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

The importance of context (placebo effects) in conservative interventions for musculoskeletal pain: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVE

Contextual effects (e.g. patient expectations) may play a role in treatment effectiveness. This study aimed to estimate the magnitude of contextual effects for conservative, non-pharmacological interventions for musculoskeletal pain conditions. A systematic review and meta-analysis of randomized controlled trials (RCTs) that compared placebo conservative non-pharmacological interventions to no treatment for musculoskeletal pain. The outcomes assessed included pain intensity, physical functioning, health-related quality of life, global rating of change, depression, anxiety and sleep at immediate, short-, medium- and/or long-term follow-up.

DATABASES AND DATA TREATMENT

MEDLINE, EMBASE, CINAHL, Web of Science Core Collection, CENTRAL and SPORTDiscus were searched from inception to September 2021. Trial registry searches, backward and forward citation tracking and searches for prior systematic reviews were completed. The Cochrane risk of bias 2 tool was implemented.

RESULTS

The study included 64 RCTs (N = 4314) out of 8898 records. For pain intensity, a mean difference of (MD: -5.32, 95% confidence interval (CI): -7.20, -3.44, N = 57 studies with 74 outcomes, GRADE: very low) was estimated for placebo interventions. A small effect in favour of the placebo interventions for physical function was estimated (SMD: -0.22, 95% CI: -0.35, -0.09; N = 37 with 48 outcomes, GRADE: very low). Similar results were found for a broad range of patient-reported outcomes. Meta-regression analyses did not explain heterogeneity among analyses.

CONCLUSION

The study found that the contextual effect of non-pharmacological conservative interventions for musculoskeletal conditions is likely to be small. However, given the known effect sizes of recommended evidence-based treatments for musculoskeletal conditions, it may still contribute an important component.

SIGNIFICANCE

Contextual effects of non-pharmacological conservative interventions for musculoskeletal conditions are likely to be small for a broad range of patient-reported outcomes (pain intensity, physical function, quality of life, global rating of change and depression). Contextual effects are unlikely, in isolation, to offer much clinical care. But these factors do have relevance in an overall treatment context as they provide almost 30% of the minimally clinically important difference.

Placebo effects in low back pain: A systematic review and meta-analysis of the literature

BACKGROUND AND OBJECTIVE

The current treatments of primary musculoskeletal low back pain (LBP) have a low to moderate efficacy, which might be improved by looking at the contribution of placebo effects. However, the size of true placebo effects in LBP is unknown. Therefore, a systematic review and meta-analysis were executed of randomized controlled trials investigating placebo effects in LBP.

DATABASES AND DATA TREATMENT

The study protocol was registered in the international prospective register of systematic reviews Prospero (CRD42019148745). A literature search (in PubMed, Embase, The Cochrane Library, CINAHL and PsycINFO) up to 2021 February 16th yielded 2,423 studies. Two independent reviewers assessed eligibility and risk of bias.

RESULTS

Eighteen studies were eligible for the systematic review and 5 for the meta-analysis. Fourteen of the 18 studies were clinical treatment studies, and 4 were experimental studies specifically assessing placebo effects. The clinical treatment studies provided varying evidence for placebo effects in chronic LBP but insufficient evidence for acute and subacute LBP. Most experimental studies investigating chronic LBP revealed significant placebo effects. The meta-analysis of 5 treatment studies investigating chronic LBP depicted a significant moderate effect size of placebo for pain intensity (SMD = 0.57) and disability (SMD = 0.52).

CONCLUSIONS

This review shows a significant contribution of placebo effects to chronic LBP symptom relief in clinical and experimental conditions. The meta-analysis revealed that placebo effects can influence chronic LBP intensity and disability. However, additional studies are required for more supporting evidence and evidence for placebo effects in acute or subacute LBP.

SIGNIFICANCE

This systematic review and meta-analysis provides evidence of true placebo effects in low back pain (LBP). It shows a significant contribution of placebo effects to chronic LBP symptom relief. The results highlight the importance of patient- and context-related factors in fostering treatment effects in this patient group. New studies could provide insight into the potential value of actively making use of placebo effects in clinical practice.

Behavioral Therapy Approaches for the Management of Low Back Pain: An Up-To-Date Systematic Review

Low back pain is one of the most common causes for seeking medical treatment and it is estimated that one in two people will experience low back pain at some point during their lifetimes. Management of low back pain includes pharmacological and non-pharmacological approaches. Non-pharmaceutical treatments include interventions such as acupuncture, spinal manipulation, and psychotherapy. The latter is especially important as patients who suffer from low back pain often have impaired quality of life and also suffer from depression. Depressive symptoms can appear because back pain limits patients’ ability to work and engage in their usual social activities. The aim of this systematic review was to overview the behavioral approaches that can be used in the management of patients with low back pain. Approaches such as electromyography (EMG) biofeedback, cognitive behavioral therapy, and mindfulness-based stress reduction are discussed as non-pharmacological options in the management of low back pain.

