Carpal Tunnel Syndrome

Carpal Tunnel Syndrome

Courtesy Guitar Player, March 1989 issue.

There is a condition of the hand which can affect persons who flex their wrists for long periods of time. It is called Carpal Tunnel Syndrome (CTS). Although rare, musicians (especially guitarists), butchers, and keyboard users are the primary targets of this affliction which manifests itself as a tingling "pins and needles" sensation in the thumb and first three fingers. (The little finger is never affected.) Sometimes it can result in shooting pains in the hand, extending up the arm, with the greatest discomfort at night.

CTS is caused by compression or entrapment of the median nerve that runs across the palm side of the wrist through a passage between the small bones of the wrist and carpal ligament. The nerve runs to the tip of the thumb, index, and middle fingers, and half way up the ring finger. When the carpal ligament swells, it compresses the median nerve, causing discomfort. Persons born with a small carpal tunnel are most predisposed to CTS. Malnutrition and poor general health can contribute to it, and it can be caused by a severe blow to the hand or wrist. Bending the wrist inward, called "flexion," seems to contribute to CTS by compressing the median nerve under the carpal ligament.

However, a feeling of pins and needles does not necessarily mean a person has a serious condition. In fact, a mild case of CTS can be caused by leaning against a bent wrist for too long. Also, such a feeling may indicate other problems (pinched nerve in the arm or shoulder). Pregnant women are prone to getting a temporary case of CTS because of the general swelling of the body tissues which can decrease the size of the carpal tunnel. Young women seem to be more likely to experience CTS than men or older women. Persons can guard against CTS by being careful not to bend the wrist too much, although in severe cases, this may not prevent CTS but may help reduce the symptoms.

Cold temperatures can contribute to the ailment, so keeping the wrists and hands warm may help. Washing the hands in warm water and doing some warm up exercises prior to doing wrist flexing work can be beneficial.

If you think you have CTS, seek medical advice. Here are some simple tests you can conduct yourself:
  • 1. Tingling in the thumb, index, middle and lower half of the ring finger, but none in the small finger.

  • 2. Bending the wrist inward with the thumb bent in toward the palm causes a sharp shooting pain. This is called "Phalen's sign."

  • 3. Tapping on the palm side of the wrist at the crease causes a feeling like that of an electric shock. This is called "Tinel's sign."

Two diagnostic tests that a doctor might give:
  • 1. The Nerve Conduction Velocity (NCV) test in which electrodes are placed on the fingers and then the median nerve is stimulated electronically while the speed of the nerve impulse is measured.

  • 2. The Electromyography (EMG) test in which fine needles are put into the muscles that the median nerve supplies to check for motor nerve damage.

Treatment varies with the severity of the case. It can be simply wrist rest for a few days. Splinting the wrist in a slightly extended position (bent back) may solve the problem by allowing the swelling of the carpal ligament to go down, freeing the entrapped nerve. Some evidence indicates that vitamin B6 is helpful, and injections of cortisone are often effective. Acupuncture may relieve the pain of CTS.

In some cases, surgery may be suggested as the quickest (or only) cure. An operation to release the entrapped median nerve is relatively simple and usually effective, however, it usually requires a month to recover full use of the wrist, and rehabilitation exercises are recommended to build the wrist muscles back up.