Urodynamic Events: Loss of a Functioning Pelvic Wall
To demonstrate that the pelvic wall is responsible for the various effects that have been observed, we can study the papilla after the pelvis has been removed. The blood flow in the capillaries is now continuous. The flow in the loops of Henle is also uninterrupted. The urine now flows continuously through the collecting ducts.

No Pelvic Wall
The blood in the capillaries appears to run countercurrent to the flow in the collecting ducts.

 

Blood Flow
When we apply xylocaine to the pelvis, the ureteral peristalsis becomes uncoupled from the pelvis and the pelvis becomes paralyzed. The flow in the collecting ducts now becomes continuous, as it did when the pelvis was removed. Similarly, the blood flow in the papilla is no longer interrupted. Physiological findings have shown that when the pelvic wall is removed or paralyzed, the osmolality and sodium concentration of the papillary tissue decreases significantly. One of the possible explanations for this decrease in tissue concentrations may be found in the effect of the peristaltic contractions on the blood flow, since blood flow, which is stopped for 30% of the time during normal peristalsis, is increased when the pelvic wall is removed or paralyzed. According to the models of the countercurrent system, a higher blood flow would result in increased removal of papillary solutes, and therefore a lower solute concentration of the papilla, in agreement with the experimental findings.

Xylocaine Paralysis