A nephrostomy is a tube placed into the kidney to drain urine when the usual urinary pathway is blocked.
A nephrostomy is usually needed because of symptoms from blocked urine flow, such as severe flank pain, fever, reduced urine drainage, or kidney swelling rather than because the tube itself is the problem.
Imaging helps confirm the blockage, decide which kidney is affected, and guide safe placement of the drainage tube.
Interventional radiologists often place nephrostomy tubes under imaging guidance to relieve pressure and protect kidney function.
The tube may be temporary or longer-term depending on why the blockage happened and how it will be treated.
This entry explains the procedure. Before you go, read the longer prep guide or find a centre that performs it.