Eugene K. Wai

Causal assessment of occupational lifting and low back pain: results of a systematic review

BACKGROUND CONTEXT Low back pain (LBP) is a common and disabling musculoskeletal disorder that often occurs in a working-age population. Determining the precise causation of LBP remains difficult. Any attempt to implicate a specific occupational activity in the genesis of LBP requires a methodologically rigorous approach. PURPOSE To conduct a systematic review of the scientific literature focused on evaluating the causal relationship between occupational sitting and LBP. STUDY DESIGN Systematic review of the literature using Medline, EMBASE, CINAHL, Cochrane Library, Occupational Safety and Health database, grey literature, hand-searching occupational health journals, reference lists of included studies, and content experts. Evaluation of study quality using a modified version of the Newcastle-Ottawa Scale. Summary levels of evidence supporting Bradford-Hill criteria for different categories of sitting and types of LBP. SAMPLES Studies reporting an association between occupational sitting and LBP. OUTCOME MEASURES Numerical association between different levels of exposure to occupational sitting and the presence or severity of LBP. METHODS A systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford-Hill criteria, between occupational sitting and LBP. RESULTS This search yielded 2,766 citations. Twenty-four studies met the inclusion/exclusion criteria and five were high-quality studies, including two case-controls and three prospective cohorts. Strong, consistent evidence was found for no association between occupational sitting and LBP. A moderate level of evidence was found for the absence of any dose-response trend. Risk estimates evaluating temporality were not statistically significant. Biological plausibility was not discussed in these studies. No evidence was available to assess the experiment criterion. CONCLUSIONS This review failed to uncover high-quality studies to support any of the Bradford-Hill criteria to establish causality between occupational sitting and LBP. Strong and consistent evidence did not support criteria for association, temporality, and dose response. Based on these results, it is unlikely that occupational sitting is independently causative of LBP in the populations of workers studied.

Systematic Review of the Prevalence of Radiographic Primary Hip Osteoarthritis

Hip osteoarthritis is a common cause of musculoskeletal pain in older adults and may result in decreased mobility and quality of life. Although the presentation of hip osteoarthritis varies, surgical management is required when the disease is severe, longstanding, and unresponsive to nonoperative treatments. For stakeholders to plan for the expected increased demand for surgical procedures related to hip osteoarthritis, including arthroplasty, it is important to first understand its prevalence. We conducted a systematic review by searching MEDLINE® and EMBASE to identify recent English language articles reporting on the prevalence of radiographic primary hip osteoarthritis in the general adult population; references including studies and primary studies from previous systematic reviews were also searched. This strategy yielded 23 studies reporting 39 estimates of overall prevalence ranging from 0.9% to 27% with a mean of 8.0% and a standard deviation of 7.0%. Heterogeneity was noted in study populations, eligibility criteria, age and gender distribution, type of radiographs, and method of diagnosis. Although the association between radiographic hip osteoarthritis and the need for eventual surgical management is still unclear, this study supports assertions that hip osteoarthritis is a prevalent condition whose treatment will continue to place important demands on health services.

Causal assessment of occupational bending or twisting and low back pain: results of a systematic review

