Special Procedures - Nephrostomy
The nephrostomy procedures involve insertion of a catheter through the skin into the kidney to drain urine. These procedures can relieve urinary obstruction, divert urine and provide access for opening of clogged or narrowed structures within the kidney, bladder and urinary tract. If there is ureteral narrowing or a tear of the ureter a placement of a ureteral stent during nephrostomy can open a clogged ureter or bypass damaged structures, which will allow urine to drain properly.
Nephrostomy and ureteral stenting may be necessary for patients whose normal urine drainage is blocked by renal stones, mass, edema (possibly post-surgical swelling), scarring, trauma or malignant encasement of the ureter.
Nephrostomy and ureteral stent procedures are performed on adults under conscious sedation. General anesthesia is necessary to complete these procedures on newborns and small children.
To begin the procedure the patient is placed on either his stomach or on his side. The radiologist uses ultrasound guidance to locate the kidney and determine the site of entry. The area is cleaned and shaved, if necessary. A local anesthetic is injected to numb the skin and a small incision is made. Under fluoroscopic x-ray guidance, a small hollow needle is inserted into the entry site. Next, a flexible guide-wire is threaded through the needle and the needle is removed. A nephrostomy tube is then placed over the guide-wire, and the guide-wire is removed leaving the catheter in place. Finally, a connecting tube is attached to the catheter and a urine-collecting bag. The bag can be attached to the leg.
One of two types of stents may be used during this procedure: an internal / external stent, or an indwelling stent if ureteral stenting is necessary. An internal / external stent is easily replaced or removed. The indwelling stent is less of a burden to the patient because there is no external bag, however, replacement or removal requires a cystoscopy by a urologist or a repeat nephrostomy by the radiologist.
The internal / external stent can allow for bypass of the ureter while it heals from surgical repair or trauma. Internal / external stents are placed in the bladder through a kidney nephrostomy procedure with one end of the stent emerging at the skin's surface. The stent is then capped.
The indwelling stent is also inserted through a kidney nephrostomy procedure, though no external connection is attached. The indwelling stent is placed in the bladder through the kidney. A nephrostomy tube is secured on the skin with stitches as a precaution for a couple of days and to provide for ready external access to the stent in case of occlusion. The tube is removed later leaving the internal stent in place.