KEYNOTES

Understanding mechanisms - evidence based implementation

Prof. Barbara Silverstein, USA
How to change society’s attitudes towards prevention of work-related musculoskeletal disorders - health promotion or risk management? What can we learn from public health research?

Why is there such societal resistance to taking steps to prevent WMSDs? Policy relavant research is necessary but not sufficient to bring about change. The issue of “personal control” of risk is fundamental to choosing effective prevention strategies. Regulatory policy has little to do with existing data or public health. It is directed at risks not within personal control. Based on the same scientific information, Australia eliminated lead based paints 50 years before the US. Why? The process of public health protection (research->risk assessment-> risk management-> risk communication) is applicable to changing behavior. Ignoring components in this process may result in inappropriate interventions. Individual and group risk perceptions depend on knowledge, newness, voluntariness, control, dreadness, catastrophic potential and equity. Lessons from public health (lead, a failed US smallpox vacination campaign and SARs) and regulation (Washington State) can help improve the prospects for WMSD prevention.

Prof. Francesco Violante, Italy and Prof. Mats Hagberg, Sweden
Current issues in case definitions for common musculoskeletal disorders among workers in clinical practice and research?

Valid case definitions for general use among researchers are crucial to advance science and a requirement for practicing clinical medicine according to science and best practise. In the history of work-related musculoskeletal disorders we have used concepts that have hampered the development of valid case definition. There are no scientific consensus criteria for most ICD-10 (International Classification of Disease) musculoskeletal related diagnoses to be considered in workers. We suggest that the process for a new feasible case-definition system for the neck and upper extremity should start by a consensus of criteria for diagnosis of common musculoskeletal disorders in primary care developed by a panel consisting of the key disciplines. Epidemiological, intervention and health surveillance case definitions may have the clinical diagnose as gold standard.

Prof. Dr. med. Bernd Hartmann, Germany
Prevention of Musculoskeletal Disorders in the Construction Industry - from Diagnostic to Ergonomy and individual Prevention.

The highest levels of loads and musculo-skeletal disorders exist in the construction industry. Investigation into the physical stress at the workplace is the basis and background for developing methods of prevention. Methods are therefore necessary that can exemplary capture patterns of loads from handling weights, working in forced postures, repetitive hand-arm-work and vibrations. Periodic health surveys of employees with high levels of physical load, and suitable diagnostic methods are essential tools for prevention. The methods of medical examination of the muskulo-skeletal-system require improvement with respect to the standardization of questionnaires and clinical diagnostics. Occupational medicine has focussed its methods of diagnostics upon functional disturbances, in contrast to the differential diagnostics of nosologic disorders by physicians.
Treatment methods for health disturbances are continually improving. However, models for the promotion of health at the workplace published to date usually cannot be applied to the actual working practice in construction work. The major incentives for awareness of prevention are education at the beginning of the apprenticeship in the centers for vocational training, or repeated health problems that force employees to consult their physician.
It is far more difficult to alter the working conditions and processes in order to reduce physical loads in construction work than in other industries. Four major reasons exist: Data on ergonomic solutions is not systematically collected, which explains the small amount of information available. The financial possibilities necessary for introducing new solutions and equipment are more limited than in most other branches. The development of ergonomic solutions in the case of non-stationary workplaces is more difficult. The tradition of thousands of years in masonry and similar branches is also a relative barrier for innovation. The evaluation of physical loads in respect to their risks to the different structures of the musculo-skeletal system brings many unsolved problems. Branch-specific organizations are suitable partners for helping solve the problems involved in the prevention of musculo-skeletal disorders, with the aid of multimodal concepts. These organizations are a great help to predominantly small enterprises that do not possess the financial basis or other possibilities for overcoming the risks and for promoting prevention themselves.

Prof. Dr. med. Siegfried Mense, Germany
Central and peripheral pain mechanisms. How can we integrate existing knowledge of pain research in preventing work-related musculoskeletal disorders?

