Percutaneous Nephrolithotomy (PCNL)

Percutaneous nephrolithotomy (PCNL) was also a huge advance in the treatment of kidney stones since it was popularised in the 1980's. Prior to that, really the only way of treating large kidney stones was with open surgery and a large incision. Some of my patients have the scars to prove it!

PCNL involves passing a rigid telescope through the loin (in the back), directly into the kidney allowing access directly onto the stone where it can be broken up and all fragments fully extracted. It is the most invasive of modern stone treatment, given that open surgery is now almost never done. It requires a general anaesthetic and is usually done in the prone position (i.e. lying on your front), although increasingly we are using a rotated supine position (i.e. lying on your back) although this depends on a number of factors.

A typical size of the instruments used through the back are 26Fr which is about 9mm in diameter. Through this single small whole, even the largest of staghorn stones can be removed. Over the last few years there has been interest in using a miniturised technique - called mini-PCNL which can vary in size but typically 14-16 Fr (5-6mm incision). This is not suitable for all larger stones, but can be an excellent choice for stones ~ <3cm.

Sometimes it is possible to combine PCNL with flexible URS. This combination is called ECIRS or Endoscopic Combined Intrarenal Surgery. This allows the benefits of the PCNL tract and ability to remove entire stones, with the manoevrability of the flexible ureteroscope to access all parts of the kidney.

The choice of these techniques will really depend on the stone, anatomy of the kidney and preference of the surgeon.

As it is more invasive, it does have a slightly higher risk profile which includes potential injury to other organs (e.g. bowel), although great care is taken to avoid this. Bleeding is a risk and typically we quote a risk of transfusion risk of 1-2% (BAUS audit data). If bleeding was to occur there is a risk of needing a radiology procedure to stop the bleeding (embolisation) - often quoted as 1 in 400 risk - and a small risk of losing the kidney (<1 in 1000). However the minimally invasive nature of the procedure and excellent complete stone-free rates, makes this an excellent choice for stones > 2cm in the kidney and there is interest in whether mini-PCNL might also be a good choice for smaller stones in selected patients.

The EAU patient information team have produced a webpage with more information on having a PCNL and also a video (embedded below) demonstrating the procedure. A pdf version can also be downloaded.