BACKGROUND CONTEXT Low back pain (LBP) is a common musculoskeletal disorder that often occurs in the working-age population. Although numerous physical activities have been implicated in its etiology, determining causation remains challenging and requires a methodologically rigorous approach. PURPOSE To conduct a systematic review focused on establishing a causal relationship between occupational bending or twisting and LBP. STUDY DESIGN A systematic review of the literature using Medline, Embase, CINAHL, Cochrane Library, and Occupational Safety and Health database, gray literature, hand-searching occupational health journals, reference lists of included studies, and experts. Evaluation of methodological quality using a modified Newcastle-Ottawa Scale for observational studies. Summary levels of evidence for each of the Bradford-Hill criteria for causality for each category of bending or twisting and type of LBP. SAMPLE Studies reporting an association between occupational bending or twisting and LBP. OUTCOME MEASURES Numerical association between different levels of exposure to bending or twisting and the presence or severity of LBP. METHODS A systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford-Hill criteria, between occupational bending or twisting and LBP. RESULTS This search yielded 2,766 citations. Ten high-quality studies reported on bending and LBP. Five were case-control studies and five were prospective cohort studies. There was conflicting evidence for association, with five studies demonstrating significant associations in the majority of their risk estimates, but no evidence for consistency. Seven studies assessed dose response, with four studies demonstrating a nonsignificant dose-response trend. Four studies were able to assess temporality, but only one demonstrated significant risk estimates. Biological plausibility was discussed by two studies. There was no available evidence for experiment. Seven high-quality studies reported on twisting and LBP. Two were case-control studies and five were prospective cohort studies. Three studies reported significant associations in the majority of their risk estimates, with no evidence for consistency. Three studies demonstrated a nonsignificant dose-response trend. Two studies were able to assess temporality, but only one study was able to demonstrate significant risk estimates. Two studies discussed biological plausibility. There was no available evidence for experiment. CONCLUSIONS A summary of existing studies was not able to find high-quality studies that satisfied more than three of the Bradford-Hill criteria for causation for either occupational bending or twisting and LBP. Conflicting evidence in multiple criteria was identified. This suggests that specific subcategories could contribute to LBP. However, the evidence suggests that occupational bending or twisting in general is unlikely to be independently causative of LBP.

Quality of life in surgical treatment of metastatic spine disease

Study Design. Overall quality of life after surgical management of metastatic disease of the spine was prospectively assessed using a validated global health status quality-of-life instrument—the Edmonton Symptom Assessment Scale. Objectives. To prospectively evaluate the efficacy of surgery in patients with metastatic spinal disease with respect to quality of life. Summary of Background Data. Management of spinal metastases is palliative and is aimed at improving quality of life at an acceptable risk. Although previous studies have evaluated physical outcomes, improvements in pain, and neurologic function after surgery, a multidimensional assessment of quality of life is more relevant in the palliative patient. Methods. Twenty-five consecutive patients undergoing surgery for spinal metastases were prospectively evaluated. Pre- and postoperative assessments were performed using the Edmonton Symptom Assessment Scale. The surgical procedure consisted of decompression and instrumented stabilization. Results. After surgery, the largest improvement was noted in the domain of pain (P < 0.00001). There were also significant improvements noted in the domains of tiredness (P = 0.004), nausea (P = 0.01), anxiety (P = 0.006), drowsiness (P = 0.044), appetite (P = 0.02), and well-being (P = 0.004). Conclusions. The current study demonstrates that in the appropriate patient, surgical management brings about a positive effect on the overall quality of life in patients with spinal metastases. The greatest benefit occurred in the reduction of a patient’s level of pain.

Causal assessment of awkward occupational postures and low back pain: results of a systematic review

BACKGROUND CONTEXT Low back pain (LBP) is a prevalent and costly musculoskeletal disorder that often occurs in the working-age population. Although numerous physical activities have been implicated in its complex etiology, determining causation remains challenging and requires a methodologically rigorous approach. PURPOSE To conduct a systematic review of the scientific literature focused on establishing a causal relationship between awkward occupational postures and LBP. STUDY DESIGN Systematic review of the literature using MEDLINE, EMBASE, CINAHL, Cochrane Library, and Occupational Safety and Health database, gray literature, hand-searching occupational health journals, reference lists of included studies, and experts. Evaluation of methodological quality using a modified Newcastle-Ottawa Scale for observational studies. Summary levels of evidence for each of the Bradford Hill criteria for causality for each category of awkward occupational posture and type of LBP. SAMPLE Studies reporting an association between awkward occupational postures and LBP. OUTCOME MEASURES Numerical association between different levels of exposure to awkward occupational postures and the presence or severity of LBP. METHODS A systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford Hill criteria, between awkward occupational postures and LBP. RESULTS This search yielded 2,766 citations. Eight high-quality studies reported on awkward occupational postures and LBP. Three were case-control studies, one was cross-sectional, and four were prospective cohort studies. There was strong evidence for consistency of no association between awkward occupational postures and LBP, with only two studies demonstrating significant associations in most of their risk estimates compared with six studies reported mainly nonsignificant associations. Two studies assessed dose response, with one study demonstrating a nonsignificant dose-response trend. Three studies were able to assess temporality, but all demonstrated nonsignificant risk estimates. Biological plausibility was discussed by two studies. There was no available evidence to assess the experiment criterion for causality. CONCLUSIONS There was strong evidence from six high-quality studies that there was no association between awkward postures and LBP. Similarly, there was strong evidence from three high-quality studies that there was no temporal relationship. Moreover, subgroup analyses identified only a handful of studies that demonstrated only weak associations and no evidence for other aspects of causality in certain specific subcategories. It is therefore unlikely that awkward occupational postures are independently causative of LBP in the populations of workers studied.

