RESUMEN
BACKGROUND: Treatment based on the Fear-Avoidance (FA) model has been found to be effective with chronic low back pain (CLBP), and in-vivo exposure of fear evoking movements is proposed as a key change mechanism. Exposure tasks may be conducted in the session (in-session exposure; ISE), in other real-life situations (between sessions exposure) as part of homework assignments, or both. Utilising a randomized, controlled dismantling study design, the aim of this study was to examine the unique effects of ISE in FA-treatment of CLBP. METHODS: Patients (N = 90) with CLBP as primary medical complaints were randomized to receive six sessions of either (a) FA-treatment with ISE (FA-ISE) or (b) FA-treatment without ISE (FA), allowing for between sessions exposure in both treatment groups. Patients were assessed with a large battery of outcome measures at four time-points (pre-treatment, post-treatment, after a booster-session and at 1-year follow-up) including pain intensity, pain catastrophising, self-efficacy, physical performance and quality of life. RESULTS: Both treatment groups (FA-ISE, FA) demonstrated statistically significant improvements on primary and most secondary outcomes, with mostly non-significant between-group differences. CONCLUSIONS: No added benefit was found for the inclusion of ISE of feared movements in FA-treatment for CLBP, delivered in a group format to participants with moderately elevated levels of fear-avoidance beliefs. Clinical trials: NCT01158339. SIGNIFICANCE: This study adds to the existing research literature demonstrating FA-treatment to be effective with CLBP, but further experimental studies are needed in order to examine under what circumstances ISE of feared movements may add to positive treatment outcomes.