Michael Feuerstein

Environmental stressors and chronic low back pain: Life events, family and work environment

&NA; Stressors in the family and job environments have been proposed to play a role in the modulation of pain, yet direct empirical support for such a role is limited. The present study investigated the relationship between general stress, family and work environments (perceived social climate), psychological distress (anxiety, depression) and pain experience (sensory, affective, evaluative) in 33 ambulatory chronic low back pain (CLBP) subjects and 35 healthy controls matched for age, sex, socioeconomic status (SES), weight and height. Results indicated that environmental Stressors/social climate measures, including family conflict, family control and general stress (Social Readjustment Rating Scale), were greater in the CLBP group. Distress measures were also higher in the CLBP group. Characteristics of the family and work environments were found to be more predictive of the affective and evaluative dimensions of pain. Increased family conflict was associated with increased distress and increased pain, while increased family independence was correlated with less distress and increased pain. Less peer cohesion, less physical comfort, and less job clarity were correlated with increased pain, but not distress. Work pressure was associated with decreased depression and less pain. These findings suggested the presence of both stress and operant mechanisms in the modulation of pain in the family, while operant and distraction mechanisms appear to characterize the relationship among work environment factors and pain.

A multidisciplinary approach to the prevention, evaluation, and management of work disability

Occupational musculoskeletal disorders represent a major challenge to the injured worker, his or her family, the various health care, health and safety, and human resource professionals that work in this area as well as employers and the workers compensation system. The epidemiology of the occupational musculoskeletal disorders and work disability indicate the problem is growing. Given the multiple factors that contribute to work disability and the complexity in the return to work process, the need to address the varied factors that contribute to work disability has become increasingly clear. Following a review of the magnitude of the problem, a conceptual framework that considers the multivariate nature of work disability is proposed as a heuristic for research and practice. Such an integrated approach argues for a broader consideration of work disability from a biomedical, biomechanical, and psychosocial framework. Last, this paper summarizes efforts to date in the areas of prevention, evaluation, and rehabilitation. The paper suggests that a number of factors have converged over the past 5–10 years that point to the need for a new approach to the problem of work disability, one that truly attempts to integrate the diverse groups and approaches of the past and seeks to develop new knowledge and strategies. It is expected that the Journal of Occupational Rehabilitation will facilitate such an integration.

Biobehavioral mechanisms of chronic low back pain

Although not a life-threatening illness, chronic low back pain represents a major health problem affecting up to 18% of the general population. The disorder is associated with significant levels of pain and disability. The social, economic, and psychological consequences of this persistent disabling pain have also been well documented. Pathophysiological processes do not adequately explain the pain and disability associated with this disorder. Environmental, psychological, and psychobiological factors have been proposed to help account for the apparent discrepancy among pathology, report of pain, and functional ability. This paper reviews the research on biobehavioral factors in chronic low back pain. Research on personality, environmental Stressors, cognitive and perceptual processes, behavioral and social learning processes, peripheral physiological correlates, and central nervous system correlates of pain is reviewed. The final section presents a model for organizing these various factors, thereby providing a framework for future research on biobehavioral mechanisms.

A controlled evaluation of paraspinal EMG biofeedback in the treatment of chronic low back pain.

Sixty-six chronic low back pain sufferers were randomly divided into three groups. Following individual assessments consisting of psychological questionnaires, pain monitoring, and measurement of paraspinal electromyogram (EMG), one group received paraspinal EMG biofeedback and another a placebo treatment. The third group received no intervention. Two further assessments were carried out on all groups immediately after treatment and at a 3-month follow-up. All groups showed significant reduction in pain, anxiety, depression, and paraspinal EMG following treatment and at follow-up, but there were no differences between groups. A regression analysis failed to identify subjects characteristics that predicted positive outcome in the biofeedback group. However, high scores on the Evaluative scale of the McGill Pain Questionnaire and high hypnotizability were significant predictors of positive outcome for the placebo group. It is concluded that paraspinal EMG biofeedback is not a specific treatment for chronic low back pain in a nonhospitalized population.

