The effect of anorectal manometry on the outcome of treatment in severe childhood constipation: A randomized, controlled trial

Objective. Approximately 50% of constipated children contract rather than r elax the external sphincter complex during a defecation attempt. Although b iofeedback training (BF) is able to change this defecation behavior, there is no additional effect of BF to conventional treatment (CT) on clinical ou tcome compared with CT alone. It has been postulated that the absence of a significant difference between these 2 treatment options might be because o f a therapeutic, "demystifying" effect of performing anorectal manometry in conventionally treated children, necessary to obtain basal manometric data . The objective of this prospective, controlled, randomized study was to ev aluate the effect of CT with 2 anorectal manometry sessions compared with C T alone (dietary advice, diary, toilet training, oral laxatives, and enemas ) on clinical outcome. Methods. A total of 212 constipated children (143 boys) who were visiting a referral pediatric gastroenterologic practice were randomized prospectivel y to CT alone (115 patients) or to CT combined with 2 manometry sessions (C TM; 97 patients). Patients were included in the study when they fulfilled a t least 2 of the 4 following criteria: stool frequency fewer than 3 per wee k, 2 or more soiling and/or encopresis episodes per week, periodic passage of very large amounts of stool every 7 to 30 days, or a palpable rectal or abdominal fecal mass. CT comprises dietary advice, a daily diary, toilet tr aining, and oral laxative treatment preceded by rectal disimpaction with en emas on 3 consecutive days. During both manometries, the child and the pare nt could watch the tracing on the computer screen. No explanation was given to either the child or the parents during the procedure. When the procedur e was finished, the tracings were clarified. Successful treatment was defin ed as a defecation frequency of 3 or more per week and fewer than 1 soiling /encopresis episode per 2 weeks and no use of laxatives. Results. Only 4 and 2 children from the CT and CTM groups showed no soiling and/ or encopresis, whereas 76% and 65%, respectively, reported the period ic passage of large stools. In 26% and 30% of the patients, a rectal scybal um was found on physical examination. The success rates at 6, 26, 52, and 1 04 weeks' follow-up were 4%, 24%, 32%, and 43% and 7%, 22%, 30%, and 35% in the CT and CTM group, respectively. No significant difference in success p ercentage was observed between the 2 groups at any time of follow-up with r elative risks (CT/CTM) and 95% confidence intervals, respectively, of 0.55 (0.16-1.89), 1.13 (0.67-1.89), 1.07 (0.69-1.65), and 1.23 (0.81-1.85). A si gnificant increase in defecation frequency was observed between the first ( intake) and second visits, which was sustained at all subsequent visits and stages of follow-up in both groups (not significant). Also in relation to the first visit, a significant decrease in encopresis episodes was shown an d a further slow but significant decrease at 52 weeks of follow-up in both groups. The manometric data obtained from the CTM group showed a low percen tage of children with normal defecation dynamics, namely 28%, which (signif icantly) increased to 38% at the last manometry. Conclusions. Anorectal manometry combined with CT compared with CT alone di d not result in higher success rates in chronically constipated children. T herefore, anorectal manometry has no additional demystifying or educational effect on clinical outcome in chronically constipated children. This obser vation together with the observation in the current and previous studies th at no correlation was found between (achievement of) normal defecation dyna mics and success and that no relation was observed between volume of urge o r critical volume and success leaves no diagnostic or therapeutic role for anorectal manometry in chronic constipated children, except its use as a di agnostic test to exclude Hirschsprung's disease. A simple CT is successful in 30% of severely constipated children who are referred to a tertiary hosp ital, underscoring the importance of longlasting and adequate laxative trea tment.