Pain-Related Endurance, Fear-Avoidance and Somatosensory Sensitivity as Correlates of Clinical Status after Lumbar Disc Surgery

Most pain and disability variance in patients with low back pain still remains unexplained. The aim of this study was to enhance the degree of explained variance by including measures of pain and tactile sensitivity as well as pain-related endurance and fear-avoidance responses. Thirty-six post lumbar disc surgery patients completed psychometric questionnaires (Avoidance-Endurance Questionnaire, Fear-Avoidance Beliefs Questionnaire, Beck Depression Inventory) and underwent quantitative sensory testing (QST) with measures of pain (pressure (PPT) and mechanical pain threshold) and tactile sensitivity (MDT). Bivariate correlations and hierarchical multiple regression analysis were computed. In addition to the contribution of fear-avoidance responses, pressure pain sensitivity and endurance behavior significantly contributed to explanations of pain variance, whereas disability was primarily predicted by fear-avoidance. While all psychological variables and MDT were positively related to pain or disability, PPT was negatively related to pain. The regression model accounted for 69 % of the variance in back pain intensity and 68 % of the variance in disability. Tactile hypaesthesia was related to increased clinical pain. Pain-related endurance responses and pressure pain hyperalgesia were significant additional predictors for pain, but not for disability. These findings are compatible with generalized disinhibition via descending pathways and a general inhibition of tactile acuity by ongoing pain.