Supine lithotomy versus prone position in minimally invasive percutaneous nephrolithotomy for upper urinary tract calculi.

Objective: To compare operative time, safety and effectiveness of minimally invasive percutaneous nephrolithotomy (MPCNL) in the supine lithotomy versus prone position.

Methods: Between January 2008 and December 2010, a total of 109 consecutive patients with upper urinary tract calculi were enrolled and randomly divided into group A (53 patients, supine lithotomy position) and group B (56 patients, prone position). The MPCNL procedures were performed under the guidance of real-time grayscale ultrasound system. The preoperative characteristics, intraoperative and postoperative parameters were analyzed and compared.

Results: All patients were successfully operated. There was no significant difference between the two groups in stone-free rate (group A 90.1 vs. group B 87.5%, p = 0.45), mean blood loss, number of access tracts, calyx puncture, mean hospital stay (group A 6 ± 1.1 vs. group B 6 ± 1.5 days, p = 0.38) and complications. But the operative time was significantly shortened in supine lithotomy position (group A 56 ± 15 vs. group B 86 ± 23 min, p < 0.001).

Conclusions: The effectiveness and safety of the supine lithotomy position for MPCNL were similar to the prone position. However, the supine lithotomy position has an important advantage of reducing the operative time. The supine lithotomy position could be a good choice to perform MPCNL.