Noninvasive and alternative management of chronic low back pain (efficacy and outcomes)

OBJECTIVES

The goal of this article is to provide a thorough literature review of available noninvasive and alternative treatment options for chronic low back pain. In particular, the efficacy of each therapy is evaluated and pertinent outcomes are described.

MATERIALS AND METHODS

A comprehensive search for available literature was done through PubMed and Cochrane data base for topics discussed in this paper.

RESULTS

Relevant current and past references were reviewed and presented to reflect the efficacy of each therapy and related outcomes.

CONCLUSIONS

There are a wide variety of noninvasive and alternative therapies for the treatment of chronic low back pain. Those with the strongest evidence in the literature for good efficacy and outcomes include exercise therapy with supervised physical therapy, multidisciplinary biopsychosocial rehabilitation, and acupuncture. Therapies with fair evidence or moderately supported by literature include yoga, back schools, thermal modalities, acupressure, and cognitive-behavioral therapy. Those therapies with poor evidence or little to no literature support include manipulation, transcutaneous electrical nerve stimulation, low-level laser therapy, reflexology, biofeedback, progressive relaxation, hypnosis, and aromatherapy. Providers delivering care for patients with chronic low back pain must carefully evaluate these available treatment options related to their efficacy or lack thereof as well as relevant outcomes.

Efficacy of EMG- and EEG-Biofeedback in Fibromyalgia Syndrome: A Meta-Analysis and a Systematic Review of Randomized Controlled Trials

Objectives. Biofeedback (BFB) is an established intervention in the rehabilitation of headache and other pain disorders. Little is known about this treatment option for fibromyalgia syndrome (FMS). The aim of the present review is to integrate and critically evaluate the evidence regarding the efficacy of biofeedback for FMS. Methods. We conducted a literature search using Pubmed, clinicaltrials.gov (National Institute of Health), Cochrane Central Register of Controlled Trials, PsycINFO, SCOPUS, and manual searches. The effect size estimates were calculated using a random-effects model. Results. The literature search produced 123 unique citations. One hundred sixteen records were excluded. The meta-analysis included seven studies (321 patients) on EEG-Biofeedback and EMG-Biofeedback. In comparison to control groups, biofeedback (BFB) significantly reduced pain intensity with a large effect size (g = 0.79; 95% CI: 0.22–1.36). Subgroup analyses revealed that only EMG-BFB and not EEG-BFB significantly reduced pain intensity in comparison to control groups (g = 0.86; 95% CI: 0.11–1.62). BFB did not reduce sleep problems, depression, fatigue, or health-related quality of life in comparison to a control group. Discussion. The interpretation of the results is limited because of a lack of studies on the long-term effects of EMG-BFB in FMS. Further research should focus on the long-term efficacy of BFB in fibromyalgia and on the identification of predictors of treatment response.

Self-efficacy and fear avoidance beliefs in chronic low back pain patients: coexistence and associated factors

A cross sectional study was conducted with the objective to assess the coexistence of self-efficacy and fear avoidance beliefs and establish the associated factors. Data collection was performed (215 individuals with lower back pain at three health services and two industries). The following instruments were used: Tampa Scale for Kinesiophobia, Beck's Depression Inventory, Piper's Fatigue Scale, Oswestry Disability Index, and the Chronic Pain Self-Efficacy Scale. Wilks' lambda test was performed, followed by MANOVA model to assess the effect of self-efficacy beliefs and fear avoidance on independent variables. Most subjects were women (65.1%), 45 years of age or younger (50.7%), with a family income between $450 and $1,350 per month (49.3%). Depression was present in 21.4%, fatigue in 29.3%, and disability in 68%. The average (standard deviation) of self-efficacy was 180.8 (60.4), and fear avoidance was 42.0 (11.5). A significant negative correlation was observed between the total score of both beliefs. The Wilks' lambda test showed that gender, income, depression, disability, and fatigue were significant and were included in the model. In the Manova analysis, low self-efficacy was associated with lower income, fatigue, depression, and level of disability (p < .001). High fear avoidance was associated to the male gender, lower income, depression, and level of disability (p < .001). The analysis of the confidence areas showed that a reduced self-efficacy and increased fear avoidance are related to an increased level of disability (p < .001). Specific intervention strategies must be implemented change these beliefs.

Investigating the effect of real-time spinal postural biofeedback on seated discomfort in people with non-specific chronic low back pain

A total of 24 participants with non-specific chronic low back pain (NSCLBP) sat for 2 h while their seated posture and low back discomfort (LBD) were analysed. A total of 16 pain developers (PDs), whose LBD increased by at least two points on the numeric rating scale, repeated the procedure 1 week later, while receiving postural biofeedback. PDs were older (p = 0.018), more disabled (p = 0.021) and demonstrated greater postural variability (p < 0.001). The ramping up of LBD was reduced (p = 0.002) on retesting, when sitting posture was less end-range (p < 0.001), and less variable (p = 0.032). Seated LBD appears to be related with modifiable characteristics such as sitting behaviour. Among people with sitting-related NSCLBP, the ramping up of LBD was reduced by modifying their sitting behaviour according to their individual clinical presentation. The magnitude of change, while statistically significant, was small and no follow-up of participants was completed. Further research should examine integrating biofeedback into comprehensive biopsychosocial management strategies for NSCLBP.

