Q: My hands and wrists sometimes ache after I’ve spent many
hours on my computer for several days in a row. I thought I had
carpal tunnel syndrome, but my doctors says it’s a repetitive
stress injury. What’s the difference?
By The Faculty of Harvard Medical School
Q: My hands and wrists sometimes ache after I’ve spent many hours on my computer for several days in a row. I thought I had carpal tunnel syndrome, but my doctors says it’s a repetitive stress injury. What’s the difference?
A: Many people are confused about these two conditions, probably because carpal tunnel syndrome is sometimes described or classified as a repetitive stress injury.
But that’s incorrect. Although both problems can cause hand pain, the underlying causes and other symptoms are different.
Carpal tunnel syndrome occurs when the median nerve (one of the three main nerves that pass through the wrist to the fingers) is compressed or pinched.
This usually occurs as the nerve passes through a tunnel of tough fibers that runs between small bones in the wrist – the carpal tunnel.
The classic symptoms are pain, weakness and tingling in the thumb, index finger, middle finger and half of the ring finger.
About 2 percent to 3 percent of the general population has carpal tunnel syndrome.
Women are about twice as likely to develop carpal tunnel syndrome as men, and the risk increases with age. It’s thought to arise from a combination of factors that increase pressure on the median nerve and surrounding tendons.
These factors include having a small carpal tunnel; a history of certain diseases such as diabetes or rheumatoid arthritis; or a previous bone dislocation or fracture.
Being overweight or obese increases the risk; so does pregnancy. Keeping your wrists bent (see illustration) while sleeping, reading or driving also appears to increase the risk.
Certain jobs that involve assembly-line work – for instance, manufacturing, sewing, cleaning and meat-, poultry-, or fish-packing – can also make people more prone to carpal tunnel syndrome.
But despite widespread belief, using a computer does not appear to increase the risk for carpal tunnel syndrome. A study of more than 5,600 Danish workers, published in the Journal of the American Medical Association in 2003, found that workplace computer use does not pose a risk of developing carpal tunnel syndrome.
And a 2001 study in Neurology of computer users at a medical facility found that heavy computer use (up to seven hours a day) did not increase a person’s risk of developing carpal tunnel syndrome.
However, computer use clearly can contribute to repetitive stress injuries, also known as repetitive strain injuries or overuse syndrome.
These work-related medical conditions, which affect the neck, shoulders, arms and hands, fall under the broad category of musculoskeletal disorders.
One common example is hand and wrist pain caused by repetitive finger motions and contracting the forearm and wrist muscles for long periods of time. Incorrect positioning of the keyboard and computer mouse, remaining in a seated posture, and gripping a computer mouse for long time periods can also contribute to these problems.
If you have a repetitive stress injury from computer overuse, it’s a good idea to have an evaluation of your workspace by an ergonomic specialist.
These experts can teach you how to avoid habits that may put you at risk for repetitive stress injuries. If that’s not possible, the following tips may help:
–Keep your wrists in a neutral position, not flexed downward or extended upward, when using your computer.
To check, place your wrist, palm facing down, on a flat, hard surface.
Put a Band-Aid lengthwise over the top of your wrist, and then move to your keyboard and type. If the Band-Aid stretches or goes slack, your wrists aren’t in a neutral position.
–Get up from your desk and stretch at least once every hour. In between, take shorter breaks to rest your hands, palms up, on your lap or on a wrist rest.
You can install software on your computer that reminds you to take micro-pauses or rest breaks and restricts your daily time on the computer.
–Be skeptical about new keyboard configurations (such as split keyboards) or mouse designs claiming to be ergonomic.
It will take many years of study to learn whether such changes translate into fewer work-related upper-extremity musculoskeletal disorders.
Submit questions to the Harvard Medical School Adviser at www.health.harvard.edu/adviser. Unfortunately, personal responses are not possible.
