The impact of voiding dysfunction on vesicoureteral reflux and renal scars

Purpose: To report the relation between voiding dysfunction and reflux, renal scars and the common findings related to voiding dysfunction in patients with vesico-ureteral reflux (VUR). Materials and methods: Between March 2002 and February 2004, 56 children underwent a video-urodynamic study (video-UDS) for evaluation of VUR. The grade of VUR, various findings of voiding dysfunction and the maximal intravesical pressure (maxPves) were assessed during voiding, and severity of renal scars were assessed via video-UDS and DMSA scans, respectively. Results: Voiding dysfunction was diagnosed in 30 patients (53.6%). The findings of voiding dysfunction were uninhibited contraction (14 patients), detrusor sphincter dyssynergia (15 patients) and bladder neck opening during the filling phase (17 patients). Urethrovaginal reflux and after contraction were noted in 6 and 8 patients, respectively. In the voiding dysfunction group, the mean VUR grade was 3.4, while this was 2.6 in 42 renal units of the normal voiding group (p=0.023). The mean maxPves values during voiding in the voiding dysfunction and normal voiding groups were 107.7 and 77cmH₂O, respectively (p=0.002). On evaluation of the relationship between voiding dysfunction and the extent of renal scarring [no scar, single scar, multiple scars, reduced size], the existence of voiding dysfunction resulted in more severe forms of renal scarring (p=0.034). Conclusions: Voiding dysfunction can cause or aggravate VUR or urinary tract infection due to an increased intravesical pressure during voiding, which can ultimately cause permanent renal damage. Therefore, treatments, such as anticholinergic drugs or biofeedback, must be performed in patients with combined VUR and voiding dysfunction for a better treatment outcome.