By Gary Evans, Medical Writer

Healthcare workers can be reluctant to abandon their favored personal protective equipment [PPE] in the absence of science. A case in point is a recent victory by surgeons to continue wearing their traditional skull caps. A previous recommendation for surgeons to fully cover their hair and ears to prevent infections has been jettisoned for a lack of evidence.

“The surgeons felt there was not any data suggesting that abandoning tradition [skull caps] really prevented any infection transmission,” says Troy Markel, MD, FACS, a member of the committee that issued the statement1 and lead author of a recent study on the issue.2

Several medical groups, including the American College of Surgeons (ACS), the Association of periOperative Nurses (AORN), and The Joint Commission, agreed. They issued a collective statement that says, “Over the past two years, as recommendations were implemented, it became increasingly apparent that in practice, covering the ears is not practical for surgeons and anesthesiologists, and in many cases counterproductive to their ability to perform optimally in the OR. … The requirement for ear coverage is not supported by sufficient evidence.”

The concern is that uncovered hair and ear particles may contaminate the sterile field during a procedure and lead to a surgical site infection (SSI). In reassessing the rationale for this “narrowly defined” recommendation, the groups concluded that “evidence-based recommendations on surgical attire developed for perioperative policies and procedures are best created collaboratively, with a multidisciplinary team representing surgery, anesthesia, nursing, and infection prevention.”

Serving on the panel representing the ACS, Markel said the push to use ear-covering “bouffant” surgical hats in recent years is not supported by the available evidence, including some simulation experiments in his study.

“This [committee] was one of the first times when we really had stakeholders come together about this topic,” he says. “In 2015, basically the leaders of the ACS and the AORN came to a head over the use of the bouffant-style hats. The surgeons did not feel there was a lot of evidence out there mandating wearing it. Members of AORN thought it best to cover the forehead and ears.”

Markel’s study tested disposable bouffants, disposable skull caps, and newly laundered cloth skull caps. A mock surgical procedure was conducted and airborne particulate and microbial contaminants were sampled.

“No significant differences were observed between disposable bouffant and disposable skull caps with regard to particle or actively sampled microbial contamination,” Markel and colleagues found. “However, when compared with disposable skull caps, disposable bouffant hats did have significantly higher microbial shed at the sterile field, as measured by passive settle plate analysis. When compared with cloth skull caps, disposable bouffants yielded higher levels of particles and significantly higher microbial shed.”

Thus, disposable bouffant hats should not be considered superior to skull caps in preventing airborne contamination in the operating room, they concluded.

“We showed that the bouffant caps that were mandated at that time really were not the best hat to be wearing,” says Markel, a pediatric surgeon at Riley Hospital for Children in Indianapolis.

While the study supported the use of skull caps, the upshot for the immediate future is that either hat style should be acceptable.

“The Joint Commission was a part of this group,” Markel says. “It is my understanding that they never formally cited centers for wearing one hat or the other, but they came out sort of informally and said they will not cite you if you are wearing a bouffant or a skull cap.”

Surgeons have a strong tradition of wearing skull caps, raising intangible issues of psychological identity and patient impressions of their provider. Markel found this line of questioning a little too speculative, pointing out instead the practical issues.

“I don’t know about psychological, but from a logistics standpoint people feel like they can’t hear well when they have their ears covered with the bouffant,” he said. “A lot of female nurses and doctors wear skull caps as opposed to bouffants because they feel that their hair is tighter inside those caps.”

The bottom line is that there are no definitive data on surgical site infections linked to various surgical hat wear, a study that if attempted would have to overcome a host of variables to achieve significance. Thus, Markel and colleagues used simulation, which has been criticized for its limitations.

“There are some naysayers that might argue we haven’t really shown a difference in SSIs, but I don’t know that a trial could be done to really look at that,” he says.


1. American College of Surgeons. A Statement from the Meeting of ACS, AORN, ASA, APIC, AST, and TJC Concerning Recommendations for Operating Room Attire. Available at:

2. Markel TA, Gormley T, Greeley D, et al. Hats Off: A Study of Different Operating Room Headgear Assessed by Environmental Quality Indicators. J Am Coll Surg 2017;225(5):573-581.