A randomised controlled study examining the short-term effects of Strain–Counterstrain treatment on quantitative sensory measures at digitally tender points in the low back

Quantitative sensory testing and exercise-induced hypoalgesia protocols in low back pain: A scoping review

A significant driver of pain in individuals with low back pain (LBP) is alterations to endogenous pain modulation (EPM). EPM can be measured using quantitative sensory testing (QST), however; there are inconsistencies in the way QST has been implemented across the low back pain literature. The objective of this scoping review was to summarize protocols used to assess EPM using QST (pain pressure threshold (PPT), temporal summation (TS), conditioned pain modulation (CPM)) or exercise-induced hypoalgesia (EIH) in LBP. Databases Medline, Embase, CINAHL and AMED were searched on June 15, 2023, for articles that used QST or EIH protocols in LBP populations. Data was extracted on participants, study design, setting and details on QST and EIH protocols. Of the 221 studies included in the review, 196 used PPT, 62 used TS and 60 used CPM; only 5 studies investigated EIH. For all QST, there was high variability in the type of equipment, timing, trials, and testing location with many studies not reporting this information. There were 4 testing modalities used for TS, and 7 different test stimuli, and 3 different conditioning stimuli used across the studies for CPM. For CPM and EIH, PPT was the most common testing modality. There were 4 types of exercises used across the 5 EIH studies. This scoping review provides a summary of QST and EIH protocols in LBP that may be used as a guide for assessment in future studies. These results demonstrate a need for the development of standardized protocols and reporting guidelines. PERSPECTIVE: This article presents a summary of measures used to assess EPM in LBP. The results show the wide variability of protocols used in the literature. Future research should focus on creating standardized protocols, reporting guidelines and providing more guidance for researchers in selecting appropriate tests for their research questions.

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.

Blinding and sham control methods in trials of physical, psychological, and self-management interventions for pain (article I): a systematic review and description of methods

ABSTRACT

Blinding is challenging in randomised controlled trials of physical, psychological, and self-management therapies for pain, mainly because of their complex and participatory nature. To develop standards for the design, implementation, and reporting of control interventions in efficacy and mechanistic trials, a systematic overview of currently used sham interventions and other blinding methods was required. Twelve databases were searched for placebo or sham-controlled randomised clinical trials of physical, psychological, and self-management treatments in a clinical pain population. Screening and data extraction were performed in duplicate, and trial features, description of control methods, and their similarity to the active intervention under investigation were extracted (protocol registration ID: CRD42020206590). The review included 198 unique control interventions, published between 2008 and December 2021. Most trials studied people with chronic pain, and more than half were manual therapy trials. The described control interventions ranged from clearly modelled based on the active treatment to largely dissimilar control interventions. Similarity between control and active interventions was more frequent for certain aspects (eg, duration and frequency of treatments) than others (eg, physical treatment procedures and patient sensory experiences). We also provide an overview of additional, potentially useful methods to enhance blinding, as well as the reporting of processes involved in developing control interventions. A comprehensive picture of prevalent blinding methods is provided, including a detailed assessment of the resemblance between active and control interventions. These findings can inform future developments of control interventions in efficacy and mechanistic trials and best-practice recommendations.

Effectiveness of placebo interventions for patients with nonspecific low back pain: a systematic review and meta-analysis

ABSTRACT

Little is known about the effectiveness of placebo interventions in patients with nonspecific low back pain (LBP). This systematic review assessed the magnitude of the effects of placebo interventions as compared to no intervention in randomized controlled trials (RCTs) including patients with LBP. Embase, MEDLINE (Ovid), and Cochrane CENTRAL databases were searched from inception to December 5, 2019. Randomized controlled trials comparing placebo intervention vs no intervention in adult patients with nonspecific LBP were included. Pain intensity, physical functioning, and health-related quality of life measured at short-term, medium-term, and long-term follow-up were the outcomes of this review. Twenty-one randomized controlled trials were included; one concerning acute LBP and one subacute LBP, whereas 19 studies reported on chronic LBP. In chronic LBP, placebo interventions were more effective than no intervention at short-term follow-up for pain intensity (standardized mean difference = -0.37, 95% confidence interval [CI] = -0.55 to -0.18, moderate-quality evidence), physical functioning (standardized mean difference -0.19, 95% CI = -0.39-0.01, moderate-quality evidence), and physical quality of life (mean difference = -2.71, 95% CI = -4.71-0.71, high-quality evidence), respectively. These effects were not significant at medium-term follow-up, and no data were available at long-term follow-up. These results show placebo interventions are more effective than no intervention at short-term follow-up in patients with chronic LBP. However, the magnitude of the effects is probably not clinically relevant (approximately 8 points on a 0-100 pain scale). Future research should identify effect modifiers and causal mechanisms explaining the short-term effects of placebo interventions in patients with chronic LBP.

