<qa>  What is the name of the procedure that is not known about the patients?When patients are going to have surgery to remove large kidney stones percutaneous nephrolithotomy PCNL, it is not clear whether the patients benefit from a course of prophylactic preoperative oral antibiotics; currently both the use of prophylactic preoperative oral antibiotics and no prophylactic oral antibiotics are considered to be within standard-of-care. 