Causal assessment of occupational standing or walking and low back pain: results of a systematic review

BACKGROUND CONTEXT Low back pain (LBP) is a widespread musculoskeletal condition that frequently occurs in the working-age population. Numerous occupational physical activities have been implicated in its etiology. PURPOSE To conduct a systematic review establishing a causal relationship between occupational standing or walking and LBP. STUDY DESIGN Systematic review of the literature. SAMPLE Studies reporting an association between occupational standing or walking and LBP. OUTCOME MEASURES Numerical association between exposure to standing or walking and the presence of LBP. METHODS A systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford-Hill criteria for causality, between occupational standing or walking and LBP. A search was conducted using MEDLINE, Embase, CINAHL, Cochrane Library, and Occupational Safety and Health database, gray literature, hand-searching occupational health journals, reference lists of included studies, and expert knowledge. Evaluation of methodological quality was performed using a modified Newcastle-Ottawa Scale. RESULTS This search yielded 2,766 citations. Eighteen studies met the inclusion criteria. Five were high-quality studies related to standing, and two were high-quality studies related to walking. For occupational standing and LBP, there was moderate to strong evidence against the association criterion, the only study examining dose response did not support this criterion, four studies examining temporality failed to support this criterion, and only one study discussed the biological plausibility criterion. For occupational walking and LBP, there was moderate evidence against a causal relationship with respect to the association, temporality, dose response, and biological plausibility criteria. No studies assessed the experiment criterion for these activities. CONCLUSIONS A summary of existing studies was not able to find any high-quality studies that satisfied more than two of the Bradford-Hill causation criteria for occupational standing or walking and LBP. Based on the evidence reviewed, it is unlikely that occupational standing or walking is independently causative of LBP in the populations of workers studied.

Causal assessment of workplace manual handling or assisting patients and low back pain: results of a systematic review

BACKGROUND CONTEXT Low back pain (LBP) is a common musculoskeletal disorder associated with a considerable social and economic burden within the working-age population. Despite an unclear etiology, numerous physical activities are suspected of leading to LBP. Declaring a causal relationship between occupational activities and LBP remains challenging and requires a methodologically rigorous approach. PURPOSE To conduct a systematic review focused on assessing the potentially causal relationship between workplace manual handling or assisting patients and LBP. STUDY DESIGN Systematic review of the literature. SAMPLES Studies reporting an association between workplace manual handling or assisting patients and LBP. OUTCOME MEASURES Numerical association between different levels of exposure to manual handling or assisting patients, and the presence or severity of LBP. METHODS A systematic review was conducted using Medline, EMBASE, CINAHL, Cochrane Library, and Occupational Safety and Health database, gray literature, hand-searching occupational health journals, reference lists of included studies, and content experts. The methodological quality of each study was assessed using a modified Newcastle-Ottawa Scale (NOS) for observational studies. The overall level of evidence supporting various Bradford-Hill criteria for causality for each category of manual handling or assisting patients and type of LBP was then evaluated. Studies were deemed of higher quality if they received a score of five or more on the modified NOS and used appropriate statistical analysis methods. RESULTS This search yielded 2,766 citations, and 32 studies met the eligibility criteria. Three high-quality studies reported on manual handling and LBP, including two prospective cohorts and one cross-sectional design. None demonstrated a significant association in most of their multivariate risk estimates. One study was able to assess dose-response and temporality, but its results did not support these criteria. Only one study discussed the biological plausibility of this association. Four high-quality studies evaluated assisting patients and LBP, including two case-controls, one cross-sectional, and one prospective cohort design. These studies were consistent in reporting no significant association. Two studies demonstrated a nonsignificant dose-response trend, and two studies discussed the biological plausibility of this association. No studies were able to demonstrate the temporality or experiment criteria. CONCLUSIONS The studies reviewed did not support a causal association between workplace manual handling or assisting patients and LBP in a Bradford-Hill framework. Conflicting evidence in specific subcategories of assisting patients was identified, suggesting that tasks such as assisting patients with ambulation may possibly contribute to LBP. It appears unlikely that workplace manual handling or assisting patients is independently causative of LBP in the populations of workers studied.

