explained.They analyzed national data and estimated that 80,000 never events occurred in U.S. hospitals between 1990 and 2010, and believe that figure may be on the low side.They also estimated that U.S. surgeons leave a foreign object such as a sponge or a towel inside a patient's body after an operation 39 times a week, perform the wrong procedure on a patient 20 times a week, and operate on the