Hand-Arm Vibration Syndrome (HAVS)

Hand-Arm Vibration injury is a general term for damages to human hand arm and fingers caused by vibration. Vibration injuries occur frequently in multiple occupations and industries, e.g. in automotive repair shops, construction work, engineering, dental care foot care and many more.

Vibration damages can be irreversible, especially the neurological part, if not discovered in time. Incipient changes in the nerves, i.e. reduction of sensibility, can be detected with Multi-Frequency Tactilometry.

Hand-Arm Vibration Syndrome (HAVS) is the medical term for symptoms caused by vibration damages that may occur in the fingers, hands and arms when working with vibrating tools or machinery. Vibration injuries are divided into three subgroups, i.e.  Neurological disorder, Vascular disorder and Muscle skeletal disorder. These damages can occur alone or in combination.

 

Neurological disorder
Early symptoms are usually tingling and/or numbness in hands and fingers. After a while, this turns to impaired sensibility and limited dexterity. A fully developed Neurological Vibration damage is irreversible, causing a high disability and work incapability. At this stage, the normal capacity of the hand is disappeared with a significant reduction to control the hand, eg. dropping things easily, inability to insert a key in a lock or to pour a drink into a glass etc.

The Carpal tunnel syndrome is another common neurological vibration damage. If this injury is cured in time, the prognosis is usually good for a full recovery.


Vascular disorder
This damage affects the hand and fingers capillaries (small blood vessels), which are constricting uncontrollably (vasospasm). The disorder gives episodes of whitening (blanching) of the fingers or part of the hand, usually triggered by cold exposure. This damage is also called "Vibration induced White Fingers" (VWF) or "secondary Raynaud's disease".

During the whitening, caused by a temporary closure of blood circulation to parts of the fingers or the hand, the person gets numbness in the areas that have become white. When the blood then returns, i.e. during the release of the vasospasm, the person is often experiencing a major discomfort such as tingling and pain.

Muscle-skeletal disorders
Muscle skeletal disorders and injuries may consist of arthritis, tendonitis and changes in muscle fibres. The damage can result in impaired grip force, reduced mobility and pain in the hand and arm.

The reduced grip strength in the hands is hard to explain but a probable cause is damage to nerves and muscle structures. These patients are often misunderstood because diagnosis is difficult and many routine clinical tests often show a normal result.

It is noteworthy that the muscle volume often is intact, but microscope studies of muscle biopsies have shown that there may be a significant change in the fibres cross-sectional areas.
 

Root Cause.
It is well known that prolonged vibration exposure is harmful to the hand and tissue and many years of vibration exposure can cause various types of hand problems. Most common is loss of sensibility, white fingers, and decreased grip force in the hands i.e. the Hand-Arm Vibration Syndrome - HAVS.

The tendency to develop vibration damages in the hands varies significantly between individuals - some get these symptoms after a few years of vibration exposure, while others can work for decades without problems.

When a vibration damage is fully developed, it is irreversible - i.e. the affected person will not recover even if the vibration exposure ceases. Furthermore, it is not possible to cure established vibration damage with medical or surgical means.

Therefore, it is extremely important to detect an incipient vibration damage as early as possible – so there is still time to issue prophylactic measures. One measure may be to alter the working methods or selection of used tool to prevent the development to an irreversible vibration injury.

 

Vibration injuries are common in many occupations where vibration exposure is common, e.g. construction workers, cutters, vehicle repair, sheet metal workers, electricians and welders. The problems are also common in occupations where the hands are exposed to very high frequency vibrations, such as dental technicians and dentists.

The damage often occurs at young and middle-aged men and the consequences can be very serious. Damage to the nerves of the hand provides reduced precision, clumsiness, impaired fine motor skills and sometimes severe pain and cramps.

White finger attacks are usually triggered by the outdoor stay in humid or cold environment and can be extremely painful.