Value of Fluoroscopic Defecography in Constipated Children With Abnormal Colon Transit Time Test Results

Background/Aims Colon transit time (CTT) test is regarded as the gold standard for evaluating colon transit function. Fluoroscopic defecography (FD) is a dynamic radiologic test to assess anorectal function. The aim is to evaluate the value of FD in constipated children with abnormal CTT test results. Methods Fifty-one children (27 girls) with a mean age of 9.8 ± 3.2 years who met Rome III criteria for constipation and older than 5 years with abnormal CTT test results underwent FD. Results Of 51 children, 27 (52.9%) showed positive findings on FD, including pelvic floor dyssynergia (PFD) (10/27, 37.0%), structural abnormality (15/27, 55.6%) (rectocele 53.3%, intussusception 33.3%, and both 13.4%), and both PFD and rectocele (2/27, 7.4%). In terms of CTT test subtype, of 35 children who had outlet obstruction type in CTT test, 19 (54.2%) had positive findings, including PFD (8/19, 42.1%), structural abnormality (9/19, 47.4%) (rectocele 55.6%, intussusception 22.2%, and both 22.2%), and both PFD and rectocele (2/19, 10.5%). Of the 16 children who had slow transit type of CTT test, 8 (50.0%) had positive findings, including PFD (2/8, 25.0%) and structural abnormality (6/8, 75.0%). Of the 6 children who had structural abnormality, 3 (50.0%) had rectocele and 3 (50.0%) had intussusception. For the 2 children (2/16, 12.5%) who had PFD, puborectalis muscle relax failure was found on FD. Puborectalis muscle relax failure was treated with biofeedback and medication. In the minor abnormalities, medication continued without additional therapeutic modalities. Conclusions FD was valuable for both diagnoses of underlying causes and interpretation of CTT test results in children with abnormal CTT test results. Therefore, this study suggests that FD and CTT tests should be incorporated into logical thinking for constipation in children.