A nephrostomy is a surgical procedure by which a tube, stent, or catheter is inserted through the skin and into the kidney to relieve a blockage in the ureter. The ureter is the fibromuscular tube that carries urine from the kidney to the bladder. When this tube is blocked, urine backs up into the kidney. Serious, irreversible kidney damage can occur because of this backflow of urine. Infection is also a common consequence of this stagnant urine. Frequently these obstructions may be re-opened or stented to allow for urine flow to the bladder.