RESUMEN
The presence of high-amplitude propagating contractions (HAPCs) has been identified as a marker of colonic neuromuscular integrity. The physiologic mechanisms of HAPCs initiation have yet to be determined. Distention secondary to colonic filling has been hypothesized as physiologic initiator. The aim of this study was to study the effect of intraluminal balloon distention in the colon of children with defecatory disorders. Colonic manometry was performed with a polyethylene balloon situated at the proximal end of the catheter, which was placed in the most proximal colonic segment reached during colonoscopy. A stepwise pressure controlled distention of the balloon was performed using barostat computer (10-50 mmHg). Propagated contractions were defined as those that migrated over at least three recording sites. They were divided into HAPCs, amplitude >60 mmHg and low-amplitude propagating contractions (LAPCs), amplitude <60 mmHg. Children with spontaneous HAPCs or HAPCs after bisacodyl provocation were considered to have normal motility. Twenty children completed the study. Among the 14 children with normal colonic motility, balloon distention elicited HAPCs in four and LAPCs in 10 children. No HAPC were elicited in six children with abnormal motility and LAPCs were seen in four of them. The balloon-induced propagated contractions had similar characteristics as those occurring spontaneously and after bisacodyl provocation but the pressure needed to elicit them and their amplitude was inconsistent. These findings suggest that intraluminal distention can trigger propagated contractions in children. This mechanism of action for induction of propagated contractions is not as consistent as the motor response found in response to bisacodyl administration.