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.
A Retrograde pyelogram is done to locate the stone in the kidney. With a small 1 centimeter incision in the loin, the Percutaneous nephrolithotomy (PCN) needle is passed into the pelvis of the kidney. The position of the needle is confirmed by fluoroscopy. 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 The needle is then withdrawn with the guide wire still inside the pelvis.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. 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 and then the stone fragments removed.
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 patient and surgeon. 
The following complications may take place:
- Injury to the colon
- Injury to the renal blood vessels
- Urinary leak may persist for a few days
- Hydrothorax if PCNL is done through 11th intercostal space
Notes and references 
- Dr.Rajgopal Shenoy K (2006). Manipal Manual of Surgery - Second Edition, p.619. CBS Publishers & Distributors, New Delhi.
- Flexible ureteroscopy-directed retrograde nephrostomy for percutaneous nephrolithotomy: description of a technique. Wynberg JB et al. J of Endourol. 2012 Oct;26(10):1268-74
A Novel 5-Part Percutaneous Access Needle With Glidewire Technique (5-PANG) for Percutaneous Nephrolithotomy: Our Initial Experience Ashish V. Patil Urology - May 2010 (Vol. 75, Issue 5, Pages 1206-1208, doi:10.1016/j.urology.2009.11.027)