Ergonomics committee struggles to define MSDs

Dispute delays research agenda

The most basic questions have stumped the National Advisory Committee on Ergonomics (NACE) as it tries to set a national research agenda: Just what is ergonomics? And what is a musculoskeletal disorder (MSD)?

"It’s been troubling to me and puzzling to me why [committee members] don’t want to define the terms, yet they want to use them," says Morton Kasdan, MD, FACS, clinical professor of plastic surgery at the University of Louisville (KY).

He also takes umbrage at the use of "ergonomic" as an adjective, as in "ergonomic interventions" and "ergonomic tools." Ergonomics is the study of the interaction of the individual and his or her work environment, Kasdan says.

Panel members argued about how narrow or broad the definition of MSD should be, or even if they should use that term. The choice has implications both for science and politics. A narrow definition could exclude some body parts that are involved in workplace injuries, while a broad one could be construed as imprecise. Even using the word "disorder" implies a chronic condition rather than an acute injury.

Ultimately, the definition affects employers, who must pay for work-related injuries through workers’ compensation but balk at paying for injuries that may be caused by nonwork-related activities.

"Many of these disorders don’t have clear diagnostic criteria, so there’s a vagueness about the diagnosis as well as the etiology. That’s what gives people concern," says Audrey Nelson, PhD, RN, FAAN, director of the Patient Safety Research Center at the James A. Haley Veterans Hospital in Tampa.

The report of the research workgroup referred to "diseases and injuries including but not limited to those of the upper extremity and lower back."

The members added a reference to the definition used by the American College of Occupational and Environmental Medicine: "disorders characterized by an abnormal condition of muscle, tendon, tendon sheath, nerve, bursa, blood vessel, bone, joint, or ligament resulting in altered structure or impaired motor or sensory function."

Further discussion ensued when the issue reached the full committee.

"There is no universally accepted definition for musculoskeletal disorders," says Lisa Brooks, CIE, manager of health and safety regulatory affairs for the International Paper Co. in Memphis, TN. "These are not single disorders. They’re a group of injuries and illnesses. What you include in that group may change depending on who defines them."

Brooks suggests that NACE reach a consensus, perhaps not a unanimous one, for a definition of MSDs to be used in the research agenda. The workgroup on guidelines called efforts to define MSDs "an exercise in futility." Nonetheless, it will use data based on the definition of the Bureau of Labor Statistics for work-related MSDs.

"It would be fantastic if we could come up with a recommendation and everyone used it, but I don’t think that’s realistic," says Brooks.

Ergonomics as a field is still evolving, and reaching agreement on terminology is part of that process, says Nelson. "To me, I think precision in terms is very important, but I don’t think that should outweigh the research priorities that were identified," she says.

In fact, NACE had little difficulty agreeing on research gaps. They are:

• More research is needed to examine the validity of diagnostic techniques, including but not limited to those used in evaluating upper extremity and lower back diseases and injuries.

• More research is needed to examine the role of psychosocial factors that contribute to or impact diseases and injuries, including but not limited to those of the upper extremity and lower back.

• Studies are needed to develop additional animal models in which the effects of physical loading on living tissues can be studied in a controlled manner.

• Additional studies are needed to examine the validity and reliability of existing exposure assessment methods and develop additional methods.

• High-quality studies are needed to determine the economic impact to organizations of what are commonly described as ergonomic interventions.

• More studies are needed focusing on interactions of the acknowledged occupational and nonoccupational multifactorial causes of diseases and injuries including but not limited to those of the upper extremity and lower back.

• Additional studies are needed on the natural history of diseases and injuries, including but not limited to those of the upper extremity and lower back.

• Studies are needed of the impact of workers’ compensation and other statutory payment mechanisms on the duration of disability and other outcomes on upper extremity and lower back disorders.

• Review the consistency of definitions used by OSHA and compare to the definitions used by the medical and scientific community.