Timothy H. Wideman

Effective Treatment of Chronic Low Back Pain in Humans Reverses Abnormal Brain Anatomy and Function

Chronic pain is associated with reduced brain gray matter and impaired cognitive ability. In this longitudinal study, we assessed whether neuroanatomical and functional abnormalities were reversible and dependent on treatment outcomes. We acquired MRI scans from chronic low back pain (CLBP) patients before (n = 18) and 6 months after (spine surgery or facet joint injections; n = 14) treatment. In addition, we scanned 16 healthy controls, 10 of which returned 6 months after the first visit. We performed cortical thickness analysis on structural MRI scans, and subjects performed a cognitive task during the functional MRI. We compared patients and controls, as well as patients before versus after treatment. After treatment, patients had increased cortical thickness in the left dorsolateral prefrontal cortex (DLPFC), which was thinner before treatment compared with controls. Increased DLPFC thickness correlated with the reduction of both pain and physical disability. Additionally, increased thickness in primary motor cortex was associated specifically with reduced physical disability, and right anterior insula was associated specifically with reduced pain. Left DLPFC activity during an attention-demanding cognitive task was abnormal before treatment, but normalized following treatment. These data indicate that functional and structural brain abnormalities—specifically in the left DLPFC—are reversible, suggesting that treating chronic pain can restore normal brain function in humans.

A prospective sequential analysis of the fear-avoidance model of pain.

ABSTRACT The primary purpose of this study was to analyze the sequential relationships proposed by the fear‐avoidance model of pain [Vlaeyen JWS et al. The role of fear of movement/(re)injury in pain disability. J Occup Rehab 1995;5:235–52]. Specifically, this study evaluated whether early change in catastrophizing predicted late change in fear of movement, and whether these factors influenced post‐treatment return‐to‐work. Secondary analyses tested relationships between (1) early change in catastrophizing, late change in depression, and disability; and (2) early change in catastrophizing, late change in pain severity, and disability. Analyses were conducted on a sample of 121 individuals (82 men and 32 women) with a work‐related musculoskeletal injury, and high baseline catastrophizing and fear of movement scores. Participants were enrolled in a 10‐week community‐based disability management intervention, and they completed measures of catastrophizing, fear of movement, depression and pain severity at pre‐, mid‐ and post‐treatment. Return‐to‐work was assessed 4 weeks following termination of the intervention. Contrary to predictions, results from correlational analyses revealed non‐significant relationships among indices of early change in catastrophizing and late changes in fear of movement, depression and pain severity. Multiple logistic regression analyses revealed that early change in catastrophizing, late changes in fear of movement and late change in pain severity were significant predictors of return‐to‐work, while late changes in depression were not. These findings highlight the importance of reductions in psychosocial risk factors in augmenting return‐to‐work outcomes. Implications for the fear‐avoidance model and future research are discussed.

Rethinking the fear avoidance model: Toward a multidimensional framework of pain-related disability

