Clinical Use of Placebo Effects in Patients With Pain Disorders

Choice over placebo administration enhances open-label placebo hypoalgesia

ABSTRACT

Many studies indicate that deceptively administered placebos can improve pain outcomes. However, the deception involved presents an ethical barrier to translation because it violates informed consent and patient autonomy. Open-label placebos (OLPs), inert treatments that are openly administered as placebos, have been proposed as an ethically acceptable alternative. Early studies have suggested that OLP can improve pain outcomes, but important questions remain as to how to maximise OLP hypoalgesia to improve treatment outcomes in pain patients. This study investigated whether providing choice over when to administer an OLP treatment has the capacity to enhance OLP hypoalgesia using an electrocutaneous pain paradigm. One hundred thirty-two healthy volunteers were randomised to 3 types of treatment: OLP with choice, OLP without choice, and no treatment (natural history). The OLP groups were further randomised such that half were tested with a consistent pain intensity and the other half were tested with variable pain intensity to mimic day-to-day variability in pain intensity in health settings. The results indicated that treatment provided with choice exhibited greater OLP hypoalgesia than that provided without choice and that greater expectancy mediated this effect. Of interest, there was no evidence for OLP hypoalgesia without choice relative to natural history. Furthermore, variability in pain intensity did not affect OLP hypoalgesia. The current findings present novel evidence that choice over treatment administration may be a cheap and effective strategy for boosting the efficacy of OLPs in the clinical care of pain.

The placebo effect in randomized-controlled trials of medical treatments for chronic rhinosinusitis: A systematic review and meta-analysis

BACKGROUND

The placebo effect observed in clinical trials evaluating medical treatments for chronic rhinosinusitis (CRS) is not well understood. This systematic review and meta-analysis sought to characterize the placebo effect present within CRS outcomes.

METHODS

A systematic review of PubMed, Scopus, and Cumulated Index in Nursing and Allied Health Nursing (CINAHL) was performed. Randomized controlled trials (RCTs) evaluating medical treatments for CRS versus placebo were included. We assessed patient-reported (sino-nasal outcome test 22 [SNOT-22], nasal obstruction, sense of smell, nasal obstruction visual analogue score [VAS], sense of smell VAS, anterior rhinorrhea, and postnasal drip) and objective (Lund-Mackay Computed tomography (CT) score, peak nasal inspiratory flow [PNIF], nasal polyp scores, 40-item Smell Identification Test, serum IgE, and blood eosinophil levels) outcomes.

RESULTS

Twenty-one RCTs were included, comprising 1437 patients (mean age 49.2 years). Biologics were the most common treatment investigated (n = 9). Eleven studies administered background steroids along with placebo. Following placebo administration, multiple patient-reported outcomes significantly decreased, including SNOT-22 (mean difference -9.49, 95% confidence interval [CI] [-11.26, -7.73]), nasal obstruction (-0.33 [-0.54, -0.13]), sense of smell (-0.22 [-0.33, -0.11]), nasal obstruction VAS (-2.47 [-2.87, -2.06]), and loss of smell VAS (-2.31 [-4.14, -0.47]) scores. For objective measures, significant changes occurred in Lund-Mackay CT score (-0.82, [-1.48, -0.16]) and PNIF (4.70, [4.76, 24.64]) with placebo. Placebo arms had the greatest impact when no background medications were used.

CONCLUSIONS

Placebo treatments have a statistically and potentially clinically significant effect on patient-reported and some objective CRS outcomes. Further investigation is required to fully understand placebo effect, which could improve assessment of RCTs and impact patient care.

Choice Enhances Placebo Hypoalgesia More in Weaker Placebo Contexts: A Partial Reinforcement Study

Providing individuals with choice over treatment has been found to enhance placebo hypoalgesia. However, this choice effect is not always present. The current study tested whether the strength of the placebo context influenced the effect of choice on placebo hypoalgesia. Using an established electrocutaneous pain paradigm, the choice effect was compared when placebo hypoalgesia was induced by Continuous Reinforcement (CRF) (strong placebo context) versus partial reinforcement (PRF) (weak placebo context). Healthy volunteers (N = 133) were randomized to receive either choice over treatment administration or no choice and then to placebo conditioning under either CRF (placebo always followed by surreptitious pain reduction during training) or PRF (placebo only followed by surreptitious pain reduction on half of the training trials). At the test, placebo hypoalgesia was greater and more resistant to extinction overall for those with choice. Importantly, however, the choice effect in enhancing the magnitude of placebo hypoalgesia was stronger after PRF than CRF. These results indicate that choice may have greater placebo-enhancing power in weaker placebo contexts. Therefore, choice may be a cheap and effective tool for improving clinical outcomes by facilitating placebo hypoalgesia when the existing treatment context is insufficient to produce placebo hypoalgesia itself. PERSPECTIVE: This study demonstrates that the enhancing effect of choice on placebo hypoalgesia is greater in a weaker placebo context. As such, offering choice could be an ethical way to effectively improve pain outcomes when placebo effects cannot be readily produced by the treatment context.