Fear, alexithymia and cancer pain

The purpose of this study was to examine the differential role of fear, anxiety, alexithymia, family factors and coping in cancer pain. Twenty-seven patients with pain related to cancer, 26 patients with chronic non-cancer pain, 26 patients with chronic illness but no pain (hypertensives) and 24 healthy controls completed a set of questionnaires during an initial interview and recorded severity and duration of pain, pain interference with activities, thoughts, behaviors and physiological responses associated with fear of pain, and coping strategies using a diary once daily for 7 days. In general, cancer patients reported lower pain levels than patients with chronic non-cancer pain. Contrary to anecdotal reports, cancer pain patients did not report fear of pain. Cancer patients and patients with chronic non-cancer pain reported similar levels of trait anxiety which was higher than non-pain patients. Alexithymia, as a measure of emotional expression, was associated with increased duration of pain in the cancer pain patients. Cancer pain patients also reported less use of coping strategies than patients with chronic non-cancer pain. Cancer patients did not report higher levels of family modeling of pain complaints or family use of medication. The perceived family environment of the cancer pain patient did not differ significantly from the 3 other groups. These results do not support anecdotal impressions that the level of reported pain and fear of pain is significantly greater in cancer pain in contrast to non-cancer pain. The results do indicate the importance of emotional expressivity in the modulation of cancer pain where the ability to assess and express emotions was associated with reduced pain.

Chronic back pain and work disability: Vocational outcomes following multidisciplinary rehabilitation.

Studies indicate that work disabled chronic back pain patients out of work for longer than three months have a reduced probability of returning to work. The escalating personal and economic costs (indemnity and health care) associated with such long term disability have facilitated efforts at multiple levels to prevent and more effectively manage work disability. Multidisciplinary rehabilitation (MDR) targeted at return to work represents one such approach. The approach is based upon a multidimensional conceptualization of work disability and integrates medical, physical, psychological, educational and vocational interventions to increase physical function, reduce pain, increase stress coping skills and facilitate return to work. Seven outpatient multidisciplinary rehabilitation outcome studies for chronic back pain were identified that met the following selection criteria: 1) diagnosis of back pain, low back pain, spinal disorder (specific and nonspecific diagnosis), 2) chronic back pain of either longer than three months since injury or longer than three months absence from work, 3) use of an outpatient multidisciplinary rehabilitation approach that included some combination of medical management, physical conditioning, pain and stress management, vocational counseling/placement and education regarding back safety and health, and 4) work reentry was the primary focus of outcome. These were reviewed to determine the effectiveness of MDR in terms of return to work outcome. Analyses revealed that an average of 71 percent of work disabled chronic back pain patients who completed a multidisciplinary rehabilitation program were working or involved in vocational rehabilitation efforts at 12 month follow-up in contrast to an average of 44 percent in corresponding comparison groups. While these studies suggest the clinical utility of a multidisciplinary approach as compared to usual care in facilitating return to work for chronic back pain patients, the literature was characterized by several methodological limitations including the absence of randomization in the majority of studies, use of insurance company denials as control groups, heterogenous samples in terms of duration of work disability, job availability at discharge, extent of impairment and disability, age and duration of pain disorder, lack of specification as to exact treatment delivered in the control or usual care groups and varying definitions of return to work outcome. Research on predictors of return to work outcome following MDR were identified and included variables in five categories: demographics, medical history, physical findings, pain and psychological characteristics. The literature provides support for the use of integrated approaches that target the medical, physical, ergonomic and psychosocial factors that can exacerbate and/or maintain work disability. Future research should address current methodological limitations in the literature and focus on: 1) identifying critical treatment components of such approaches, 2) developing innovative screening methods to identify high risk cases to facilitate earlier more targeted efforts to assist such individuals, and 3) consider variations in the staging of various combinations of interventions in an effort to develop more cost-effective variations in the multidisciplinary approach.

The pain behavior scale: Modification and validation for outpatient use

The present study investigated the validity of an inpatient pain behavior rating scale modified for outpatient use. A series of 43 consecutive outpatients referred for evaluation of chronic pain was examined using the Pain Behavior Scale (PBS) and other psychometric instruments. Analyses revealed significantly higher Pain Behavior Scale scores for low back and multiple pain-site groups. The results also indicated a high degree of internal consistency of the scale. A multiple regression analysis, predicting observed pain behavior from reported pain behavior, indicated that decreased activity accounted for 32% of the variance in the PBS score. A similar regression for pain experience found that the pain level and the sensory scale score on the McGill Pain Questionnaire accounted for 39% of the PBS variance. Psychological characteristics including disease conviction, self-control, depression, and anxiety explained 45% of the variability in the PBS score. Thus, the scale is related to pain intensity, interference with activities, and a variety of psychological characteristics. The scale provides a measure of observable pain behavior that is also relatively independent of these clinical data sources. The Pain Behavior Scale as modified for outpatient use provides a brief index of pain behavior with potential use in the comprehensive evaluation of the pain patient.

