Carpal Tunnel Syndrome

Carpal tunnel syndrome is a disorder in which the median nerve is compressed at the wrist causing symptoms like tingling, pain, coldness, and sometimes weakness in parts of the hand. It is the best known of a class of disorders called repetitive strain injuries.

Anatomy

The median nerve runs through the carpal tunnel, a canal in the wrist that is surrounded by bone on three sides, and a fibrous sheath (theflexor retinaculum) on the other. In addition to the nerve, many of the hand’s tendons pass through this canal. The median nerve can be compressed by swelling of the contents of the canal, by soft tissue swelling in and around the tunnel or even by direct pressure from part of a broken or dislocated bone. However, bone dislocations are a rare cause of carpal tunnel syndrome.

Incidence

The syndrome is much more common in women than it is in men (see Carpal Tunnel Syndrome and Women).

Symptoms

The first symptoms usually appear when trying to sleep. Symptoms range from a burning, tingling numbness in the fingers (especially the thumb and the index and middle fingers) to difficulty gripping, making a fist, or dropping things. Most early sufferers mistakenly blame the tingling numbness on their sleeping position, thinking their hands have had restricted circulation and are “falling asleep”. If left untreated the symptoms often progress to intense pain which restricts hand functionality. It is known as a hidden disability, because people can do some things with their hands and appear to have normal hand function, but often live with severely restricted hand activity due to the pain.

Causes

Some cases of carpal tunnel syndrome are due to work-related cumulative trauma of the wrist. It is commonly caused by strain placed on the hand, for instance gripping and typing, which are usually performed repetitively in a person’s occupation. The condition was first diagnosed in Australia in the 80s when musicians started to use synthesizers heavily and people using these instruments started to get hand and wrist pain. The condition went mostly undiagnosed in the US until the mid 90s when computers became more popular in the workplace.

There are a number of causes of carpal tunnel syndrome. They can be either traumatic, or non-traumatic.

Repetitive stress induced carpal tunnel strain is the leading cause of carpal tunnel syndrome in most industrialized countries. In the USA for instance, repetitive stress induced carpal tunnel syndrome is the biggest single contributing factor to lost time at work. This type of carpal tunnel syndrome results in billions of dollars of workers compensation claims every year.

Repetitive hand and wrist action often results in subcutaneous tissues becoming injured and swollen. These tissues include fascia, muscle, ligament, tendon, sheaths, retinaculum and peripheral nerve and blood vessels. In restricted passages of the body, swollen soft tissue can become compressed together creating intense pressure. Adjacent soft tissue can adhere together when compressed under theseconditions over a prolonged period.

Trauma-based causes:

  • Fractures of one of the arm bones, particularly a Colles’ fracture.
  • Dislocation of one of the carpal bones of the wrist.
  • Hematoma forming inside the wrist, because of internal haemorrhaging.
  • Deformities due to abnormal healing of old bone fractures.

Non-traumatic causes generally happen over a period of time, and are not triggered by one certain event. Examples include:

  • Tenosynovitis, which is inflammation of the joint. Part of the process of inflammation is swelling, and this compresses the nerve.
  • With pregnancy and hypothyroidism, fluid is retained in tissues, which swells the joint.
  • Acromegaly, a disorder of growth hormones, compresses the nerve by the abnormal growth of bones around the hand and wrist.
  • Tumours (though not necessarily cancer), such as a ganglion or a lipoma, can protrude into the carpal tunnel, reducing the amount of space.
  • Diabetes, rheumatoid arthritis, and obesity tend to cause swelling, thus decreasing the amount of space in the carpal tunnel.
  • Idiopathic causes, which no one can explain, can also cause this disease.

Common activities that have been identified as contributing to repetitive stress induced carpal tunnel syndrome include:

  • Computer keyboarding or typing
  • Playing video games
  • Playing a musical instrument
  • Driving a vehicle, motorcycle or flying a plane
  • Pushing a lawn mower (both the pressure and the vibration are to blame)
  • Any activity where hand use is vigorous and routine could contribute (surgeons, dentists)

Often people suffering from carpal tunnel syndrome can have multiple contributing factors which are aggravated by vigorous hand activities and repetitive stress trauma to the hand.

Proper attention to ergonomic considerations can reduce or eliminate these kinds of injuries.

Diagnosis

There are two easy methods to test for carpal tunnel syndrome. One is squeezing or clenching the hand and noticing a lack of strength.

A second test, known as Phalen’s maneuver, is grab the fingers and pull back the hand back, up towards yourself, approaching but not reaching a 90 degree angle. If this position hurts, tingles or burns within the first 10 seconds then carpal tunnel syndrome exists. The quicker the pain starts, the more advanced the condition.

A classic, though less effective method, Tinel’s sign, is a way to detect irritated nerves. It is performed by lightly banging (percussing) over the nerve to elicit a sensation of tingling or “pins and needles” in the distribution of the nerve. In a person with carpal tunnelsyndrome where the median nerve is compressed at the wrist, Tinel’s sign is often “positive” and causes tingling in the thumb, index, and middle fingers. Tinel’s sign is sometimes referred to as “distal tingling on percussion” or DTP.

Treatment and Prevention

There is a lot of discussion about what is the most effective treatment for CTS. There are five basic categories:

  1. Wear immobilizing braces or wrist splints
  2. Have localized steroid injections
  3. Soft Tisssue Therapy
  4. Prioritize activities and Ergonomics
  5. Carpal Tunnel Release Surgery

Immobilizing Braces

Rigid immobilizing braces and wrist spints can help some people, but they are limiting, unsightly and uncomfortable to wear. Over several weeks braces and splints often result in hand and forearm muscle atrophy. Any treatment that deteriorates muscle mass is questionable at best.

