The operating room personnel and your surgeon go to great lengths to make sure your surgery is done in as sterile an environment as possible.  Modern techniques in sterilization and wound preparation help to minimize  risks of infection. 

A five minute scrub is performed by the surgeon to clean the forearms and wrists and hands.  After this, a sterile gown is worn. 

The wound is thoroughly draped, and seen here, the anesthesiologist has been walled off from the surgical field with a sterile clear plastic drape.

All instruments which are used must be sterile.  If an instrument is small, and can be sterilized, it is.  The operating microscope is draped with a sterile barrier sheet.