Carpal Tunnel Syndrome

Carpal Tunnel Syndrome

The carpal tunnel is the passageway in the wrist and is made up of the arching carpal bones (eight bones in the wrist) and the ligament connecting the pillars of the arch (the transverse carpal ligament). The median nerve and the tendons that connect the fingers to the muscles of the forearm pass through the tightly spaced tunnel.

Carpal tunnel syndrome occurs when the median nerve becomes pinched due to swelling of the nerve or tendons or both. The median nerve provides sensation to the palm side of the thumb, index, middle fingers, as well as the inside half of the ring finger and muscle power to the thumb. When this nerve becomes pinched, numbness, tingling and sometimes pain of the affected fingers and hand may occur and radiate into the forearm.

While there are many possible causes of carpal tunnel syndrome, the vast majority of people with the condition have no known cause.

However, we do know that excessive repetitive movements of the arms, wrists or hands can aggravate the carpal tunnel bringing out the symptoms of carpal tunnel syndrome. Untreated, this can become chronic, but when detected early, carpal tunnel syndrome can be treated and recovery is possible in a few months. Severe carpal tunnel syndrome can also be treated, but recovery may take up to a year or longer and may not be complete.

What Are the Symptoms of Carpal Tunnel Syndrome?

Usually, people with carpal tunnel syndrome first notice that their fingers "fall asleep" and become numb at night. They often wake up with numbness and tingling in their hands. The feeling of burning pain and numbness may generally run up the center of the person's forearm, sometimes as far as the shoulder. As carpal tunnel syndrome becomes more severe, symptoms are noticed during the day.

What Happens in Severe Cases of Carpal Tunnel Syndrome?

When chronic irritation occurs around the median nerve, it becomes constricted and is continually pushed against the ligament above it. When the nerve is continually constricted, it can become compressed to the point that it begins to deteriorate. This results in a slowing of nerve impulses, which may cause a loss of feeling in the fingers and a loss of strength and coordination at the base of the thumb. If the condition is not treated, it could result in permanent deterioration of muscle tissue.

Do Certain Medical Conditions Make People More Likely to Develop Carpal Tunnel Syndrome?

People with rheumatoid arthritis, diabetes or other metabolic conditions like thyroid disease may be more likely to develop carpal tunnel syndrome. These conditions affect the nerves directly, making them more vulnerable to compression.

What Tests Help Diagnose Carpal Tunnel Syndrome?

Two useful clinical tests for diagnosing carpal tunnel syndrome are the Tinel and Phalen maneuvers. Tingling sensations in the fingers caused by tapping on the palm side of the wrist is a positive Tinel test, whereas reproduction of symptoms by flexing the wrist is a positive Phalen test. (Dr. Phalen created this maneuver many years ago when he was a hand surgeon at The Cleveland Clinic.)

If needed, an electromyogram, which includes nerve conduction studies, is done to document the extent of nerve damage. An electromyogram is a test that measures the electrical activity in your nerves and muscles. Nerve conduction studies measure the ability of specific nerves to transmit electrical impulses or messages.

The nerve conduction studies, however, will not become positive until there is significant nerve damage. In addition, the severity of a person's symptoms is often not correlated with the findings of a nerve conduction study.

How Is Carpal Tunnel Syndrome Treated?

There are several ways to treat carpal tunnel syndrome:

• Lifestyle changes. Treatment first involves adjusting the way the person performs a repetitive motion: Changing the frequency with which the person performs the motion and increasing the amount of rest time between movements.
• Immobilization. Treatment also includes immobilizing the wrist in a splint to minimize or prevent pressure on the nerves. Splints that support the wrist in a comfortable neutral position can be of great value if worn at night to relieve painful numbness or tingling. This can provide a restful sleep and allow the median nerve to endure daytime activities.
• Medication. Patients may be given short courses of anti-inflammatory drugs or injections of cortisone (steroids) in their wrist to reduce swelling. Injections are most successful when people have mild to moderate carpal tunnel syndrome as a result of an acute (sharp or severe) flare-up.
• Surgery. If carpal tunnel syndrome does not respond to conservative treatment, then surgery is the next treatment option. During surgery, your surgeon will open the carpal tunnel and cut the ligament, relieving the pressure. Carpal tunnel surgery is quite effective at relieving painful symptoms when the condition involves only nerve constriction.

When carpal tunnel syndrome is just one manifestation of repetitive stress, the surgery cannot be expected to relieve symptoms that are not attributable to carpal tunnel syndrome. The difficulty is not in recovering from the operation, but in recovering the ability to return to work, especially to the same job that caused the repetitive disorder to occur. Whether or not true carpal tunnel symptoms recur in these patients, many continue to have pain and are unable to use their hands to any great extent.

What Can I Do To Prevent Carpal Tunnel Syndrome?

To help prevent carpal tunnel syndrome:

• Sleep with your wrists straight or use a splint.
• Keep your wrists straight when using tools but try not to use splints.
• Avoid flexing and extending your wrists repeatedly.
• Perform conditioning and stretching exercises.