BACKGROUND: Symptoms of lumbar disc herniation can be induced by both mechanical compression of the nerve roots and by biochemical irritants from the disc tissues. Proinflammatory cytokines, as well as stress are potent stimulators of the hypothalamic-pituitary-adrenal axis, reflected in enhanced release of cortisol from the adrenal cortex. Altered cortisol production is also associated to behaviour and coping patterns. The aim of the present study was to explore the relation between pain, physical function, psychosocial factors and quality of life to the diurnal cortisol variability, in patients with lumbar disc herniation.
METHOD: This study had a cross-sectional design. Forty-two patients with lumbar disc herniation, verified by magnetic resonance imaging and a clinical examination by an orthopaedic surgeon, were included in the study. All patients were scheduled for disc surgery. The diurnal cortisol variability was examined before surgery. The patients were dichotomised into two groups based on low or high diurnal cortisol variability. Pain, disability, work related stress, quality of life, coping and fear avoidance beliefs, were estimated by standardised questionnaires.
RESULTS: The low diurnal cortisol variability group was distinguished by a higher median score regarding leg pain at activity and significantly more disability (p<0.05). The patients with a low diurnal cortisol variability had significantly lower coping self-statement scores, but higher pain coping catastrophising scores (p<0.05).
CONCLUSION: Patients with lumbar disc herniation and a low diurnal cortisol variability had lower physical function, perceived lower possibilities of influencing their pain, and were more prone to catastrophise than patients with lumbar disc herniation and a high diurnal cortisol variability.
2008. Vol. 12, no 5, p. 633-40