Trigger point dry needling versus strain-counterstrain technique for upper trapezius myofascial trigger points: a randomised controlled trial

BACKGROUND

Treatment of active myofascial trigger points includes both invasive and non-invasive techniques.

OBJECTIVES

To compare the effects of upper trapezius trigger point dry needling (DN) and strain-counterstrain (SCS) techniques versus sham SCS.

STUDY DESIGN

Randomised controlled trial.

METHOD

34 study subjects with active trigger points were randomly assigned to one of three treatment groups, and received either three sessions of DN (n=12), six sessions of SCS (n=10), or sham SCS (n=12) over a 3-week period. Subjective pain response and subjects' own ratings of perceived disability were measured.

RESULTS

The analysis of variance mixed model showed a significant time effect for pain (p<0.001), elicited pain (p<0.001), pain pressure threshold (p<0.01), and neck disability index (p=0.016). Pain at rest decreased in all groups, as follows: DN 18.5 mm (95% CI 4.3 to 32.7 mm); SCS 28.3 mm (95% CI 12.4 to 44.1 mm); sham SCS 21.9 mm (95% CI 3.5 to 40.1 mm). Reductions in disability score (points) were significant in the SCS group (5.5, 95% CI 1.6 to 9.4) but not in the DN (1.4, 95% CI -4.9 to 2.1) or sham SCS (1.8, 95% CI -6.4 to 2.7) groups. There was no significant group×time interaction effect for any variables studied.

CONCLUSIONS

There were no differences between the sham SCS, SCS, and DN groups in any of the outcome measures. DN relieved pain after fewer sessions than SCS and sham SCS, and thus may be a more efficient technique. Future studies should include a larger sample size.

TRIAL REGISTRATION NUMBER

NCT01290653.

The effect of journal impact factor, reporting conflicts, and reporting funding sources, on standardized effect sizes in back pain trials: a systematic review and meta-regression

BACKGROUND

Low back pain is a common and costly health complaint for which there are several moderately effective treatments. In some fields there is evidence that funder and financial conflicts are associated with trial outcomes. It is not clear whether effect sizes in back pain trials relate to journal impact factor, reporting conflicts of interest, or reporting funding.

METHODS

We performed a systematic review of English-language papers reporting randomised controlled trials of treatments for non-specific low back pain, published between 2006-2012. We modelled the relationship using 5-year journal impact factor, and categories of reported of conflicts of interest, and categories of reported funding (reported none and reported some, compared to not reporting these) using meta-regression, adjusting for sample size, and publication year. We also considered whether impact factor could be predicted by the direction of outcome, or trial sample size.

RESULTS

We could abstract data to calculate effect size in 99 of 146 trials that met our inclusion criteria. Effect size is not associated with impact factor, reporting of funding source, or reporting of conflicts of interest. However, explicitly reporting 'no trial funding' is strongly associated with larger absolute values of effect size (adjusted β=1.02 (95 % CI 0.44 to 1.59), P=0.001). Impact factor increases by 0.008 (0.004 to 0.012) per unit increase in trial sample size (P<0.001), but does not differ by reported direction of the LBP trial outcome (P=0.270).

CONCLUSIONS

The absence of associations between effect size and impact factor, reporting sources of funding, and conflicts of interest reflects positively on research and publisher conduct in the field. Strong evidence of a large association between absolute magnitude of effect size and explicit reporting of 'no funding' suggests authors of unfunded trials are likely to report larger effect sizes, notwithstanding direction. This could relate in part to quality, resources, and/or how pragmatic a trial is.

Manual therapy for the management of pain and limited range of motion in subjects with signs and symptoms of temporomandibular disorder: a systematic review of randomised controlled trials

There is a lack of knowledge about the effectiveness of manual therapy (MT) on subjects with temporomandibular disorders (TMD). The aim of this systematic review is to synthetise evidence regarding the isolated effect of MT in improving maximum mouth opening (MMO) and pain in subjects with signs and symptoms of TMD. MEDLINE(®) , Cochrane, Web of Science, SciELO and EMBASE(™) electronic databases were consulted, searching for randomised controlled trials applying MT for TMD compared to other intervention, no intervention or placebo. Two authors independently extracted data, PEDro scale was used to assess risk of bias, and GRADE (Grading of Recommendations Assessment, Development and Evaluation) was applied to synthetise overall quality of the body of evidence. Treatment effect size was calculated for pain, MMO and pressure pain threshold (PPT). Eight trials were included, seven of high methodological quality. Myofascial release and massage techniques applied on the masticatory muscles are more effective than control (low to moderate evidence) but as effective as toxin botulinum injections (moderate evidence). Upper cervical spine thrust manipulation or mobilisation techniques are more effective than control (low to high evidence), while thoracic manipulations are not. There is moderate-to-high evidence that MT techniques protocols are effective. The methodological heterogeneity across trials protocols frequently contributed to decrease quality of evidence. In conclusion, there is widely varying evidence that MT improves pain, MMO and PPT in subjects with TMD signs and symptoms, depending on the technique. Further studies should consider using standardised evaluations and better study designs to strengthen clinical relevance.

