Percutaneous nephrolithotomy (PNL): PNL is the treatment of choice for large stones located within the kidney that cannot be effectively treated with either SWL or URS. General anesthesia is usually required to perform a PNL. The main advantage of this approach compared to traditional open surgery is that only a small incision (about one centimeter) is required in the flank. The urologist then places a guide wire through the incision. The wire is inserted into the kidney under radiographic guidance and directed down the ureter. A passage is then created around the wire using dilators to provide access into the kidney. An instrument called a nephroscope is then passed into the kidney to visualize the stone. Fragmentation can then be done using an ultrasonic probe or a laser. Because the tract allows passage of larger instruments, your urologist can suction out or grasp the stone fragments as they are produced. This results in a higher clearance of stone fragments than with SWL or URS. Once the procedure is complete, a tube is usually left in the flank to drain the kidney for a period of time, from overnight to several days.

Percutaneous nephrolithotomy (PCNL) is a surgical procedure to remove stones from the kidney by a small puncture wound (up to about 1 cm) through the skin. It is most suitable to remove stones of more than 2 cm in size and which are present near the pelvic region. It is usually done under general anesthesia or spinal anesthesia.