Carpal Tunnel Syndrome

Apr 11, 2006 4:38 PM

Definition

Carpal tunnel syndrome is a disorder of the hand (caused by swollen tendons in the wrist) resulting from repetitious, forceful motion of the hands and wrists.

Description

The carpal tunnel is a narrow tunnel formed by the bones and other tissues of the wrist through which the nerves, ligaments and tendons extend to the hand. When a person repeats the same hand and wrist movements day in and day out, the excess strain causes tendons to swell and become inflamed. This repetition presses on the main nerve of the hand (the median nerve), causing pain in the hand and wrist. This is called carpal tunnel syndrome.

Causes

Carpal tunnel syndrome is more common in people who have jobs that require pinching or gripping with the wrist held bent. People at risk are typists, carpenters, grocery checkers, assembly-line workers, meat packers and mechanics, to name a few. Carpal tunnel syndrome can be associated with non-work related events; such as an injury or fracture to the wrist; diseases such as diabetes, rheumatoid arthritis; or thyroid disease, pregnancy, obesity and hobbies/activities; such as sewing, gardening and racquet sports.

Symptoms

A person may have symptoms in one or both hands, but the hand used most often will usually show the following symptoms first:

• Numbness or tingling in the hand and fingers (thumb, index and middle)
• Pain in the wrist, palm or forearm
• More numbness or pain at night than during the day
• More pain as the hand or wrist is used
• Trouble gripping objects
• Weakness in the thumb

Diagnosis

Diagnosing carpal tunnel syndrome can prove difficult because conditions produce similar symptoms. These conditions range from nerve and blood disorders, to arthritis, bursitis and tumors. If carpal tunnel syndrome is suspected, the wrist will be examined for movement restrictions and pain, and a nerve conduction velocity test or electromyography will also be conducted. Nerve conduction velocity or (NCV) is a test that measures how fast nerve impulses are conducted through the nerve. The doctor gives a mild electrical shock to stimulate a particular nerve. The shock is administered through the skin and underlying tissue. After each shock, a recording electrode (placed a set distance from the site of the shock) detects the response from the stimulated nerve. The lag between the shock and the response is measured. An electromyography or (EMG) is a test in which the electrical activity in a muscle is analyzed. By placing small electrodes on the skin over the muscle or inserting needle electrodes into the muscle, the electrical activity of the muscle contracting or at rest is recorded.

Treatment

Standard conservative treatment (lasting at least several weeks) involves wearing a wrist brace or splint, resting the injured hand, modifying the work environment and taking an anti-inflammatory medication (such as ibuprofen: brand names Advil, Medipren, Motrin, Nuprin), naproxen (Aleve), or aspirin to reduce the swelling. If the swelling, inflammation or pain is not alleviated with an anti-inflammatory drug, the doctor may inject cortisone into the carpal tunnel. Some therapists believe that vitamin B6 supplements may sometimes relieve the symptoms of carpal tunnel syndrome, particularly in women who are pregnant or taking birth control pills and are deficient in this vitamin. If conservative therapy fails, surgery is recommended if any of the following symptoms are present:

• thenar atrophy (weakness of the thumb muscles)
• acute carpal tunnel syndrome with unresolving symptoms
• carpal tunnel syndrome with trauma
• carpal tunnel syndrome mass (tumorous condition)

There are different surgical procedures designed to relieve pressure on the median nerve. The most common procedure is called open carpal tunnel release. During open carpal tunnel release, a small incision is made in the palm of the hand and the palmar fascia (membrane in the palm). Using a scalpel, the transverse carpal ligament is cut, thus alleviating pressure on the median nerve. This procedure can also be done using an endoscope and is called endoscopic carpal tunnel release. With endoscopic carpal tunnel, a small fiberoptic scope is used to find the transverse carpal ligament, thus eliminating the cutting of the palmar fascia. Another surgical procedure for carpal tunnel syndrome is balloon carpal tunnel-plasty. The procedure utilizes a balloon catheter (a small tube for passage into a structure), a pressure gauge and a custom designed nerve protector that protects the median nerve and tunnel contents during the inflation. The balloon catheter is inserted into the carpal canal through an incision in the wrist and is inflated. This stretches the ligament and makes more room for the median nerve. Post-operative Care Immediately after the operation, the wrist is likely to be somewhat uncomfortable and there may be some pain, but discomfort should not persist for more than a day or two. The patient is encouraged to move the hand and wrist as soon as possible. If non-absorbable nylon stitches were used to close the incision, they will be removed once the incision is healed; absorbable stitches are not removed. After surgery, some use of the hand will exist within a week or so. Usually, full use of the hand is achieved about six weeks after surgery. The patient may need wrist splints to support the wrist for a short time after surgery. Exercises can be performed to strengthen the fingers and keep the joints from becoming too stiff. Results from surgery are generally quite good if severe weakness has not developed. Most likely, one will be able to resume normal activities, but the patient should avoid putting too much strain on the wrist. Surgical complications include postoperative infection, acute hematoma, arterial injury, direct injury to the median nerve, postoperative pain, stiffness, reflex sympathetic dystrophy and recurrent carpal tunnel syndrome from incomplete transection of the transverse carpal ligament.