Association between rectal diameter and response to treatment with parasacral transcutaneous electrical nerve stimulation and behavioral changes in children and adolescents with bladder and bowel dysfunction

Parasacral Transcutaneous Electrical Stimulation (TENS) is one of the treatments for children with Bladder and Bowel Dysfunction (BBD). Some studies showed that children with increased Rectal Diameter (RD) have more Functional Constipation (FC). However, RD prediction in maintenance of BBD after treatment was never evaluated. Our aim is to evaluate the association between RD and response to treatment in children and adolescents with BBD. This study evaluated patients from 5-17 years old with BBD. Dysfunctional Voiding Scoring System (DVSS), Rome IV criteria, and the Constipation Score were used. RD was measured using abdominal ultrasound before treatment according to the technique established by Klijn et al. and was considered enlarged when >3cm. No laxatives were used during treatment. Descriptive analysis and binary regression were performed and the area under the ROC curve was calculated. Forty children were included (mean age 8.4±2.8 years, 52.5% male). Before treatment, RD was enlarged in 15 children (37.5%) (mean diameter 3.84±0.6cm), with FC persisting post-treatment in 11/15(73.3%). Those patients also required more laxatives following treatment and had more severe FC. Binary regression showed pretreatment RD to be an independent predictor of the persistence of FC post-treatment (OR=9.56; 95%CI:2.05-44.60). In ROC curve analysis, the sensitivity was 100% (95%CI: 0.49-1.0) and specificity 77.14% (95%CI:0.60-0.90) for rectal diameter >3 cm. The likelihood ratio was 4.38 (95%CI:2.40-8.0) for the persistence of BBD following treatment. RD appears to be relevant in the evaluation of children with BBD, not only as a diagnostic tool but also as a predictor of treatment outcome.