The pressure-flow relationship of the normal ureter

We performed ureteral pressure-flow studies in 10 patients, all of whom had radiographically nondilated ureters and were undergoing a surgical procedure in which the ureter was exposed. The mean ureteral pressures at perfusion rates of 2, 5, 10, and 15 ml per min were 6.2, 7.9, 11.3, and 13.7 cm of water respectively. The mean pressures at each perfusion rate significantly differed from each other, except those at 2 and 5 ml per min. A statistically linear relationship exists between pressure and perfusion rates within the range of 2 and 15 ml per min.