Douglas P. Gross

A population-based survey of back pain beliefs in Canada.

Study Design. Population-based survey. Objectives. To assess the back pain beliefs in 2 provinces in Canada to inform a population-based educational campaign. Summary of Background Data. Beliefs, attitudes, and recovery expectations appear to influence recovery from back pain, yet prevailing public opinions about the condition have been little studied. Methods. Telephone surveys were conducted with 2400 adults in 2 Canadian provinces. Surveys included the Back Beliefs Questionnaire, and additional questions concerning age, gender, recent and lifetime back pain, coping strategies for back pain, and awareness and persuasiveness of media information concerning back pain. Results. A high prevalence of back pain was reported, with a lifetime prevalence of 83.8%, and 1-week prevalence of 34.2%. Generally, a pessimistic view of back pain was held. Most agreed that back pain makes everything in life worse, will eventually stop one from working, and will become progressively worse with age. Mixed opinions were observed regarding the importance of rest and staying active. A significant minority (12.3%) reported taking time off from work for their last back pain episode. Those individuals taking time off from work held more negative back pain beliefs, including the belief that back pain should be rested until it gets better. Conclusions. Public back pain beliefs in the 2 Canadian provinces sampled are not in harmony with current scientific evidence for this highly prevalent condition. Given the mismatch between public beliefs and current evidence, strategies for reeducating the public are needed.

The prognostic value of functional capacity evaluation in patients with chronic low back pain: part 1: timely return to work.

Study Design. Historical cohort study. Objectives. We examined the validity of the Isernhagen Work Systems’ Evaluation in predicting timely return to work. Summary of Background Data. Functional Capacity Evaluations are used commonly to determine readiness for return to work, yet little is known of their validity. Methods. Workers’ compensation claimants undergoing Functional Capacity Evaluations following work-related low back injury were studied. Two cohorts were formed, one on which exploratory analyses were conducted and a second for confirmation. Evaluation indicators were the number of tasks in the protocol rated as failed and performance during the floor-to-waist lift task. The primary outcome investigated was time receiving total temporary disability benefits (as a surrogate of return to work) and a secondary outcome was time until claim closure in the year following Evaluation. Cox proportional-hazards regression was used to determine the prognostic effect of Evaluation crudely and after controlling for potential confounders. Results. Few patients (4%) were found to pass all Evaluation tasks, yet most experienced total temporary disability suspension and claim closure within 1 year following Functional Capacity Evaluations. Better Evaluation performance was related to faster time to suspension of total temporary disability benefits and claim closure after controlling confounding factors, but explained little of the variation in these outcomes (~10%). Performance on the floor-to-waist lift was as predictive as the number of failed tasks in the entire Functional Capacity Evaluations protocol. Conclusions. Better performance on Evaluation was weakly associated with faster recovery; however, the amount of variation explained was small. One task in the Evaluation was as predictive as the entire protocol.

Effectiveness of Interferential Current Therapy in the Management of Musculoskeletal Pain: A Systematic Review and Meta-Analysis

Background Interferential current (IFC) is a common electrotherapeutic modality used to treat pain. Although IFC is widely used, the available information regarding its clinical efficacy is debatable. Purpose The aim of this systematic review and meta-analysis was to analyze the available information regarding the efficacy of IFC in the management of musculoskeletal pain. Data Sources Randomized controlled trials were obtained through a computerized search of bibliographic databases (ie, CINAHL, Cochrane Library, EMBASE, MEDLINE, PEDro, Scopus, and Web of Science) from 1950 to February 8, 2010. Data Extraction Two independent reviewers screened the abstracts found in the databases. Methodological quality was assessed using a compilation of items included in different scales related to rehabilitation research. The mean difference, with 95% confidence interval, was used to quantify the pooled effect. A chi-square test for heterogeneity was performed. Data Synthesis A total of 2,235 articles were found. Twenty studies fulfilled the inclusion criteria. Seven articles assessed the use of IFC on joint pain; 9 articles evaluated the use of IFC on muscle pain; 3 articles evaluated its use on soft tissue shoulder pain; and 1 article examined its use on postoperative pain. Three of the 20 studies were considered to be of high methodological quality, 14 studies were considered to be of moderate methodological quality, and 3 studies were considered to be of poor methodological quality. Fourteen studies were included in the meta-analysis. Conclusion Interferential current as a supplement to another intervention seems to be more effective for reducing pain than a control treatment at discharge and more effective than a placebo treatment at the 3-month follow-up. However, it is unknown whether the analgesic effect of IFC is superior to that of the concomitant interventions. Interferential current alone was not significantly better than placebo or other therapy at discharge or follow-up. Results must be considered with caution due to the low number of studies that used IFC alone. In addition, the heterogeneity across studies and methodological limitations prevent conclusive statements regarding analgesic efficacy.