PRACTITIONER SUMMARY

The effect of real-time postural biofeedback on LBD was examined among people with LBP. Postural biofeedback matched to the individual clinical presentation significantly reduced LBD within a single session. Further research should examine the long-term effectiveness of postural biofeedback as an intervention for LBP.

Two psychological interventions are effective in severely disabled, chronic back pain patients: a randomised controlled trial

BACKGROUND

Many pain patients appreciate biofeedback interventions because of the integration of psychological and physiological aspects. Therefore we wanted to investigate in a sample of chronic back pain patients whether biofeedback ingredients lead to improved outcome of psychological interventions.

METHOD

One hundred and twenty-eight chronic back pain patients were randomly assigned to cognitive-behavioural therapy (CBT), cognitive-behavioural therapy including biofeedback tools (CBT-B) or waitlist control (WLC). The sample was recruited from a highly disabled group including many patients with low education status and former back surgeries. Measures on pain, physical functioning, emotional functioning, coping strategies and health care utilisation were taken at pretreatment, posttreatment and 6 months of follow-up.

RESULTS

The results indicated significant improvements on most outcome measures for CBT-B and CBT in comparison to WLC. CBT-B and CBT were equally effective (e.g. ITT effect sizes for pain intensity: CBT-B, 0.66 (95% CI 0.39-0.95); CBT, 0.60 (95% CI 0.33-0.87)).

CONCLUSION

In conclusion, biofeedback ingredients did not lead to improved outcome of a psychological intervention. Cognitive-behavioural treatment as a "package" of respondent, operant and cognitive interventions was effective for ameliorating pain-related symptoms for chronic back pain patients treated in an outpatient setting. The high treatment acceptability associated with biofeedback ingredients can also be achieved with pure psychological interventions.

Extrinsic feedback and management of low back pain: A critical review of the literature

Effective intervention for low back pain (LBP) can include feedback in one form or other. Although extrinsic feedback (EF) can be provided in a number of ways, most research has not considered how different EF characteristics (e.g. timing and content) influence treatment outcomes. A systematic search related to feedback and LBP was performed on relevant electronic databases. This narrative review aims to describe the forms of feedback provision in the literature regarding management of LBP, and to discuss these in light of previously recommended principles for the use of extrinsic feedback. The present review found support for the provision of EF that focuses on content characteristics including program feedback, summary results feedback, and external focus of attention. Temporal characteristics should enhance the use of intermittent or self-selected feedback. The literature does not support the provision of concurrent or constant EF. As much of the literature related to EF in the management of LBP has not considered content and timing characteristics we have identified future research directions that will clarify the use of content and timing characteristics of EF relative to the management of LBP.

A systematic review on the effectiveness of physical and rehabilitation interventions for chronic non-specific low back pain

Low back pain (LBP) is a common and disabling disorder in western society. The management of LBP comprises a range of different intervention strategies including surgery, drug therapy, and non-medical interventions. The objective of the present study is to determine the effectiveness of physical and rehabilitation interventions (i.e. exercise therapy, back school, transcutaneous electrical nerve stimulation (TENS), low level laser therapy, education, massage, behavioural treatment, traction, multidisciplinary treatment, lumbar supports, and heat/cold therapy) for chronic LBP. The primary search was conducted in MEDLINE, EMBASE, CINAHL, CENTRAL, and PEDro up to 22 December 2008. Existing Cochrane reviews for the individual interventions were screened for studies fulfilling the inclusion criteria. The search strategy outlined by the Cochrane Back Review Groups (CBRG) was followed. The following were included for selection criteria: (1) randomized controlled trials, (2) adult (≥ 18 years) population with chronic (≥ 12 weeks) non-specific LBP, and (3) evaluation of at least one of the main clinically relevant outcome measures (pain, functional status, perceived recovery, or return to work). Two reviewers independently selected studies and extracted data on study characteristics, risk of bias, and outcomes at short, intermediate, and long-term follow-up. The GRADE approach was used to determine the quality of evidence. In total 83 randomized controlled trials met the inclusion criteria: exercise therapy (n = 37), back school (n = 5), TENS (n = 6), low level laser therapy (n = 3), behavioural treatment (n = 21), patient education (n = 1), traction (n = 1), and multidisciplinary treatment (n = 6). Compared to usual care, exercise therapy improved post-treatment pain intensity and disability, and long-term function. Behavioural treatment was found to be effective in reducing pain intensity at short-term follow-up compared to no treatment/waiting list controls. Finally, multidisciplinary treatment was found to reduce pain intensity and disability at short-term follow-up compared to no treatment/waiting list controls. Overall, the level of evidence was low. Evidence from randomized controlled trials demonstrates that there is low quality evidence for the effectiveness of exercise therapy compared to usual care, there is low evidence for the effectiveness of behavioural therapy compared to no treatment and there is moderate evidence for the effectiveness of a multidisciplinary treatment compared to no treatment and other active treatments at reducing pain at short-term in the treatment of chronic low back pain. Based on the heterogeneity of the populations, interventions, and comparison groups, we conclude that there are insufficient data to draw firm conclusion on the clinical effect of back schools, low-level laser therapy, patient education, massage, traction, superficial heat/cold, and lumbar supports for chronic LBP.

