The ureters are the paired tubes that conduct urine from the kidneys to the bladder. They are extremely delicate structure and are approximately ten inches in length. When a ureter becomes blocked (often as a result of a kidney stone that descends into the ureter), a tremendous amount of pain may result. This may be a dull, aching pain in the back as the kidney swells up with urine that cannot pass beyond the beyond the blockage. Additionally, a second kind of pain called colic may occur. Colic is an intermittent, severe pain that causes writhing, an inability to get comfortable in any position, and sometimes nausea, vomiting and sweating. This type of pain occurs as the muscular wall of the ureter contracts in an attempt to propel the stone down the ureter.
A blockage of the ureter can occur from either inside or outside of the ureter. The most common cause for obstruction in the ureter is the presence of a stone within the ureter. However, there are extrinsic in reasons for blockage of the ureter including tumors of the prostate or cervix, enlarged lymph nodes as seen in lymphomas, and uterine fibroids.
When a kidney is blocked as a result of an obstruction, you may experience pain, fever, inability to keep food down and urinary infections. It is often advisable to bypass the ureteral obstruction by way of a ureteral stent. A ureteral stent is a small tube made out of non-reactive silastic material, about ten inches in length, with pigtail-like loops at each end. It is a hollow tube, similar to a very thin straw. This ureteral stent is inserted into the ureter in a procedure performed in the operating room. It is positioned using cystoscopy, in which a small telescope is passed into the bladder, and fluoroscopy, which is a dynamic Xray. The small slit where the ureter enters the bladder is identified under direct visual guidance, and the stent is passed into the ureter, beyond the obstruction and into the kidney. When properly seated, one end of the stent will lie within the kidney, the other end of the stent will lie within the urinary bladder, and the straight portion of the stent will lie within the ureter. In this situation, despite obstruction from a stone or from other sources, urine will pass from the kidney into the bladder by way of the stent.
The stent is most often left in on a temporary basis until the obstruction can be removed. However, in some people with chronic obstructions, a stent can be left in indefinitely. In this situation, it is imperative that the stent be changed at least every twelve weeks because of the potential for brittleness and blockage of the stent from the salts present in the urine.
After the stent is placed you may experience any of the following symptoms: When you urinate you may experience some pressure in the kidney on the side in which the stent is placed because as you urinate some of the urine passes up the stent into the kidney and the filling of the kidney will sometimes cause discomfort. You may experience urinary urgency and frequency because the delicate inner lining of the bladder can be irritated by the presence of the stent. Occasionally, irritation of the bladder form the stent can cause bleeding with urination.
After the obstruction has been taken care of, the stent can easily be removed by means of a minor cystoscopic procedure.
Andrew Siegel, M.D.
255 W. Spring Valley Ave.