What is R.S.I.?

Repetitive Strain Injury (RSI) is a blanket term used to describe a variety of disorders. The most common of which is Carpal Tunnel Syndrome (CTS). CTS is a condition by which the median nerve ceases to function properly. The median nerve runs down the arm and into the hand and supplies sensation to the thumb, index finger, middle finger and half of the ring finger. The nerve also branches off to the thenar muscles of the thumb. These muscles help move the thumb and are very important in the motion called opposition by which the thumb can touch each of the other fingers.

This is usually thought to occur due to pressure on the nerve as it runs into the wrist through an opening called the carpal tunnel. The carpal tunnel is an opening that is made up of the carpal bones of the wrist and the transverse carpal ligament. In the cross section of the wrist below it is easy to see the anatomy of the carpal tunnel. The median nerve and the flexor tendons run into the hand through this opening.

Compression of the carpal tunnel causes the median nerve and flexor tendons to be trapped between the carpal bones and the transverse carpal ligament. The flexor tendons have a protective surface of tenosynovium which allows the tendons to glide against each other in the various movements of the hand . However inflamation of the tendons due to the compression of the carpal tunnel and repetitive movement of the hand wrist causes the tenosynovium to covering of the tendons to thicken increasing the pressure in the carpal tunnel. The median nerve is the softest structure within the carpal tunnel, it is squeezed against the transverse carpal ligament reaching a point at which the nerve cannot function properly. Pain and numbness in the hand begins, 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.

The key concept to remember is that anything which causes abnormal pressure on the median nerve will result in the symptoms of pain, numbness and weakness of carpal tunnel syndrome.

 

The cost of R.S.I.?

The cost of RSI for the individual suffer varies with the severity of each case. At its least, and in the early stages, pain and numbness in the hand and wrist may simply be an inconvienience. However if the conditions which caused the RSI continue the condition can worsen. At its most severe RSI can severely hamper the lives of suffers. They may have to give up playing sports which put pressure on the hand and wrist, driving a car can become painful, in jobs where the hand and wrist are in constant use they may be forced to give up work altogether. For employers the cost of putting their staff at risk of RSI is twofold. Firstly a decrease in productivity and an increase in absenteeism. In the USA 48% of all reported workplace illnesses in 1990 where due to RSI, up from 18% in 1980. Secondly, more and more employees are instituting legal action against their employers, claiming their working conditions caused them to develop RSI. As the article from the recent British press shows, damages in such cases can be substantial.

Designer Awarded £25,000 For Mouse Injury.

A major international oil company has been ordered to pay a former employee £25,000 after she suffered Repetitive Strain Injury from using a computer mouse the wrong way. The 26 year old Graphic Designer, from Braintree Essex, experienced hand and arm pains after using a mouse to do complex drawings at their London Headquarters in the Strand, Central London. "I found my work station was unsuitable and it turns out I must have been holding the mouse in an awkward way - I was never shown how to use it" she said following the three - day hearing at Colchester Trial Centre. Her employer sent her to a doctor and reduced her workload after she began to suffer the pain. "But in time the workload increased again and before I knew it I was suffering the same symptoms" she said. "I used to come home in tears many days with the pain. It affected my life outside work. I could not do my hair or peel potatoes - the housework was difficult. Eventually I had to leave."

The dangers of excessive cold in injury treatment

Whilst cold therapy has a beneficial effect in the treatment of injuries, there is a danger in some cases that excessive cold can cause further lasting injury. The following article taken from the BBC News website (Tuesday 3rd October 2000) highlights this danger.

Chilling Tale For Ice Pack Addicts.

Caution advised over frozen pea solution
People who use a packet of frozen peas to bring down the swelling on a bruise or strain could be risking frostbite, say doctors. Most people associate frostbite with high-altitude mountaineers or polar explorers, but simply leaving an icepack in place for more than half an hour could cause severe tissue damage. Frostbite happens when healthy tissue is frozen by contact with extreme cold. When it freezes, blood can no longer flow to the effected area, and the flesh begins to die and turn black. Normally, in mountaineers, the extremities such as fingers and toes are most prone to frostbite, as they have the poorest blood supply - and mountaineers who spend long periods in extremely cold conditions occasionally have to have toes amputated on their return. But wherever frostbite occurs, very often the only solution for doctors is simply to completely cut out the affected tissue, often causing permanent disability. Doctors from Crosshouse Hospital in Kilmarnock Scotland, writing in the British Medical Journal of Sports Medicine, wrote about a young PE teacher who treated an injured right foot with a bag of frozen chips wrapped in a towel.

Lost feeling
This was left in place for at least 40 minutes, and while the pain from the foot injury subsided, the following day her foot was blackened and painful, and she had lost feeling in some of her toes. Surgeons were forced to excise a large chunk of dead flesh from the foot, and she sustained nerve damage to two of her toes. The authors warn that extreme cold anaesthetsises the skin, which may be good idea to beat a painful injury, but also stops the body being alerted to tissue damage going on underneath. The Association of Chartered Physiotherapists in Sports Medicine say that a maximum safe period for icepack application should be no longer than 30 minutes. The pack, or bag of vegetables should be wrapped in a damp towel, and that in areas where there is little fat or muscle beneath the skin, should be used only for 10 minutes.