Orthopaedic surgeons and vibrating tools – can there be too much vibration?

Introduction
Orthopaedic surgeons have always been long associated with using power tools at work. This can be either for something simple like removing a plaster cast or for more complex surgery for e.g. a knee replacement. They are an unique group within the medical profession who are exposed to hand held air and battery powered vibrating tools in the course of their work. The aim of this article is to look at the evidence available to assess the risk for orthopaedic surgeons from developing symptoms relating to the use of vibrating tools. It is something which is usually ignored by most surgeons but by no means uncommon.

HAVS
What is HAVS? HAVS stands for Hand Arms Vibrating Syndrome. The previous terminology for this condition was vibration white finger. The symptoms were first described by Professor Loriga in Italy in 1911, although the link was not made between the symptoms and vibrating hand tools until a study undertaken by Alice Hamilton MD in 1918. She formed her theory through following the symptoms reported by quarry cutters and carvers in Bedford, Indiana. She also discovered the link between an increase in HAV symptoms and cold weather as 1918 was a particularly harsh winter.

The first scale for assessing the condition, the Taylor-Pelmear scale, was published in 1975, but it was not listed as a prescribed disease in the United Kingdom until 1985, and the Stockholm scale introduced in 1987. In 1997 the Miners High Court awarded £127,000 in compensation to seven coal miners for vibration white finger. A UK government fund set up to cover subsequent claims by ex-coalminers had exceeded £100 million in payments by 2004.

The understanding of HAVS is constantly changing and the symptoms are divided into:

1. Vascular-blanching
2. Neurological-tingling
3. Musculoskeletal-loss of dexterity

The above symptoms can occur individually in isolation or together as a group. Exposure to vibration over a prolonged period of time can make some of these symptoms irreversible as evidenced from workers compensation claims in other professions using similar vibrating tools.

The symptom which was thought to be most disabling was vascular and this was the only symptom which was compensated till recently. But now it is becoming evident that the neurological symptoms are possibly more disabling than the vascular ones and the Industrial Injuries Advisory Council has recommended that people suffering from neurological symptoms will be eligible for workers compensation as well.

How much of vibration is safe? What does the law say?
According to the latest European directive which came into force in the UK in 2005 the maximum vibration limit of 2.5 ms-2 per day. Although there is considerable variation in the different types of saws used testing of these have shown that the order of magnitude is similar to other industries using high powered saws. Using the Hand Arm Vibration Calculator it has been calculated that orthopaedic surgeons could reach the advised limit of vibration after only 26 minutes of a vibrating tool usage in one day.

Although the use of these powered saws varied from surgeon to surgeon depending on individual practice and case mix, a typical orthopaedic surgeon doing a whole day list comprising four to five hip or knee replacements will easily exceed this maximum limit.

What is the evidence?
Potentially irreversible symptoms of HAVS are of concern to any surgeon. There are innumerable numbers of articles in the literature looking at this problem in the general workforce using vibrating tools but surprisingly few articles in the prevalence of this condition in orthopaedic surgeons.

The earliest reported article is from Mirbod et al in 1993. They looked mainly at the use of hand held plaster saws and concluded that this did not cause a serious problem as far as vibration was concerned. This was a small study involving 54 individuals and the equipment used had a vibration level of 2.3 to 2.4 ms-2.

In 2007 there has been a study published by Roberts et al from University of Aberdeen looking into this problem in a bit more detail. They had previously described that orthopaedic surgeons have an increased incidence of HAVS compared to a control group which in this case was gynaecologists in a pilot study.

Roberts et al have shown by means of a postal questionnaire to 2040 members of the British Orthopaedic Surgeons that they reported a statistically significant difference in the prevalence of tingling and numbness of the fingers while at work. This was in comparison to 1797 members of the Royal College of Gynaecologists. They concluded in their study that the observed differences could be related to exposure to hand held vibrating tools at work. This was a survey of self reported symptoms with no objective measurement of disease. But it does point out the higher prevalence of this debilitating sometimes irreversible condition in orthopaedic surgeons. It also raises questions about patient safety if surgeons are experiencing symptoms while operating. There is definitely a need for a more objective measurement of this problem and hopefully this will be addressed in the near future.

How do we reduce the risk?
The European directive 2002 on power tools recommends an extensive risk assessment in all work places where there is exposure of individuals to any form of power tools. This should include in vivo testing of orthopaedic tools. Manufacturers of power tools should clearly supply information regarding the vibration produced by different tools. Symptomatic surgeons will have to delegate tasks involving using vibrating tools to trainees so that vibration exposure could be spread more equally. They can also look at better case mix in a way that cases which require minimal use of vibrating tools are mixed with those requiring more.

Conclusion
In conclusion the use of vibrating power tools above the recommended safe limits may be harmful to orthopaedic surgeons. The symptoms of HAVS with relation to the use of vibrating tools is well reported in many industries but surprisingly under reported amongst orthopaedic surgeons. More objective assessment is necessary but as the few studies mentioned in this article have reported this is not an uncommon problem and is one which we should all be aware of.

References

1. Roberts SC, Harrild K, Mollison J, Murhy E, Ashcroft GP (2007). Comparison of sensorineural symptoms between UK orthopaedic surgeons and gynaecologists. Occupational Medicine (Lond) 57(2):104-11. Epub 2006 Dec 6.
2. Roberts SC, Koti M, Ashcroft GP, Gorman DG. Assessment of risk to orthopaedic surgeons from hand-transmitted vibration. J Bone Joint Surg Br 2001;83-B(Suppl.III):343-344.
3. The European Parliament and The Council. Directive 2002/44/EC. Off J Eur Commun 2002;45(L 177):13-19.
4. Health and Safety Executive. Statutory Instruments 2005 No. 1093: The Control of Vibration at Work Regulations 2005. London: The Stationery Office Books, 2005.
5. Department for Work and Pensions. A Guide to Industrial Injuries Disablement Benefits, DB1 edn. Leeds: DWP Communications, 2004.
6. Mirbod SM, Yoshida H, Inaba R, Iwata H. Exposure to segmental vibration and noise in orthopaedists. Ind Health 1993;31:155-164.
7. Brammer AJ, Taylor W, Lundborg G. Sensorineural stages of the hand-arm vibration syndrome. Scand J Work Environ Health 1987;13:279-283.
8. McGeoch KL, Lawson IJ, Burke F, Proud G, Miles J. Diagnostic criteria and staging of hand-arm vibration syndrome in theUnited Kingdom. IndHealth 2005;43:527-534.
9. Industrial Injuries Advisory Council. Hand-Arm Vibration Syndrome: Report by the Industrial Injuries Advisory Council in Accordance with Section 171 of the Social Security Administration Act 1992 Reviewing the Prescription of the Vascular and Sensorineural Components of Hand-Arm Vibration Syndrome, Cm 6098 edn. Norwich: The Stationary Ofiice, 2004.
10. Poole K, Mason H. Disability in the upper extremity and quality of life in hand-arm vibration syndrome. Disabil Rehabil 2005;27:1373-1380.
11. Yamamoto H, Zheng KC, Ariizumi M. A study of the hand-arm vibration syndrome in Okinawa, a subtropical area of Japan. Ind Health 2002;40:59-62.
12. Futatsuka M, Inaoka T, Ohtsuka R, Sakurai T, Moji K, Igarashi T. Hand-arm vibration in tropical rain forestry workers. Cent Eur J Public Health 1995;3(Suppl.):90-92.

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