Urodynamics and massive vesicoureteral reflux

Purpose: Urodynamic studies are the key to management and reconstruction of bladder pathology. In the face of high grade vesicoureteral reflux measured pressures and volumes reflect the combined storage characteristics of the upper and lower tracts. We examined the influence of high grade reflux on measured volume and compliance (change in volume/change in pressure). Materials and Methods: A total of 18 children with high grade vesicoureteral reflux underwent urodynamic evaluation with and without ureteral occlusion. Occlusion was created in the operative suite using ureteral occlusion balloons. After fluoroscopic confirmation of the absence of reflux bladder pressure was measured during filling at a rate of 12.5 cc per minute. During ureteral occlusion bladder capacity was defined as leakage around the urethral catheter, bladder pressure greater than 40 cm. water or volume exceeding estimated bladder capacity for age, as determined by the formula, bladder capacity in ml. = (age + 2) x 30. The ureteral occlusion balloons were removed and similar measurements were obtained in the presence of reflux. Compliance was calculated for the first and last 50% (initial and terminal compliance, respectively) of bladder capacity. Results: Mean initial compliance without and with ureteral occlusion was 19.6 versus 13.2 cm. water (33% decrease). Mean terminal compliance without and with occlusion was 12.9 versus 8.6 cm. water (33% decrease, p <0.005). Bladder capacity decreased a median of 16%. Underlying bladder pathology was evaluated to determine the patients who would benefit most from ureteral occlusion studies. Patients with neurogenic bladder, posterior urethral valves and primary reflux had similar changes in measured compliance with ureteral occlusion. Patients with poor terminal compliance without occlusion and those with bilateral vesicoureteral reflux had greater changes in compliance with occlusion but these changes were not statistically significant (p >0.05). Age was indicative of a significant decrease in terminal compliance with ureteral occlusion, since older patients had the greatest change in terminal compliance (p <0.005). Conclusions: High grade vesicoureteral reflux influences measured lower tract volume and compliance.