Wrong-site surgeries seen as rare, preventable

Degree of harm was generally low

Wrong-site surgery is extremely rare and major injury from it even rarer, according to a study supported by the Agency for Healthcare Research and Quality and published in the April 2006 issue of Archives of Surgery.1

Researchers led by Mary R. Kwaan, MD, MPH, of Brigham and Women's Hospital and Harvard School of Public Health in Boston, estimate that a wrong-site surgery serious enough to result in a report to insurance risk managers or in a lawsuit would occur approximately once every five to 10 years at a single large hospital.

The study assessed all wrong-site surgeries reported to a large medical malpractice insurer between 1985 and 2004 and found that the number of wrong-site surgeries conducted on limbs or organs other than the spine occurred once in every 112,994 operations. In addition, 40 cases of wrong-site surgery were identified among 1,153 malpractice claims and 259 instances of insurance loss related to surgical care. Of that total, 25 of the cases were non-spine wrong-site surgeries, with the remainder involving surgery of the spine.

Another interesting finding involved the universal protocols from the Joint Commission on the Accreditation of Healthcare Organizations (JCAHO), which went into effect in July 2004. According to the researchers, available medical records for 13 of the 25 non-spine wrong-site surgery cases show that injury was temporary and minor in 10 of the cases, but that JCAHO's "Universal Protocol for Preventing Wrong Site, Wrong Procedure, Wrong Person Surgery" might have prevented eight of the cases.

An 'uncommon' event

"Our interest was in wrong-site surgery, how it happens, and what kinds of cases are at risk for wrong-site surgery events," says Kwaan, a surgical research fellow at the Brigham & Women's Center for Surgery & Public Health. "We also had some interest in finding out how hospitals reacted to the site verification protocol."

The main point Kwaan would like to emphasize is that based on her findings, wrong-site surgery "is not a common adverse event." Previously, she says, there had not been much data on the problem. "A lot of the discussion on this problem is based on case reports, so we do not have denominators," she explains. "Also, we wanted to compare [the rate of wrong-site surgeries] with lots of other well-known errors, like a retained foreign body. We now have a number: one in 10,000. That is far more uncommon than leaving a sponge in the abdomen."

The other key issue, says Kwaan, is degree of harm, which was low in the instances found in her study. "Retained foreign bodies mostly result in pretty serious harm," she observes. "In our cases, most involved a scar requiring a second operation, but not a major disability — and none of the cases resulted in death," she adds.

Structured protocols

"The final point it's important to cite is that when we reviewed the medical records, the events appeared not to have been preventable by the [JCAHO] site preparation protocol," adds Kwaan. "This is a very important finding: Despite this protocol being fairly extensive, unfortunately it is not expected to prevent every single case of wrong-site surgery. We found it prevented 62% with diligent enforcement."

Kwaan describes the protocols as "fairly structured," with three main components. "One is pre-op verification, with recommendations to check things like the consent document or having the histories and physical documents in the medical record," she explains. "The second is marking the site, which has gotten a lot of attention, and the third is a time-out."

While these are "fairly specific" components of what JCAHO would like a hospital to do, she says they don't specify exactly how you actually bring these about.

"It seems [from discussions with hospitals] like there was some confusion about what procedures should be done," Kwaan notes. "Even though the requirements are not rocket science, they could be quite cumbersome if not planned correctly."

Given the fact that the protocols are not foolproof, what does Kwaan recommend? "For now, one of the things we think is important is to have a site verification protocol in your hospital that is simple; this will promote compliance," she says. "Avoid cumbersome protocols and redundant checks, where everybody knows they are checking the same thing three other people checked. Although there is no data on this, we don't feel it will increase compliance — in fact, we feel it will make it easier to violate the protocols."

The pre-op verification process, she continues, should involve two health care professionals — and one should be the surgeon. The other should be the nurse or anesthesiologist, who will verify the documents. "The most relevant is the informed consent," says Kwaan. "We also advocate that hospital policy have a very clear protocol for inconsistencies, so if something comes along that is not matching the OR schedule, a lot of emphasis should be placed on how that will be resolved."

Finally, says Kwaan, in the cases that were studied, "A lot of initial errors occurred in the clinic weeks before surgery – the patient wasn't scheduled correctly, radiology did not label something correctly, or the documentation was not correct. We want to alert the surgeon that this is their responsibility," she says. "One way [to avoid such errors] is to have steps taken in the clinics to ensure the correct site is identified and agreed upon with the patient — to make sure they have specified the correct side and site. Then, it's important to verify that in the consent document."

Quality managers should be aware, says Kwaan, that patient safety protocols are an up-and-coming topic. "You will hear more and more about them for other types of procedures; you will read about it in the literature as we learn more and think of ways to prevent errors," she says. "You will see a lot of protocol-driven prevention measures — these will hopefully be based on evidence. If you read the JCAHO protocol and you haven't thought that much about it about, it doesn't sound like a difficult thing to do, but we found so much variety in the ways hospitals interpreted them. Even how you mark the site can be a very complicated administrative decision. It requires a lot of thought and research."

For more information, contact:

Mary R. Kwaan, MD, MPH, Brigham and Women's Hospital and Harvard School of Public Health, Boston, MA. E-mail: mkwaan@partners.org.


  1. Kwaan MR, Studdert DM, Zinner MJ, Gawande A, Incidence, Patterns, and Prevention of Wrong-Site Surgery. Arch Surg. 2006;141:353-358.