Nearly 20 years ago the Fear Avoidance Model (FAM) was advanced to explain the development and persistence of disabling low back pain. The model has since inspired productive research and has become the leading paradigm for understanding disability associated with musculoskeletal pain conditions. The model has also undergone recent expansion by addressing learning, motivation and self-regulation theory [10,34]. In contrast to these extensions, however, one relatively constant aspect of the model is the recursive series of fear-related cognitive, affective, and behavioral processes shown in Figure 1 [31,32,34]. Despite the endurance and popularity of these cyclical relationships their level of empirical support remains unclear. For instance, recent prospective studies have failed to support the proposed sequential relationships between psychological risk factors [5,36]. Also, the validity of several fundamental assumptions that underlie these cyclical relationships has yet to be fully examined, including the characterization of fear as phobia, the inextricable link between pain and disability, and the independence of disability from pain-related physiological processes. As the FAM continues to evolve, it is critical to clarify whether its cyclical relationships should be retained. The purpose of this topical review is to evaluate the empirical support and theoretical assumptions of the FAM’s cyclical relationships and to highlight implications for future theoretical advancement. Figure 1 Graphical Display of the Fear Avoidance Model (reproduced from Vlaeyen and Linton, 2000 & 2012 [32,34]) Empirical support for cyclical relationships A key component of the FAM cycle is the prospective, sequential inter-relationships between catastrophizing, fear, depression, and pain-related disability, and the role of fear as a common conduit for recovery. Several studies have shown broad support for the FAM using cross-sectional or longitudinal analyses [18,28]. However, particular prospective study designs are needed to confirm the sequence and direction of relationships proposed in Figure 1 [3]. Two recent studies using a three-panel, prospective design failed to show that changes in pain catastrophizing precede changes in pain-related fear or that changes in fear precede changes in depression [5,36]. Three recent longitudinal studies have also examined whether pain-related fear acts as a common predictor of both pain intensity and pain-related disability [13,27,39]. Fear uniquely predicted disability in one study [39] and failed to prospectively predict pain in all studies [13,27,39]. Contrary to model predictions, pain catastrophizing had direct and independent relationships with pain (even after controlling for fear), and pain intensity emerged as a predictor of disability even after controlling for model-relevant risk factors [27,39]. Disuse Syndrome, the proposed downstream mechanism through which fear and avoidance influence disability, is another important link in the FAM cycle. Disuse syndrome is a broadly conceived, adverse condition resulting from prolonged physical inactivity [6]. FAM proponents have focused on the effects of disuse on musculoskeletal and cardiovascular systems [31–33], suggesting that physical deconditioning and disability are caused by fear-driven inactivity. Previous work, however, has shown inconsistent links between inactivity or deconditioning among individuals with chronic pain relative to pain-free control groups [24,29]. Furthermore, though pain-related fear is closely linked to avoidance of specific pain-related behaviors [18], this risk factor is not consistently related to objective measures of general disuse or physical fitness in either prospective or cross-sectional studies [7,19,22]. Collectively, these findings suggest that avoidance of specific feared movements does not translate into widespread inactivity, and that fear is unlikely to influence disability through the proposed disuse syndrome mechanism. While the FAM emphasizes cyclical relationships between its risk factors (catastrophizing, fear, depression), recent findings support cumulative interactions. For example, patients with elevated scores on a greater number of risk factors (i.e. those with a higher cumulative risk load) are more likely to develop prolonged pain and disability [35,38]. The clinical value of this approach is highlighted by findings that a single measure of cumulative risk load shows greater predictive strength and scope than combined severity measures of catastrophizing, fear and depression [37]. Additionally, stratifying clinical interventions based on cumulative risk leads to improved outcome and reduced treatment cost [14]. While the cyclical relationships of the FAM offer appealingly specific clinical implications (e.g. treating catastrophizing before fear), model-relevant interventions fail to meet this level of specificity [23] and increasing evidence suggests that cumulative risk load may be a more important target of treatment.

Differential predictors of the long-term levels of pain intensity, work disability, healthcare use, and medication use in a sample of workers’ compensation claimants

&NA; The fear avoidance model of pain (FAM) conceptualizes pain catastrophizing as the cognitive antecedent of pain‐related fear, and pain‐related fear as the emotional antecedent of depression and disability. The FAM is essentially one of mediation whereby pain‐related fear becomes the process by which depression or disability ensue. However, emerging literature suggests that pain catastrophizing, pain‐related fear, and depression might be at least partially distinct in their prediction of different pain‐related outcomes. The primary purpose of the present study was to evaluate whether psychological factors in the FAM (pain catastrophizing, pain‐related fear, and depression) differentially predict long‐term pain‐related outcomes. Toward this objective, we conducted a prospective study using a cohort of 202 individuals with subacute work‐related musculoskeletal injuries. Participants completed a 7‐week physical therapy program with a functional rehabilitation orientation. Posttreatment measures of fear of movement, pain catastrophizing, depression, and pain self‐efficacy were used to predict the persistence of pain symptoms, healthcare use, medication use, and return‐to‐work at one‐year follow‐up. Results from hierarchical linear and logistic regression analyses revealed that pain catastrophizing and fear of movement act as differential predictors of long‐term pain‐related outcomes. Specifically, we found unique relationships between pain catastrophizing and long‐term pain intensity, and fear of movement and long‐term work disability. After controlling for pain intensity and FAM variables, pain self‐efficacy was shown to be a unique predictor of medication use. Implications for the FAM and the clinical management of musculoskeletal pain conditions are discussed. Unique relationships were found between pain catastrophizing and long‐term pain intensity, between fear of movement and long‐term work disability, and between pain self‐efficacy and medication use at one‐year follow‐up.

