Finding the balance in complex regional pain syndrome. Expertise, optimism, and evidence

Complex regional pain syndrome (CRPS), perhaps more than any other chronic pain disorder, is perplexing. It is highly disabling, particularly once it has “set in,” and it has a tendency to polarize the community—some view it as a quasidiagnosis to obscure malingering or conceal substandard clinical skills,1 and others as a multiple system overprotective response.2 What is agreed is that its pathophysiology is not completely understood and that it is difficult to treat. In light of this rather murky backdrop, we welcome the new perspectives article in this issue of Neurology® by Birklein et al.3 They describe their own clinical approach to the problem and their impressions of what works, what does not, and where the field might be heading. The lead author is the most prolific and arguably the most important researcher in this field, and the article clearly draws on a wealth of expertise and clinical experience probably unmatched globally. The article reminds us of the remaining substantial challenges that we face: for example, the need for prospective studies, higher quality clinical trials and audits, and a putative model that accounts for the transition from acute CRPS to chronic CRPS, which is arguably characterized by distinct pathophysiology. Anyone who treats a good number of CRPS patients will recognize the clinical patterns to which the authors allude and be comforted by the realization that even this group, at the top of the field, share the same substantial treatment challenges.G.L.M. is supported by a Principal Research Fellowship from the National Health & Medical Research Council of Australia ID 1061279

Interventions for treating pain and disability in adults with complex regional pain syndrome - An overview of systematic reviews

This article is available open access through the publisher’s website at the link below. Copyright © 2013 The Cochrane Collaboration.Background - There is currently no strong consensus regarding the optimal management of complex regional pain syndrome although a multitude of interventions have been described and are commonly used. Objectives - To summarise the evidence from Cochrane and non-Cochrane systematic reviews of the effectiveness of any therapeutic intervention used to reduce pain, disability or both in adults with complex regional pain syndrome (CRPS). Methods - We identified Cochrane reviews and non-Cochrane reviews through a systematic search of the following databases: Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects (DARE), Ovid MEDLINE, Ovid EMBASE, CINAHL, LILACS and PEDro. We included non-Cochrane systematic reviews where they contained evidence not covered by identified Cochrane reviews. The methodological quality of reviews was assessed using the AMSTAR tool. We extracted data for the primary outcomes pain, disability and adverse events, and the secondary outcomes of quality of life, emotional well being and participants' ratings of satisfaction or improvement. Only evidence arising from randomised controlled trials was considered. We used the GRADE system to assess the quality of evidence. Main results - We included six Cochrane reviews and 13 non-Cochrane systematic reviews. Cochrane reviews demonstrated better methodological quality than non-Cochrane reviews. Trials were typically small and the quality variable. There is moderate quality evidence that intravenous regional blockade with guanethidine is not effective in CRPS and that the procedure appears to be associated with the risk of significant adverse events. There is low quality evidence that bisphosphonates, calcitonin or a daily course of intravenous ketamine may be effective for pain when compared with placebo; graded motor imagery may be effective for pain and function when compared with usual care; and that mirror therapy may be effective for pain in post-stroke CRPS compared with a 'covered mirror' control. This evidence should be interpreted with caution. There is low quality evidence that local anaesthetic sympathetic blockade is not effective. Low quality evidence suggests that physiotherapy or occupational therapy are associated with small positive effects that are unlikely to be clinically important at one year follow up when compared with a social work passive attention control. For a wide range of other interventions, there is either no evidence or very low quality evidence available from which no conclusions should be drawn. Authors' conclusions - There is a critical lack of high quality evidence for the effectiveness of most therapies for CRPS. Until further larger trials are undertaken, formulating an evidence-based approach to managing CRPS will remain difficult

Pain education for patients with non-specific low back pain in Nepal: Protocol of a feasibility randomised clinical trial (PEN-LBP Trial)