Strain counterstrain technique to decrease tender point palpation pain compared to control conditions: a systematic review with meta-analysis

BACKGROUND

Strain counterstrain (SCS) is an indirect osteopathic manipulative technique that uses passive positioning to relieve tender point (TP) palpation pain and associated dysfunction.

OBJECTIVE

The purposes of this systematic review with meta-analysis were to 1) determine the pooled effect of SCS on TP palpation pain compared to a control condition and 2) assess the quality of the overall evidence.

DATA SOURCE

A search conducted using the MEDLINE with AMED, PUBMED, CINAHL, and SCOPUS databases for publications from January 2002 and April 2012 yielded 29 articles for eligibility screening.

STUDY SELECTION

Included studies were limited to randomized control trials comparing TP palpation pain after isolated SCS treatment compared to control conditions assessed with a visual analog scale. Other study designs or manipulative treatments were excluded.

DATA EXTRACTION

Two reviewers adhered to a predetermined study protocol following current Cochrane Collaboration recommendations to independently extract the data with standardized extraction forms and assess studies for methodological quality and determine risks of bias.

RESULTS

Five randomized control trials were included for qualitative and quantitative analysis. The pooled effect of SCS was a reduction of TP palpation pain (p < 0.001, 95% CI -0.291 to -0.825). The overall evidence quality was low: while all studies met at least 8 of 12 methodological quality criteria, most were low quality.

CONCLUSIONS

This systematic review and meta-analysis found low quality evidence suggesting that SCS may reduce TP palpation pain. Future studies with larger samples of better quality studies with patient populations that assess long-term pain, impairment, and dysfunction outcomes could enrich the literature.

Dose optimization for spinal treatment effectiveness: a randomized controlled trial investigating the effects of high and low mobilization forces in patients with neck pain

STUDY DESIGN

Randomized controlled trial. Objective To determine if force magnitude during posterior-to-anterior mobilization affects immediate and short-term outcomes in patients with chronic, nonspecific neck pain.

BACKGROUND

The optimal dose of mobilization to effectively treat patients with neck pain is not known.

METHODS

Patients with neck pain of at least 3 months in duration (n = 64) were randomized to receive a single treatment of posterior-to-anterior mobilization applied with 30 N or 90 N of mean peak force (3 sets of 30 seconds) or a placebo (detuned laser) on the spinous process at the painful spinal level. Pressure pain threshold, pain measured with a visual analog scale (range, 0-100 mm), cervical range of motion, and spinal stiffness at the painful spinal level (measured with a custom device and normalized as a percentage of C7 stiffness) were assessed before, immediately after, and at a mean ± SD follow-up of 4.0 ± 1.8 days following treatment. Repeated-measures analysis of covariance and Bonferroni-adjusted post hoc tests determined group differences for each outcome measure after treatment and at follow-up.

RESULTS

At follow-up, the 90-N group had less pain than the 30-N group (mean difference, 11.3 mm; 95% confidence interval: 0.1, 22.6 mm; P = .048) and lower stiffness than the placebo group (mean difference, 17.5%; 95% confidence interval: 4.2%, 30.9%; P = .006). These differences were not present immediately after treatment. There were no significant between-group differences in pressure pain threshold or range of motion after treatment or at follow-up.

CONCLUSION

A specific dose of mobilization, in terms of applied force, appears necessary for reducing stiffness and potentially pain in patients with chronic neck pain. Changes were not observed immediately after mobilization, suggesting that its effects are not directly mechanical.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry ( http://www.anzctr.org.au/): ACTRN12611000374965.

LEVEL OF EVIDENCE

Therapy, level 1b-.

Musculoskeletal physical outcome measures in individuals with tension-type headache: a scoping review

INTRODUCTION

Individuals with tension-type headache (TTH), in addition to headache pain, typically suffer from pericranial muscle tenderness and increased cervical muscle tone. Physical and physiological outcomes related to musculoskeletal function, however, are not commonly assessed in clinical studies and not systematically proposed as outcome measures in headache-related practice guidelines.

OBJECTIVES

To review which musculoskeletal outcomes are used in the clinical assessment of patients with TTH and which are associated with headache pain and related dysfunction.

