A Study of Urodynamic Parameters at Different Bladder Filling Stages for Predicting Upper Urinary Tract Dilatation

To identify more accurate predictors of upper urinary tract dilatation (UUTD) in neurogenic bladder (NB) children, we studied the relationship among urodynamic parameters at different bladder filling stages, detrusor leak point pressure (DLPP) and UUTD.

A total of 158 children (3-16 years) with NB were included and then divided into 2 groups according to whether their NB diagnosis was complicated with UUTD: the UUTD group (39 patients) and those without UUTD group (control group, 119 patients). The bladder filling phase was divided into 3 equal parts: the early, middle, and end filling stages. The bladder compliance (BC) and detrusor pressure (△Pdet) at each phase and DLPP at the end filling stage were recorded.

A BC<8 mL/cm H2O both in the middle and end stages is more specific than a BC<9 mL/cm H2O in the end stage (72%, 73%, vs. 66%), and △Pdet >8 cm H2O in the early stage, 20 cm H2O in the middle stage and 25 cm H2O in the end stage are more sensitive than △Pdet >40 cm H2O in the end stage (82%, 85%, 85%, vs. 49%). A DLPP cutoff value of 20 cm H2O showed higher sensitivity for predicting UUTD than 40 cm H2O.

Low BC and a high △Pdet in the middle and end filling stages are more accurate factors than classic indicators for predicting UUTD. In addition, a DLPP value of >20 cm H2O in the end bladder filling stage shows high sensitivity.