Balloon expulsion test as a screen for outlet obstruction in children with chronic constipation

Chronic constipation (CC) is a common problem in pediatrics and is often the result of obstructed defecation. The aim of the present study was to study the feasibility and efficacy of the balloon expulsion test (BET) in the diagnosis and management of children with CC.

Retrospective study comparing BET and high-resolution anorectal manometry (ARM). The BET was done together with ARM in 29 children, ages 8 to 19 years, with CC. For BET, a 60-mL balloon was used. Passage of balloon in 1 minute or less was considered normal.

Fifteen of the 29 children had a normal BET. Of these, 14 also had an ARM, all of which were normal (except for 2 cases with a hypertonic baseline anal sphincter). Thus 12 of 14 with BET and ARM were normal on both (correlation between the tests 86%). Of the 14 children that failed BET, 10 had distal abnormalities by ARM, contrast studies, EMG, or assessment by a pelvic physical therapist. All of the patients with a nonrelaxing sphincter or outlet obstruction were treated with laxatives, anal sphincter Botox, and/or pelvic physical therapy and biofeedback. In follow-up of at least 3 months, all of the patients with a failed BET were improved.

We found a high correlation between a normal ARM and BET. If the BET is abnormal and the ARM does not identify a cause for the distal obstruction, additional studies may be needed, including contrast enema, defecography, or electromyography. BET appears to be a safe, reliable, and useful test in the evaluation and management of CC in children.