Introduction Low back pain (LBP) is the leading cause of years lived with disability in Nepal and elsewhere. Management of LBP that is evidence-based, easily accessible, cost-effective and culturally appropriate is desirable. The primary aim of this feasibility study is to determine if it is feasible to conduct a full randomised clinical trial evaluating the effectiveness of pain education as an intervention for individuals with LBP in Nepal, relative to guideline-based physiotherapy treatment. The findings of the study will inform the planning of a full clinical trial and if any modifications are required to the protocol before undertaking a full trial. Methods/analysis This protocol describes an assessor-blinded feasibility clinical trial investigating feasibility of the pain education intervention in patients with non-specific LBP in a physiotherapy hospital in Kathmandu, Nepal. Forty patients with LBP will be randomly allocated to either pain education or guideline-based physiotherapy treatment (control). Outcomes will be assessed at baseline and at a 1 week post-treatment. The primary outcomes are related to feasibility, including: (1) participant willingness to participate in a randomised clinical trial, (2) feasibility of assessor blinding, (3) eligibility and recruitment rates, (4) acceptability of screening procedures and random allocation, (5) possible contamination between the groups, (6) intervention credibility, (7) intervention adherence, (8) treatment satisfaction and (9) difficulty in understanding the interventions being provided. Ethics/dissemination The protocol was approved by Nepal Health Research Council (NHRC; registration number: 422/2017) and University of Otago Human Ethics Committee for Health (registration number: H17/157). The results of the study will be presented at national and international conferences and published in a peer-reviewed journal. Trial registration number NCT03387228; Pre-results

Results of a feasibility randomised clinical trial on pain education for low back pain in Nepal: The Pain Education in Nepal-Low Back Pain (PEN-LBP) feasibility trial

Objectives The aims of this study were to: (1) develop pain education materials in Nepali and (2) determine the feasibility of conducting a randomised clinical trial (RCT) of a pain education intervention using these materials in Nepal. Design A two-arm, parallel, assessor-blinded, feasibility RCT. Setting A rehabilitation hospital in Kathmandu, Nepal. Participants Forty Nepalese with non-specific low back pain (mean [SD] age 41 [14] years; 12 [30%] women). Interventions Eligible participants were randomised, by concealed, 1:1 allocation, to one of two groups: (1) a pain education intervention and (2) a guideline-based physiotherapy active control group intervention. Each intervention was delivered by a physiotherapist in a single, 1-hour, individualised treatment session. Primary outcome measures The primary outcomes were related to feasibility: recruitment, retention and treatment adherence of participants, feasibility and blinding of outcome assessments, fidelity of treatment delivery, credibility of, and satisfaction with, treatment. Assessments were performed at baseline and at 1 week post-treatment. Secondary outcome measures Pain intensity, pain interference, pain catastrophising, sleep disturbance, resilience, global rating of change, depression and quality of life. Statistical analyses were conducted blind to group allocation. Results Forty participants were recruited. Thirty-eight participants (95%) completed the 1-week post-treatment assessment. Most primary outcomes surpassed the a priori thresholds for feasibility. Several findings have important implications for designing a full trial. Secondary analyses suggest clinical benefit of pain education over the control intervention, with larger decrease in pain intensity (mean difference=3.56 [95% CI 0.21 to 6.91]) and pain catastrophising (mean difference=6.16 [95% CI 0.59 to 11.72]) in the pain education group. Pain intensity would seem an appropriate outcome for a full clinical trial. One minor adverse event was reported. Conclusion We conclude that a full RCT of pain education for back pain in Nepal is feasible and warranted. Trial registration number NCT03387228; Results

Moving in an environment of induced sensorimotor incongruence does not influence pain sensitivity in healthy volunteers: A randomised within-subject experiment

