Carpal tunnel syndrome is the term given to the syndrome which arises when the median nerve, traveling through the "tunnel" of the wrist bones, is compressed by the tendons which also run through the carpal tunnel. The nerve responds to this compression by sending back pain signals, and by not carrying normal information, which provides sensation and motor impulses to the hand.
back to topCarpal tunnel syndrome is common, affecting 0.1% of the general population, and as many as 15% of workers in high-risk industries, such as electronic parts assemblers, musicians, and dental hygienists. Although the use of highly repetitive wrist movements appears to be correlated with the development of carpal tunnel syndrome, other factors, such as medical conditions like diabetes, rheumatoid arthritis, thyroid disease, and pregnancy may be even more important. Nonetheless, the incidence rises with increasing repetition of hand use (such as typing), and by a high level of force with each motion, (such as meat packers), in whom the incidence of carpal tunnel syndrome has been reported as high as 15%.
back to topThe diagnosis of carpal tunnel syndrome is suggested by the presence of numbness, tingling, and pain in the area of distribution of the median nerve, which includes the thumb, index, middle and ring fingers. The pain is often worse at night, and can radiate to; that is, feel as though it is coming from, the forearm and arm.
However, not everyone with these symptoms has carpal tunnel syndrome. Other conditions which can cause these symptoms include arthritis or disc disease in the vertebrae of the neck, general problems with peripheral nerves, and a compression syndrome of the median nerve closer to the spinal cord than the wrist.
Symptoms which would suggest the problem is not carpal tunnel syndrome include: pain which radiates above the shoulder, numbness with coughing or sneezing, or numbness without pain.
back to topThe definitive diagnostic procedure is a study of the nerve as it goes through the wrist, called an electromyograph (EMG). This study will detect over 90% of persons with carpal tunnel syndrome; however, some normal people have positive tests, and many people with carpal tunnel syndrome in one wrist but no symptoms in the other will nonetheless have a positive EMG. Thus, although the EMG is the best test we have, it is not perfect. The cost of the EMG is approximately $600 - $700.
back to topTreatment is surgical or non-surgical. Non-surgical treatment is usually the first choice, and may include: using the wrist less, wearing a wrist splint, and anti-inflammatory medicines, including injection into the wrist of a steroid. These are especially valuable for people with mild symptoms, or which come only infrequently.
Although effort is often put into the redesign of workstations, it is unclear whether this helps the reversal or prevention of carpal tunnel syndrome.
The surgical treatment of carpal tunnel syndrome should be considered when symptoms have failed to respond to splinting, steroid injection, and oral anti-inflammatory medications. The symptoms should be severe enough to interfere with the patient's activities, and the diagnosis should be based on a careful exam and EMG. Some patients with acute carpal tunnel syndrome may need immediate surgical decompression. After surgery, office workers can be back on the job in one week; however, carpenters or athletes may be incapacitated for 4 to 6 weeks.
Keith W. Roach, M.D. at the University of Chicago
<http://uhs.bsd.uchicago.edu/~roach/carpal-tunnel.html>
The median nerve runs into the hand to supply sensation to the thumb, index finger, long finger, and half of the ring finger. The nerve also supplies a branch to the muscles of the thumb, the thenar muscles.
One of the first symptoms of carpal tunnel syndrome is numbness in the distribution of the median Nerve. This is quickly followed by pain in the same distribution. The pain may also radiate up the arm to the shoulder, and, sometimes the neck. If the condition is allowed to progress, weakness of the thenar muscles can occur. This results in an inability to bring the thumb into opposition with the other fingers and hinders one's grasp.
Looking at a cross section of the wrist allows one to visualize the anatomy of the carpal tunnel. The carpal tunnel is an opening into the hand that is made up of the bones of the wrist on the bottom and the transverse carpal ligament on the top. Through this opening, the median nerve and the flexor tendons run into the hand. The median nerve lies just under the transverse carpal ligament.
The flexor tendons allow us to move the hand, such as when we grasp objects. The tendons are covered by a material called tenosynovium. The tenosynovium is very slippery, and allows the tendons to glide against each other as the hand is used to grasp objects. Any condition which causes irritation or inflammation of the tendons can result in swelling and thickening of the tenosynovium. As all of the tendons begin to swell and thicken, the pressure begins to increase in the carpal tunnel because the bones and ligaments that make up the tunnel are not able to stretch in response to the swelling. Increased pressure in the carpal tunnel begins to squeeze the median nerve against the transverse carpal ligament. Eventually, the pressure reaches a point when the nerve can no longer function normally. Pain and numbness in the hand begins.
There are many conditions which can result in irritation and inflammation of the tenosynovium, and eventually cause carpal tunnel syndrome. Different types of arthritis can cause inflammation of the tenosynovium directly. A fracture of the wrist bones may later cause carpal tunnel syndrome if the healed fragments result in abnormal irritation on the flexor tendons. Anything which causes abnormal pressure on the median nerve will result in the symptoms of pain, numbness and weakness of carpal tunnel syndrome. Recently, physicians have begun to recognize that activities that involve highly repetitive use of the hands can result in carpal tunnel syndrome. This is thought to be caused by inflammation of the tenosynovium due to overuse.
<http://www.sechrest.com/mmg/cts/anatomy.html>
back to topIn the early stages of carpal tunnel syndrome, a simple brace will sometimes decrease the symptoms, especially the numbness and pain occurring at night.
Anti-inflammatory medications may also help control the swelling of the tenosynovium and reduce the symptoms of carpal tunnel syndrome.
If this fails to control your symptoms an injection of cortisone into the carpal tunnel may be suggested. This medication will decrease the swelling of the tenosynovium and may give temporary relief of symptoms.
If all of the previous treatments fail to control the symptoms of carpal tunnel syndrome, surgery will be required to reduce the pressure on the median nerve.