Carpal Tunnel Syndrome

What Is Carpal Tunnel Syndrome?

The carpal tunnel is located at the juncture of the palm and wrist. The actual “tunnel” suggested by the name is mainly formed by four carpal bones. These form an archway, allowing passage of certain tendons and nervous tissue into the palm, roughly in the direction of the thumb. These control some of the movement, sensation, and functions of the hand. The median nerve that runs through the carpal tunnel confers sensation to the index finger, middle finger, thumb, and the part of the third finger nearest to the palm. This nerve also controls some of the muscles of the thumb. Carpal tunnel syndrome may occur if the carpal arch is somehow congested, is subject to excessive internal pressure, or otherwise becomes impinged upon.

Symptoms associated with carpal tunnel syndrome include:

• Pain that is intense and spread throughout the arm, but may also be reduced or dispelled by flicking or shaking the hand
• Impaired motion in the thumb or hand
• Numbness in the thumb or fingers served by the medial nerve
• Tingling sensation in the affected hand or fingers
• Stiffness in the affected hand on waking

Carpal tunnel syndrome is associated with compression of the median nerve and tendons as they travel through the carpal tunnel. This may be caused by an abnormal build-up of material within the synovial membranes of the carpal tunnel. These membranes are present to protect and cushion the tendons as they pass through the tunnel. Any significant swelling in these membranes reduces the space within the carpal tunnel and may result in the symptoms mentioned above. Swelling in the other soft tissues in or around the arch can also result in carpal tunnel syndrome.

Symptoms of carpal tunnel syndrome can gradually become worse and culminate in a loss of sensation or motor control in the affected hand. Carpal tunnel syndrome is thought to be more prevalent in women. Estimates suggest that it is present in approximately 9% of women, compared to 6% of men.

Causes of Carpal Tunnel Syndrome

Some researchers do not agree on the factors associated with carpal tunnel syndrome. There is a slightly controversial theory that it is associated with repetitive movements of the hands or fingers, such as those involved in long-term typing. Some claim that there is little or no actual evidence to support this claim. However, many observational studies and reports conclude that occupations such as office work, healthcare, and the service industry are associated with an increased probability of complaints of carpal tunnel by the people employed in them. Some cases of carpal tunnel syndrome arise with no association to any of these factors or conditions. Other cases of carpal tunnel syndrome may be associated with a variety of disorders and conditions associated with increased soft-tissue swelling. Examples of these include:

• Many forms of arthritis, including rheumatoid arthritis
• Diabetes
• High blood pressure
• Hypothyroidism
• Gout
• Obesity
• Pregnancy

Treatments for Carpal Tunnel Syndrome

There are many treatment options that address the effects of carpal tunnel syndrome. First-line treatment, or treatment for mild to moderate cases, include splinting. This involves fitting the hand with a device similar to a cast or brace. This keeps the wrist in a position that limits the pressure on the carpal tunnel, i.e. a neutral position, without bending or flexing the wrist. The splint may only need to be worn at night, which prevents wrist positions that increase carpal arch compression during sleep, but can also be effective if worn during the day. Wearing a splint may be more suitable for those who do not want to go through more advanced procedures, such as surgery. However, some studies suggest that splinting is not an effective long-term solution for carpal tunnel syndrome.

Other conservative lines of treatment involve drug therapy. The pain of carpal tunnel syndrome is often elicited by inflammatory molecules released by the compressed tissues that irritate the median nerve. Therefore, drugs that can reduce inflammation, or inhibit its production, may be effective in some cases of carpal tunnel syndrome. These drugs include corticosteroids. Steroid drugs may be given orally, or in the form of an injection directly into the affected area. This may reduce pain, and also contribute to the control of swelling within the carpal arch. Steroid therapy is generally recommended for short-term treatment of these symptoms, as prolonged use is associated with adverse events such as gastrointestinal disorders, organ damage, and increases in bodyweight. Corticosteroid therapy may also result in the side effect of additional pressure within the carpal arch, resulting in an increase of symptom severity.

Alternative drugs to treat pain in this condition include non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen. However, some studies have shown that these have minimal or short-term effects on pain relief in cases of carpal tunnel syndrome. Other alternatives include local anesthetics such as procaine, lidocaine, or tetracaine. These are generally administered by injection, in a manner similar to that of corticosteroid injections. Local anesthetics may also be delivered via a transdermal patch, which has been found to be associated with significant pain relief.

The last resort in carpal tunnel syndrome treatment is often surgery. These interventions can result in effective and long-term relief from pain or sensory disturbances resulting from carpal tunnel compression. Surgery involves slicing the transverse carpal ligament, which forms the “floor” of the tunnel (when the hand is placed palm down), in two. This releases the pressure on the median nerve, thus effectively reversing numbness or pain. This option is associated with significant reduction in pain and other symptoms in mild, moderate and severe cases of carpal tunnel syndrome. Surgery for carpal tunnel syndrome may result in complications such as scarring, impaired grip strength, and pain in the top half of the hand.

Conclusion

Carpal tunnel syndrome is a condition in which the median nerve or tendons of the hand are compressed as they travel through the carpal arch away from the rest of the arm. This may result in increased weakness, loss of sensation, or pain in the affected extremity. Carpal tunnel syndrome has a somewhat controversial link to repetitive strain encountered in many occupations that require hand and finger movements such as typing. It is also associated with conditions such as pregnancy, diabetes, and hypertension. Treatment for carpal tunnel syndrome range from drugs, such as steroids or local anesthetics, to surgery. A discussion with your physician or pain specialist will result in effective treatment for your case of carpal tunnel syndrome.

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