A common source of hand numbness, weakness and pain, carpal tunnel syndrome is caused by increased pressure on the median nerve which enters the hand from the forearm through an area called the carpal tunnel.
What causes carpal tunnel syndrome?
Eight bones make up the wrist. These carpal bones form a "C" shaped ring covered by the transverse carpal ligament. The carpal ligament is part of the tissue that holds the wrist joint together. The ligament and bones form the narrow carpal tunnel through which the median nerve and the tendons that flex the fingers and thumbs pass. This carpal tunnel is only about as big around as thumb. If there is swelling in the carpal tunnel or something else takes up space, there is even less room and the medial nerve is likely to get pinched or pressured.
There are several possible reasons for developing carpal tunnel syndrome, including:
- Repetitive strain or overuse: A combination of repetitive, forceful and awkward or stressed motions of hands and wrists, especially when done for prolonged periods without rest, may cause carpal tunnel problems. Using vibrating power tools and heavy assembly line work are two common causes of such injuries.
- Physical characteristics: In some people, the carpal tunnel is smaller than in others. Also, some people have other mechanical problems in the wrist joint that cause pressure on the median nerve.
- Certain diseases and conditions: Thyroid problems, diabetes, rheumatoid arthritis, fluid retention during pregnancy or menopause, a cyst or tumor in the canal, and other conditions make someone more susceptible to carpal tunnel syndrome.
- Injury: Trauma or injury to the wrist, such as a sprain or fracture, can cause swelling in the carpal tunnel area.
What are the symptoms of carpal tunnel syndrome?
Symptoms usually begin gradually and can occur both at night while at rest and during the day with activity. The most common symptoms may include:
- Pain, numbness or tingling in the palm of the hand, the palm side of the wrist and forearm, and the fingers (except the little finger).
- A feeling of swollen fingers, though they may not look swollen.
- A sense of weakness in the hand and a tendency to drop things.
- Possible difficulty telling the difference between hot and cold to touch.
How is carpal tunnel syndrome treated?
The earlier treatment is started, the more effective it is for patients.
The first step for treating carpal tunnel syndrome is non-surgical care. In many cases, these treatments are successful. Treatments may include the following:
- Rest and immobilization: The first treatment generally involves resting the affected hand and wrist by avoiding activities that may worsen symptoms. In many cases, an immobilizing wrist brace or splint is worn during activities that aggravate symptoms and/or at night to keep the wrist in a natural position during sleep.
- Medication: Over-the-counter pain relievers and anti-inflammatory medications can lessen pain and swelling.
- Activity alteration: Taking frequent breaks from repetitive activities and stretching before and after activities may help.
- Injections: A corticosteroid injection may provide temporary relief.
- Treating other conditions: If carpal tunnel syndrome is caused by an underlying physical problem, such as diabetes or water retention from pregnancy, treating the underlying condition will often relieve carpal tunnel symptoms.
Carpal tunnel release surgery is the most common surgical procedure. The surgery is done on an outpatient basis, so it does not normally require an overnight hospital stay.
Surgery is often required on both wrists, though both are not operated on at the same time. It may take several weeks to a few months after surgery for complete use of the wrist and hand to return.
The most common form of surgery is open release surgery. In this procedure, an incision of up to two inches long is made in the wrist and then the carpal ligament is cut to enlarge the carpal tunnel and release pressure on the median nerve.