Catastrophizing and Perceived Injustice Risk Factors for the Transition to Chronicity After Whiplash Injury

Study Design. The article will summarize research that has supported the role of pain catastrophizing and perceived injustice as risk factors for problematic recovery after whiplash injury. Objective. This article focuses on two psychological variables that have been shown to impact on recovery trajectories after whiplash injury; namely pain catastrophizing and perceived injustice. Summary of Background Data. Research has shown that psychological variables play a role in determining the trajectory of recovery after whiplash injury. Methods. This article will focus on two psychological variables that have been shown to impact on recovery trajectories after whiplash injury; namely pain catastrophizing and perceived injustice. The article will summarize research that has supported the role of pain catastrophizing and perceived injustice as risk factors for problematic recovery after whiplash injury. Results. Several investigations have shown that measures of catastrophizing and perceived injustice prospectively predict problematic trajectories of recovery after whiplash injury. Basic research points to the potential roles of expectancies, attention, coping and endogenous opioid dysregulation as possible avenues through which catastrophizing might heighten the probability of the persistence of pain after whiplash injury. Although research has yet to systematically address the mechanisms by which perceived injustice might contribute to prolonged disability in individuals with whiplash injuries, there are grounds for suggesting the potential contributions of catastrophizing, pain behavior and anger. Conclusion. A challenge for future research will be the development and evaluation of risk factor–targeted interventions aimed at reducing catastrophizing and perceived injustice to improve recovery trajectories after whiplash injury.

Comparing the responsiveness of a brief, multidimensional risk screening tool for back pain to its unidimensional reference standards: The whole is greater than the sum of its parts

TOC summary A brief, multidimensional risk‐factor questionnaire predicted treatment‐related changes beyond several unidimensional questionnaires, suggesting that it may be a valuable measure of back pain recovery. ABSTRACT Back pain is a leading cause of disability. Previous research suggests that modifiable risk factors influence recovery from back pain, and practice guidelines recommend integrating such factors within primary care management. Toward this goal, a brief, multidimensional questionnaire, the STarT Back Tool, was designed to facilitate risk assessment by reducing the need to administer multiple, unidimensional questionnaires. However, aspects of this tool’s clinical utility remain unaddressed. For instance, it is unclear whether this tool is responsive to treatment‐related changes or whether clinically meaningful information is lost when it replaces multiple risk questionnaires. This study compared the responsiveness of the STarT Back Tool to its corresponding full‐length measures, and evaluated its ability to detect clinically meaningful improvement. The study sample included 300 participants that consulted their doctor with disabling back pain. The STarT Back Tool and its reference standard questionnaires (disability, catastrophizing, fear, and depression) were administered at baseline and 4 months later. Regression analyses tested whether, after controlling for its reference standard questionnaires, the STarT Back Tool (independent variable) predicted treatment‐related changes in global improvement, pain severity, disability, catastrophizing, fear, and depression (dependent variables). Receiver operating characteristic analyses determined the level of STarT Back change needed for clinically meaningful improvement. STarT Back scores predicted changes in all dependent variables except depression. Reductions in STarT Back scores predicted meaningful improvement on all dependent variables. These findings suggest that the STarT Back Tool, instead of multiple risk questionnaires, can be used to measure recovery from back pain. Implications for future research and clinical practice are discussed.

Clinically meaningful scores on pain catastrophizing before and after multidisciplinary rehabilitation: a prospective study of individuals with subacute pain after whiplash injury.

Objectives:Pain catastrophizing has emerged as a significant risk factor for problematic recovery after musculoskeletal injury. As such, there has been an increased focus on interventions that target patients’ levels of catastrophizing. However, it is not presently clear how clinicians might best interpret scores on catastrophizing before and after treatment. Thus, the purpose of this study was to provide preliminary guidelines for the clinical interpretation of scores on pain catastrophizing among individuals with subacute pain after musculoskeletal injury. Methods:A sample of 166 occupationally disabled individuals with subacute pain due to a whiplash injury participated in this study. Participants completed a 7-week standardized multidisciplinary rehabilitation program aimed at fostering functional recovery. Participants completed the Pain Catastrophizing Scale (PCS) upon program commencement and completion. One year later, participants indicated their pain severity and involvement in employment activities. Separate receiver operating characteristic curve analyses were conducted to determine absolute pretreatment and posttreatment and percent change scores on the PCS that were best associated with clinically important levels of pain and employment status at the follow-up. Results:An absolute pretreatment PCS score of 24 best identified patients according to follow-up clinical outcomes. Posttreatment PCS scores of 14 and 15 best identified patients with high follow-up pain intensity ratings and those who did not return to work, respectively. PCS reductions of approximately 38% to 44% were best associated with return to work and low pain intensity ratings at follow-up. Discussion:The results indicate scores on catastrophizing before and after treatment that are clinically meaningful. These results may serve as preliminary guidelines to assess the clinical significance of interventions targeting pain catastrophizing in patients with subacute pain after musculoskeletal injury.