Behavioural treatment for chronic low-back pain

BACKGROUND

Behavioural treatment is commonly used in the management of chronic low-back pain (CLBP) to reduce disability through modification of maladaptive pain behaviours and cognitive processes. Three behavioural approaches are generally distinguished: operant, cognitive, and respondent; but are often combined as a treatment package.

OBJECTIVES

To determine the effects of behavioural therapy for CLBP and the most effective behavioural approach.

SEARCH STRATEGY

The Cochrane Back Review Group Trials Register, CENTRAL, MEDLINE, EMBASE, and PsycINFO were searched up to February 2009. Reference lists and citations of identified trials and relevant systematic reviews were screened.

SELECTION CRITERIA

Randomised trials on behavioural treatments for non-specific CLBP were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the risk of bias in each study and extracted the data. If sufficient homogeneity existed among studies in the pre-defined comparisons, a meta-analysis was performed. We determined the quality of the evidence for each comparison with the GRADE approach.

MAIN RESULTS

We included 30 randomised trials (3438 participants) in this review, up 11 from the previous version. Fourteen trials (47%) had low risk of bias. For most comparisons, there was only low or very low quality evidence to support the results. There was moderate quality evidence that:i) operant therapy was more effective than waiting list (SMD -0.43; 95%CI -0.75 to -0.11) for short-term pain relief;ii) little or no difference exists between operant, cognitive, or combined behavioural therapy for short- to intermediate-term pain relief;iii) behavioural treatment was more effective than usual care for short-term pain relief (MD -5.18; 95%CI -9.79 to -0.57), but there were no differences in the intermediate- to long-term, or on functional status;iv) there was little or no difference between behavioural treatment and group exercise for pain relief or depressive symptoms over the intermediate- to long-term;v) adding behavioural therapy to inpatient rehabilitation was no more effective than inpatient rehabilitation alone.

AUTHORS' CONCLUSIONS

For patients with CLBP, there is moderate quality evidence that in the short-term, operant therapy is more effective than waiting list and behavioural therapy is more effective than usual care for pain relief, but no specific type of behavioural therapy is more effective than another. In the intermediate- to long-term, there is little or no difference between behavioural therapy and group exercises for pain or depressive symptoms. Further research is likely to have an important impact on our confidence in the estimates of effect and may change the estimates.

Placebo interventions for all clinical conditions

BACKGROUND

Placebo interventions are often claimed to substantially improve patient-reported and observer-reported outcomes in many clinical conditions, but most reports on effects of placebos are based on studies that have not randomised patients to placebo or no treatment. Two previous versions of this review from 2001 and 2004 found that placebo interventions in general did not have clinically important effects, but that there were possible beneficial effects on patient-reported outcomes, especially pain. Since then several relevant trials have been published.

OBJECTIVES

Our primary aims were to assess the effect of placebo interventions in general across all clinical conditions, and to investigate the effects of placebo interventions on specific clinical conditions. Our secondary aims were to assess whether the effect of placebo treatments differed for patient-reported and observer-reported outcomes, and to explore other reasons for variations in effect.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library Issue 4, 2007), MEDLINE (1966 to March 2008), EMBASE (1980 to March 2008), PsycINFO (1887 to March 2008) and Biological Abstracts (1986 to March 2008). We contacted experts on placebo research, and read references in the included trials.

SELECTION CRITERIA

We included randomised placebo trials with a no-treatment control group investigating any health problem.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information. Trials with binary data were summarised using relative risk (a value of less than 1 indicates a beneficial effect of placebo), and trials with continuous outcomes were summarised using standardised mean difference (a negative value indicates a beneficial effect of placebo).

