Carpal Tunnel Syndrome

The carpal tunnel syndrome results from a pinched nerve in the wrist. It includes symptoms due to nerve dysfunction, including numbness and weakness.

The end of the median nerve crosses over the wrist bones just beside the base of the thumb. Its fibers go to the abductor muscle of the thumb (which move the thumb toward the small finger) and also to the skin over the thumb and index finger. The nerve shares the narrow carpal tunnel with all of the tendons that flex the fingers. The nerve and tendons are held in place by the wrist bones below and the thick transverse carpal ligament above. The transverse carpal ligament is just underneath the skin.

If the transverse carpal ligament becomes thickened or inflamed, the size of the canal shrinks. This causes the nerve to hurt and malfunction. There can also be pain from inflamed tendons (a tendonitis).

Illustration of a wrist brace on a hand with a computer keyboard in the backgroundA number of illnesses and injuries will thicken the transverse ligament causing carpal tunnel syndrome.  These include repetitive movement (using power tools, using a computer, etc.), fractures, rheumatoid arthritis, diabetes, and acromegaly.  Fluid retention and edema from hypothyroidism or pregnancy will also cause pressure on the nerve.

Diagnosis

The symptoms of carpal tunnel syndrome include pain and numbness in the wrist, the thumb and the index fingers. The pain is often worse at night and will wake people from sleep. It is improved by shaking out the hands. The pain is also worse with prolonged use and especially with driving. If the syndrome is suspected, an EMG and nerve conduction study is performed. The test will show that the nerve impulses slow down at the wrist where the nerve is damaged.

Treatment

The first and most important issue is making sure the diagnosis is correct. Tendonitis can masquerade as a carpal tunnel syndrome. If the diagnosis is certain, wrist splints are usually prescribed. These are worn at night and when doing activities that cause pain. They work about half of the time. A cortisone injection will help symptoms, but only for a few weeks or months. The cortisone injections have some risk of damaging the nerve. In conditions where improvement is expected (like pregnancy), a cortisone injection may be considered. At other times, the temporary relief is not worth the risk of damaging the nerve.

Surgical Procedures

Illustration of hands before and after carpal tunnel surgery"Carpal tunnel release" is the name of the most common surgical procedure.  It is abbreviated as "CTR."   To perform the release, the surgeon divides the transverse carpal ligament in half.  This gives the nerve more room. The operation can be done using either a minimally invasive (endoscopic) or an open technique.  The endoscopic procedure is less painful and has a faster recovery but the risks are slightly greater than the older open surgery.

For either operation, patients are given a local anesthetic (to the hand only) or a regional anesthetic (to the whole arm, or a general anesthetic (asleep).  One type is not necessarily better or safer than the others.  Some patients like to watch the procedure and others just want to be asleep.

Results

The surgery works about ninety-five percent of the time.  It does not work all the time.  Patients can return to light work after just a few days following the endoscopic surgery. After open carpal tunnel surgery, patients return to their normal activities in a few weeks. Physical therapy helps insure a smoother recovery.

Other "cures"

Chiropractic and acupuncture may offer temporary relief.  TENS units are often helpful for the pain and can be used long term.  Non-steroidal anti-inflammatory drugs and mild painkillers are reasonable.

Other alternative treatments are unlikely to help.  Unfortunately, some unscrupulous people have advertised a great many "new" procedures and "breakthroughs" to treat carpal tunnel syndromes.  Found in popular magazines and newspapers, these may promise miracles but do not work at all.  For example, one treatment commonly touted uses a commonly available laser pointer. (such as is used during shows and presentations).  Shining a common laser pointer at the wrist does absolutely nothing except waste the patient's time and money.  The laser pointer providers often tell of amazing results but have never been able to prove that their inventions have done any good.  Beware of things that sound too good to be true. 

Go to the next page on contusions, sprains and strains.

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