Percutaneous Nephrolithotomy (PCNL)

This card describes percutaneous nephrolithotomy, usually shortened to PCNL, a procedure for removing kidney stones through the skin of the back. It is written for patients, families and students as general education, and the treating urologist decides what is suitable for each person. It sits alongside ureteroscopy and shock wave lithotripsy in the stone procedures drawer.

What it is

"Percutaneous" means through the skin, and "nephrolithotomy" means removing a stone from the kidney. Cleveland Clinic describes PCNL as a minimally invasive surgery, with fewer complications and faster healing than open surgery, but still a major operation that is more invasive than other stone treatments. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) says the urologist uses a thin viewing tool called a nephroscope, which is inserted directly into the kidney through a small cut in the back.

Why it is done

Cleveland Clinic says PCNL is usually suggested when other kidney stone treatments do not work or are not possible. It describes the typical candidate as someone with a stone of 2 centimeters or larger, a stone with an irregular shape that makes passing difficult or impossible, or a person who cannot have treatments such as laser ureteroscopy or shock wave lithotripsy.

MedlinePlus lists related reasons: an X-ray shows the stone is too large to pass by itself or to treat from the bladder side, the flow of urine is blocked, pain persists after treatment, the stone is causing infections or damaging the kidney, or infected urine needs to be drained.

How it is done, in outline

MedlinePlus says PCNL is done under general anesthesia, so the person is asleep. In most cases the person lies on the stomach so the urologist can reach the kidney through the back, though Cleveland Clinic notes that other positions are sometimes used. The surgeon makes a small cut, about half an inch or 1 centimeter, passes a needle into the kidney, widens the tract, and leaves a plastic sheath in place so that instruments can pass through to the stone.

The stone is then taken out, or broken into pieces first. NIDDK says that for larger stones the doctor may use a laser, and Cleveland Clinic mentions a laser or a shock wave device (a lithotripter). See the card on laser lithotripsy for how the laser step works. Afterward, MedlinePlus says a tube may be placed in the kidney (a nephrostomy tube), and a stent may be placed in the ureter so urine can drain and the kidney can heal. Cleveland Clinic gives a typical operating time of about two to four hours.

Recovery

Hospital stays vary between sources. Cleveland Clinic says most people stay one day, MedlinePlus says many can go home within 24 hours unless there are problems, and NIDDK says several days may be needed. Centers differ, so the care team can describe what to expect locally. MedlinePlus says the surgeon removes the tubes once X-rays show the stones are gone and the kidney has healed, and that the procedure may be repeated if stones remain.

Cleveland Clinic says small amounts of blood in the urine for a week or two are normal, and that most people recover in two to four weeks. Most return to work or school after about a week, while people with physically demanding jobs may need at least two weeks. It advises avoiding heavy lifting, nothing heavier than a gallon of water (about 8.5 pounds), for at least two weeks, and suggests a checkup four to six weeks after the procedure. It describes the ureteral stent as sometimes the most painful part of recovery.

Cleveland Clinic lists the following as reasons to call a provider right away: heavy bleeding or discolored drainage at the incision, blood clots that look like ketchup, dark blood in the urine, fever of 100 F (38 C) or higher, signs of infection such as chills, headache or a bad odor around the surgical site, skin separation at the stitches, or increased pain.

Risks

MedlinePlus calls PCNL generally safe and lists these possible complications: pieces of stone left behind (which may need more treatment), bleeding around the kidney, kidney function problems, stone pieces blocking urine flow, and kidney infection. Cleveland Clinic's list also includes anesthesia risks, healing problems, a collection of clotted blood (hematoma), fluid buildup at the surgical site (seroma), sepsis or a complicated urinary tract infection, and the possibility that the stone cannot be removed or that additional procedures are needed.

Cleveland Clinic reports a success rate of about 75% to 98%. Individual outcomes vary, and the urologist can say what such a range means for a specific stone.

Questions to ask your clinician

• Why is PCNL being suggested instead of ureteroscopy or shock wave lithotripsy for my stone?
• Will a laser or another device be used to break the stone first?
• Will I have a nephrostomy tube, a stent or both afterward, and for how long?
• How many days should I expect to stay in the hospital?
• What activity limits apply, and for how many weeks?
• What is the chance that a second procedure will be needed to clear remaining pieces?
• Which signs should make me call you right away or go to an emergency room?