Study design, materials and methods
A retrospective analysis was performed on the data of free imaging uroflowmetry in hospitalized children finally diagnosed with neurogenic bladder from January 2025 to September 2025. All children underwent free uroflowmetry, video-urodynamic study (VUDS) and free imaging uroflowmetry during hospitalization, and were divided into three groups accordingly: the free uroflowmetry group (FF group), the video-urodynamic study group (VUDS group) and the free video uroflowmetry group (FVU group). The uroflowmetry parameters (maximum flow rate (Qmax), average flow rate (Qave), voiding-time, voided-volume, post-void residual urine(PVR)) and imaging positive events (presence or absence of vesicoureteral reflux(VUR), detrusor-sphincter dyssynergia(DSD), and pseudo-residual urine) were compared among the three groups.
Results
A total of 35 children were enrolled in this study, including 24 males and 11 females, with a mean age of 7.80±2.11 years. Among them, 8 children failed to complete the pressure-flow study due to inability to void caused by urethral discomfort during catheterized video-urodynamic study. All children successfully completed free uroflowmetry and free video uroflowmetry. There were no significant differences in uroflowmetry parameters including Qmax, Qave,voiding-time,voided-volume, PVR between the FF group and the FVU group (P>0.05), while both groups showed significant differences in these five indicators compared with the VUDS group (P<0.05). The incidence of imaging positive events was 88.57% in the FVU group and 91.43% in the VUDS group, with no significant difference between the two groups (P>0.05).
Interpretation of results
In this study, 22.9% of children were unable to void during VUDS with catheterization.Significant differences in Qmax,Qave,voiding-time,voided-volume, PVR were observed between FU and FVU compared to VUDS, indicating that urethral catheterization significantly impacts voiding function. Furthermore, the absence of significant differences in imaging findings between the FVU and VU suggests that free video uroflowmetry effectively visualizes bladder-urethral morphology.
Concluding message
FVU is performed without indwelling catheters, enabling the assessment of voiding function under conditions that closely mimic natural micturition. Additionally, through advanced imaging modalities, this technique can simultaneously and clearly visualize the morphological structures of the bladder and urethra, while accurately identifying critical pathological conditions such as DSD, increased pseudo-residual urine, and VUR. Therefore, FVU serves as a highly effective complementary tool to both VUDS and FF, and more importantly,an important method for evaluating bladder function in primary hospitals or other medical institutions lacking pressure-flow study equipment.