Facts of Life
Facts of Life:
Issue Briefings for Health Reporters
Vol. 9, No. 6
June 2004
Is There Light at the End of the Carpal Tunnel?
The Issue
The Facts
Curing Carpal Tunnel Syndrome
Expert Sources
References
The Issue:
Although
often considered a white-collar malady, carpal tunnel syndrome and other
repetitive stress disorders are injuries caused by frequent unvarying use
of part of the musculoskeletal system. Repeated point-and-click motions may
be the most publicized culprit, but repeated movements to assemble parts
on a factory line and frequent use of motorized hand tools probably cause
more cases of carpal tunnel syndrome. Repetitive stress injuries ranked among
the top three causes of workplace injuries in 2002, costing more than $60
billion in lost wages, health care expenses, legal costs and worker’s
compensation claims. [1].
Making the Diagnosis
The carpal
tunnel syndrome diagnosis is very specific, involving inflammation and
compression of the nerve and tendons that run through the carpal tunnel,
a narrow passage linking the arm and hand that is created by the bones
of the wrist and a tough ligament that binds the bones together. In common
use, painful conditions like tendonitis and osteoarthritis get lumped under
the complaint of “carpal tunnel,” making it difficult to determine
what to treat.
Although research on carpal
tunnel syndrome has centered on work habits and ergonomically unsound environments,
recent studies suggest that factors like gender, obesity and overall stress
levels could affect the risk of developing the syndrome and determine its
severity.
The Facts:
- Several studies
suggest that women, people between the ages of 41 and 60 and those
who are obese are more likely to have carpal tunnel syndrome. [8] A long-term
study of industrial workers suggests a link between carpal tunnel
syndrome
and cigarette smoking. [9]
- Rates of carpal tunnel syndrome increase with age for men, while the
rates for women are highest between ages 45 and 54. [5]
- Psychological distress may raise the risk of carpal tunnel syndrome.
[10, 11]
- A 2003 study found “no compelling scientific basis” behind
genetic tests for carpal tunnel syndrome risk given to 20 railroad
workers seeking injury compensation from their employer. [4]
- Office machinery and
hand tools caused more than 60 percent of carpal tunnel syndrome diagnoses
in a Massachusetts
workers’ comp
case study. [2]
- Medical data-entry workers who extended their wrists more than 20 degrees
while typing were at greater risk of developing carpal tunnel syndrome
than their co-workers, according to a Taiwanese study. [2]
- A study of people who
use computers for seven or more hours a day found no significantly higher
incidence of
carpal tunnel syndrome than
in the general population, suggesting factors other than repetitive tasks
may
affect the disease’s development. [14]
- New Hampshire employers who received regular inspections from local
Occupational Safety and Health Administration officials saw a decline
in the annual
rate of carpal tunnel syndrome among their workers, from 38 cases
in 10,000 to 3.8 cases in 10,000 over a five-year span. [7]
- A carpal tunnel diagnosis involves more than pain: Only 1.4 percent
of 5,658 Danish computer workers in a yearlong study had the full
array of symptoms that are normally associated with carpal tunnel syndrome.
[3]
- Increased breathing rate and muscle tension across the upper body can
accompany tasks like typing and using a computer mouse, possibly
contributing to carpal tunnel syndrome even at ergonomic work stations. [13]
- Surgical treatment relieves symptoms better than splint treatment in
moderate to severe cases of carpal tunnel syndrome, according to
a review of published studies. [6]
- Highly repetitive tasks can damage bone in rats, suggesting that tasks
like typing or hand tool use may cause similar damage in humans with
carpal tunnel syndrome and other musculoskeletal disorders. [12]
Curing
Carpal Tunnel Syndrome
Factory or office workers with a sore wrist, shooting
pains up an arm and a crippled grip can testify to all the splints,
pills and exercises they have tried in an attempt to find a cure for
their condition. But as physicians readily admit, the exact diagnosis
behind carpal tunnel syndrome and other repetitive stress disorders
that affect the musculoskeletal system is still being debated. And
it can be difficult to treat a disease unless its specific causes are
well known.
“Because there are still so many questions about the underlying
conditions, there’s uncertainty about the best type of treatment,” says
Ann Barr, P.T., Ph.D., of Temple University. “Sufferers are often
prescribed a package of treatments, including physical therapy, ergonomics
and medication, and we’re not sure which treatment is actually
working.”
Barr
and her colleagues in the Temple School of Health Professions and
School of Medicine
were recently awarded a $1.7 million grant from
NIH’s National Institute of Arthritis and Musculoskeletal and
Skin Diseases to find out whether work injuries caused by repetitive
stress can be treated before they turn into a chronic disability.
Their
five-year study will look at which treatments, from ergonomic work
stations to doses of
non-steroidal anti-inflammatory drugs like
ibuprofen, work best for keeping conditions like carpal tunnel under
control. Although such treatments are already commonly prescribed,
Barr says it’s still not certain whether any of them “actually
heal tissue.” The team hopes to identify the specific biological
effects of each treatment type so that therapy can be better matched
to a patient’s exact complaint.
