Carpal Tunnel Syndrome

by Eric T. Ortinau, MD

Carpal Tunnel Syndrome (CTS) is the most common and well-known of the compression neuropathies (pinching of a nerve). It is estimated that 1 million adults in the United States are treated each year for CTS. The growing exposure of CTS and its causes has led to an increase in awareness and prevention, particularly in the workplace. The condition arises when the median nerve (1 of 3 main nerves to the hand) becomes compressed or pinched at the level of the wrist.

The median nerve travels from the neck, down the upper arm and forearm, across the wrist, into the carpal tunnel. A ligament (the transverse carpal ligament) from above and several bones of the hand from below form this tunnel. The median nerve and several tendons emerge from underneath this ligament and travels to the thumb, index, long, and part of the ring finger. Another branch to the median nerve also goes to the group of muscles just below the thumb. CTS occurs when this ligament becomes thickened or inflamed, causing the median nerve to be pinched inside the carpal tunnel. The synovium (lubricating tissue around the tendons) inside the carpal tunnel may also become inflamed, further pinching the nerve.

The main cause of CTS seems to be related to repetitive, forceful motion of the hand that causes irritation of the nerve, thickening of the ligament, and inflammation of the synovium. Certain occupations employing this type of wrist movement can play a part in this process. CTS can also be part of "double crush syndrome", which consists of pinching of the median nerve at the level of both the wrist and the neck. Other causes of CTS include rheumatoid arthritis, thyroid disorders, and pregnancy.

CTS can present as numbness and/or tingling of the involved fingers or as heaviness, clumsiness, or pain in the hand. Any of these symptoms may arise during prolonged, repetitive motion of the hand and wrist. The numbness or tingling tends to be common at night and one may wake up and shake his or her fingers to "wake them up." The pain from CTS can radiate not only into the fingers, but up into the forearm or upper arm. CTS is diagnosed by physical examination and/or by a nerve conduction test. Examination by your physician may include tapping the wrist over the nerve or holding the wrist in a certain bent position to reproduce the classic CTS symptoms. A very advanced sign of carpal tunnel syndrome may be the wasting away of the muscles below the thumb. The nerve conduction test may be ordered right away to diagnose CTS or later when surgery is being considered. This study measures how fast nerve impulses are traveling and CTS will show delay in this conduction at the level of the wrist.

Conservative treatment is almost always attempted first for CTS, especially for new onset patients. Anti-inflammatory medicines to decrease ligament and synovial swelling are commonly prescribed. Splints to keep the hands in a favorable position can be worn at night and/or at work. Activity or work modification may also improve the symptoms of CTS. Many modifications in the workplace including chair height, palm rests, keyboard orientation, and elimination of certain repetitive motions have already been implemented by many employers. Other methods of conservative treatment may include Cortisone injection, which give variable results but may be harmful to the nerve itself. Alternative methods including yoga, acupuncture, and manipulation have been tried by some with limited results.

Surgery for CTS is usually recommended when 6 to 12 weeks of conservative therapy have not provided relief. Currently, the most common surgical procedure performed for CTS is a mini-open carpal tunnel release. A small incision (less than one inch long) is made in the palm and the thickened ligament is cut relieving the pinching and pressure on the underlying nerve. The ligament heals in its newly released position with more room for the nerve and tendons to function in the carpal tunnel. This mini-open incision seems to have replaced the older larger incisions and appears to be just as effective with less risk than the newer endoscopic carpal tunnel release techniques. The surgery itself is an outpatient procedure, which takes roughly ten minutes. A splinter bulky dressing is used for 7 to 10 days. The stitches and dressing are then removed and therapy for motion and strengthening may be implemented. In general, patients might return to typing or computer work as soon as 3 weeks and heavy labor or lifting as soon as 4 weeks after surgery.

The results of CTS are generally very favorable. The majority of patients have a very good result with decrease or disappearance of the tingling, pain, or heaviness in the hand and increase in hand strength. Many patients will have relief within 24 hours of surgery, but complete relief may take days or even months and relief may occasionally be incomplete.

CTS is certainly a common entity in our population today. It is a condition that is readily diagnosed and treated with largely excellent results. If you feel that you may have developed or are developing CTS, you may wish to contact us for an evaluation.