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Serving as an electrical connection between three and a half fingers and the spinal cord, the median nerve courses down the arm and eventually through a tunnel in the wrist. The flexor tendons which bend the fingers run through this same tunnel, making the space rather tight. Carpal tunnel syndrome (CTS) occurs when the median nerve is pinched or compressed, causing a sometimes progressive disorder which may lead to wrist pain and numbness as well as tingling in the hands and certain fingers. There may be associated weakness in grip and a feeling of incoordination.
Some people are more likely to get carpal tunnel syndrome than others. For example, people who are born with small tunnels in the wrist or who have a tendency to collect fluid around their tendons and joints are more likely to have problems with pressure on the median nerve. Repetitive activities with intensive hand use--such as assembly line work or typing--can further aggravate their condition by irritating the flexor tendons, which in turn causes the tendon linings to swell and put pressure on the median nerve.
CTS also occurs more often in women than men, usually between the ages of 30 and 70 years. People who have medical problems such rheumatoid arthritis, hypothyroidism, diabetes, and renal failure are also more likely to develop carpal tunnel syndrome. These conditions create varying degrees of swelling, inflammation and susceptibility of nerves to injury.
Since office activities can sometimes exacerbate CTS, it is a good idea to examine the way you work. Activities which keep your wrists in a flexed position for long periods of time--such as resting your forearms on the edge of your desk, using a keyboard that is placed too high or too low, and repetitive filing with flexed wrists--should be modified. Lower or raise your work surface if necessary. Also, keep your wrists neutral when filing and writing for long periods. Be careful about suddenly increasing the time you spend on these activities, i.e. typing for three days straight to finish a report--even though you rarely type. Conditioning is not just important to athletes. In order to help avoid musculoskeletal ailments, everybody needs to have adequate conditioning for whatever activities they pursue.
Common symptoms of carpal tunnel syndrome include wrist pain and numbness as well as tingling in the hands, mostly in the thumb, index, middle and half of the ring finger; loss of grip strength; loss of dexterity; a pins and needles feeling that gets worse at night and occasionally swelling. The symptoms may first occur during the night, because the hand at rest allows the fluid pressure to build up on the nerve. When the condition advances, symptoms occur during waking hours as well, perhaps while driving, typing or doing other activities which involve frequent or continuous wrist flexion.
If a patient is experiencing any of the above symptoms, a physician--after a complete history and physical exam--may choose to order electrical testing of the nerve function. Electrodiagnostic testing is a useful adjunct to the physical examination in many cases of carpal tunnel syndrome. Usually performed by a neurologist, this testing has two parts. The nerve conduction test measures the speed at which the electrical signals are being carried from the brain to and from the hand via the median nerve. Electromyography evaluates the electrical activity of the muscles, looking for any abnormalities including evidence of muscle atrophy.
It is important to note that just the presence of abnormalities on the electrodiagnostic test does not make the diagnosis. These tests are only to corroborate and clarify a clinical diagnosis of carpal tunnel syndrome made after a good history and physical examination.
The treatment for CTS varies depending on how far the disease has progressed. In the early stages, noninvasive procedures such as a removable wrist brace or anti-inflammatory medicines can be used. Braces hold the wrist straight, thereby keeping the tunnel as wide as possible and often reducing symptoms. A physician may also identify the activities which bring on the pain and suggest alternatives--such as alternating activities, taking breaks or setting up a work site to minimize irritation. Later on, a cortisone injection into the carpal tunnel can be helpful by decreasing swelling in the flexor tendons and taking pressure off nerves.
When these non-surgical treatments fail to eliminate the symptoms, surgical intervention may be necessary to decompress the median nerve and relieve the symptoms. Generally an outpatient procedure under local anesthesia, carpal tunnel surgery involves cutting the ligament at the top of the carpal tunnel to widen the tunnel and make more space for the nerve and tendons. Following the surgery, the hand is kept bandaged for several days, and elevating the hand and moving the fingers can further keep swelling to a minimum and speed recovery. Generally, depending on the pre-operative severity, the patient will be able to resume normal activities between 4 to 8 weeks after surgery, although it may take several months to reach maximum strength.