METHODS

Literature searches were performed in MEDLINE, PubMed, the Cochrane databases and EMBASE using terms relating to musculoskeletal physical outcomes in TTH.

RESULTS

Twenty-six studies met selection criteria. Physiological outcomes typically reported in laboratory studies were trigger points, pressure pain threshold, range of motion and tenderness. A greater number of trigger points and lower pressure pain threshold were reported in patients with episodic TTH in comparison with healthy subjects. Individuals with chronic TTH, when compared with non-headache controls, consistently showed a greater number of trigger points, a lower value of pressure pain threshold and a more severe forward head posture.

CONCLUSION

Musculoskeletal outcomes, such as trigger points, pressure pain threshold and forward head posture should inform TTH pathophysiology, diagnosis and interdisciplinary patient care.

Effect of a single session of muscle-biased therapy on pain sensitivity: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Muscle-biased therapies (MBT) are commonly used to treat pain, yet several reviews suggest evidence for the clinical effectiveness of these therapies is lacking. Inadequate treatment parameters have been suggested to account for inconsistent effects across studies. Pain sensitivity may serve as an intermediate physiologic endpoint helping to establish optimal MBT treatment parameters. The purpose of this review was to summarize the current literature investigating the short-term effect of a single dose of MBT on pain sensitivity in both healthy and clinical populations, with particular attention to specific MBT parameters of intensity and duration.

METHODS

A systematic search for articles meeting our prespecified criteria was conducted using Cumulative Index to Nursing and Allied Health Literature (CINAHL) and MEDLINE from the inception of each database until July 2012, in accordance with guidelines from the Preferred Reporting Items for Systematic reviews and Meta-Analysis. Relevant characteristics from studies included type, intensity, and duration of MBT and whether short-term changes in pain sensitivity and clinical pain were noted with MBT application. Study results were pooled using a random-effects model to estimate the overall effect size of a single dose of MBT on pain sensitivity as well as the effect of MBT, dependent on comparison group and population type.

RESULTS

Reports from 24 randomized controlled trials (23 articles) were included, representing 36 MBT treatment arms and 29 comparative groups, where 10 groups received active agents, 11 received sham/inert treatments, and eight received no treatment. MBT demonstrated a favorable and consistent ability to modulate pain sensitivity. Short-term modulation of pain sensitivity was associated with short-term beneficial effects on clinical pain. Intensity of MBT, but not duration, was linked with change in pain sensitivity. A meta-analysis was conducted on 17 studies that assessed the effect of MBT on pressure pain thresholds. The results suggest that MBT had a favorable effect on pressure pain thresholds when compared with no-treatment and sham/inert groups, and effects comparable with those of other active treatments.

CONCLUSION

The evidence supports the use of pain sensitivity measures by future research to help elucidate optimal therapeutic parameters for MBT as an intermediate physiologic marker.

Strain-counterstrain to treat restrictions of the mobility of the cervical spine in patients with neck pain: a sham-controlled randomized trial

OBJECTIVE

Strain-counterstrain is an osteopathic technique which is widely used for treating mobility restrictions in the neck. We aimed to investigate whether a single strain-counterstrain intervention is more effective than a sham intervention in improving restricted cervical range of motion in patients with neck pain.

METHODS

61 adult patients with neck pain and restricted cervical mobility were randomly allocated to receive either a single strain-counterstrain intervention or a sham treatment. After outcome measurement all patients received full individualized osteopathic treatment. Mobility of the cervical spine was measured by a blinded observer using the Cervical Range of Motion (CROM) tool. In addition, patients rated pain intensity and assessed the treatment effect. The main outcome measure was the sum of changes in mobility restriction (in %) after treatment compared to normal mobility.

RESULTS

All patients completed the study. Mobility restriction decreased by 2.0% (SD 6.9%) in the group receiving strain-counterstrain treatment and 0.6% (SD 5.7%) in the group receiving sham treatment (mean difference 1.5%, 95% confidence interval -1.7 to 4.8%; p=0.35). There were no significant differences between groups for secondary outcomes. After receiving the full osteopathic treatment the group initially receiving strain-counterstrain improved by another 4.2% (7.0%; p=0.003) and the group initially receiving sham by another 5.6% (SD 6.8%; p<0.001).

CONCLUSIONS

Strain-counterstrain as a single intervention did not have immediate effects on mobility and pain over a sham treatment. Future studies should probably focus on the investigation of full osteopathic treatment.

Strain counterstrain: current concepts and clinical evidence

Strain counterstrain is an osteopathic manipulative technique about which research is only recently emerging. This master class reviews the evidence investigating proposed physiologic mechanisms and clinical effects of strain counterstrain. Clinical application guidelines are presented with specific treatments for key clinical scenarios.