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Cumulative Trauma Disorder

What is CTD
What causes CTD
What are the symptoms
Types of CTD
Who is at risk
Some numbers
Ergonomic Tips
Micropauses

Useful CTD Information Web Sites

Cumulative Trauma Disorders
Cumulative Trauma Disorder (CTD) is a general term for disorders that occur from prolonged, repetitious use of muscles of the arms and hands. The Carpal Tunnel Syndrome (CTS) is the most common ailment brought on by repetitive hand motion. Others are: Thoracic Outlet Syndrome, Trigger Finger, DeQuervain's Tenosynovitis etc.

Why the Name?
Cumulative:it keeps adding up
Trauma: injury to the body that happens secondary to some physical cause
Disorder: a dysfunction of the normal body processes. A group of symptoms, for example pain, tingling or weakness that describes the manifestations of a certain disorder are usually referred to as a syndrome.

Synonyms for Cumulative Trauma Disorders include: Repetitive Strain Injury (RSI), Occupational Overuse Syndrome (OOS), Repetitive Motion Syndrome (RMS).

These complaints often occur at the same time or develop in people who already have overuse symptoms. They complaints are preventable and can be controlled by a change in living and work patterns.

CTDs are most often the result of repeated physical movements doing damage to tendons, nerves, muscles, and other soft body tissues. The soft body tissues become irritated and inflamed and, over time, repetitive motions, excessive force, and extremes of motion can strain the soft tissues, reducing circulation. These stresses create tiny tears in the muscles and tendons, which become inflamed. In extreme cases it can cause permanent tissue damage and disability.

A large number of cases of CTD are related to computer use, though other repetitive work task such as heavy lifting as well as hand-intensive sports and hobbies such as knitting or playing a musical instrument, can cause or aggravate CTD.
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What causes CTDs
The cause is generally restricted blood flow. When a muscle is tensed, capillaries bringing blood to the muscle are compressed and flow of blood interrupted. As the muscle is held in tension, no fresh oxygenated blood is supplied. As a result of the lack of oxygen, the cells produce lactic acid, the amount of which quickly builds up, causing pain. If the muscle is not allowed to relax, cellular degeneration can rapidly increase. The tensed muscles also pressure the surrounding nerves causing tingling, numbness and, eventually, injury. In addition, the lack of blood increases the likelihood of degeneration and inflammation throughout the system thus retarding healing. The cycle may stops when the hands are relaxed but by the time symptoms appear, the damage has already started and it will take less stress to bring the symptoms back in the future.

Repeated tensing of the hand can cause the fibres of the tendons running through the carpal tunnel to separate or break. This causes friction between the tendon and its sheath (the tenosynovium) and ultimately tendonitis. Tenosynovitis occurs when the sheath cannot properly lubricate the tendon it surrounds due to the repetitive hand movement and the sheath itself becomes inflamed. Tightly gripping something for too long and forceful movements can lead to problems as well.
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Types of CTDs
The most commonly known type of CTD is Carpal Tunnel Syndrome (CTS). CTS occurs when repetitive, awkward movements of the hand and wrist cause tendons to swell and compress the mesial nerve. An early sign of CTS is tingling and intermittent numbness of part of the hand. CTS sufferers feel pain shooting up the arm from the wrist and spreading to the shoulders, neck and back.
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What are the symptoms
Some of the symptoms for CTD are:

Tightness, discomfort, stiffness, or pain in the hands, wrists, fingers, forearms or elbows

Tingling, coldness or numbness in the hands

Clumsiness or loss of strength and coordination in the hands

Pain that wakes you up at night

Feeling a need to massage your hand, wrists and arms.

Who is at Risk
Those at risk include: computer users, assembly-line workers, stock clerks, warehouse workers, drivers, transcriptionists, garment workers, athletes, meat and poultry processors, painters, writers, gardeners, golfers, carpenters, bank tellers, data entry clerks, accountants, bricklayers, secretaries, construction workers, CAD and graphic designers, programmers, silkscreeners, artists, needlepoint hobbyists, draftsmen, gardeners, crafts enthusiasts, sportsmen, musicians, knitters, crocheters, checkout clerks and anyone else who uses their hands continually or forcefully. In addition, pregnant women and certain other conditions, have a higher risk due to fluid retention.
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Some numbers
By some estimates, about 14 million people have visited a doctor for CTD of the hand and perhaps another 40 million have experienced symptoms but did not seek professional help. According to the Bureau of Labour, CTDs of all kinds account for 60% of all reported occupational illnesses. The estimated direct cost to businesses was over $25 billion in 1993 just in the U.S. The National Center for Health Statistics reported that 849,000 new problem visits were made to physicians in office-based practices in 1994 due to CTS and carpal tunnel release operations are the second most common surgical procedure in the U.S. OSHA shows CTS as having the highest median days away from work, greater than fractures or even amputations. A survey revealed that CTS is the costliest Cumulative Trauma Disorder, with back injuries second. However, after factoring in not only lost days and medical expenses (which alone can reach $29,000) but also temporary help and overall lost productivity, the overall cost could reach a whopping $60,000+ per incident. Finally, the National Institute of Occupational Safety and Health (NIOSH) has predicted that 50% of the work force will suffer from RSIs (of all kinds) by the year 2000.
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Ergonomic Tips

Rest your hands frequently, especially when any tingling, numbness, pain, cramping, etc. occurs.
Rest your palms, not your wrist, on a wrist-rest or the desktop.
When using a keyboard/mouse, your hands should be slightly lower than your elbows. An adjustable keyboard tray mounted under the desktop may be necessary.
Keep your hands in line with your forearms as much as possible, not bent in/out or up/down at the wrist.
Rest your elbows on your chair's armrests and adjust them so the weight of your arms is supported by the armrests, not supported by your shoulders.
Use a foot-rest if your feet are not flat on the floor.
The top of your monitor should be about eye level so you aren't bending your neck up.
Sit upright so your head is above your shoulders. Don't slouch forward.
Take frequent breaks and do stretching exercises to replenish blood flow, which is restricted by continuous muscle use, especially involving your hands.
Alter your posture time to time but keep within the guidelines of correct sitting most of the time.
Sit so the natural hollow stays in your lower back. A good adjustable chair should allow this.
Position your monitor and keyboard in front of you, not to the side.
Use larger barreled pens (12mm, 1/2" or more in diameter) to make them easier to grasp.
Don't wear wrist splints for extended periods during the day. Some muscles may atrophy.
Don't type with long fingernails.
Cut back or discontinue the use of tobacco products.
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Micropauses
One of the recommended strategies to reduce the risk of CTD is to take frequent breaks (micropauses) in your computer work. Micropauses are 5-10 seconds breaks every few minutes. Software exists that reminds you to take a micropause and make the break relaxing. To download a free copy of this software click here.

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