MAIN RESULTS

Outcome data were available in 202 out of 234 included trials, investigating 60 clinical conditions. We regarded the risk of bias as low in only 16 trials (8%), five of which had binary outcomes.In 44 studies with binary outcomes (6041 patients), there was moderate heterogeneity (P < 0.001; I(2) 45%) but no clear difference in effects between small and large trials (symmetrical funnel plot). The overall pooled effect of placebo was a relative risk of 0.93 (95% confidence interval (CI) 0.88 to 0.99). The pooled relative risk for patient-reported outcomes was 0.93 (95% CI 0.86 to 1.00) and for observer-reported outcomes 0.93 (95% CI 0.85 to 1.02). We found no statistically significant effect of placebo interventions in four clinical conditions that had been investigated in three trials or more: pain, nausea, smoking, and depression, but confidence intervals were wide. The effect on pain varied considerably, even among trials with low risk of bias.In 158 trials with continuous outcomes (10,525 patients), there was moderate heterogeneity (P < 0.001; I(2) 42%), and considerable variation in effects between small and large trials (asymmetrical funnel plot). It is therefore a questionable procedure to pool all the trials, and we did so mainly as a basis for exploring causes for heterogeneity. We found an overall effect of placebo treatments, standardised mean difference (SMD) -0.23 (95% CI -0.28 to -0.17). The SMD for patient-reported outcomes was -0.26 (95% CI -0.32 to -0.19), and for observer-reported outcomes, SMD -0.13 (95% CI -0.24 to -0.02). We found an effect on pain, SMD -0.28 (95% CI -0.36 to -0.19)); nausea, SMD -0.25 (-0.46 to -0.04)), asthma (-0.35 (-0.70 to -0.01)), and phobia (SMD -0.63 (95% CI -1.17 to -0.08)). The effect on pain was very variable, also among trials with low risk of bias. Four similarly-designed acupuncture trials conducted by an overlapping group of authors reported large effects (SMD -0.68 (-0.85 to -0.50)) whereas three other pain trials reported low or no effect (SMD -0.13 (-0.28 to 0.03)). The pooled effect on nausea was small, but consistent. The effects on phobia and asthma were very uncertain due to high risk of bias. There was no statistically significant effect of placebo interventions in the seven other clinical conditions investigated in three trials or more: smoking, dementia, depression, obesity, hypertension, insomnia and anxiety, but confidence intervals were wide.Meta-regression analyses showed that larger effects of placebo interventions were associated with physical placebo interventions (e.g. sham acupuncture), patient-involved outcomes (patient-reported outcomes and observer-reported outcomes involving patient cooperation), small trials, and trials with the explicit purpose of studying placebo. Larger effects of placebo were also found in trials that did not inform patients about the possible placebo intervention.

AUTHORS' CONCLUSIONS

We did not find that placebo interventions have important clinical effects in general. However, in certain settings placebo interventions can influence patient-reported outcomes, especially pain and nausea, though it is difficult to distinguish patient-reported effects of placebo from biased reporting. The effect on pain varied, even among trials with low risk of bias, from negligible to clinically important. Variations in the effect of placebo were partly explained by variations in how trials were conducted and how patients were informed.

Motor control learning in chronic low back pain

STUDY DESIGN

A randomized prospective cohort study of participants with chronic low back pain, seeking physical therapy, with follow-up at weeks 6 and 28. Effects of conventional physiotherapy and physiotherapy with the addition of postural biofeedback were compared.

OBJECTIVE

To evaluate the benefits of postural biofeedback in chronic low back pain participants.

SUMMARY OF BACKGROUND DATA

Biofeedback using electromyographic signals has been used in chronic low back pain with mixed results. Postural feedback had not been previously used.

METHODS

Demographic and psychological baseline data along with range of motion were analyzed from a sample of 47 chronic participants with low back pain randomized into conventional physiotherapy with or without the addition of postural biofeedback.

RESULTS

After 6 months, there were 21 dropouts. The participants with biofeedback had markedly improved status in visual analog pain scales, short form-36, and range of motion.

CONCLUSION

The study strongly suggests that postural feedback is a useful adjunct to conventional physiotherapy of chronic low back pain participants.

Imperfect placebos are common in low back pain trials: a systematic review of the literature

The placebo is an important tool to blind patients to treatment allocation and therefore minimise some sources of bias in clinical trials. However, placebos that are improperly designed or implemented may introduce bias into trials. The purpose of this systematic review was to evaluate the adequacy of placebo interventions used in low back pain trials. Electronic databases were searched systematically for randomised placebo-controlled trials of conservative interventions for low back pain. Trial selection and data extraction were performed by two reviewers independently. A total of 126 trials using over 25 different placebo interventions were included. The strategy most commonly used to enhance blinding was the provision of structurally equivalent placebos. Adequacy of blinding was assessed in only 13% of trials. In 20% of trials the placebo intervention was a potentially genuine treatment. Most trials that assessed patients' expectations showed that the placebo generated lower expectations than the experimental intervention. Taken together, these results demonstrate that imperfect placebos are common in low back pain trials; a result suggesting that many trials provide potentially biased estimates of treatment efficacy. This finding has implications for the interpretation of published trials and the design of future trials. Implementation of strategies to facilitate blinding and balance expectations in randomised groups need a higher priority in low back pain research.

Behavioural treatment for chronic low-back pain

BACKGROUND

Behavioural treatment, commonly used in the treatment of chronic low-back pain (CLBP), is primarily focused at reducing disability through the modification of environmental contingencies and cognitive processes. In general, three behavioural treatment approaches are distinguished: operant, cognitive and respondent.

