Because you can't control your bladder when under anesthesia, urinary catheters are frequently utilized during surgery. A foley catheter is often implanted prior to surgery to maintain the bladder empty throughout the procedure. This allows time for an anesthesiologist to complete all necessary tests and procedures before moving forward with major surgery. A cystoscopy is performed during which the doctor looks into the bladder using a small telescope attached to a lighted tube called a cystoscope. The doctor may also use this opportunity to examine the tissue surrounding the bladder and any polyps or tumors that may have formed there. A suprapubic cystostomy is performed instead to place a stent into the bladder after removal of all or part of it. This prevents urine from leaking through the surgical site once anesthesia has worn off. A nephrostomy is done instead when immediate intervention is needed to save someone's kidney. In this case, the surgeon makes an opening in the skin above the hip or back and places a hollow needle through the skin and into the kidney. A wire loop on the other end of the needle is then used to pull the kidney outside the body through the hole. A catheter is then placed through the skin into the kidney where it remains until the wound has healed enough to close up.