Is it possible to use urodynamic variables to predict upper urinary tract dilatation in children with neurogenic bladder-sphincter dysfunction?

OBJECTIVE

To investigate the possibility of using urodynamic variables to predict upper urinary tract dilatation (UUTD) in children with neurogenic bladder-sphincter dysfunction (NBSD).

PATIENTS AND METHODS

The study included 200 children with NBSD, of whom 103 had UUTD and 97 did not; they were examined using routine urological, neurological and urodynamic methods. The group with UUTD was divided into three subgroups (group 1-3, from mild to severe hydronephrosis). A urodynamic risk score (URS) was calculated, including a detrusor leak-point pressure (DLPP) of >40 cmH2O, a bladder compliance (BC) of <9 mL/cmH2O and evidence of acontractile detrusor (ACD).

RESULTS

The postvoid residual urine volume (PVR), DLPP, incidences of ACD and DLPP of >40 cmH2O were greater and the BC significantly less in groups 1-3 than in the control group. Moreover, the BC decreased, while the PVR, DLPP and the incidence of DLPP of >40 cmH2O were significantly higher in group 3 than in group 2. The relative safe cystometric capacity of groups 2 and 3 were lower, respectively, than that of the control and group 1, and the relative unsafe cystometric capacity (RUCC) and relative risk rate of cystometric capacity (RRRCC) were significantly greater with the severity of UUTD. The maximum detrusor pressure on voiding or at maximum flow rate, and the Abrams-Griffiths number for voluntary contractile bladders, of the UUTD group were significantly higher than those of the control group. There was a positive correlation between URS and UUTD.

CONCLUSIONS

The selective use of urodynamic variables might be valuable for predicting the risk of UUTD in children with NBSD. Decreased BC, and increased DLPP and ACD are the main urodynamic risk factors, and they reciprocally increase the occurrence and grades of UUTD. The grades of UUTD are compatible with increases in RUCC, RRRCC and URS.