Some kidney stone patients will form very large stones that are associated with bacteria infection. These stones can often occupy the entire inside portion of the kidney and cause blockage and inflammation of the kidney tissue. It is important to remove all of the stone material in order to remove the source of the bacteria infection in these patients and this usually means an operation is necessary. The percutaneous nephrolithotomy (PCNL) is an operation to remove large stones from the kidney and involves the insertion of a tube, the size of the middle finger, through a one inch incision in the back and into the kidney. A endoscopic instrument is then inserted through the tube and is used to look at the inside of the kidney and see the stone. An ultrasound probe or laser fiber is inserted through the instrument and used to break up the stone and suck it out of the kidney. Removing all of the stone material relieves the blockage of the kidney and allows the kidney to work better. The stones often have infection inside them and removing the stones and keeping the patient on antibiotics will stop the infection and new stone growth.