The correlation between the transverse rectal diameter and urodynamic findings in children with neurogenic bowel and bladder dysfunction

BACKGROUND: The aim of this study was to examine the correlation between the transverse rectal diameter and urodynamic findings in children with neurogenic bowel and bladder dysfunction. METHODS: Between 2014 and 2022, we prospectively evaluated 81 consecutive spina bifida children with neurogenic bowel and bladder dysfunction (35 boys and 46 girls, mean age 9.5 ± 3.4 years). All patients underwent echosonographic measurement of transverse rectal diameter and urodynamic studies. RESULTS: We found a strong negative correlation between transverse rectal diameter and maximum bladder capacity (r = −0.682, p < 0.001) and compliance (r = −0.690, p < 0.001). There was also a strong positive correlation between transverse rectal diameter and maximal detrusor pressure (r = 0.650, p < 0.001), leak point pressure (r = 0.793, p < 0.001), and PVR (r = 0.762, p < 0.001). In ROC analysis, transverse rectal diameter demonstrated good performance for distinguishing children with upper urinary tract deterioration, with an AUC of 0.857 (95% CI 0.761–0.953). A transverse rectal diameter ≥40 mm was 83.3% sensitive and 100% specific for the diagnosis of unfavorable urodynamic patterns. CONCLUSION: There is a correlation between the transverse rectal diameter and urodynamic findings in children with neurogenic bowel and bladder dysfunction. Ultrasonographically assessed transverse rectal diameter of ≥40 mm may be used as a risk factor for upper urinary tract deterioration (unfavorable urodynamic findings). We suggest the transverse rectal diameter echosonographic measurement use as an integral part of the diagnostic approach in children with neurogenic bowel and bladder dysfunction, as it can help decision-making while waiting for urodynamic testing.