200713 Hand-arm vibratory syndrome

Compiled from: United States Coast Guard and British Occupational Health Research Foundation websites.

Hand transmitted vibration (HTV) is one of the hazards that seafarers face in the course of employment on board ships. Operators of chipping machines, needle guns, vibrators, grinders or other vibratory or percussive tools are particularly at risk. Frequent and/or prolonged exposure can cause a range of permanent injuries to hands and arms known collectively as hand-arm vibration syndrome (HAVS). If not addressed in time, permanent disability is likely with medico-legal repercussions.

The syndrome has two main components, one affecting the circulation of blood to the fingers, commonly known as vibration white finger (VWF), the other affecting sensation in the fingers. Symptoms include neuropathy, carpal tunnel syndrome, tendonitis, and ulnar nerve syndrome. Indicators include tingling, numbness, blanching of the fingers, clumsiness or weakened grip, pain at night in the hands, wrists or arms or any other shoulder, arm, wrist or finger disorder. Factors such as age, sex, circulatory problems, exposure to cold and dampness, diet, smoking and work habits make some people more vulnerable than others.

There are national regulations governing the use (onshore only) of vibratory tools in several countries but for most of the world's seafarers, there is little awareness of the problem and no uniform guidelines on safe limits of exposure on board ship. Hand tool manufacturers have recognised the potential risk of harm and have taken steps both in the design of tools and in the accompanying user instructions to minimise the risk. Safety instructions now include warnings to the effect that repetitive work motion or vibration can cause injury to hands and arms.

Senior officers onboard ship must spread awareness among those who regularly operate such tools. Regular onboard training sessions must show users the proper methods of holding the tools, the length of time such a tool can be safely used without a break. The importance of proper handgrip force; gloves, position, posture, keeping body and hands warm and dry; avoiding anything inhibiting blood circulation in the shoulders, arms, wrists and fingers; keeping wrists straight; and avoidance of repeated bending of wrists and hands must be emphasised.

Many SMS manuals require a pre-job risk assessment and use of vibratory tools should not be overlooked in that analysis. Health surveillance both during pre-boarding medical examination and onboard monitoring can help in early detection of HAVS.

The best way of managing someone with HAVS is immediate removal from or reduction of further HTV exposure. Stopping smoking and reducing exposure to cold, damp conditions may help prevent symptoms worsening and aid recovery.