Percutaneous (through the skin) lithotripsy refers to a treatment of kidney stones through a small cut in the skin made in a person’s back side, which is directly behind the kidney.
This approach allows for a surgeon to get access to the kidney directly from the skin without going through the bladder or ureter. The small stab incision is usually the size of a dime, but that is actually large enough to allow the use of our larger available instruments that can break the stone into pieces that may be removed from the kidney with ease.
This approach is ideal for patients with very large stones >2 cm (just under an inch and larger). Whereas ureteroscopy is limited by the use of very thin instruments, making the procedure time consuming, if we are treating a larger stone, percutaneous lithotripsy (PCNL) allows us to remove pieces as big as 1 cm with each pass of our instrument into the kidney. We also have very efficient and powerful tools besides the laser technology, such as the ultrasonic stone breakers and hammer-like pneumatic machines.
To learn more about the machines used you may see their websites:
After patients are asleep with general anesthesia, patients typically have a small catheter placed the bladder. Then patients are positioned to lay on their belly with their back up. Next, using x-ray and/or ultrasound guidance and usually with the help of an x-ray doctor (radiologist) a needle is placed from the skin directly into the kidney with the stone. With the same incision, we are then able to dilate the tract, to create a tunnel from the skin directly into the kidney. Through this tunnel, we then are able to place a larger camera inside the kidney, visualize the stone and proceed with stone removal with graspers and are able to pulverize the stone into smaller pieces that are further removed.
At the conclusion of the procedure, and depending on the duration of surgery, presence of bleeding, we conclude the surgery by leaving a tube that sticks out from the incision in the back side of the patient. This drain is temporary and is usually removed once urine clears up from bleeding and there are no plans to look back into the kidney.
In rare cases, the volume of stones is so large, that I discuss with patients the possibility of doing at least 2 trips to the operating room to clear out all the stone burden because taking care of all stones in one trip to the operating room may just take too much time under anesthesia.
PCNL length of surgery primarily depends on the size and location of the stone. At times it is difficult to access the kidney from the skin and sometimes it is a struggle to get in the correct spot with our instruments to reach the stone. With stone burden 1-3 cm, the procedure usually lasts about 2 hours, however, with larger stone and those especially taking up a lot of the kidney, the procedure may take up to 3+ hours, though, in these cases, I often prefer to split the operation into 2 trips, so as to decrease side effects of prolonged anesthesia.
General anesthesia (heavy sedation with a ventilator) is recommended for best results. With general anesthesia, we are able to control patient's breathing and thus allow for better targeting of the stone and also control pain during the operation.