Isolated Upper Pole Access in Percutaneous Nephrolithotomy: A Large-Scale Analysis from the CROES Percutaneous Nephrolithotomy Global Study

Purpose: We analyzed the indications for and outcomes of percutaneous nephrolithotomy using upper pole access. Materials and Methods: Between 2007 and 2009 prospective data were collected by the Clinical Research Office of the Endourological Society (CROES) from consecutive patients at 96 centers globally. Data on 4,494 patients were included in this analysis. Patients were divided into upper and lower pole access groups based on the location of percutaneous renal access. Preoperative characteristics and outcomes were compared between the 2 groups by univariate and multivariate tests. Results: The upper pole access group had more staghorn stones (21.7% vs 15.5%, p<0.001) and a greater stone burden (mean +/- SD 476 +/- 390.5 vs 442 +/- 344.9 mm(2), p = 0.091). Mean operative time was 92.4 +/- 46.1 and 75.1 +/- 41.3 minutes in the upper and lower pole groups, respectively (p < 0.001). The stone-free rate was lower in the upper pole access group (77.1% vs 81.6%, p = 0.030). The overall complication rate was higher in the upper pole group with a higher incidence of hydrothorax (5.8% vs 1.5%) but a lower incidence of pelvic perforation (1.8% vs 3.2%). Mean hospital stay was longer in the upper pole group (p = 0.048). Success and complication rates were similar in upper pole access subgroups, defined as definitive (staghom and isolated upper calyceal stones) and elective (pelvic, middle calyceal and lower pole stones) indications. Conclusions: Isolated upper pole access is indicated in a select group of patients with complex stones. Upper calyceal and staghom stones are more commonly managed by upper pole access, which is associated with a higher complication rate and longer hospital stay as well as a lower stone-free rate due to procedure complexity.