Earlier
research by Barr and colleagues sheds some light on the damage inflicted
by repetitive
motions — in rats. The researchers found
that rats trained to reach for food pellets over and over again with
the space of a few hours developed signs of inflammation and reabsorbed
bone in their wrist and shoulders after 12 weeks. The low-stress repetitive
reaching is similar to motions that occur while typing or continually
placing parts on a factory assembly line, the scientists suggest, although
they acknowledge only clinical studies can determine if those movements
produce the same damage to human skeletal joints.
So far, researchers like Barr are concentrating on ways to keep repetitive
stress injuries from getting worse. The biological studies could highlight
certain behaviors that increase the risk of carpal tunnel syndrome
and similar disorders and suggest changes in work patterns and environments.
Barr says, however, that it is hard to get people to change their behaviors
before they start feeling significant pain or discomfort, at which
point the damage has already been done.
Expert
Sources:
Ann E. Barr, P.T., Ph.D.
Temple College of Health Professions
(215) 707-5964
aebarr@temple.edu
Kurt T. Hegmann, M.D., M.P.H.
University of Utah School of Medicine
(801) 587-3333
khegmann@dfpm.utah.edu
Alan Hedge, Ph.D., C.P.E.
Cornell University
(607) 255-1957
ah29@cornell.edu
Marie Haring-Sweeney
National Institute for Occupational Safety and Health
(513) 533-8339
marie.sweeney@cdc.hhs.gov
References
1. News release,
August 31, 2002. American Academy of Orthopaedic Surgeons: “Musculoskeletal
Disorders Are the No. 1 Workplace Injury in America.” Last accessed
at http://www.newswise.com/articles/view/31441/ on May 10, 2004.
2. Wellman, H. et al. (2004) Work-related carpal tunnel syndrome (WR-CTS)
in Massachusetts, 1992-1997: source of WR-CTS, outcomes, and employer
intervention practices. American Journal of Industrial Medicine, 45,
139-152.
3. Liu, C.W. et al. (2003) Relationship between carpal tunnel syndrome
and wrist angle in computer workers. Kaohsiung Journal of Medical
Science,
1112, 617-623.
4. Andersen, J.H. et al. (2003) Computer use and carpal tunnel syndrome:
a 1-year follow-up study. Journal of the American Medical Association,
289, 2963-2969.
5. Schulte, P.A. and G. Lomax (2003) Assessment of the scientific
basis for genetic testing of railroad workers with carpal tunnel syndrome.
Journal of Occupational and Environmental Medicine, 45, 592-600.
5. Nakasato, Y.R. (2003) Carpal tunnel syndrome in the elderly. Journal
of the Oklahoma State Medical Association, 96, 113-115.
6. Verdugo, R.J. et al. (2003) Surgical versus non-surgical treatment
for carpal tunnel syndrome. Cochrane Database of Systematic Reviews,
3, CD001552.
7. May, D.C. (2002) Results of an OSHA ergonomic intervention program
in New Hampshire. Applied Occupational and Environmental Hygiene, 11,
768-773.
8. Becker, J. et al. (2002) An evaluation of gender, obesity, age
and diabetes mellitus as risk factors for carpal tunnel syndrome. Clinical
Neurophysiology, 1113, 1429-1434.
9. Nathan, P.A. et al. (200222) Predictors of carpal tunnel syndrome:
an 11-year study of industrial workers. Journal of Hand Surgery, 24,
644-651.
10. Roquelaure Y. et al. (2001) Prevalence, incidence and risk factors
of carpal tunnel syndrome in a large footwear factory. International
Journal of Occupational Medicine and Environmental Health, 14, 357-367.
11. Lundberg, U. (2002) Psychophysiology of work: stress, gender,
endocrine response, and work-related upper extremity disorders. American
Journal of Industrial Medicine, 41, 383-392.
12. Barr, A. E. et al. (2003) Repetitive, negligible force reaching
in rats induces pathological overloading of upper extremity bones.
Journal of Bone and Mineral Research, 18, 2023-2032.
13. Peper, E. et al. (2003) The integration of electromyography (SEMG)
at the workstation: Assessment, treatment and prevention of repetitive
strain injury (RSI). Applied Psychophysiology and Biofeedback, 28,
167-182.
14. Stevens, J.C. et al.
(2001) The frequency of carpal tunnel syndrome in computer users
at a medical facility. Neurology, 56, 1568-1570.
The Center for the Advancement
of Health is an independent nonprofit organization that promotes
greater recognition of how psychological, social, behavioral,
economic and
environmental factors influence health and illness. The Center advocates the highest
quality research and communicates it to the medical community and the public. The
fundamental aim of the Center is to translate into policy and practice the growing body of
evidence that can lead to the improvement and maintenance of the health of individuals and
the public. The Center was founded by the John D. and Catherine T. MacArthur Foundation
and the Nathan Cummings Foundation, which continue to provide core funding. Funding for
this series was provided by the Robert Wood Johnson Foundation.
For Information Contact:
Kristina Campbell
Editor, Health Behavior News Service
Center for the Advancement of Health
2000 Florida Ave., NW, Suite 210
Washington, DC 20009
p. 202.387.2829 / f. 202.387-2857
press@cfah.org
http://www.cfah.org
© Copyright 2004, Center for the Advancement of Health
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