Percutaneous Nephrolithotomy, or PCNL, is a procedure for removing medium-sized or larger kidney stones from the patient’s urinary tract by means of a nephroscope passed into the kidney through a track created in the patient’s back. The term “percutaneous” means that the procedure is done through the skin and Nephrolithotomy is a term formed from two Greek words that mean “kidney” and “removing stones by cutting.”
Kidney stones range in size from microscopic groups of crystals to objects as large as golf balls. Most calculi, however, pass through the urinary tract without causing problems. They are formed when the urine becomes supersaturated (overloaded) with mineral compounds that can form stones. This super saturation may occur because the patient has low urinary output, is excreting too much salt, or has very acid urine. The purpose of PCNL is the removal of renal calculi in order to relieve pain, bleeding into or obstruction of the urinary tract, and/or urinary tract infections resulting from blockages.
A standard percutaneous nephrolithotomy is performed under general anaesthesia and usually takes about three to four hours to complete. After the patient has been anesthetized, the surgeon makes a small incision, about 0.5 in (1.3 cm) in length in the patient’s back on the side overlying the affected kidney. The surgeon then creates a track from the skin surface into the kidney and enlarges the track using a series of Teflon dilators or bougies. A sheath is passed over the last dilator to hold the track open.
After the track has been enlarged, the surgeon inserts a nephroscope, which is an instrument with a fibre optic light source and two additional channels for viewing the inside of the kidney and irrigating (washing out) the area. The surgeon may use a device with a basket on the end to grasp and remove smaller kidney stones directly. Larger stones are broken up with an ultrasonic or electrohydraulic probe, or a holmium laser lithotriptor. The holmium laser has the advantage of being usable on all types of calculi.
A catheter is placed to drain the urinary system through the bladder and a nephrostomy tube is placed in the incision in the back to carry fluid from the kidney into a drainage bag. The catheter is removed after 24 hours. The nephrostomy tube is usually removed while the patient is still in the hospital but may be left in after the patient is discharged.