Steven J. Linton

Fear-avoidance and its consequences in chronic musculoskeletal pain: a state of the art

&NA; In an attempt to explain how and why some individuals with musculoskeletal pain develop a chronic pain syndrome, Lethem et al.(Lethem J, Slade PD, Troup JDG, Bentley G. Outline of fear‐avoidance model of exaggerated pain perceptions. Behav Res Ther 1983; 21: 401‐408).ntroduced a so‐called ‘fear‐avoidance’ model. The central concept of their model is fear of pain. ‘Confrontation’ and ‘avoidance’ are postulated as the two extreme responses to this fear, of which the former leads to the reduction of fear over time. The latter, however, leads to the maintenance or exacerbation of fear, possibly generating a phobic state. In the last decade, an increasing number of investigations have corroborated and refined the fear‐avoidance model. The aim of this paper is to review the existing evidence for the mediating role of pain‐related fear, and its immediate and long‐term consequences in the initiation and maintenance of chronic pain disability. We first highlight possible precursors of pain‐related fear including the role negative appraisal of internal and external stimuli, negative affectivity and anxiety sensitivity may play. Subsequently, a number of fear‐related processes will be discussed including escape and avoidance behaviors resulting in poor behavioral performance, hypervigilance to internal and external illness information, muscular reactivity, and physical disuse in terms of deconditioning and guarded movement. We also review the available assessment methods for the quantification of pain‐related fear and avoidance. Finally, we discuss the implications of the recent findings for the prevention and treatment of chronic musculoskeletal pain. Although there are still a number of unresolved issues which merit future research attention, pain‐related fear and avoidance appear to be an essential feature of the development of a chronic problem for a substantial number of patients with musculoskeletal pain.

A review of psychological risk factors in back and neck pain.

STUDY DESIGN The literature on psychological factors in neck and back pain was systematically searched and reviewed. OBJECTIVES To summarize current knowledge concerning the role of psychological variables in the etiology and development of neck and back pain. SUMMARY OF BACKGROUND DATA Recent conceptions of spinal pain, especially chronic back pain, have highlighted the role of psychological factors. Numerous studies subsequently have examined the effects of various psychological factors in neck and back pain. There is a need to review this material to ascertain what conclusions may be drawn. METHODS Medical and psychological databases and cross-referencing were used to locate 913 potentially relevant articles. A table of 37 studies was constructed, consisting only of studies with prospective designs to ensure quality. Each study was reviewed for the population studied, the psychological predictor variables, and the outcome. RESULTS The available literature indicated a clear link between psychological variables and neck and back pain. The prospective studies indicated that psychological variables were related to the onset of pain, and to acute, subacute, and chronic pain. Stress, distress, or anxiety as well as mood and emotions, cognitive functioning, and pain behavior all were found to be significant factors. Personality factors produced mixed results. Although the level of evidence was low, abuse also was found to be a potentially significant factor. CONCLUSIONS Psychological factors play a significant role not only in chronic pain, but also in the etiology of acute pain, particularly in the transition to chronic problems. Specific types of psychological variables emerge and may be important in distinct developmental time frames, also implying that assessment and intervention need to reflect these variables. Still, psychological factors account for only a portion of the variance, thereby highlighting the multidimensional view. Because the methodologic quality of the studies varied considerably, future research should focus on improving quality and addressing new questions such as the mechanism, the developmental time factor, and the relevance that these risk factors have for intervention.

The Fear-Avoidance Model of Musculoskeletal Pain: Current State of Scientific Evidence

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.

Can we screen for problematic back pain? A screening questionnaire for predicting outcome in acute and subacute back pain.

OBJECTIVES Because musculoskeletal pain is the second most frequent reason for seeking health care, the aims of this study were to determine the value of psychosocial variables in evaluating risk for developing chronic back pain problems and to develop a screening methodology to identify patients likely to have a poor prognosis. STUDY DESIGN A prospective study was conducted on consecutive patients with acute or subacute back pain, in which patients completed a screening questionnaire and were then followed up for 6 months to determine outcome. The primary outcome variable was accumulated sick leave. METHODS One hundred forty-two consecutive patients were asked to complete a questionnaire designed for this study. This questionnaire contained 24 items concerning psychosocial aspects of the problem. Six months later, patients were contacted to complete outcome questions about accumulated sick leave. RESULTS A total of 97% of the patients completed both questionnaires. Although patients, on average, improved greatly, 18% had 1-30 days and 20% had fewer than 30 days of sick leave during the follow-up period. Five variables were found to be the strongest predictors of sick leave outcome (fear-avoidance work beliefs, perceived improvement, problems with work function, stress, and previous sick leave), correctly classifying 73% of the patients as opposed to a chance rate of 33%. A total score was evaluated as a means of judging risk and found to be strongly related to outcome. CONCLUSION Potent psychosocial risk factors associated with future sick absenteeism were identified. Because the total score was related to outcome, the instrument may have use in screening patients with acute or subacute spinal pain in clinical situations.

