[Pyelorenal reflux. I. Actual and presumed routes]

An acute increasing pressure in the renal pelvis effects the phenomenon of pyelo-renal backflow. There is a confusing number of ways of the pyelo-renal backflow described so far, yet only few types of these ways can be verified by various and detailed investigations. 1. The pyelo-tubulous backflow (ptR) is a true backflow of the contents of the renal pelvis into the tubuli of the kidney. In no case tubuli rupture, because other ways of backflow are preferred instead of. 2. The pyelo-sinous extravasation (SE) is an outflow of the contents of the pelvis into the renal sinus owing to a rupture of the fornix. Starting from the ruptured fornix a descending extravasation spreads out between the pelvic wall and the adipose tissue in renal sinus, whereas an ascending extravasation spreads out between the flank of the pyramid and the adipose tissue. Horn-like arched ascending extravasations have been mistaken frequently for a backflow into the arcuate veins or even into their perivenous spaces. 3. The pyelo-venous backflow (pvR) is a transflow of the contents of the pelvis into an interlobar vein ruptured jointly with the fornix. 4. The pyelo-lymphatic backflow (plR) is a transport of the extravasation via lymph vessels. There can be a single way of backflow as well as divers combinations of the above mentioned types.