormalities in the contractile activity of the colon are implicated to play an important role. 11–13 Several studies have used low-resolution colonic manometry to record contractile activity in children with constipation, commonly reporting a reduced frequency of high-amplitude propagating sequences (HAPS) and an absent or diminished meal response. 14,15 Such findings indicate that a potential colonic neuropathy may exist. More recently, studies utilizing high-resolution manometry have emerged. 11,16 In one of these studies, colonic manometry was performed prior to (partial) colectomy in severely constipated children. 11 This study provided manometric evidence of a neuropathy by showing that the normal suppression of motor activity between bisacodyl-induced HAPS did not occur in a subgroup of constipated children with neurogenic abnormalities confirmed on histological examination of their removed colonic tissue. Recently, high-resolution colonicmanometrywas used toprovide adetailedcharacterization of propagating motor patterns prior to and after a meal in healthy adults. 17 One of the key findings was a postprandial increase in retrograde cyclic propagating motor patterns in the distal colon, comprising pressure events with a slow wave frequency of 2–6 per minute. 17 The rapid increase in this motor pattern after a meal (within 1 min of starting to eat) suggests that it is influenced by extrinsic neural input. 17 This postprandial response was absent in adult patients with slow-transit constipation, leading the authors to hypothesize the existence of a possible neuropathy in the extrinsic parasympathetic innervation of the colon in these constipated adults. 13 Whether or not such motor pattern abnormalities exist in children with chronic intractable constipation has not yet been established. Therefore, in this study, our aim was to quantify the colonic motor patterns in such children utilizing high-resolution colonic manometry. These data were then compared to the previously published manometric findings from