Can cost utility evaluations inform decision making about interventions for low back pain

BACKGROUND CONTEXT Low back pain (LBP) is associated with high health-care utilization and lost productivity. Numerous interventions are routinely used, although few are supported by strong evidence. Cost utility analyses (CUAs) may be helpful to inform decision makers. PURPOSE To conduct a systematic review of CUAs of interventions for LBP. STUDY DESIGN Systematic review. METHODS A search strategy combining medical subject headings and free text related to LBP and health economic evaluations was executed in MEDLINE. Cost utility analyses combined with randomized controlled trials for LBP were included. Studies that were published before 1998, non-English, decision analyses, and duplicate reports were excluded. Search results were evaluated by two reviewers, who extracted data independently related to clinical study design, economic study design, direct cost components, utility results, cost results, and CUA results. RESULTS The search produced 319 citations, and of these 15 met eligibility criteria. Most were from the United Kingdom (n=8), published in the past 3 years (n=12), studied chronic LBP or radiculopathy (n=13), and had a follow-up >12 months (n=13). Combined, there were 33 study groups who received a mean 2.1 interventions, most commonly education (n=17), exercise therapy (n=13), spinal manipulation therapy (n=7), surgery (n=7), and usual care from a general practitioner (n=7). Mean baseline utility was 0.57, improving to 0.67 at follow-up; the mean difference in utility improvement between study groups was 0.04. Based on available data and converted to US dollars, the cost per quality-adjusted life year ranged from

Evidence-informed management of chronic low back pain with physical activity, smoking cessation, and weight loss

304 to 579,527 dollars, with a median of 13,015 dollars. CONCLUSIONS Few CUAs were identified for LBP, and there was heterogeneity in the interventions compared, direct cost components measured, indirect costs, other methods, and results. Reporting quality was mixed. Currently published CUAs do not provide sufficient information to assist decision makers. Future CUAs should attempt to measure all known direct cost components relevant to LBP, estimate indirect costs such as lost productivity, have a follow-up period sufficient to capture meaningful changes, and clearly report methods and results to facilitate interpretation and comparison.

Causal assessment of occupational carrying and low back pain: results of a systematic review

The management of chronic low back pain (CLBP) has proven to be very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing among available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions most likely to result in clinically meaningful improvements, there is often uncertainty about the most appropriate intervention for a particular patient. To help understand and evaluate the various commonly used nonsurgical approaches to CLBP, the North American Spine Society has sponsored this special focus issue of The Spine Journal, titled Evidence-Informed Management of Chronic Low Back Pain Without Surgery. Articles in this special focus issue were contributed by leading spine practitioners and researchers, who were invited to summarize the best available evidence for a particular intervention and encouraged to make this information accessible to nonexperts. Each of the articles contains five sections (description, theory, evidence of efficacy, harms, and summary) with common subheadings to facilitate comparison across the 24 different interventions profiled in this special focus issue, blending narrative and systematic review methodology as deemed appropriate by the authors. It is hoped that articles in this special focus issue will be informative and aid in decision making for the many stakeholders evaluating nonsurgical interventions for CLBP.