Abstract

Aim: The purpose of this study was to evaluate the effects of the urethral catheter on the voiding parameters in urodynamic studies in children.

Material and Method: The study was designed between January and July of 2007 at our University Pediatric Surgery Department. 54 patients (14 girls, 40 boys; 8.6±3.13 years) from which urodynamic study was requested were enrolled in this prospective study. In the three successive cystometry and pressure-flow investigations the first and second were performed with urethral catheter, the third one was performed after removing the catheter in free flow style. The uroflowmetric values of voiding with and without catheter were then compared. Cases with excessive VUR (grade 4 and 5) were excluded from the study. Statistical analysis was made by using the SPSS 11.0 software. Wilcoxon and Chi- Square test were used.

Results: The maximum flow rates (Qmax) increased from 10.38 ml/sec with voiding with catheter to 17.50 ml/sec with voiding without catheter; this increase was statistically significant (p<0.05). The postvoid residue (PVR) decreased from 0.32 ml with voiding with catheter to 0.16 ml with voiding without catheter; this decrease was statistically significant (p<0.05). In the group without catheter the change of the flowmetric curves from pathologic to normal was also significant (p<0.05). 77.5 % of the boys and 21.4 % of the girls displayed low flow rates with catheter. There was a significant difference in postvoiding residual between the genders after voiding without catheter (p<0.05).

Conclusion: The results of the study revealed significant difference in the uroflowmetric parameters between voiding with and without catheter. This difference was more evident in the boys. Therefore, we have to be aware of the effect of the urethral catheter when evaluating urodynamic studies. In patients with flow rates indicating an obstruction flow rate measurement should be done without catheter.