Percutaneous Nephrostomy

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Kidney Stones:

Obstructing kidney stones are extremely common,and the IVP test, CAT scan or renal sonogram can demonstrate the dilated obstructed renal collecting system. The IVP test gives more information about size and exact location of the stone which usually hangs up in the ureter at two or three typical locations. The most common site of obstruction is right at the bottom of the ureter where it joins the urinary bladder. This is called the vesico-ureteral junction. The size of the stone is important because most of the smaller stones pass spontaneously into the bladder within 24 hours merely by giving the patient intravenous hydration and narcotic pain killers to control the pain. Once the stone passes through into the urinary bladder, the pain goes away. Larger stones (larger than 9 mm in diameter) may have a more difficult time passing through. These larger stones may need to be retrieved by the Urologist with a retrograde pyelogram procedure. Kidney stones can be collected by urinating into a strainer and their chemical composition may be analyzed.

ULTRASONIC LITHOTRIPSY: The water bath ultrasonic lithotripsy machine which has become popular in the past 10 years is very useful for large visible stones located in the renal pelvis up in the kidney itself. Once the stone has dropped down into the ureter, this machine cannot be used. Rather, a retrograde flexible ureteroscope must be advanced into the ureter by the Urologist in the Operating Room under general Anesthesia to remove the stone.

If these preliminary procedures to remove the stone are unsuccessful for one reason or another, the Urologist may ask the interventional radiologist to perform a Percutaneous nephrostomy procedure.

The patients serum BUN, Creatinine, Coagulation profile are reviewed. The patient is pre-treated with intravenous antibiotics. The patient is sedated with the usual cocktail of sublimaze and versed. The BUN and Creatinine are frequently abnormally elevated indicating renal impairment from the obstruction.

Percutaneous nephrostomy Procedure:

Indications for Procedure: Obstructive uropathy (i.e. blocked kidney output)

Preparation: Intravenous antibiotics are give prior to the nephrostomy.

Risks and complications: Bleeding, infection, sepsis.

Procedure: Sterile technique and Local Anesthesia with xylocaine is used. The interventional radiologist advances a thin needle into the obstructed renal collecting system under ultrasound or fluoroscopic guidance. When urine backflow is obtained indicating needle position in the renal collecting system, Iodinated Contrast material is hand-injected and xray pictures of the renal collecting system and ureter are obtained showing the anatomy and site of obstruction. A guide wire can then be advanced into the ureter, and over the guide wire a drainage tube can be advanced into the obstructed system. The tube is either advanced into the bladder past the stone or left in place above the obstructing stone in which case the urine flows out into a collection bag.

In cases of ureteral or bladder obstruction from pelvic tumor, this procedure may be done to relieve the urinary obstruction.

Dr. Dach performing a percutaneous nephrostomy
in the interventional lab at Memorial Pembroke Hospital