Endourology is based on needle and guidewire access to the kidney and the upper urinary tract. Once guidewire access is obtained, various catheters can then be placed into the kidney, either for drainage or for facilitation of antegrade intrarenal or ureteral endoscopic procedures. The tract must first be established and should provide a straightforward route to the kidney, allowing bloodless instrumentation. If more than renal drainage is desired, endoscopic surgery can then continue as a single or staged procedure. With recent advances, many invasive open urologic procedures are now performed endoscopically through small-diameter percutaneous access tracts