Operation room setup. Before the initiation of the procedure, patients were kept in the prone split-leg position to avoid the extra time for repositioning. The real (a) and virtual (b) operation room setup was shown to perform an SBES in prone split-leg position of right PNL and left URS. SBES, simultaneous bilateral endoscopic surgery; PNL, percutaneous nephrolithotomy; URS, ureteroscopic lithotripsy.