Evaluating the definition of "stone free status" in contemporary urologic literature

Abstract

Objective: There is no standardized definition of stone free after renal stone surgery. The lack of standardization prompted a review of the current urologic literature, to assess the definitions of stone free status, and how imaging is used to determine stone free status.

Methods: A literature search on PubMed for the MeSH terms for percutaneous nephrolithotomy (PCNL), ureteroscopy with lithotripsy, shock wave lithotripsy (SWL), and laser lithotripsy, published in English between January 2007 and January 2010 was performed. Case reports, articles not evaluating stone free outcomes, and review articles were excluded. Articles were evaluated for the treatment modality, definition of stone free status, and the imaging modality employed to determine stone free status.

Results: This search yielded 417 articles of which 249 met inclusion criteria. Stone free was defined in 169 articles (68%). The most common definition of stone free was "no stones" (47%), but a total of seven different definitions were encountered. The most common treatment modality was PCNL (47%), followed by SWL (33%), and URS (13%). The most common detection modality was KUB alone (28%), the second most common being KUB and US combined (22%).

Conclusions: Nearly one-third of articles evaluating surgical management of urinary calculi do not define stone free status; when stone free is defined, there is wide variation as to that definition. Furthermore, vast differences exist in the type of imaging used to define stone free status. The urologic community should standardize the reporting of stone free outcomes in the urologic literature.