WEDNESDAY, July 20 (HealthDay News) -- The number of surgical errors at VA medical centers is on the decline, a new study finds.

In reviewing adverse events and close calls in these operating rooms over a three-year period, researchers report in the July 15 issue of the Archives of Surgery that possible reasons for the drop were a greater emphasis on safety, as well as improved training and communication.

Although the estimated number of errors at VHA medical centers varies by location since each may have different methods for defining an adverse event, researchers from the VA scoured a national database to identify mistakes occurring between 2006 and 2009 and code them into various categories, such as type, body part and cause.

The study showed that about half of the adverse events took place in the operating room, but their severity, on average, decreased. The researchers found the number of monthly adverse events per month dropped to 2.4 from 3.21 in a previous study. The rate of "highest harm" adverse events also fell by 14 percent each year. Close calls, however, increased from 1.97 reports per month to 3.24.

Researchers also found that reports of surgeons operating on the wrong body part ranged between 0.09 per 10,000 patients in some locations to 4.5 per 10,000 patients -- a 50-fold difference.

Although the authors found 204 root causes that contributed to the errors, the most common reason for mistakes was a lack of standardization of clinical processes.

The authors noted their findings should benefit those involved in procedures at these facilities.

"Despite the overall decrease in patient harm, opportunities exist to further decrease the number of incorrect surgical and invasive procedures," the study's authors said in a news release from the journal. "We must continue to improve."

More information

The U.S. Department of Veterans Affairs provides more information on veteran's health and wellness.