[Pressure changes in the renal pelvis of the dogs in response to a sudden rise in intravesical pressure, examined in the presence of resico ureteral reflux with artificial ureter and/or pelvis].

This study is to determine which part or the upper urinary tract, ureter or pelvis causes more significant delay in the pressure wave-front propagation from the bladder to the pelvis when a reverse flow of the urine occurs. A sudden rise in the intravesical pressure of the dog was produced by stimulating the vesical branches of pelvic nerve with a train of electrical impulses with 10 Hz for 60 sec. In order to eliminate the physiological mechanism that presents a reverse flow of the urine at the uretero-vesical junction, a 3 cm vinyl tube was inserted into the ureteral orifice in all experiments except the cases with ureteral substitution (group II and III). Changes in intrapelvic pressure were measured from 7 dogs without substitution of either ureter or pelvis, and used as the control responses for comparison with those recorded from the dogs with artificial ureter and/or pelvis. Artificial ureter was made by a vinyl tube of 25 cm, whereas artificial pelvis was made by a 3 ml plastic chamber. Twenty-eight dogs were divide into 3 groups. Group I consisted of 7 dogs whose pelvises were replaced by artificial ones. Group II included 8 dogs whose ureters were substituted by artificial ones, and group III consisted of 6 dogs whose both ureter and pelvis were replaced by artificial ones. Results obtained were as follows; (1) There was no significant difference between the maximum intravesical pressure and the maximum intrapelvic pressure recorded from every dog in all groups. (2) The onset time of intrapelvic response recorded from the control dog showed a delay from that of intravesical response by 2.05 +/- 1.03 sec. (3) The onset time of intrapelvic response recorded from group I, II and III were 0.51 +/- 0.94 sec., 1.95 +/- 1.10 sec., 0.10 +/- 0.25 sec., respectively. (4) Statistically significant difference in the delay of response was observed only between the responses recorded from the control or group II and the responses recorded from group I or III. The above results suggested that the major site causing a significant delay in the pressure wave-front propagation from the bladder to the pelvis is the pelvic area including caryx, but not the ureteral region, when a reverse flow of the urine occurs.