OBJECTIVES

To determine if behavioural therapy is more effective than reference treatments for CLBP, and which type of behavioural treatment is most effective.

SEARCH STRATEGY

We searched the CENTRAL, MEDLINE, EMBASE, and PsycLIT databases up to October 2003. References of identified randomised trials and relevant systematic reviews were screened.

SELECTION CRITERIA

Only randomised trials on behavioural treatment for non-specific CLBP were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the methodological quality and extracted the data. The magnitude of effect was assessed by computing a pooled effect size for post-treatment and long-term results for each comparison, for each domain (i.e., behavioural outcomes, overall improvement, back pain specific and generic functional status, return to work, and pain intensity) using the random effects model.

MAIN RESULTS

Seven studies (33%) were considered high quality. Comparing behavioural treatment to waiting list control (WLC) revealed strong evidence (4 trials, 134 people) in favour of a combined respondent-cognitive therapy for a medium positive effect on pain, and moderate evidence (2 trials, 39 people) in favour of progressive relaxation for a large positive effect on pain and behavioural outcomes (short-term only). When comparing operant treatment to WLC no significant differences could be detected on general functional status (strong evidence: 2 trials, 87 people) or on behavioural outcomes (moderate evidence; 3 trials, 153 people) (short-term only). There is limited evidence (1 trial, 98 people) that a graded activity program in an industrial setting is more effective than usual care for early return to work and reduced long-term sick leave. There is limited evidence (1 trail, 39 people) that there are no differences between behavioural treatment and exercises. Finally, there is moderate evidence (6 trials, 210 people) that there are no significant differences in short-term and long-term effectiveness when behavioural components are added to usual treatment programs for CLBP (i.e. physiotherapy, back education) on pain, generic functional status and behavioural outcomes.

AUTHORS' CONCLUSIONS

Combined respondent-cognitive therapy and progressive relaxation therapy are more effective than WLC on short-term pain relief. However, it is unknown whether these results sustain in the long term. No significant differences could be detected between behavioural treatment and exercise therapy. Whether clinicians should refer patients with CLBP to behavioural treatment programs or to active conservative treatment cannot be concluded from this review.

Placebo interventions for all clinical conditions

BACKGROUND

Placebo interventions are often claimed to improve patient-reported and observer-reported outcomes, but this belief is not based on evidence from randomised trials that compare placebo with no treatment.

OBJECTIVES

To assess the effect of placebo interventions.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2002), MEDLINE (1966 to 2002), EMBASE (1980 to 2002), Biological Abstracts (1986 to 2002), and PsycLIT (1887 to 2002). We contacted experts on placebo research, and read references in the included trials.

SELECTION CRITERIA

We included randomised placebo trials with a no-treatment control group investigating any health problem.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. We contacted study authors for additional information.

MAIN RESULTS

Outcome data were available in 156 out of 182 included trials, investigating 46 clinical conditions. We found no statistically significant pooled effect of placebo in 38 studies with binary outcomes (4284 patients), relative risk 0.95 (95% confidence interval (CI) 0.89 to 1.01). The pooled relative risk for patient-reported outcomes was 0.95 (95% CI 0.88 to 1.03) and for observer-reported outcomes 0.91 (95% CI 0.81 to 1.03). There was heterogeneity (P=0.01) but the funnel plot was symmetrical. There was no statistically significant effect of placebo interventions in the four clinical conditions investigated in three trials or more: pain, nausea, smoking, and depression, but confidence intervals were wide. We found an overall effect of placebo treatments in 118 trials with continuous outcomes (7453 patients), standardised mean difference (SMD) -0.24 (95% CI -0.31 to -0.17). The SMD for patient-reported outcomes was -0.30 (95% CI -0.38 to -0.21), whereas no statistically significant effect was found for observer-reported outcomes, SMD -0.10 (95% CI -0.20 to -0.01). There was heterogeneity (P<0.001) and large variability in funnel plot results even for big trials. There was an apparent effect of placebo interventions on pain (SMD -0.25 (95% CI -0.35 to-0.16)), and phobia (SMD -0.63 (95% CI -1.17 to -0.08)); but also a substantial risk of bias. There was no statistically significant effect of placebo interventions in eight other clinical conditions investigated in three trials or more: nausea, smoking, depression, overweight, asthma, hypertension, insomnia and anxiety, but confidence intervals were wide.

REVIEWERS' CONCLUSIONS

There was no evidence that placebo interventions in general have clinically important effects. A possible small effect on continuous patient-reported outcomes, especially pain, could not be clearly distinguished from bias.

Placebo treatment versus no treatment

BACKGROUND

Placebo interventions are often believed to improve patient reported and observer reported outcomes, but this belief is not based on evidence from randomised trials that compare placebo with no treatment.

