Injury to the ureteral blood supply can result in scarring and narrowing of the inside diameter of the ureter, which in turn can cause inhibited flow of urine known as obstruction. Like the renal pelvis, the ureter has nothing to do with actual urine production. However, it is critically important that the ureter function normally. If urine is not transported in a timely fashion, the kidney can become filled with urine, a condition that can compromise normal kidney function and the person's general health. Blockage in any part of the urinary tract is known as obstruction, referring to an obstruction in the flow of urine from the kidney out of the body.
Obstruction presents two types of problems.
First, it can cause the urinary tract to become filled up with an excess amount of fluid. Second, when urine does not flow normally, kidney filtering functions are compromised and the kidney begins to lose its ability to process the waste material in the blood. This is not an immediate event but occurs gradually, over several weeks. Problems with the kidneys and the urinary tract can generate a great deal of pain. Obstruction causes pain by filling the tubes of the urinary tract with too much fluid.