Biobehavioral factors in cancer pain

&NA; Despite the presence of pathology in cancer pain, the pain experience in adult cancer patients cannot be totally explained by the extent of such pathology. Unlike chronic benign pain very little research on the role of biobehavioral factors has been conducted to help explain this paradox. The literature on the role of biobehavioral factors in the cancer pain experience is reviewed. A brief review of epidemiology and pathophysiology is presented. Following this, the biobehavioral literature was organized according to research on psychological characteristics and environmental factors. Research addressing affective, cognitive, behavioral and physiological reactions to pain was also discussed. Despite the paucity of studies, the review suggested the following:personality factors do not appear to play a consistent role in the modulation of pain in cancer patients;the work on environmental influences on cancer pain indicate a weak association between such factors as social network and pain intensity;studies on affective state indicate minimal relationships to pain, and lastly,studies on cognitive responses to pain in cancer patients and their influence on the pain experience have not been conducted. To date, in the areas where biobehavioral factors have been investigated, the findings appear modest. However, many potential variables, e.g., self‐esteem, the role of family, the role of models, past or current work environments, social learning factors and responses to pain such as fear, somatization and reattribution have not been explored with cancer patients. While the influence of biobehavioral factors in adult cancer pain appear to be relatively modest, the literature is not extensive. Increased efforts at more precisely determining the input of such factors in cancer pain are warranted, particularly given the role of such variables in other recurrent and chronic pain states.

Psychological Factors Affecting Isokinetic Trunk Strength Testing in Patients with Work-Related Chronic Low Back Pain

Psychological factors are assumed to play a major role in pain-related work disability. Assessment of pain-related disability using a functional capacity evaluation, usually includes assessment of trunk strength and range of motion. Isokinetic strength testing is a method used to measure strength and function of isolated muscles and has been reported to be an objective, quantifiable assessment of trunk function. Given that psychological factors are purported to play a role in pain-related disability, it would be important to assess their influence on measurement of physical function. The present study was conducted to assess the influence of psychological variables on isokinetic trunk strength performance. One hundred and eighty-six consecutive male outpatients referred to a work-rehabilitation center were given a functional capacity evaluation. All patients had been out of work for at least 3 months with the chief complaint of low back pain. The evaluation included isokinetic trunk strength testing and measurement of psychological variables (pain levels, distress, pain coping, pain behavior, somatization, expectation to return to work) that have been known to contribute to pain-related disability. Data analyses revealed significant correlations among psychological variables and measures of trunk strength and function. The findings provide support for a relationship between psychological variables and isokinetic strength testing performance.

Biobehavioral pain profile: development and psychometric properties

&NA; Although a number of self‐report indices that measure intensity and psychosocial components of the pain experience are available, these measures do not assess the range of cognitive, behavioral, and physiological reactions frequently associated with pain. This paper describes the initial determination of the psychometric properties of the Biobehavioral Pain Profile (BPP) developed to measure these reactions. The BPP is a 41‐item self‐report scale tested in a sample of 617 subjects with chronic recurrent pain, chronic non‐malignant pain or chronic malignant pain. Kaisers measure of sampling adequacy was 0.918. Factor analysis revealed 6 theoretically meaningful factors: Environmental Influences, Loss of Control, Health Care Avoidance, Past and Current Experience, Physiological Responsivity, and Thoughts of Disease Progression. Cronbachs alpha scores for the specific subscales ranged from r = 0.77 to r = 0.94. Test‐retest reliability for the scales ranged from 0.57 to 0.73. Low correlations among the BPP and general indices of fear, depression, anxiety, body consciousness and social desirability are reported. The BPP appears to provide a unique composite assessment of self‐report of behavioral, physiological, and cognitive reactions to pain experienced by individuals with a wide range of pain problems.