Behavioral treatment for chronic low back pain: a systematic review within the framework of the Cochrane Back Review Group.

Study Design. A systematic review of randomized controlled trials. Summary of Background Data. The treatment of chronic low back pain is not primarily focused on removing an underlying organic disease but at the reduction of disability through the modification of environmental contingencies and cognitive processes. Behavioral interventions are commonly used in the treatment of chronic (disabling) low back pain. Objectives. To determine whether behavioral therapy is more effective than reference treatments for chronic nonspecific low back pain and which type of behavioral treatment is most effective. Methods. The authors searched the Medline and PsychLit databases and the Cochrane Controlled Trials Register up to April 1999, and Embase up to September 1999. Also screened were references of identified randomized trials and relevant systematic reviews. Methodologic quality assessment and data extraction were performed independently by two reviewers. The magnitude of effect was assessed by computing a pooled effect size for each domain (i.e., behavioral outcomes, overall improvement, back pain–specific and generic functional status, return to work, and pain intensity) using the random effects model. Results. Only six (25%) studies were high quality. There is strong evidence (level 1) that behavioral treatment has a moderate positive effect on pain intensity (pooled effect size 0.62; 95% confidence interval [CI] 0.25, 0.98), and small positive effects on generic functional status (pooled effect size 0.35; 95% CI: 0.04, 0.74) and behavioral outcomes (pooled effect size 0.40; 95% CI: 0.10, 0.70) of patients with chronic low back pain when comparedwith waiting-list controls or no treatment. There is moderate evidence (level 2) that a addition of behavioral component to a usual treatment program for chronic low backpain has no positive short-term effect on generic functional status (pooled effect size 0.31; 95% CI: 0.01, 0.64), pain intensity (pooled effect size 0.03; 95% CI: 0.30,0.36), and behavioral outcomes (pooled effect size 0.19; 95% CI: 0.08, 0.45). Conclusions. Behavioral treatment seems to be an effective treatment for patients with chronic low back pain,but it is still unknown what type of patients benefit most from what type of behavioral treatment.

Fear-avoidance model of chronic musculoskeletal pain: 12 years on.

It is widely acknowledged that pain is a universal experience that affects human beings across the life span, serving an important protective function. Typical protective behaviors are the withdrawal from the noxious stimulus, nonverbal expressions that signal others for impending harm, and verbal utterances. Some of these occur involuntarily, as a reflex, whereas other behaviors are more deliberate. However, there is accumulating evidence that it is not pain itself, but the meaning of pain that predicts the extent to which individuals engage in these protective behaviors [1,3]. About a decade ago, we summarized the research evidence supporting the role of fear of pain in the development of chronic pain disability, presented a model incorporating basic mechanisms, but also noted a number of unresolved issues that called for further scientific attention [39] (Fig. 1). In the last decade, the number of studies on this subject has increased exponentially [21], and novel directions are being proposed [6]. Two main stances have emerged. First, although pain has intrinsic threatening features, the threat value of similar pain stimulus may vary across contexts and individuals. Second, protective responding may be adaptive in the short term, but may paradoxically worsen the problem in the long term. In the current updated review, we briefly summarize the progress made since, and highlight a selected number of remaining challenges and areas for future research.

Early identification of patients at risk of developing a persistent back problem: the predictive validity of the Orebro Musculoskeletal Pain Questionnaire.

ObjectiveTo test the predictive utility of the Örebro Musculoskeletal Pain Screening Questionnaire in identifying patients at risk for developing persistent back pain problems. DesignProspective, where participants completed the questionnaire and their cases were followed for 6 months to assess outcome with regard to pain, function, and absenteeism due to sickness. ParticipantsOne hundred seven patients, recruited from seven primary care units. ResultsDiscriminant analyses showed that the items on the questionnaire were significantly related to future problems. For absenteeism due to sickness, 68% of the patients were correctly classified into one of three groups, whereas an even distribution would have produced 33%. The analyses for function correctly classified 81%, and for pain 71%, into one of two groups, compared with a chance level of 50%. A total score analysis demonstrated that a cutoff score of 90 points had a sensitivity of 89% and a specificity of 65% for absenteeism due to sickness, and a sensitivity of 74% and a specificity of 79% for functional ability. ConclusionsThe results underscore that psychological variables are related to outcome 6 months later, and they replicate and extend earlier findings indicating that the Örebro Screening Questionnaire is a clinically reliable and valid instrument. The total score was a relatively good predictor of future absenteeism due to sickness as well as function, but not of pain. The results suggest that the instrument could be of value in isolating patients in need of early interventions and may promote the use of appropriate interventions for patients with psychological risk factors.