OBJECTIVES

To assess the effect of placebo interventions.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register (The Cochrane Library, issue 3, 1998), MEDLINE (Jan 1966 to Dec 1998), EMBASE (Jan 1980 to Dec 1998), Biological Abstracts (Jan 1986 to Dec 1998), PsycLIT (Jan 1887 to Dec 1998). Experts on placebo research were contacted and references in the included trials were read.

SELECTION CRITERIA

Randomised placebo trials with a no-treatment control group investigating any health problem were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Outcome data were available in 114 out of 130 included trials, investigating 40 clinical conditions. Outcomes were binary in 32 trials (3795 patients) and continuous in 82 (4730 patients). We found no statistically significant pooled effect of placebo in studies with binary outcomes, relative risk 0.95 (95 per cent confidence interval 0.88 to 1.02). The pooled relative risk for subjective (patient reported) outcomes was 0.95 (0.86 to 1.05) and for objective (observer reported) outcomes 0.91 (0.80 to 1.04). There was statistically significant heterogeneity (P < 0.03), but no evidence of sample size bias (P = 0.56). We found an overall positive effect of placebo treatments in trials with continuous outcomes, standardised mean difference -0.28 (95 per cent confidence interval -0.38 to -0.19). The standardised mean difference for subjective outcomes was -0.36 (-0.47 to -0.25), whereas no statistically significant effect was found for objective outcomes, standardised mean difference -0.12 (-0.27 to 0.03). There was statistically significant heterogeneity (P < 0.001), and evidence of sample size bias (P = 0.05). There was no statistically significant effect of placebo interventions in eight out of nine clinical conditions investigated in three trials or more (nausea, relapse in prevention of smoking and depression, overweight, asthma, hypertension, insomnia and anxiety), but confidence intervals were wide. There was a modest apparent analgesic effect of placebo interventions, standardised mean difference -0.27 (-0.40 to -0.15), but also a substantial risk of bias.

REVIEWER'S CONCLUSIONS

There was no evidence that placebo interventions in general have clinically important effects. A possible moderate effect on subjective continuous outcomes, especially pain, could not be clearly distinguished from bias.

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 compared with 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.

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 compared with 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.

Behavioural treatment for chronic low back pain

BACKGROUND

The treatment of chronic low back pain is not primarily focused on removing an underlying organic pathology, but at the reduction of disability through the modification of environmental contingencies and cognitive processes. Behavioural interventions are commonly used in the treatment of chronic (disabling) low back pain.

OBJECTIVES

The objective of this systematic review was to determine if behavioural therapy is more effective than reference treatments for chronic non-specific low back pain, and which type of behavioural treatment is most effective.

SEARCH STRATEGY

We searched the Medline, PsycLit databases, and the Cochrane Controlled Trials Register up to April 1999, Embase up to September 1999. We also screened references of identified randomised trials and relevant systematic reviews.

SELECTION CRITERIA

Only randomised trials on any type of behavioural treatment for non-specific chronic low back pain were included.

DATA COLLECTION AND ANALYSIS

Methodological quality assessment and data extraction was done by two reviewers independently. The magnitude of effect was assessed by computing a pooled effect size for each domain (i.e., behavioural outcomes, overall improvement, back pain specific and generic functional status, return to work, and pain intensity) using the random effects model.

MAIN RESULTS

Only 6 studies (25%) were high quality. There is strong evidence (level 1) that behavioural treatment has a moderate positive effect on pain intensity (pooled effect size 0.62; 95% 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 behavioural outcomes (pooled effect size 0.40; 95% CI 0.10, 0.70) of chronic low back pain patients when compared to waiting list controls or no treatment. There is moderate evidence (level 2) that an additional behavioural component to a usual treatment program for chronic low back pain 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 behavioural outcomes (pooled effect size 0.19; 95% CI - 0.08, 0.45).

REVIEWER'S CONCLUSIONS

Behavioural treatment seems to be an effective treatment for chronic low back pain patients, but it is still unknown what type of patients benefit most from what type of behavioural treatment.

Conservative treatment of acute and chronic nonspecific low back pain. A systematic review of randomized controlled trials of the most common interventions

STUDY DESIGN

A systematic review of randomized controlled trials.

OBJECTIVES

To assess the effectiveness of the most common conservative types of treatment for patients with acute and chronic nonspecific low back pain.

SUMMARY OF BACKGROUND DATA

Many treatment options for acute and chronic low back pain are available, but little is known about the optimal treatment strategy.

METHODS

A rating system was used to assess the strength of the evidence, based on the methodologic quality of the randomized controlled trials, the relevance of the outcome measures, and the consistency of the results.

RESULTS

The number of randomized controlled trials identified varied widely with regard to the interventions involved. The scores ranged from 20 to 79 points for acute low back pain and from 19 to 79 points for chronic low back pain on a 100-point scale, indicating the overall poor quality of the trials. Overall, only 28 (35%) randomized controlled trials on acute low back pain and 20 (25%) on chronic low back pain had a methodologic score of 50 or more points, and were considered to be of high quality. Various methodologic flaws were identified. Strong evidence was found for the effectiveness of muscle relaxants and nonsteroidal anti-inflammatory drugs and the ineffectiveness of exercise therapy for acute low back pain; strong evidence also was found for the effectiveness of manipulation, back schools, and exercise therapy for chronic low back pain, especially for short-term effects.

