Science Ambiguous On Ergonomic Injuries
Science seems to be muddying, not clarifying, the connection between the workplace and musculoskeletal ailments.
In June, the Mayo Clinic released a study that found that extensive computer use does not increase an individual's risk of carpal tunnel syndrome.
The study, published in Neurology, the journal of the American Academy of Neurology, looked at a group of Mayo Clinic employees who spent up to seven hours a day on computers. The study found that only 10.5 percent of the participants met the clinical criteria for CTS, a result reportedly similar to that found in the general population in previous studies.
Earlier this year, the National Academy of Sciences released a report on ergonomic injuries that had both proponents and opponents of ergonomic regulations claiming victory. (See NU, Jan. 22, page 1.) According to the NAS report, the "weight of evidence" justified identifying several work-related factors for the occurrence of musculoskeletal disorders of the lower back and upper extremities.
However, the report also stated that "psychosocial" factors–including job dissatisfaction, monotonous work and high stress–were associated with upper extremity disorders.
Bruce C. Wood, assistant general counsel at the Washington-based American Insurance Association, believes the NAS study "vindicates the judgment of those who want to ensure through various means that a repetitive injury truly happened in the workplace."
However, he is not convinced that the Mayo Clinic study alone will affect "the compensability or non-compensability of a repetitive motion injury." He pointed out that the study was of a very small group, CTS is only one kind of repetitive motion injury, and most states require workers' compensation claimants to show only that work was one contributing cause.
Similarly, Clayton A. Peimer, professor of orthopedic surgery and chief of hand surgery at the University at Buffalo, State University of New York, stated that "scientifically valid studies" require "a very large group of patients" in order to screen out a number of risk factors that may be present.
As an example, Dr. Peimer, who stressed that he was not speaking as an epidemiologist, indicated that due to large population studies and an extensive history of experience, it has been known since the mid-1930s that "patients who are heavier, older and female are more likely to have CTS." (In fact, J. Clarke Stevens, an M.D. who co-conducted the Mayo Clinic study, has said that the major risk factors for developing CTS "are being female and middle-aged.")
Additionally, Dr. Peimer stated that studies have shown that endocrine diseases such as thyroid abnormalities, pancreatic conditions such as insulin and diabetic abnormalities, and arthritic conditions increase the risk of CTS.
Nancy Schroeder, assistant vice president for workers' comp at the National Association of Independent Insurers in Des Plaines, Ill., also believes that additional scientific studies must be performed. "It's in everyone's interest, particularly the insurers that are paying workers' compensation claims, to find out more about gradual injuries, what causes them, whether they are work-related and how they could be prevented," she said.
Dr. Peimer, one of the first U.S. physicians to use the single-portal endoscope in a minimally invasive procedure for carpal tunnel release, acknowledged that there are activities that put people at risk. "So your body mass is up, you're older, your circulation is a little different and you're having some symptoms provoked by prolonged activities such as typing, holding the phone or driving–does that mean it's work-related?" he asked. "You're only at work eight hours a day; there are 16 other hours where you get to do other things."
In the past, people who performed heavy farm or industrial work often learned to live with their symptoms of musculoskeletal disorder, often at their physicians' suggestion, Dr. Peimer noted.
To some extent this is true even today. While working in Africa, he saw individuals performing heavy labor and walking for miles for nourishment. "If you're trying to survive day-to-day trying to get enough water and food your hand being numb was just not something you would necessarily pay attention to."
Dr. Peimer also has noticed that patients who are not paid for time off, such as businessowners, physicians and farmers, tend to return to work quickly even after surgery for carpal tunnel release.
In marked contrast, studies have shown repeatedly that "disability time increases when patients are on workers' compensation," Dr. Peimer said.
Keith Lessner, vice president of safety and environment for the Alliance of American Insurers in Downers Grove, Ill., said his organization advocates applying what is already known about repetitive motion injuries "in a way that makes sense." But the Alliance also believes that "our public policy approach ought to be evolving and staying even with what we know," he added.
"As we learn more, we can have a more effective, more broad-reaching public policy. But if we get ahead [of scientific knowledge] we face the same problems [as] with the Clinton proposal. If we get behind it, we're going to leave people exposed who do not necessarily need to be exposed," Mr. Lessner cautioned.
Reproduced from National Underwriter Property & Casualty/Risk & Benefits Management Edition, August 27, 2001. Copyright 2001 by The National Underwriter Company in the serial publication. All rights reserved.Copyright in this article as an independent work may be held by the author.
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