A nephrolithotomy is a surgical procedure to remove kidney stones directly through the kidney. It’s used when stones are too large to pass on their own or to be treated with less invasive methods like shock wave therapy. The modern version, called percutaneous nephrolithotomy (PCNL), is the standard approach today. It involves making a small incision in your back and threading instruments through a narrow tube to break up and extract the stone.
How PCNL Differs From Open Surgery
Traditional open nephrolithotomy required a large flank incision, typically between the ribs, to physically expose the kidney. Surgeons would clamp the blood supply, split the kidney open along its edge, and remove the stones by hand. This was once the gold standard, but the recovery was long and the procedure carried significant risks from the large incision alone.
Percutaneous nephrolithotomy replaced open surgery for nearly all cases. Instead of a large cut, the surgeon creates a tract roughly the width of a pencil through your back and into the kidney, using ultrasound and X-ray imaging to guide the path. A small camera called a nephroscope is passed through this tract to locate the stone, which is then broken into pieces and removed. Current guidelines from the American Urological Association recommend PCNL as the first-line treatment for large kidney stones, and open surgery is now rarely performed.
When Nephrolithotomy Is Needed
PCNL is typically reserved for kidney stones larger than 2 centimeters, or for stones that are oddly shaped or located in hard-to-reach parts of the kidney. The most common reason is a staghorn calculus, a branching stone that fills the central collecting area of the kidney and extends into two or more of its drainage channels. A complete staghorn stone can occupy more than 80% of the kidney’s internal drainage system, making it impossible to treat with shock waves or smaller scope-based procedures.
Your doctor may also recommend PCNL for smaller stones that haven’t responded to other treatments, or when a stone’s composition makes it resistant to shock wave lithotripsy. A meta-analysis of 62 studies covering over 7,000 patients found that PCNL achieves a higher stone-free rate than the main alternative (retrograde surgery performed through the urinary tract), for stones both above and below 2 centimeters in size.
What Happens During the Procedure
PCNL is performed under general anesthesia. You’ll be positioned face-down or on your side, and the surgical team will use a combination of ultrasound and fluoroscopy (real-time X-ray) to pinpoint the stone’s exact location. A needle is inserted through your back into the kidney, and a guidewire is threaded through that needle to create a secure path.
The tract is then gradually widened using a series of progressively larger dilators until it’s wide enough to fit a protective sheath, typically about 1 centimeter in diameter. The nephroscope passes through this sheath, giving the surgeon a direct view inside the kidney. For smaller stones, the surgeon can grab fragments whole. Larger stones need to be broken apart first using one of several energy sources: a pneumatic device that hammers the stone, an ultrasonic probe that vibrates it apart, or a laser fiber that vaporizes it into dust. Laser lithotripsy has become increasingly popular because it can reduce stones to fine particles that are suctioned out through the sheath, reducing the need to repeatedly withdraw and reinsert instruments.
Once the stone is cleared, the surgeon may place a small drainage tube (called a nephrostomy tube) through the tract and into the kidney, along with a temporary internal stent that runs from the kidney to the bladder. These keep the drainage pathway open while the area heals.
Recovery Timeline
Most patients spend one night in the hospital and go home the following afternoon. If a nephrostomy tube was placed, it’s usually removed the day after surgery while you’re still in the hospital. The bladder catheter comes out one to two days after surgery, either before discharge or at a follow-up visit. The internal ureteral stent stays in place for about a week before being removed in clinic.
You can expect some blood in your urine for the first few days, which is normal. Most people return to light daily activities within a week, though heavy lifting and strenuous exercise are generally off-limits for two to four weeks. Your surgical team will schedule imaging to confirm the stone has been fully cleared.
Preparing for Surgery
Before the procedure, you’ll go through a preoperative assessment that includes a review of your medical history, a physical exam, and blood and urine tests. Because PCNL requires general anesthesia, standard fasting guidelines apply: you can drink clear liquids up to two hours before the procedure and eat a light meal up to six hours beforehand. Heavier foods like fried or fatty meals require eight or more hours of fasting. Your surgical team will let you know well in advance which medications to continue, pause, or adjust, particularly blood thinners.
Risks and Complications
PCNL is effective, but it carries more risk than less invasive stone procedures. In a study of 201 patients at a tertiary care center, bleeding was the most common intraoperative complication, occurring in about 10% of cases. Roughly the same percentage of patients needed a blood transfusion. Renal pelvis perforation, where the instrument punctures the inner lining of the kidney’s drainage system, happened in 1.5% of cases.
In the days following surgery, blood in the urine (hematuria) was the most frequent issue, affecting 18.4% of patients. Fever occurred in about 13%, and urinary tract infections developed in 5%. A small number of patients (1.5%) developed urosepsis, a serious bloodstream infection that requires urgent treatment. Pleural injury, where fluid collects around the lung due to the access point being near the lower ribs, also occurred in 1.5% of patients and was managed with a chest drain. Major injuries to surrounding organs like the colon, spleen, or liver were not observed.
Overall, the complication rate is higher and hospital stays are longer compared to retrograde procedures done through the urinary tract. But for large or complex stones, PCNL remains the most reliable way to achieve complete stone clearance in a single session.