Impact of case volumes on the outcomes of percutaneous nephrolithotomy.

BACKGROUND: Previous studies have demonstrated relationships between case volumes and outcomes in surgery. Little is known about the impact of case volumes on the outcomes of percutaneous nephrolithotomy (PCNL). OBJECTIVE: To investigate the influence of case volumes on the efficacy and safety outcomes of PCNL. DESIGN, SETTING, AND PARTICIPANTS: From November 2007 to December 2009, prospective data were collected by the Clinical Research Office of the Endourological Society from consecutive patients over a 1-yr period in 96 centers globally. Data of 3933 patients in the Global PCNL study database were included in this study. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Patients were divided into low- and high-volume groups based on the median annual case volume of their respective treatment center. Preoperative characteristics and outcomes were compared between the two groups. Case volume was treated as a continuous variable. The relationship between case volume and stone-free (SF) rate, complication rate, and duration of hospital stay was explored using multivariate regression analysis. RESULTS AND LIMITATIONS: SF rates were higher in high-volume centers (82.5% vs 75.1%; p value <0.001). Complication rates were lower in high-volume centers (15.9% vs 21.7%; p value 0.002), whereas the mean (standard deviation [SD]) duration of stay was shorter in high-volume centers (3.4 [2.6] vs 4.9 [3.7] d; p value <0.001). SF rate increased with case volume, whereas complication rate and duration of stay diminished with increasing case volumes after adjusting for stone burden, urine culture status, American Society of Anesthesiologists score, and the presence of staghorn stones. The highest SF rates were observed in centers with >120 cases per year. CONCLUSIONS: Centers that perform high numbers of PCNLs per year achieve better results. Both the efficacy and safety outcomes of PCNL improve with the number of surgeries performed in a given center per year.

The Clinical Research Office of the Endourological Society Percutaneous Nephrolithotomy Global Study: tract dilation comparisons in 5537 patients.

PURPOSE: The study focused on the use of balloon or telescopic/serial dilation methods in percutaneous nephrolithotomy (PCNL) in the Global PCNL Study. PATIENTS AND METHODS: Centers worldwide provided data from consecutive patients who were treated with PCNL during a 1-year period. Tract dilation was performed using a balloon or telescopic/serial dilator. Patient characteristics, perioperative complications, and treatment outcomes were assessed by the treating physician. Postoperative complications were graded according to the modified Clavien grading system. RESULTS: A total of 5537 eligible patients were entered in the database from November 2007 to December 2009, including 2277 (41.1%) who received balloon dilation and 3260 (58.9%) who received telescopic/serial dilation. The predominant method used was telescopic/serial dilation in Asia (94.7%) and South America (98.0%), and balloon dilation in North America (82.6%). In Europe, the rates of balloon (50.7%) and telescopic/serial (49.3%) dilation procedures were similar. The rates of bleeding (9.4% vs. 6.7%), blood transfusions (7.0% vs. 4.9%), and drop in mean hematocrit level (4.5% vs. 2.5%) were higher in the balloon vs. telescopic/serial dilator group. Clavien scores II and IIIA were slightly in favor of the telescopic/serial dilator group. Median operative time was longer in the balloon dilation group (94.0 min vs. 60.0 min). CONCLUSIONS: The Global PCNL Study has identified differences in the method of dilation used between centers in Asia, Europe, and the United States. In the balloon dilation group, a total longer operative time and higher bleeding and transfusion rates were observed. The differences in outcome may be influenced by patient heterogeneity, including previous anticoagulation therapy or surgical procedures, in addition to the number of stones treated and rate of staghorn calculi, which were all higher in the balloon group.