From The Ergoweb® Learning Center

New Findings Could Help Workers Avoid Carpal Tunnel Syndrome

Just days after one group of researchers downgraded the importance of overuse of the wrist and hand in developing carpal tunnel syndrome (CTS), findings from other researchers suggest the angle of wrist flexion is a culprit. The findings from the two February studies adds to the list of risk factors for the painful musculoskeletal disorder (MSD), increasing the fund of ergonomics knowledge that can be applied to the task of designing tools, workstations and work processes that minimize the risks.

In carpal tunnel syndrome, the median nerve, running from the arm into the hand, becomes pressed or squeezed at the wrist. This nerve controls sensations to the thumb’s palm side and part of all the fingers except the little finger. Wrist postures that are bent or flexed cause increased pressure on the nerve.

“The scientific support for the concept [that carpal tunnel is caused by overuse] is, on average, relatively weak,” said David Ring, MD, in a news release from the American Academy of Orthopaedic Surgeons (AAOS).” The major risk factor for carpal tunnel is genetic.” Exactly what those genetic factors are is not known, he says, but they could be related to the structure of the hand and wrists. Dr. Ring is an assistant professor of orthopaedic surgery at Harvard Medical School and a hand surgeon at Massachusetts General Hospital, Boston. The findings were presented on February 16 at the 74th AAOS Annual Meeting in San Diego.

In the most recent study, reported in a news release of the Human Factors and Ergonomics Society (HFES), a group of human factors/ergonomics researchers from the University of California at San Francisco and McMaster University in Ontario, Canada, established limits on how much a wrist can be flexed before nerve damage sets in. The researchers concluded that when sustained pressure on the carpal tunnel reaches 30 mmHG, injury is likely to occur. They recommended keeping the pressure below 30 mmHG. Other recommendations: sustained wrist extension