A percutaneous nephrostomy is a small rubber catheter that is placed into the kidney to drain urine. These catheters are placed in patients who have an obstructed kidney, ureter or bladder. Frequently the cause of obstruction is tumor, stone or stricture. The catheter is placed through the flank and goes directly into the middle of the kidney, where the urine collects before it passes into the ureter. The catheter relieves an obstructed kidney by draining the urine out of the body through the catheter and into a bag.
Several weeks after the urine is satisfactorily drained it may be possible to pass a wire beyond the obstruction and into the bladder. A new, longer catheter can be placed over the wire. The near-end will be in the kidney and the far-end will be in the bladder. This type of catheter is called a nephroureteral stent. This type of catheter may be capped to allow all of the urine to pass from your kidney through the catheter and into the bladder.