CONCLUSIONS

The quality of the design, execution, and reporting of randomized controlled trials should be improved, to establish strong evidence for the effectiveness of the various therapeutic interventions for acute and chronic low back pain.

Cognitive-behavioural therapy versus EMG biofeedback in the treatment of chronic low back pain

Forty-four chronic, but relatively well functioning, low back pain patients were assigned to either Cognitive Behaviour Therapy (CBT). Electromyographic Biofeedback (EMGBF) or Wait List Control (WLC). Both treatments were conducted over eight sessions in groups of four subjects. Results at post-treatment indicated significant improvements in functioning on measures of pain intensity, perceived level of disability, adaptive beliefs about pain and the level of depression in both the CBT and EMGBF conditions. These improvements were not evident for the WLC condition. At 6 months follow-up, treatment gains were maintained in the areas of pain intensity, pain beliefs, and depression, for both treatment groups, with further improvements occurring in anxiety and use of active coping skills. No significant differences were found between CBT and EMGBF on any of the outcome measures at either post-treatment or at 6 months follow-up. Further research is required to determine the degree to which these results reflect the mild level of psychological impairment and disability status of patients in the present study.

Efficacy of multidisciplinary pain treatment centers: a meta-analytic review

Sixty-five studies that evaluated the efficacy of multidisciplinary treatments for chronic back pain were included in a meta-analysis. Within- and between-group effect sizes revealed that multidisciplinary treatments for chronic pain are superior to no treatment, waiting list, as well as single-discipline treatments such as medical treatment or physical therapy. Moreover, the effects appeared to be stable over time. The beneficial effects of multidisciplinary treatment were not limited to improvements in pain, mood and interference but also extended to behavioral variables such as return to work or use of the health care system. These results tend to support the efficacy of multidisciplinary pain treatment; however, these results must be interpreted cautiously as the quality of the study designs and study descriptions is marginal. Suggestions for improvement in research designs as well as appropriate reports of research completed are provided.

Attention, not anxiety, influences pain

Four hypotheses about the influences of anxiety and attention on pain impact were tested in a critical experiment: (1) anxiety increases pain; (2) anxiety decreases pain; (3) attention to pain increases pain; (4) only the combination of anxiety and attention to pain increases pain (interaction hypothesis). In a 2 x 2 design, anxiety (low vs high) and attention (attention vs distraction from the pain) were experimentally manipulated. Subjects received 20 electrically produced painful stimuli. Subjective pain experiences, skin conductance responses and heart rate responses gave no support for a pain impact increasing effect of anxiety. The anxiety-attention interaction hypothesis did not receive any support either. There was some support, only from the heart rate responses, that anxiety reduces pain impact. The critical factor appeared to be attention. Attention to the pain stimulus was related to a stronger pain impact (indicated by all measures) and to less subjective habituation, compared to distraction.

Neglected factors in chronic pain treatment outcome studies--referral patterns, failure to enter treatment, and attrition

An increasing number of chronic pain treatment outcome studies have appeared in the literature. In general, these studies support the efficacy of multidisciplinary pain programs, as well as specific treatment modalities such as biofeedback and relaxation. Reviews of this literature have tended to be cautiously optimistic. Some concerns, however, have been raised about the methodological adequacy of these studies, particularly in terms of the lack of control groups, the brief duration of follow-up periods, and the vague criteria used for establishing the success of the therapeutic interventions. Other factors that mitigate conclusions regarding the generalizability of the favorable results reported need to be considered. In this paper 3 rarely discussed topics that are implicit within most treatment outcome studies and that need to be given greater attention are examined. These topics include: (1) referral patterns to pain clinics (who are referred to pain clinics, when, and how representative is the referred sample?); (2) failure to enter treatment (e.g., exclusion criteria, lack of available financial support to cover the cost of treatment, patient's refusal to accept recommendations), and consequently, the representativeness of the treated sample; and (3) patient's attrition. In this paper we discuss each of these factors as they underscore important qualifications that have to be made in evaluating treatment outcome studies.

Long-term efficacy of EMG biofeedback for chronic rheumatic back pain

Short-term effects of EMG biofeedback for chronic rheumatic back pain have been documented, however, the long-term efficacy of this treatment modality has not yet been established. Twenty-two patients of an original sample of 24 patients who participated in a treatment outcome study [6] were followed up 2.5 years after they had been treated with either EMG biofeedback, pseudotherapy, or conventional medical treatment alone. The results indicate that patients treated with EMG biofeedback maintained beneficial effects and differ significantly from the control groups both on behavioral and cognitive responses to the pain, but not global pain intensity ratings. These data support the long-term utility of biofeedback for chronic rheumatic back pain.