Preventive interventions for back and neck pain problems: what is the evidence?

Study Design. A review of controlled trials. Objectives. To determine which interventions are used to prevent back and neck pain problems as well as what the evidence is for their utility. Summary of Background Data. Given the difficulty in successfully treating long-term back and neck pain problems, there has been a call for preventive interventions. Little is known, however, about the value of preventive efforts for nonpatients, e.g., in the general population or workplace. Methods. The literature was systematically searched to locate all investigations that were: 1) specifically designed as a preventive intervention; 2) randomized or nonrandomized controlled trials; and, 3) using subjects not seeking treatment. Outcome was evaluated on the key variables of reported pain, report of injury, dysfunction, time off work, health-care utilization, and cost. Conclusions were drawn using a grading system. Results. Twenty-seven investigations meeting the criteria were found for educational efforts, lumbar supports, exercises, ergonomics, and risk factor modification. For back schools, only one of the nine randomized trials reported a significant effect, and there was strong evidence that back schools are not effective in prevention. Because the randomized trials concerning lumbar supports were consistently negative, there is strong evidence that they are not effective in prevention. Exercises, conversely, showed stable positive results in randomized controlled trials, giving consistent evidence of relatively moderate utility in prevention. Because no properly controlled trials were found for ergonomic interventions or risk factor modification, there was not good quality evidence available to draw a conclusion. Conclusions. The results concerning prevention for subjects not seeking medical care are sobering. Only exercises provided sufficient evidence to conclude that they are an effective preventive intervention. There is a dire lack of controlled trials examining broad-based multidimensional programs. The need for high quality outcome studies is underscored.

Occupational Psychological Factors Increase the Risk for Back Pain: A Systematic Review

The purpose of this review was to summarize current knowledge concerning the role of psychological workplace variables in back pain. To this end the literature on psychological factors and back pain was systematically searched and analyzed. Psychological and medical databases and cross-referencing were used to locate 975 studies. To be included in this review, studies had to have a prospective design, include a psychological predictor variable, report on back pain, and be published in English. Twenty-one studies fulfilled the criteria for psychological workplace factors. The results showed a clear association between psychological variables and future back pain. There was strong evidence that job satisfaction, monotonous tasks, work relations, demands, stress, and perceived ability to work were related to future back pain problems. Further, moderate evidence was established for work pace, control, emotional effort at work, and the belief that work is dangerous. There was inconclusive evidence about work content. The attributable fraction indicated that substantial reductions in the number of cases of back pain could be achieved if the exposure to the psychological risk factor was eliminated. Although the methodological quality of the studies varied, they were deemed to provide “best evidence,” and the consistency of the findings suggests that they are relatively robust. It is concluded that psychological work factors play a significant role in future back pain problems. However, there is still a lack of knowledge concerning the mechanisms by which these operate. These results suggest that a change in the way we view and deal with back pain is needed. Applying knowledge about psychological factors at work might enhance prevention as well as rehabilitation.

Early Identification and Management of Psychological Risk Factors (“Yellow Flags”) in Patients With Low Back Pain: A Reappraisal

Originally the term “yellow flags” was used to describe psychosocial prognostic factors for the development of disability following the onset of musculoskeletal pain. The identification of yellow flags through early screening was expected to prompt the application of intervention guidelines to achieve secondary prevention. In recent conceptualizations of yellow flags, it has been suggested that their range of applicability should be confined primarily to psychological risk factors to differentiate them from other risk factors, such as social and environmental variables. This article addresses 2 specific questions that arise from this development: (1) Can yellow flags influence outcomes in people with acute or subacute low back pain? and (2) Can yellow flags be targeted in interventions to produce better outcomes? Consistent evidence has been found to support the role of various psychological factors in prognosis, although questions remain about which factors are the most important, both individually and in combination, and how they affect outcomes. Published early interventions have reported mixed results, but, overall, the evidence suggests that targeting yellow flags, particularly when they are at high levels, does seem to lead to more consistently positive results than either ignoring them or providing omnibus interventions to people regardless of psychological risk factors. Psychological risk factors for poor prognosis can be identified clinically and addressed within interventions, but questions remain in relation to issues such as timing, necessary skills, content of treatments, and context. In addition, there is still a need to elucidate mechanisms of change and better integrate this understanding into the broader context of secondary prevention of chronic pain and disability.