Purpose: Urodynamic studies are the key to management and reconstructi
on of bladder pathology. In the face of high grade vesicoureteral refl
ux measured pressures and volumes reflect the combined storage charact
eristics of the upper and lower tracts. We examined the influence of h
igh grade reflux on measured volume and compliance (change in volume/c
hange 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 operativ
e suite using ureteral occlusion balloons, After fluoroscopic confirma
tion of the absence of reflux bladder pressure was measured during fil
ling at a rate of 12.5 cc per minute. During ureteral occlusion bladde
r capacity was defined as leakage around the urethral catheter, bladde
r pressure greater than 40 cm. water or volume exceeding estimated bla
dder 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. Comp
liance 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 occl
usion 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 ureter
al occlusion studies. Patients with neurogenic bladder, pasterior uret
hral valves and primary reflux had similar changes in measured complia
nce with ureteral occlusion. Patients with poor terminal compliance wi
thout occlusion and those with bilateral vesicoureteral reflux had gre
ater changes in compliance with occlusion but these changes were not s
tatistically significant (p > 0.05). Age was indicative of a significa
nt decrease in terminal compliance with ureteral occlusion, since olde
r patients had the greatest change in terminal compliance (p < 0.005).
Conclusions: High grade vesicoureteral reflux influences measured low
er tract volume and compliance.