IRSST - Institut de recherche Robert-Sauvé en santé et en sécurité du travail

Clinical and Neuromechanic Determinants in the Development of Low Back Disability in Workers


Musculoskeletal injuries, especially those affecting the spine, are the primary factor responsible for functional disabilities in Québec. These musculoskeletal injuries or conditions significantly reduce workers’ chances of living in good health, particularly older workers. With the aging of Québec’s labour force, it is essential that clinical interventions in this sector of healthcare be improved, especially for workers who will eventually be required to prolong their active participation in the labour market over the coming decades.

Beyond the injury itself, musculoskeletal dysfunction and pathologies have considerable psychological consequences for the individual. With respect to society in general, the management of this type of health problem brings with it substantial socioeconomic costs. Over the past decades, Western society has witnessed an increase in the availability of services in and accessibility to healthcare, and, concurrently, an explosion in the number of consultations for musculoskeletal ailments. One ailment stands out from the rest because of its frequent occurrence, complexity and the high expenses involved with it. Low back pain is now the second reason that people see doctors and is the most common musculoskeletal injury. In industrialized societies, the lifetime prevalence of low back pain varies between 70% and 85%, while its annualized prevalence oscillates between 15% and 45%. Given this reality and its significant impact on active working populations, using a longitudinal cohort study, the team attempted to determine the clinical, psychological and physical factors that explain the appearance and development of disabilities related to a history of low back pain. The principal objective of the study consisted of determining whether the initial pain, the attendant psychological factors, motor skills in the presence of pain and pain modulation mechanisms play a role in the progression of the functional disabilities and absenteeism associated with low back pain in a group of workers who had experienced at least one recent and major episode of low back pain.

In the scope of this study, 100 workers with a history of nonspecific low back pain were recruited. Over approximately 15 months, these workers underwent three laboratory evaluations in which various physiological parameters (muscular activity, movement patterns and profile of sensitivity to pain) were measured. The participants also took part in a clinical assessment, in which the progression of the clinical pain, functional disabilities and other psychological factors associated with pain were evaluated. These measures enabled the research team to establish which factors could predict disability or absenteeism associated with low back pain in the short (at the time of the initial assessment), medium (seven months) and long (15 months) term.

Our study’s findings reveal that the workers who participated presented with slight levels of pain and disability at the time they were included in the project, although they had all reported episodes of low back pain over the past years. Among the factors associated with workers’ disability and absenteeism, the clinical variables commonly used in the practice environment (assessment of current pain level) and several psychological states measured by questionnaire appear to be the most effective in predicting the functional status of workers in the short, medium and long-term. Motor abilities in the presence of pain and pain modulation mechanisms did not enable us to predict the clinical status of workers suffering low back pain within our worker sample.

The findings lead us to believe that a holistic perspective should govern the care of workers suffering from low back pain and the disabilities related to it, one that includes a history, the nature of the past episodes and the psychological factors involved in lumbar pain. The painful episodes should therefore not be considered and treated as isolated phenomena. Accordingly, in addition to measures to evaluate the disability and pain, assessment and monitoring tools for workers suffering low back pain should also include an assessment of the psychological factors that influence the condition’s progression.

Additional Information

Category: Research Report
  • Martin Descarreaux
  • Vincent Cantin
  • Mathieu Piché
  • Jean-Daniel Dubois
  • Arnaud Lardon
  • Isabelle Pagé
Research Project: 2012-0002
Research Field: Occupational Rehabilitation
Online since: October 25, 2016
Format: Text