Stone | Percutaneous Nephrolithotomy (PNL)

Description of Procedure


A percutaneous nephrolithotomy (PNL) is a minimally invasive procedure which is used for large stones within the kidney. It is not used for stones within the ureter or bladder.


Percutaneous - through the skin

Nephro - into the kidney

Lithotomy - removal of stone


It is used when there is a large stone burden (typically over 1-2 cm in size) not amenable to extracorporeal shockwave lithotripsy or ureteroscopy (retrograde intra-renal surgery, 'RIRS'). While this procedure is more invasive than ESWL, it is more effective for larger stones especially if they are hard. This is the treatment of choice for staghorn calculi which are stones which fill just about the entire collecting system.


PNL requires a general anesthetic. This procedure is collaborative involving a urologist, radiologist and surgical team (anesthesia, nursing and radiology technician). A sub-specialized radiologist is required. They are done at the Stone Centre at Vancouver Hospital.


What to expect for preparation:

  1. Imaging - we need CT prior to treatment. We will arrange if you have not had the CT done
  2. Anesthesia consultion is sometime required
  3. Blood tests and ECG
  4. Fasting from the night before
  5. Medications: you will receive instructions on any changes. In general, you will be required to stop all medications that predispose to bleeding (e.g. Plavix, Coumadin/Warfarin, aspirin)
  6. Overnight hospital stay


How is it done?

PNL is essentially a controlled entry into the kidney through the skin through a 1 cm incision. Everything is monitored in real time using video system and fluoroscopy

  1. OBTAINING ACCESS: In Vancouver Coastal Health, a specialist radiologist obtains 'access' to the stone within the collecting system of the kidney. This is done in a controlled manner in an operating room using ultrasound and fluoroscopy. An access sheath is placed over the guidewire and the entry portal is enlarged until the instruments can be placed into the collecting system. The access sheath actually goes through the meat (parenchyma) of the kidney. Sometimes more than 1 access port is required depending on the amount and location of stone
  2. A variety of instruments are used through a special camera system to fragment and remove the stone. Lithotripsy is a general term which means 'breaking stone'. Any of the following may be used:
    1. Laser
    2. Electrohydraulics
    3. Pneumatic
    4. Ultrasonic devices
  3. Removal of the framents with irrigation, grasping forceps and/or special baskets
  4. Placement of a drainage tube which goes through the collecting system and retains access should it be needed


Checking for success.

Post-procedure check is done with a CT KUB on the day after surgery prior to discharge. Fortunately, the majority of patients will be able to leave the hospital stone free. Sometime additional procedures such as shock wave lithotripsy (ESWL), ureteroscopy or even a repeat PNL are required. In some cases a ureteral stent may be left to allow fragments to pass and/or allow the collecting system to heal properly. 


You will be informed if additional procedures such as stent retrieval or more stone surgery are required.


Possible Risks

A great benefit of PNL is that it can render patients stone free with a less invasive procedure than historically would have been required. Fortunately, open surgery is rarely required since it needed a large cut in the skin with a few days in hospital and several weeks-months of healing. While PNL is much better than open surgery, it does have risks. The overall risk of a major event (such as a blood transfusion) is 5-10%; more serious complications occur in about 1-2% of cases. These include the following:

  1. Bleeding requiring blood transfusion. Risk is about 5%. This most commonly occurs during the procedure but may occur on a delayed basis within the first month after surgery. If you see a sudden increase in heavy bleeding which persists, inform your doctor and goto hospital. In some cases, embolization of part of the kidney is required.
  2. Damage to adjacent organs (e.g. spleen, colon, liver, lung) can occur. This is very uncommon less than 1%
  3. Injury to the collecting system (e.g. a perforation of the renal pelvis). Usually managed by leaving a stent in place for several weeks. Fortunately these sorts of injuries tend to heal well
  4. Sepsis/Infection: these tend to occur with struvite or infection stones. Usually managed by antibiotics
  5. Rare complications much less than 1%: loss of kidney, injury to lung, major vascular injury requiring open surgery


After Procedure

If you have questions that are not answered here, please contact us.

What to Expect

Is quite normal to have some blood in the urine and bruising in the flank following the procedure. Distal typically resolve within days to a few weeks. As long as the blood in the urine is light it is generally of no concern.


Urinary tract infection can occasionally occur, especially at the type of stone being removed is an infection type of stone. Antibiotics role was given around the time of the procedure to prevent infection but if you have a fever please inform your urologist.


Sometimes a temporary tube is LEFT in the skin. It will be removed once it is safe to do so. If there is leakage from the skin site following removal of any tubal or on discharge from hospital it will usually resolve within a few days.



Please inform your physician if you have any of the following:


  1. Heavy bleeding in the urine which is not clearing with increasing fluid intake
  2. Feel faint or lightheaded despite taking adequate fluids and food
  3. High fever
  4. Severe pain



You may resume regular diet as soon as you are discharged from hospital


No heavy physical activity or exercise for 3 weeks following surgery.


Resume medications as per instruction.

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