Once visualized, the renal fascia should be mobilized free of its attachments and then opened and dissected. The renal hilum should be carefully identified and exposed. The tumor should be accurately localized using a combination of high-quality preoperative imaging, intraoperative visualization, and intraoperative ultrasonography (which establishes the location and depth of the lesion in three dimensions). Using intraoperative color Doppler ultrasound, it should be confirmed that occlusion of the renal vessels results in complete interruption of blood flow to the tumor and surrounding parenchyma.

Once the tumor has been characterized, intravenous mannitol should be infused to help minimize renal ischemic injury during tumor excision. Mannitol increases renal plasma flow, reduces intracellular edema, and promotes osmotic diuresis to flush out debris and casts from the renal tubules (see Plate 10-1).