Carpal Tunnel Syndrome:  Five Facets to Prevention

Carpal Tunnel Syndrome (CTS) is becoming a major concern in a variety of occupational settings.  The relevance of the crippling hand disorder is increasing:  the Bureau of Labor Statistics (BLS) reports that over 31,000 workers developed this disorder from occupational exposure in 1997, up from 23,000 in 1988.  OSHA handed out two of its largest proposed penalties (for $4.3 million to John Morrell and Company, and for $3.1 million to IBP, Inc.) largely due to the existence of this cumulative trauma disorder at the subject companies. 

Some of the occupations where CTS is more prevalent include the following:  electronic component assembly, meat packing, clothing manufacturing, food handling/distribution.  Five factors (wrist deviation, gripping forces, frequency of gripping, duration of gripping, and carpal tunnel restriction) can influence CTS development.  What can be done to prevent it from developing? 

Overall Program

A good prevention program can be compared to the two hands of the body; the right hand represents the overall program, and the left hand represents the engineering aspects.  The five facets of the overall program follow:

Screening
Medical screening is one way to determine the condition of prospective or current employees.  This screening can be comprised of the following:

• A medical history that seeks to determine existing activities and symptoms
• Physical examination using such tests as Tinel's Test and Phalen's Test
• Nerve conduction testing
• Electromyogram
• X-rays
• Isometric strength testing

This testing allows you to evaluate current medical status.

Training
An informed workforce is generally a more responsive workforce.  Teaching employees what constitutes safe and unsafe work practices, and the role of other factors will help them to reduce the potential for occurrence of CTS.
 

Exercise
The importance of both rest and exercise as methods of relieving the restriction should be stressed.  There is good information available regarding specific exercises that can be used to help prevent CTS.
 

Administrative
One example of an administrative approach is to rotate employees, thereby reducing the duration of exposure.  A second is the provision of wrist supports, for use during sleep when medically prescribed.
 

Engineering Aspects
This last facet of an overall program has five facets of its own.

Engineering Aspects

Frequency
Reducing the frequency with which an activity must be performed, if all other factors are kept constant, will reduce the overall dose.  Reducing dose lessens the potential for injury.  As an example, mechanically performing high volume runs so that only low volume runs need to be manually handled is one such method of reducing frequency.

Force
The stresses on the tendons will relate to the magnitude of the exertion.  If the force can be reduced, the stresses are generally reduced.  One method of doing this is to provide tools with proper diameter handles. 

Deviation
Studies of wrist deviation have shown significant reduction in strength with increasing flexion or extension.  The amount of deviation also correlates directly with a potential for CTS development.  The best posture is to maintain the wrist in the same position as though it were at the worker's side.  Inclining work surfaces and modifying hand tools deviations are two approaches to reduce wrist deviation. 

Duration
Reducing the time an activity will take also often reduces dose and, therefore the potential for CTS development.  Keeping hand travel short is one method of reducing duration.

Restriction
The imposition of external restrictions occurs as a result of contact with materials being handled or work surfaces.  Whenever possible, these restrictions should be eliminated. 

Other Factors

Two "environmental" factors that also play a role in Carpal Tunnel Syndrome development are temperature and vibration.  The presence of temperatures below 70 F increase the potential for CTS development, as does significant vibration.  Eliminating these factors results in the reduction of the potential for CTS development.  While only a "thumbnail" sketch, the use of these guidelines can help you to "get a good grip" on controlling the occurrence of CTS in your company.

Revised from the National Safety Council's Trade and Services Newsletter