Dynamics of upper urinary tract in man. Peroperative electrophysiological findings in patients with manifest or suspected hydronephrosis.

In 31 patients undergoing surgery in treatment of hydronephrosis, peroperative pelvic pressure measurements were made. EMG records were taken from pelvis and ureter, and occasional measurements of urine flow were made. In 6 instances these studies were also made in the contralateral "normal" kidney, but in 2 of these patients the diseased kidney was not studied. Pelvic pressure during antidiuresis in these 6 "normal" kidneys was about 5 mmHg, and pelvic activity of frequency 5/min. Pelvi-ureteric impulse transmission was anterograde and conduction times were constant. Conduction ratios varied. During forced diuresis mild pelvic pressure rises were seen together with transient increase in pelvic activity over the period of pressure increase. In the studies of hydronephrotic kidneys no significant differences were seen in pelvic pressure of frequency of pelvic activity compared with the "normal" kidney studies, but impulse transmission was markedly disturbed, manifest by varying conduction times, and, on occasion, total dissociation of activity within the pelvis, and between the pelvis and ureter. The more severe the degree of hydronephrosis, the more marked the disturbance. The findings are similar to those made in experiments with pigs after establishment of varying degrees of urine flow obstruction.