surgery

Medical errors kill more than 200,000 people every year in the United States, according to a study published in September.

Add them all up and "you have probably the third leading cause of death" in the country, Dr. Peter Pronovost, senior vice president for patient safety and quality at Johns Hopkins Hospital, told CNN during a 2012 investigation into common medical mistakes.

10 shocking medical mistakes

Wu said patients should tell their surgeons "everything that they know about themselves," including their past experiences with surgery and anesthesia, whether they have any allergies, and if they're prone to bruising or heavy bleeding.

"The question people should always ask is, 'Do I need this surgery?' " Wu said. "In some cases not having surgery is riskier than having the surgery ... but for many, many things, the surgery is quite discretionary. You have a choice."