Advances in percutaneous nephrostolithotomy

A percutaneous approach to the kidney was first described in 1955 by Goodwin and colleagues [1]. This approach, with the insertion of a nephrostomy tube, was used to provide drainage for ail obstructed renal unit. This example led to the recognition that the same access could also be used as a working channel, resulting in the percutaneous removal of a kidney stone, as first reported by Fernstrom and Johansson [2] in 1976. Shortly thereafter, dilation of the percutaneous tract became routine, and soon practitioners performed rigid and flexible nephroscopy and intrarenal manipulation and fragmentation of calculi. Thus bean the era of percutaneous renal surgery, as familiar to all urologists. Over the past 30 years, percutaneous nephrostolithotorny (PCNL) has largely replaced open renal surgery for the management of large uppertract calculi. In a nationwide study using the International Classification of Disease, Ninth Revision (ICD-9), procedure and diagnostic codes, Morris and colleagues [3,4] found that between 1988 and 2002, the annual use of PCNL in the United States increased from 1.2 per 100,000 to 2.5 per 100,000 residents while open surgery declined from a total of 1980 cases in 1992 to only 332 cases in 1998 when Medicare beneficiaries with nephrolithiasis were assessed [3 4]. As with all new treatments and especially minimally invasive treatments available in 2006, a pertinent question is: How many procedures does one have to perform before competence is achieved? Allen and colleagues [5] evaluated the cases of an endourologist with no solo PCNL experience and reviewed such parameters as operating time, fluoroscopy time, and radiation dose. This data was then compared with those of an expert endourologist with over 1600 cases. They found that after 115 cases these parameters reached a plateau for the novice surgeon and were equivalent to those of the expert surgeon.