Compliance studies, pressure flow measurements and renal function assessment in patients with upper urinary tract dilatation.

The compliance index was determined in 38 hydronephrotic kidneys undergoing diagnostic pressure flow studies. A good correlation was found between this index and the result of the pressure flow study but no consistent relationship was observed between the index and relative renal function as assessed by renographic means. The ability of the compliance index to predict functional deterioration in patients with hydronephrosis must be questioned.