This is an original research on the application of free video uroflowmetry (FVU)  in evaluating lower urinary tract dysfunction (LUTD) in children.  Free uroflowmetry, performed without catheter in urethra, is commonly used for screening LUTD in children,but lacks visualization of bladder-urethral morphology and vesicoureteral reflux (VUR). Video urodynamic study (VUR) covers these, but urethral catheters in site may induce artifact. To overcome these shortcoming, we performed FVU to evaluate its feasibility and role in evaluating LUTD in children.

Retrospective analysis was performed in children with LUTD at Dongguan Children's Hospital between Sep.2024 and Feb 2025. The cases was divided into 3 groups: free uroflowmetry group (FU), video urodynamics group (VU), and FVU group. Parameters collected including maximum flow rate (Qmax), average flow rate (Qave), voiding-time, voided-volume, post-void residual urine(PVR)) and imaging findings [VUR, detrusor-sphincter dyssynergia (DSD), pseudo-residual urine]. Pseudo-residual urine refers to refluxed urine returning to the bladder after complete voiding. Instilling contrast into bladder agent via transurethral catheterj and then removel catheter before FVU, which is performe under C-arm fluoroscopyr. Statistical analysis used ANOVA, chi-square tests, and paired t-tests, with significance set at P < 0.05.

Documents collected from 26 children (15 male, 11 female; mean age 7.96±2.67 years) qualified for analysis, including severe enuresis (n=13), non-neurogenic neurogenic bladder (n=7), neurogenic bladder (n=3), urgency incontinence (n=2), and bladder-bowel dysfunction (n=1). Three children were unable to void due to urethral pain during VUD. Both FU and FVU showed significant differences compared to VU in Qmax, Qave, voiding-time, and PVR (P < 0.05) (Table1). Imaging findings showed no significant difference between FVU (16/26) and VU (17/26) (P > 0.05) (Table2).

In this study, 11.5% of children were unable to void during VU with catheter in urethra. Significant differences in Qmax, Qave, voiding-time, and PVR were observed between FU and FVU compared to VU, indicating that urethral catheter significantly impacts the voiding function. Furthermore, the absence of significant differences in imaging findings between the FVU and VU suggesting that FVU ia able to show bladder-urethral morphology and he presence or absence of VUR. Cosidering FVU is more close to a physiological state to show voiding function, it serves as a more valuable complement to conventional FU and VU in pediatric LUTD evaluation in children.

FVU is a useful tool to evaluate LUTD in children, not only show the parameters collected from FU but also visualizing anatomical abnormalities and VUR.

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