Summary

Low Back Pain

Low back pain (LBP) affects a significant part of the population and has a great social and economic cost to the community.

The annual incidence for LBP is 2-5% of the population; with 80% of individuals having an occurence at least once in their lifetime.

The Panel estimates that there could be 40,000 work-related back injuries  each year. Worksafe Australia has estimated that back injuries are costing Australia $600 million a year in compensation costs, lost working days, lowered productivity and increased industrial disruption.

There has been a general absence of programs and measures to prevent or reduce the incidence and adverse effects of LBP. A National Strategy for Prevention of Occupational Backpain has now been developed by Worksafe Australia.

Dynamometers

Force measuring devices called dynamometers have been developed to assess muscle performance. Testing of the major joints of the extremities by dynamometry has become widespread. They are also being used in the assessment and rehabilitation of patients with LBP.

The incorporation of microprocessor technology in dynamometers in recent years has enabled more efficient acquisition, analysis and display of data. The technology has expanded the capacity to study dynamic muscle function.

Dynamometers are usually operated by qualified physiotherapists with referral of patients by medical practitioners.

Testing of the Limb Muscles

There are over 50 sites using this technology in Australia for testing limbs, usually in the context of sports medicine and physiotherapy.

Some recent reports have questioned the quality of measurements obtained from dynamometers. The Panel considers that there is a need for operators to be aware of the limitations of the data obtained from dynamometric measurements.

Testing of the Back Muscles

Over the last two years dynamometers for low back testing have become available in Australia with about 13 in use. Their capital cost ranges from $80,000 to $270,000.

The literature on the clinical use and benefit of dynamometers  is still limited. The Panel sees a need for operators to document and publish their clinical experience with these machines.

The various machines available make use of different testing protocols, patient stabilisation systems, patient postures, assumed axes of movement and data bases. The results obtained from the different machines are not comparable.

The Panel considers that:

Dynamometers are devices with a potential to usefully contribute to the assessment and management of LBP.

When properly used, these machines can provide a quantitative measure of a patient's progress in a program of rehabilitation.  Some machines may be more appropriate than others in providing a measure of fitness to undertake real life tasks.

Dynamometers may also be cap ble of providing useful information on diagnosis and prognosis of a spectrum of conditions contributing to LBP. However, with the current status of the technology, additional work is needed on these applications, to define and improve levels of reliability. Further normative data for different types of subject and a range of normal and pathological  conditions are required.

The evaluation of different types of dynamometers should be encouraged and supported by users of the technology, employer groups and insurance agencies.

The use of dynamometry to identify persons suspected of malingering  is not supported in view of the uncertainties  as to the reliability of the technology and data interpretation. Research should be undertaken to objectively define patient effort during testing.

Use of the technology should be integrated with appropriate health services required to manage back-injured  persons.