Objectives: It has been proposed that in the same way that conflict between vestibular and visual inputs leads to motion sickness, conflict between motor commands and sensory information associated with these commands may contribute to some chronic pain states. Attempts to test this hypothesis by artificially inducing a state of sensorimotor incongruence and assessing self-reported pain have yielded equivocal results. To help clarify the effect sensorimotor incongruence has on pain we investigated the effect of moving in an environment of induced incongruence on pressure pain thresholds (PPT) and the pain experienced immediately on completion of PPT testing. Methods: Thirty-five healthy subjects performed synchronous and asynchronous upper-limb movements with and without mirror visual feedback in random order. We measured PPT over the elbow and the pain evoked by testing. Generalised linear mixed-models were performed for each outcome. Condition (four levels) and baseline values for each outcome were within-subject factors. Results: There was no effect of condition on PPT (p = 0.887) or pressure-evoked pain (p = 0.771). A sensitivity analysis using only the first PPT measure after each condition confirmed the result (p = 0.867). Discussion: Inducing a state of movement related sensorimotor incongruence in the upper-limb of healthy volunteers does not influence PPT, nor the pain evoked by testing. We found no evidence that sensorimotor incongruence upregulates the nociceptive system in healthy volunteer

Pain: A Statistical Account

Perception is seen as a process that utilises partial and noisy information to construct a coherent understanding of the world. Here we argue that the experience of pain is no different; it is based on incomplete, multimodal information, which is used to estimate potential bodily threat. We outline a Bayesian inference model, incorporating the key components of cue combination, causal inference, and temporal integration, which highlights the statistical problems in everyday perception. It is from this platform that we are able to review the pain literature, providing evidence from experimental, acute, and persistent phenomena to demonstrate the advantages of adopting a statistical account in pain. Our probabilistic conceptualisation suggests a principles-based view of pain, explaining a broad range of experimental and clinical findings and making testable prediction

What you wear does not affect the credibility of your treatment: A blinded randomized controlled study

© 2016 Elsevier Ireland Ltd Objective Professional appearance is easily modifiable, and might alter the effects of a clinical encounter. We aimed to determine whether professional attire influences a patient's perception of treatment credibility. Methods We performed a single-blind randomized controlled study on 128 patients with acute non-specific low back pain who were about to receive treatment in primary care. The treating clinician was randomly allocated to wear formal attire (experimental condition) or casual attire (control condition) to the consultation. Clinicians provided a standardized briefing on the rationale behind the patient's forthcoming treatment. Treatment credibility (Credibility and Expectancy Questionnaire) was assessed immediately after this briefing. Results All patients received the experimental or control condition as allocated and provided complete primary outcome data. Formal attire had no effect on perceived treatment credibility (Mean difference between groups 1.2 [95%CI-1.1 to 3.5]). Age was the only significant predictor of treatment credibility; older patients rated treatment credibility higher (Beta = 0.16 [95%CI 0.08 to 0.24]). Conclusion In a trial setting, whether or not a clinician is formally dressed has no effect on perceptions of treatment credibility in patients with acute low back pain. Practice implication Clinicians should dress comfortably without fear of losing credibility

A Child's Concept of Pain: An International Survey of Pediatric Pain Experts.

A child's 'concept of pain' refers to how they understand what pain actually is, what function pain serves, and what biological processes are thought to underpin it. We aimed to determine pediatric pain experts' opinions of: (1) the importance and usefulness of assessing a child's concept of pain in clinical and/or research settings; (2) the usefulness of the content of items within currently published adult-targeted resources for assessing a child's concept of pain; and (3) important domains of a child's concept of pain to assess. Forty-nine pediatric pain experts (response rate = 75.4%) completed an online survey. Descriptive statistics and frequency of responses were analyzed. Experts from all included disciplines reported that assessing a child's concept of pain is important and useful both clinically and in a research setting (>80% reported very or extremely useful for each item). Experts considered that the content of 13 items from currently published adult-targeted resources was useful, but the wording was too complex for children aged 8-12 years. Experts considered that all seven of the proposed domains of a child's concept of pain was important to assess. The findings can be used to inform the development of an assessment tool for a child's concept of pain