Work-related muscle pain is probably due to a multitude of factors that act in concert, with different emphasis in different patients.
Peripheral mechanisms: the most important factor likely are tonic contractions due to poor coordination and/or psychological stressors. Tonic muscle activity is associated with ischaemia and a drop in tissue pH. Under these conditions substances are released (serotonin, ATP, protons) that sensitise or excite muscle nociceptors. Focal structural damage of individual muscle fibres is likewise probable.
Central mechanisms: activity in muscle nociceptors is known to be particularly effective in inducing spinal neuroplastic changes such as hyperexcitability of sensory neurones followed by an expansion of the affected region in the spinal cord (central sensitisation, felt as hyperalgesia and spread of pain). The nociceptive input from muscle inhibits homonymous motoneurones and impairs motor coordination of the painful muscles. Stress-induced activity in descending motor pathways such as the spinoreticular tract may lead to involuntary tonic contractions or cocontraction of agonists and antagonists. A particularly important aspect is a possible dysfunction of descending anti-nociceptive pathways that normally suppress pain sensations. If this system has a reduced activity, low levels of activity in muscle nociceptors can lead to strong pain.

Prof. Tores Theorell, Sweden
Work-related musculoskeletal disorders related to stress- how can they be prevented? Changing individual behaviour or developing organisation?

Changing individual behaviour or developing organisation? There is growing evidence that external factors in the work environment, psychosocial as well as physical, are of importance to many health outcomes, including musculoskeletal disorders. Such environmental factors are perceived by the individual and there is a never-ending discussion whether the main target of health promoting workplace interventions should be the individual or the organisation. Both with regard to psychosocial and physical factors in the environment, it is obvious that coping could be improved on the individual level and that organisational improvement could be health promoting. One of the problems in this controversy has been that it is practically more easy to perform well-conducted controlled studies of health promotion on the individual level. Organisational interventions require larger samples, are much more difficult to design and are often lost in the evaluation process due to structural changes, for instance merger, outsourcing and downsizing. In the planning phase of organisational interventions good intentions are often diluted and the power of the intervention therefore weakened. These difficulties may explain why there are more controlled studies indicating good health promotion effects of interventions on the individual level than there are on the organisational level. The contribution will discuss these problems theoretically and also give examples of organisational and individual interventions that have been successful.

Prof. Dr. Frank Lehmann-Horn, Germany
How can we better understand established factors of risk and protection by research on function of neuro-muscular system, joint and disc?

Louise Rutz-LaPitz, Switzerland
Neuromuscular Disorders: Knowledge of Motor Control as well as Motor Learning Principles is a “must” for the interdisciplinary rehabilitation team.

Motor Control is the study of the nature and cause of movement. Knowledge of the Systems Model of Motor Control, which is task oriented, helps in the assessment and understanding of the clients problems which is the baseline for rehabilitation. Motor Learning is the study of the acquisition or modification of skills. Motor Learning principles assist the therapist with strategies on how to guide the client to their best performance with carryover / learning to everyday life situations.

Dr. Eva Schonstein, Australia
How to achieve evidence based integrative approaches towards prevention and rehabilitation ? What can we learn from successful case studies?

Musculoskeletal work-related disability amongst employed adults carries a significant cost, both in terms of personal suffering and economic loss.
Attempts to prevent injury in the workplace have by and large failed, due to economic and human factors.
Recently, assessment and management of musculoskeletal work-related conditions has focused on prevention of long term disability and some notable successes have been reported. There has been an exponential rise in the number of clinical trials that deal with efficacy of treatments to prevent long term disability due to musculoskeletal conditions, making a compelling argument for the application of evidence-based practice.
Our task now is to teach stake-holders how to apply the principles of evidence-based practice, participatory and multidisciplinary assessment, and management of work-related disability to every day practice.

Prof. Dr. Jan Dul, The Netherlands
How can interventions on work-related musculoskeletal disorders successfully be integrated into the business world?

Prevention of work-related musculoskeletal disorders (WMSD's) is not a big issue in the business world. Companies are striving for competitiveness, and are interested in programs that create more quality for less money. Although prevention of WMSD's may be cost-effective at macro-economic level, at micro level this is not believed to be true by most organizations. It seems that only legislation, fear for claims or complaints of workers can force interventions. The business world might become interested in programs that create less WMSD's, if it can be shown that these programs are cost-effective on the short and longer term. Moreover, when primary prevention of musculoskeletal disorders is rephrased and integrated into a concept of human-centered design of products and processes, in which both social and micro-economic goals are considered, a shift from the negative side of business to the positive side of business might be possible. In such approach, prevention of work-related musculoskeletal disorders is a tool for an economic goal, although this is not possible in all situations. In this keynote address, a model is given, and examples are shown, on how human-centered design of products and processes may contribute to competitive advantage of companies. Consequences are discussed for the positioning of the ergonomics field and its experts in the business world.