Enhanced Therapeutic Alliance Modulates Pain Intensity and Muscle Pain Sensitivity in Patients With Chronic Low Back Pain: An Experimental Controlled Study

Background Physical therapy influences chronic pain by means of the specific ingredient of an intervention as well as contextual factors including the setting and therapeutic alliance (TA) between provider and patient. Objective The purpose of this study was to compare the effect of enhanced versus limited TA on pain intensity and muscle pain sensitivity in patients with chronic low back pain (CLBP) receiving either active or sham interferential current therapy (IFC). Design An experimental controlled study with repeated measures was conducted. Participants were randomly divided into 4 groups: (1) AL (n=30), which included the application of active IFC combined with a limited TA; (2) SL (n=29), which received sham IFC combined with a limited TA; (3) AE (n=29), which received active IFC combined with an enhanced TA; and (4) SE (n=29), which received sham IFC combined with an enhanced TA. Methods One hundred seventeen individuals with CLBP received a single session of active or sham IFC. Measurements included pain intensity as assessed with a numerical rating scale (PI-NRS) and muscle pain sensitivity as assessed via pressure pain threshold (PPT). Results Mean differences on the PI-NRS were 1.83 cm (95% CI=14.3–20.3), 1.03 cm (95% CI=6.6–12.7), 3.13 cm (95% CI=27.2–33.3), and 2.22 cm (95% CI=18.9–25.0) for the AL, SL, AE, and SE groups, respectively. Mean differences on PPTs were 1.2 kg (95% CI=0.7–1.6), 0.3 kg (95% CI=0.2–0.8), 2.0 kg (95% CI=1.6–2.5), and 1.7 kg (95% CI=1.3–2.1), for the AL, SL, AE, and SE groups, respectively. Limitations The study protocol aimed to test the immediate effect of the TA within a clinical laboratory setting. Conclusions The context in which physical therapy interventions are offered has the potential to dramatically improve therapeutic effects. Enhanced TA combined with active IFC appears to lead to clinically meaningful improvements in outcomes when treating patients with CLBP.

Work-related recovery expectations and the prognosis of chronic low back pain within a workers' compensation setting.

Objective: We examined the association between work-related recovery expectations and return-to-work in patients with chronic back pain. Methods: A prospective cohort of workers receiving time-loss benefits for back pain of at least 6 weeks’ duration was studied. Workers completed a battery of measures, including a work-related recovery expectations questionnaire. Outcomes included surrogate indicators of timely return-to-work (days until suspension of time-loss benefits) and recovery (claim closure) censored at 1 year. Analysis included multivariable Cox and logistic regression. Results: The sample was predominantly male (63%), with a mean age of 42 years. Positive work-related recovery expectations predicted a 26% faster suspension of time-loss benefits (95% confidence interval = 8–40%) and explained 7% of the variation in this outcome. Conclusion: Recovery expectations provide important information for predicting time to return-to-work, as measured through suspension of time-loss benefits (R2 approximately 7%) in patients with chronic back pain.

Does functional capacity evaluation predict recovery in workers’ compensation claimants with upper extremity disorders?

Objectives: Functional capacity evaluations (FCEs) are commonly used to determine return-to-work readiness and guide decision making following work related injury, yet little is known of their validity. The authors examined performance on the Isernhagen Work Systems’ FCE as a predictor of timely and sustained recovery in workers’ compensation claimants with upper extremity disorders. A secondary objective was to determine whether FCE is more predictive in claimants with specific injuries (that is, fracture) as compared to less specific, pain mediated disorders (that is, myofascial pain). Methods: The authors performed a longitudinal study of 336 claimants with upper extremity disorders undergoing FCE. FCE indicators were maximum performance during handgrip and lift testing, and the number of tasks where performance was rated below required job demands. Outcomes investigated were days receiving time-loss benefits (a surrogate of return to work or work readiness) in the year following FCE, days until claim closure, and future recurrence defined as whether benefits restarted, the claim reopened, or a new upper extremity claim was filed. Cox and logistic regression were used to determine the prognostic effect of FCE crudely and after controlling for potential confounders. Analysis was performed separately on claimants with specific and pain mediated disorders. Results: Most subjects (95%) experienced time-loss benefit suspension within one year following FCE. The one year recurrence rate was 39%. Higher lifting performance was associated with faster benefit suspension and claim closure, but explained little variation in these outcomes (r2 = 1.2–11%). No FCE indicators were associated with future recurrence after controlling for confounders. Results were similar between specific injury and less specific groups. Conclusions: Better FCE performance was a weak predictor of faster benefit suspension, and was unrelated to sustained recovery. FCE was no more predictive in claimants with specific pathology and injury than in those with more ambiguous, pain mediated conditions.

Predicting timely recovery and recurrence following multidisciplinary rehabilitation in patients with compensated low back pain.

