Percutaneous nephrolithotomy (PCNL or PCN) is a

minimally-invasive procedure Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definition ...

to remove

stones In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compound, chemical composition, and the way in which it is formed. Rocks ...

from the

kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

by a small puncture wound (up to about 1 cm) through the skin. It is most suitable to remove stones over 2 cm in size or which are present near the

pelvic The pelvis (: pelves or pelvises) is the lower part of an anatomical trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis or pelvic skeleton). ...

region. It is usually done under

general anesthesia General anaesthesia (UK) or general anesthesia (US) is medically induced loss of consciousness that renders a patient unarousable even by painful stimuli. It is achieved through medications, which can be injected or inhaled, often with an analgesi ...

spinal anesthesia Spinal anaesthesia (or spinal anesthesia), also called spinal block, subarachnoid block, intradural block and intrathecal block, is a form of neuraxial regional anaesthesia involving the injection of a local anaesthetic with or without an opioi ...

. Since its development by Dr Janak Desai in 2000, PCNLs have become the standard treatment for complex and large kidney stones, and have largely obviated the need for open surgical procedures.

Procedure

retrograde pyelogram Pyelogram (or pyelography or urography) is a form of imaging of the renal pelvis and ureter. Types include: * Intravenous pyelogram – In which a contrast solution is introduced through a vein into the circulatory system. * Retrograde pyelogra ...

is first done to locate the stone in the kidney. Contrast is diluted to the ratio of 1:3. If the ureteric

catheter In medicine, a catheter ( ) is a thin tubing (material), tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. ...

is placed in the upper pole of the kidney, it should be pulled down so that the tip is inside the

renal pelvis The renal pelvis or pelvis of the kidney is the funnel-like dilated part of the ureter in the kidney. It is formed by the convergence of the major calyces, acting as a funnel for urine flowing from the major calyces to the ureter. It has a mucous ...

; this helps for proper filling of the

renal calyces The renal calyces ( calyx) are conduits in the kidney through which urine passes. The minor calyces form a cup-shaped drain around the apex of the renal pyramids. Urine formed in the kidney passes through a renal papilla at the apex into the mi ...

. The contrast is injected slowly to prevent

extravasation Extravasation is the leakage of a fluid out of its contained space into the surrounding area, especially blood or blood cells from vessels. In the case of inflammation, it refers to the movement of white blood cells through the capillary wall, ...

. Fluoroscopy monitoring should be continuous so that the sequence of calyces filled can help to identify the position of posterior calyx. With a small (1cm) incision in the

loin The loins, or lumbus, are the sides between the lower ribs and pelvis, and the lower part of the back. The term is used to describe the anatomy of humans and quadrupeds, such as horses, pigs, or cattle. The anatomical reference also applies to p ...

, the PCN needle is passed into the

pelvis The pelvis (: pelves or pelvises) is the lower part of an Anatomy, anatomical Trunk (anatomy), trunk, between the human abdomen, abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also c ...

of the kidney. The position of the needle is confirmed by

fluoroscopy Fluoroscopy (), informally referred to as "fluoro", is an imaging technique that uses X-rays to obtain real-time moving images of the interior of an object. In its primary application of medical imaging, a fluoroscope () allows a surgeon to see t ...

ultrasound Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...

. A guide wire is passed through the needle into the pelvis. The needle is then withdrawn with the guide wire still inside the pelvis. Over the guide wire, the dilators are passed and a working sheath is introduced. The most common standard types of dilation are Amplatz dilation, metal telescopic dilation, and balloon dilation. A nephroscope is then passed inside and small stones taken out. In case the stone is big, it may first have to be crushed using ultrasound probes. The most difficult portion of the procedure is creating the tract between the kidney and the flank skin. Most of the time this is achieved by advancing a needle from the flank skin into the kidney, known as the antegrade technique. A retrograde technique has recently been updated wherein a thin wire is passed from inside the kidney to outside the flank with the aid of a flexible ureteroscope. This technique may reduce radiation exposure for both the patient and the surgeon.

Complications

The following complications may take place: * Injury to the colon * Injury to the lungs * Injury to the renal blood vessels * Urinary leak may persist for a few days * Infection and

sepsis Sepsis is a potentially life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage of sepsis is followed by suppression of the immune system. Common signs and s ...

Hydrothorax Hydrothorax is the synonym of pleural effusion in which fluid accumulates in the pleural cavity. This condition is most likely to develop secondary to congestive heart failure, following an increase in hydrostatic pressure within the lungs. More r ...

, if done through the 11th intercostal space * Bleeding * Death

Notes and references

{{Urologic procedures Urologic surgery