4Work related neck–shoulder pain: a review on magnitude, risk factors, biochemical characteristics, clinical picture and preventive interventions
Section snippets
Occurrence of work-related neck–shoulder disorder
There is a vast amount of epidemiological literature dealing with work-related neck–shoulder disorders as a major health problem in many occupations. Still, the work-relatedness in the sense of a well-established dose–response relationship or a calculated etiological fraction is poorly documented. This is due to several factors presenting varying degrees of difficulty for a straightforward interpretation. First of all, the term ‘neck–shoulder disorders’ covers a broad spectrum ranging from
Muscle nociception
Neurophysiological studies have indicated that small-diameter, slowly conducting afferent nerve fibres from skeletal muscle have to be excited in order to elicit pain. A high proportion of these fibres terminate in free nerve endings with nociceptive properties.32 Nociceptors are sensitive to chemical substances released from damaged or overloaded cells and excessive tissue deformation.33 Nociceptors have been shown to respond to several algesic substances such as bradykinin, serotonin, and
Morphological and biochemical studies of myalgia
During recent years, several studies on biochemical and morphological processes in myalgic human muscle have been published and will be the focus in this section.
Clinical diagnosis of neck and shoulder myalgia
The basis for the diagnostic criteria of neck and shoulder myalgia is relatively vague, and the diagnostic terminology and methods for assessment of neck and upper-limb musculoskeletal disorders are variable. This implies that several more or less specific and partly overlapping diagnoses exist in clinical practice and epidemiological research. A typical anamnesis with progressing neck and shoulder pain and no other symptoms or signs does not require investigations such as radiography, magnetic
Preventive interventions
The first recommendations given by the NRC report is that a broad comprehensive effort to promote ergonomic as well as other preventive strategies is highly justified.14 This is based on the consequences of musculoskeletal disorders for both the individual and society, in combination with the evidence that these problems are at least to some degree preventable. The broad consensus of the multifactorial element in the development of musculoskeletal neck–shoulder disorders indicates the need for
Summary
This review has focused on the physiology of neck–shoulder pain and trapezius myalgia, its possible relationship to work, risk factors for its development, the latest knowledge on changes in structure and biochemical milieu in painful muscles, and the most-used standards for diagnosing neck–shoulder disorders as well as the state of the art in rehabilitation.
The review confirms earlier findings of evidence for a causal relationship between neck and shoulder disorders and highly repetitive work,
Conflict of interest statement
There are no conflicts of interest. No financial or personal relationship has inappropriately influenced this work.
Acknowledgements
The authors would like to thank Professor Björn Gerdle, Division of Rehabilitation Medicine, Linköping, Sweden, and Professor Gisela Sjøgaard, National Institute of Occupational Health, Denmark, for their scientific input into this review based on their great insight into risk factors, pain physiology and rehabilitation medicine, and their contribution to many studies advancing the knowledge in this field. Researcher Anne Katrine Blangsted is also thanked for her skilled assistance in searching
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