Study Design. Historical cohort study. Objectives. We investigated factors predictive of timely and sustained recovery following multidisciplinary rehabilitation in Workers’ Compensation claimants with low back pain. Summary of Background Data. It is still unknown which factors predict better outcomes among back pain patients enrolled in intensive rehabilitation programs. Previously, few consistent predictors have been reported. Methods. We created and tested predictive models using data from clinical and administrative databases of the Alberta Workers’ Compensation Board. Predictive models were built on a cohort of subjects admitted for multidisciplinary rehabilitation in 1999 and tested on subjects admitted in 2000. Cox regression was used to evaluate days to time-loss benefit suspension and days to claim closure following admission for rehabilitation. Logistic regression was used to evaluate risk of future recurrence as judged through time-loss benefit resumption, claim reopening, or new back-related claims filing. Results. Prediction models were variable between exploratory and confirmatory stages, and few variables were found to predict consistently. The number of preadmission healthcare visits was the most robust predictor of all recovery outcomes. Recurrence rates were 18% in 1999 and 22% in 2000. A higher number of preadmission healthcare visits and more previous back-related claims were associated with higher risk of recurrence. Conclusions. The number of preadmission healthcare visits was the most robust prognostic indicator with more healthcare visits related to delayed recovery and higher risk of recurrence. Recurrence rates following successful functional restoration were consistent with the episodic and recurrent nature of low back pain.

Functional Capacity Evaluation Performance Does Not Predict Sustained Return to Work in Claimants With Chronic Back Pain

Objectives: Functional Capacity Evaluation (FCE) is used to determine return-to-work readiness. We investigated the ability of the Isernhagen Work Systems’ FCE to predict sustained return-to-work and future pain and disability in workers’ compensation claimants with chronic back pain. Methods: Prospective study of 130 claimants undergoing FCE for chronic back problems. FCE indicators included number of failed tasks and floor-to-waist lift weight. Recovery indicators included days to suspension of time-loss benefits and future recurrence. Subjects were contacted after one year to determine pain intensity and disability. Analysis included Cox and logistic regression. Results: Fewer failed tasks (HRR 0.94 (0.91–0.98) and higher floor-to-waist lift (HRR 1.38 (1.17–1.62) were associated with faster return-to-work. FCE was not associated with future recurrence, or reported pain intensity, or disability in subjects reached for follow-up. Conclusions: Better FCE performance was mildly associated with indicators of faster return-to-work. However, FCE is not related to recurrent back problems, future pain intensity, or self-reported disability.

The prognostic value of Functional Capacity Evaluation in patients with chronic low back pain: Part 2: Sustained recovery

Study Design. Historical cohort study. Objectives. We investigated the ability of the Isernhagen Work Systems’ Functional Capacity Evaluation to predict sustained recovery. Summary of Background Data. Functional Capacity Evaluation is commonly used to determine readiness or ability for safe return to work following musculoskeletal injury, implying a low risk of future recurrence or “reinjury.” However, this theoretical construct has not yet been tested. Methods. Workers’ compensation claimants who underwent Functional Capacity Evaluation following low back injury and subsequently demonstrated recovery in the form of suspension of total temporary disability benefits or claim closure were studied. The number of failed tasks and performance on the floor-to-waist lift task in the protocol were used as indicators of Functional Capacity Evaluation performance. Indicators of sustained recovery included whether or not total temporary disability benefits restarted, the claim was reopened, or a new back claim was filed. Logistic regression was used to determine the prognostic effect of Functional Capacity Evaluation alone and after controlling for suspected confounding variables. Results. Overall, 46 of 226 patients (20%) experienced a recurrent back-related event within the year following Functional Capacity Evaluation. Opposite to the initial hypothesis, a lower number of failed Functional Capacity Evaluation tasks was consistently associated with higher risk of recurrence after controlling for potential confounding variables. Performance on the floor-to-waist lift task was not related to future recurrence. Conclusions. Contrary to Functional Capacity Evaluation theory, better Functional Capacity Evaluation performance as indicated by a lower number of failed tasks was associated with higher risk of recurrence. The validity of Functional Capacity Evaluation’s purported ability to identify claimants who are “safe” to return to work is suspect.

What low back pain is and why we need to pay attention

Low back pain is a very common symptom. It occurs in high-income, middle-income, and low-income countries and all age groups from children to the elderly population. Globally, years lived with disability caused by low back pain increased by 54% between 1990 and 2015, mainly because of population increase and ageing, with the biggest increase seen in low-income and middle-income countries. Low back pain is now the leading cause of disability worldwide. For nearly all people with low back pain, it is not possible to identify a specific nociceptive cause. Only a small proportion of people have a well understood pathological cause-eg, a vertebral fracture, malignancy, or infection. People with physically demanding jobs, physical and mental comorbidities, smokers, and obese individuals are at greatest risk of reporting low back pain. Disabling low back pain is over-represented among people with low socioeconomic status. Most people with new episodes of low back pain recover quickly; however, recurrence is common and in a small proportion of people, low back pain becomes persistent and disabling. Initial high pain intensity, psychological distress, and accompanying pain at multiple body sites increases the risk of persistent disabling low back pain. Increasing evidence shows that central pain-modulating mechanisms and pain cognitions have important roles in the development of persistent disabling low back pain. Cost, health-care use, and disability from low back pain vary substantially between countries and are influenced by local culture and social systems, as well as by beliefs about cause and effect. Disability and costs attributed to low back pain are projected to increase in coming decades, in particular in low-income and middle-income countries, where health and other systems are often fragile and not equipped to cope with this growing burden. Intensified research efforts and global initiatives are clearly needed to address the burden of low back pain as a public health problem.