Every year, an estimated 4,044 surgical "never events" occur in the United States, according to a new research. Never events are mistakes committed by a surgeon that could have been avoided, like the surgeon leaving sponges in patients, operating on wrong side or performing wrong operation. These mistakes cost the healthcare system millions of dollars.

The study was conducted by researchers from Johns Hopkins University School of Medicine. Researchers estimate that between 1990 and 2010, 80,000 of these events occurred in American hospitals.

"There are mistakes in health care that are not preventable. Infection rates will likely never get down to zero even if everyone does everything right, for example. But the events we've estimated are totally preventable. This study highlights that we are nowhere near where we should be and there's a lot of work to be done," said study leader Marty Makary, M.D., M.P.H., an associate professor of surgery at the Johns Hopkins University School of Medicine.

The data for the study came from National Practitioner Data Bank that has records of all medical malpractice claims. Researchers found that over 20 years, about 9,744 paid malpractice judgments were awarded with payments totaling $1.3 billion.

Makary said that these estimates can be lower than the actual number of never-events as the objects are discovered only when the patient experiences pain or complications.

Many hospitals have patient safety procedures that prevent never events. For example, surgeons must first make sure that the person on the operation table is the right one. Using indelible ink to mark the site of operation also reduces risk of the person being operated on the wrong side. Dr. Makary said that most hospitals have procedures to count the number of sponges, towels and surgical instruments after the surgery. However, these methods aren't fool-proof, he added.

Dr. Makary said that the occurrence of these mistakes can be reduced by public reporting of such cases. This will not only give patients the power to choose a hospital based on its track record but also "put hospitals under the gun to make things safer."