Localized Steroid Injections

Steriod injections can be quite effective for temporatry relief from the symptoms and pain of CTS for a short time frame while a longterm strategy that fits with one’s life style is developed. However, it is not a long-term solution. Ethical medical professionals would only resort to localized steroid injections for a short time until another acceptable treatment option could be identified.

Soft Tissue Therapy

Many people are turning to soft tissue therapy as a way to prevent pain and avoid sleep loss and work interruption. Soft tissue therapy can result from doing exercises, visits to chiropractors and using a new class of medical device which for many CTS sufferers offers relief from CTS pain and hand tingling in days. These are different from other over-the-counter CTS treatments and are not rigid immobilizing braces.Worn during sleep, soft tissue devices gently reshape soft tissue in and around the Carpal Tunnel and eliminates hand pain, numbness and sleep interruption. A particular treatment, known as Carpal Solution Therapy, has been shown to improve CTS symptoms in 80 to 90% of the people that try it. It often allows people to get back to their active life styles with minimal disruption.

One recommended stretching exercise is:

  1. Sit in a chair.
  2. Place the right elbow into your side, palm side of the hand facing upwards.
  3. Using the left hand, push the right hand down by applying pressure to the four largest fingers.
  4. Hold for two seconds.
  5. Release the stretch by taking the pressure off the fingers and just letting the hand naturally come back.
  6. Perform 10 repetitions, switch arm configuration and perform 10 more repetitions.

Prioritizing Hand Activities and Ergonomics

Using our hands is a defining characteristic of the human condition. While avoiding activities that cause repetitive stress is an option that can help avoid the pain, it causes people to curtail their careers, forfeit earnings and give up whole segments of their lives. Our self esteem as human beings and contributors at home, at work and at recreation is directly tied to the way we use our hands. Giving up activity is a poor option for most people.

More frequent rest can be useful if it can be orchestrated into ones schedule. But rest is not very practical in todays active work environment. It has been shown that taking multiple mini breaks during the stressfull activity is more effective than taking occasional long breaks. There are two applications available that allow one to set up a proper breaking schedule by blocking input to the computer.

The first to appear was a commercial solution called WorkPace, which was followed eventually by a free software alternative known as WorkRave. Both applications have recommended defaults, following the most effective average break configuration which is a 30 sec. pause every 3 to 5 minutes (the more severe the pain, the more often one should take this break). During this break it would be best to perform a stretching exercise or simply let one’s arms dangle to the ground. Note that one will find these breaks very disruptive at first, but once adjusted to them, they will make a huge difference in carpal tunnel pain, possibly giving more stress reduction than all other treatments combined.

Changes in diet relate to providing the body with the nutrients it needs to reduce the flamatory action of the carpal muscles in order to reduce pressure on the nerve, thus allowing it to heal, as well as providing nutrients needed to repair nerves. No specific vitamin or nutrient has been shown to have a noticeable anti-inflammatory effect, but taking a diverse multivitamin can have a noticeable effect on reducing inflammation in the body. Using an over-the-counter anti-inflammatory such as Aspirin or Ibuprofen is very effective as well.

Pain relievers (ex: Tylenol) will only mask the pain and only an anti-inflamatory will give the carpal nerve time to heal. Certain vitamins and nutrients can also be taken to repair nerve damage, such as amino acids, vitamin B complex and hypercium (an extract of St John’s Wort).

A more aggressive option is an injection of cortisone, to reduce swelling.

More pro-active ways to reducing the stress on the carpal tunnel involve adopting a more ergonomic work and life enviroment such as using an ergonomic keyboard (and perhaps switching from a QWERTY key layout to a more efficient Dvorak Simplified Keyboard layout). Studies have shown ergonomic keyboards reduce wrist stress by 30% or more and Dvorak reduces stress an additional 30%. It’s also important that one’s body be aligned properly with the keyboard. This is most easily accomplished by bending one’s elbows to a 90 degree angle and making sure the keyboard is at the same height as the elbows. Also it is important not to put physical stress on the wrists by hanging the wrist on the edge of a desk, or exposing the wrists to strong vibrations (ex: manual lawn mowing).

Carpal Tunnel Relief Surgery

While there is a surgical relief to carpal tunnel syndrome, full recovery is achieved in less than 60% of cases. Often surgeons
counsel patient to change their careers and undergo surgery. Downtime and rehabilitation can take up to three months resulting in a significant loss of earnings, depression and loss of self esteem. Also, since carpal tunnel syndrome is a “syndrome”, not a disease, if repetitive stress activities are continued, then surgery will likely have to be repeated within a year or two. This makes surgery a choice of last resort for carpal tunnel syndrome treatment. Most insurers and healthcare professionals recommend exhasuting all conservative options before resorting to Carpal Release Surgery.

Long Term Recovery

Long-term chronic carpal tunnel syndrome can result in permanent nerve damage. However, most carpal tunnel syndrome sufferers either change their hand use pattern or posture at work or find a soft tissue therapy that allows them to return to full activity without hand pain and sleep disruption. Most people end up prioritizing their activities and give up the least important activities so that they can minimize pain and perform the essential tasks.

Many people change jobs to avoid continued repetitive stress tasks. Some find success by adjusting their repetitive movements, the frequency with which they do the movements, and the amount of time they rest between periods when they perform the movements. The early signs of carpal tunnel syndrome should not be ignored. Early denial of carpal tunnel strain is a sure way to lead to full carpal tunnel syndrome.

Article text based on the Wikipedia, licensed under the GFDL. See “Carpal tunnel syndrome” at Wikipedia.org.

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