How does the doctor put in a kidney stent?

Via a cystoscope: The doctor will need to look into your bladder with an instrument called a cystoscope. He/she will be able to see the opening where the ureter empties into the bladder and place a stent up to the kidney.

Artery vs ureter: A renal artery stent (to treat high blood pressure from kidney artery narrowing) is inserted using a catheter placed into either the groin or wrist artery. Using xrays, the catheter is advanced into the kidney artery and the stent deployed using a balloon advanced over a small guidewire. A ureteral stent is advanced through a catheter placed into the urinary bladder to restore the flow of urine.