Research studies focusing on the fear-avoidance model have expanded considerably since the review by Vlaeyen and Linton (Vlaeyen J. W. S. & Linton, S. J. (2000). Fear-avoidance and its consequences in chronic musculoskeletal pain: a state of the art. Pain, 85(3), 317--332). The fear-avoidance model is a cognitive-behavioral account that explains why a minority of acute low back pain sufferers develop a chronic pain problem. This paper reviews the current state of scientific evidence for the individual components of the model: pain severity, pain catastrophizing, attention to pain, escape/avoidance behavior, disability, disuse, and vulnerabilities. Furthermore, support for the contribution of pain-related fear in the inception of low back pain, the development of chronic low back pain from an acute episode, and the maintenance of enduring pain, will be highlighted. Finally, available evidence on recent clinical applications is provided, and unresolved issues that need further exploration are discussed.

Objectives:The aim of the Consensus on Health Economic Criteria (CHEC) project is to develop a criteria list for assessment of the methodological quality of economic evaluations in systematic reviews. The criteria list resulting from this CHEC project should be regarded as a minimum standard.Methods:The criteria list has been developed using a Delphi method. Three Delphi rounds were needed to reach consensus. Twenty-three international experts participated in the Delphi panel.Results:The Delphi panel achieved consensus over a generic core set of items for the quality assessment of economic evaluations. Each item of the CHEC-list was formulated as a question that can be answered by yes or no. To standardize the interpretation of the list and facilitate its use, the project team also provided an operationalization of the criteria list items.Conclusions:There was consensus among a group of international experts regarding a core set of items that can be used to assess the quality of economic evaluations in systematic reviews. Using this checklist will make future systematic reviews of economic evaluations more transparent, informative, and comparable. Consequently, researchers and policy-makers might use these systematic reviews more easily. The CHEC-list can be downloaded freely fromhttp://www.beoz.unimaas.nl/chec/.

Since pain-related fear may contribute to the development and maintenance of chronic low back pain (CLBP), an exposure in vivo treatment (EXP) was developed for CLBP patients. We examined the effectiveness as well as specific mediating mechanisms of EXP versus operant graded activity (GA) directly and 6 months post-treatment in a multi-centre randomized controlled trial. In total, 85 patients suffering from disabling non-specific CLBP reporting at least moderate pain-related fear were randomly allocated to EXP or GA. It was demonstrated that EXP, despite excelling in diminishing pain catastrophizing and perceived harmfulness of activities, was equally effective as GA in improving functional disability and main complaints, although the group difference almost reached statistical significance favouring EXP. Both treatment conditions did not differ in pain intensity and daily activity levels either. Nor was EXP superior to GA in the subgroup of highly fearful patients. Irrespective of treatment, approximately half the patients reported clinically relevant improvements in main complaints and functional disability, although for the latter outcome the group difference was almost significant favouring EXP. Furthermore, the effect of EXP relative to GA on functional disability and main complaints was mediated by decreases in catastrophizing and perceived harmfulness of activities. In sum, this study demonstrates that up to 6 months after treatment EXP is an effective treatment, but not more effective than GA, in moderately to highly fearful CLBP patients, although its superiority in altering pain catastrophizing and perceived harmfulness of activities is clearly established. Possible explanations for these findings are discussed.

The aims of the current study were twofold. First, the factor structure, reliability (i.e., internal consistency), and validity (i.e., concurrent criterion validity) of the Tampa Scale for Kinesiophobia (TSK), a measure of fear of movement and (re)injury, were investigated in a Dutch sample of patients with work-related upper extremity disorders (study 1). More specifically, examination of the factor structure involved a test of three competitive models: the one-factor model of all 17 TSK items, a one-factor model of the TSK (Woby SR, Roach NK, Urmston M, Watson P. Psychometric properties of the TSK-11: a shortened version of the Tampa Scale for Kinesiophobia. Pain 2005;117:137-44.), and a two-factor model of the TSK-11. Second, invariance of the aforementioned TSK models was examined in patients with chronic musculoskeletal pain conditions (i.e., work-related upper extremity disorders, chronic low back pain, fibromyalgia, osteoarthritis) from The Netherlands, Sweden, and Canada was assessed (study 2). Results from study 1 showed that the two-factor model of the TSK-11 consisting of 'somatic focus' (TSK-SF) and 'activity avoidance' (TSK-AA) had the best fit. The TSK factors showed reasonable internal consistency, and were modestly but significantly related to disability, supporting the concurrent criterion validity of the TSK scales. Results from study 2 showed that the two-factor model of the TSK-11 was invariant across pain diagnoses and Dutch, Swedish, and Canadian samples. Altogether, we consider the TSK-11 and its two subscales a psychometrically sound instrument of fear of movement and (re)injury and recommend to use this measure in future research as well as in clinical settings.

Patients' initial beliefs about the success of a given pain treatment are shown to affect final treatment outcome. The Credibility/Expectancy Questionnaire (CEQ) has recently been developed as measure of treatment credibility and expectancy. The objectives of this study were (1) to investigate the factor structure of the CEQ in a sample of chronic low back pain (CLBP) patients by means of a confirmatory factor analysis, (2) to examine the association between treatment credibility and expectancy and patient characteristics, and (3) to assess whether treatment expectancy and credibility are associated with the outcome of rehabilitation treatment. CLBP patients (n=167) were randomized to either active physical therapy (n=51), cognitive-behavioral therapy (n=57), or a combination therapy (n=59), and completed the CEQ after a careful explanation of the treatment rationale. Confirmatory factor analysis supported the 2-factor structure (credibility/expectancy) of the CEQ. Lower credibility was associated with higher pain-related fear and lower internal control of pain, and lower expectancy with higher levels of pain-related fear and no radiating pain. Multiple linear regression analyses revealed that after controlling for age, sex, treatment center, pain-intensity at baseline, duration of disability, and irrespective of the treatment offered, expectancy was significantly associated with disability and satisfaction. Credibility was significantly associated with patient-specific symptoms and satisfaction. For global perceived effect, treatment expectancy was predictive in active physical therapy only, and treatment credibility was a significant predictor in combination therapy only. Although the associations found were low to modest, these results underscore the importance of expectancy and credibility for the outcome of different active interventions for CLBP and might contribute to the development of more effective treatments.