Lifting capacity is associated with central sensitization and non-organic signs in patients with chronic back pain.

PURPOSE: To analyze the associations between lifting capacity, and central sensitization (CS) and non-organic signs (NOS) in patients with chronic back pain (CBP) attending vocational rehabilitation. MATERIALS AND METHODS: Cross-sectional observational multicenter study among patients with CBP undergoing a return to work assessment within care as usual. Main analyses: step 1: partial correlation between lifting capacity, and CS, NOS, and additional variables; step 2: multiple regression in stepwise forward method for dependent variable lifting capacity, and for independent variables CS and NOS, and additional variables significant (p < 0.05) at step 1. All analyses were controlled for sex. RESULTS: Fifty-six patients of mean age 42.5 years and 59% women participated in the study. Correlations between lifting capacity and CS and NOS were r = -0.53 and r = -0.50, respectively. CS and NOS, as well as age and sex, contributed significantly to the final regression model, which explained 57.6% of variance. CONCLUSIONS: After controlling for confounders, CS and NOS were negatively associated with lifting capacity in patients with CBP. Explained variance was substantially higher than previously reported studies.Implications for RehabilitationThe identification of central sensitization and non-organic signs (NOS) in patients with chronic back pain can alert clinicians about central nervous system being in a hypersensitive state and about pain behavior.Central sensitization and NOS are relevant determinants of lifting capacity.Better understanding of the factors affecting lifting capacity lead to better design and tailoring of interventions, resulting in optimized vocational rehabilitation programs and faster return to work.

A pilot study in the association between Waddell Non-organic Signs and Central Sensitization.

STUDY DESIGN: A cross-sectional observational multicenter pilot-study was performed within care as usual in three rehabilitation centers in the Netherlands. OBJECTIVE: To explore the relationship between Waddell Non-organic Signs (NOS) and Central Sensitization (CS) in patients with chronic back pain. SUMMARY OF BACKGROUND DATA: A possible relationship between NOS and CS is theoretically plausible, but it has never been tested. METHODS: A cross-sectional observational multicenter pilot-study was performed in three rehabilitation centers in the Netherlands. Patients with chronic back pain were included. Main measures were Waddell's NOS, a battery of eight clinical tests performed during a physical examination, and Central Sensitization Inventory (CSI), a questionnaire measuring symptoms originating from CS. Analyses included Spearman correlation and univariate multiple regression analysis with NOS as dependent variable, CSI as independent, and controlled for confounders (psychosocial variables). RESULTS: Data of n = 56 patients (59% female, mean age 42.6 years) were obtained. Correlation between NOS and CSI was rs = 0.34 (p = 0.01). After controlling for confounders, CSI did not independently predict NOS. CONCLUSION: In this pilot study, CS was moderately related to NOS, but CS did not independently contribute to NOS after controlling for confounders. The results suggest that NOS may not exclusively be non-organic tests, although questions remain. The results of this pilot study can help to develop larger studies to allow replication and more detailed analyses.