Increased sensitivity to physical activity among individuals with knee osteoarthritis: Relation to pain outcomes, psychological factors, and responses to quantitative sensory testing

Summary Sensitivity to physical activity was related to measures of central sensitization and pain catastrophizing and cross‐sectionally predicted worse pain, function, and physical performance. ABSTRACT Recent findings suggest that certain individuals with musculoskeletal pain conditions have increased sensitivity to physical activity (SPA) and respond to activities of stable intensity with increasingly severe pain. This study aimed to determine the degree to which individuals with knee osteoarthritis (OA) show heightened SPA in response to a standardized walking task and whether SPA cross‐sectionally predicts psychological factors, responses to quantitative sensory testing (QST), and different OA‐related outcomes. One hundred seven adults with chronic knee OA completed self‐report measures of pain, function, and psychological factors, underwent QST, and performed a 6‐min walk test. Participants rated their discomfort levels throughout the walking task; an index of SPA was created by subtracting first ratings from peak ratings. Repeated‐measure analysis of variance revealed that levels of discomfort significantly increased throughout the walking task. A series of hierarchical regression analyses determined that after controlling for significant covariates, psychological factors, and measures of mechanical pain sensitivity, individual variance in SPA predicted self‐report pain and function and performance on the walking task. Analyses also revealed that both pain catastrophizing and the temporal summation of mechanical pain were significant predictors of SPA and that SPA mediated the relationship between catastrophizing and self‐reported pain and physical function. The discussion addresses the potential processes contributing to SPA and the role it may play in predicting responses to different interventions for musculoskeletal pain conditions.

A Rasch analysis of the pain catastrophizing scale supports its use as an interval-level measure.

Objectives:To evaluate the properties of the Pain Catastrophizing Scale (PCS) from a Rasch paradigm. Methods:A secondary analysis of 235 patients with work-related pain conditions was performed using the Rasch methodology. Unidimensionality, item fit, location independence, differential item functioning, response option structure, and linearity were evaluated for the 13-item PCS score. Results:Two items (8 and 12) required rescoring to address disordered response thresholds. Significant misfit to the Rasch model was corrected through the use of testlets based on the original 3 factors of the PCS (rumination, magnification, and helplessness). After rescoring and creation of testlets, the scale showed good fit to the Rasch model (&khgr;2=6.93, P=0.91) and could be logically considered an interval-level scale. No evidence of differential item functioning was found for sex or location of pain. The items in the scale covered the spectrum of catastrophizing levels reported by the sample. A transformation matrix is presented that allows simple conversion of ordinal to interval-level scores. Discussion:The results of this secondary analysis suggest that the PCS can be appropriately evaluated as an interval-level scale when the composite 13-item score is considered, as has been standard practice to date. Implications for clinical and research use are discussed.

Development of a Cumulative Psychosocial Factor Index for Problematic Recovery Following Work-Related Musculoskeletal Injuries

Background Psychosocial variables such as fear of movement, depression, and pain catastrophizing have been shown to be important prognostic factors for a wide range of pain-related outcomes. The potential for a cumulative relationship between different elevated psychosocial factors and problematic recovery following physical therapy has not been fully explored. Objective The purpose of this study was to determine whether the level of risk for problematic recovery following work-related injuries is associated with the number of elevated psychosocial factors. Design This was a prospective cohort study. Methods Two hundred two individuals with subacute, work-related musculoskeletal injuries completed a 7-week physical therapy intervention and participated in testing at treatment onset and 1 year later. An index of psychosocial risk was created from measures of fear of movement, depression, and pain catastrophizing. This index was used to predict the likelihood of experiencing problematic recovery in reference to pain intensity and return-to-work status at the 1-year follow-up. Results Logistic regression analysis revealed that the number of prognostic factors was a significant predictor of persistent pain and work disability at the 1-year follow-up. Chi-square analysis revealed that the risk for problematic recovery increased for patients with elevated levels on at least 1 psychosocial factor and was highest when patients had elevated scores on all 3 psychosocial factors. Limitations The physical therapy interventions used in this study were not standardized. This study did not include a specific measure for physical function. Conclusions The number of elevated psychosocial factors present in the subacute phase of recovery has a cumulative effect on the level of risk for problematic recovery 1 year later. This research suggests that a cumulative prognostic factor index could be used in clinical settings to improve prognostic accuracy and to facilitate clinical decision making.