The Optimal Learning Cocktail for Placebo Analgesia: A Randomized Controlled Trial Comparing Individual and Combined Techniques

This study investigated for the first time the effects of individual and combined application of 3 learning techniques (verbal suggestions, classical conditioning, and observational learning) on placebo analgesia and extinction. Healthy participants (N = 206) were assigned to 8 different groups in which they were taught through either a verbal suggestion, a conditioning paradigm, a video observing someone, or any combination thereof that a placebo device (inactive transcutaneous electric nerve stimulation [TENS]) was capable of alleviating heat pain, whereas one group did not (control). Placebo analgesia was quantified as the within-group difference in experienced pain when the placebo device was (sham) 'activated' or 'inactivated' during equal pain stimuli, and compared between groups. Placebo analgesia was induced in groups with 2 or 3 learning techniques. Significantly stronger placebo analgesia was induced in the combination of all 3 learning techniques as compared to the individual learning techniques or control condition, underlining the additional contribution of 3 combined techniques. Extinction did not differ between groups. Furthermore, pain expectancies, but not state anxiety or trust, mediated placebo analgesia. Our findings emphasize the added value of combining 3 learning techniques to optimally shape expectancies that lead to placebo analgesia, which can be used in experimental and clinical settings. PERSPECTIVE: This unique experimental study compared the individual versus combined effects of 3 important ways of learning (verbal suggestions, classical conditioning, and observational learning) on expectation-based pain relief. The findings indicate that placebo effects occurring in clinical practice could be optimally strengthened if healthcare providers apply these techniques in combination.

The development of the Therapeutic Group Context Questionnaire: Reliability and validity measures based on telehealth Group-based Pain Management Programs

INTRODUCTION

In 2016, the Centers for Disease Control and Prevention analyzed the National Health Interview Survey data and found that the occurrence of chronic pain and high-impact chronic pain in the USA was 20.4% and 8%, respectively. Group-based Pain Management Programs have been viewed as significant treatments aiding patients with self-management of chronic pain. The onset of coronavirus disease 2019 (COVID-19) at the beginning of 2020, widely eliminated the in-person Group-based Pain Management Programs. The exploration of therapeutic contextual factors such as the therapeutic alliance and group dynamics in telehealth Group-based Pain Management Programs appears warranted for which reason the Therapeutic Group Context Questionnaire was developed.

METHODS

The therapeutic alliance and group dynamics items in the Therapeutic Group Context Questionnaire were developed from an extensive literature review and underwent examination of content validity, internal consistency, reliability, and validity through telehealth Group-based Pain Management Programs.

RESULTS

Content validity of the Therapeutic Group Context Questionnaire was established in five separate stages and the psychometrics of the Therapeutic Group Context Questionnaire was found to be very good with high internal consistency and reliability (r = 0.85-0.97) and the ability of the Therapeutic Group Context Questionnaire to differentiate between high and low scorers on the SF-36 emotional well-being measure.

DISCUSSION

The examination of therapeutic contextual factors via telehealth Group-based Pain Management Programs using the Therapeutic Group Context Questionnaire appears possible in view of the very good psychometric properties described above. Investigation of therapeutic contextual factors through the Therapeutic Group Context Questionnaire may provide greater insight into the role that these factors may have in telehealth programs and their impact on pain outcomes. Future investigation of the Therapeutic Group Context Questionnaire in non-telehealth Group-based Pain Management Programs, as well as, other disorders being addressed via telehealth appears warranted.

Efficacy of topical versus oral analgesic medication compared to a placebo in injured athletes: A systematic review with meta-analysis

BACKGROUND

Athletes are injured frequently and often take analgesic medication. Moreover, athletes commonly use non-prescription topical and oral medications with little guidance. Despite wide use, relatively few studies exist on the efficacy of pain medication in injured athletes compared to a placebo.

OBJECTIVE

To determine efficacy of topical or oral medications in pain reduction compared to a placebo in injured athletes.

STUDY DESIGN

A systematic review and meta-analysis.

METHODS

We conducted an electronic search using Medline/Pubmed, Web of Science, Ovid, and SportDiscus for all literature relating to topical or oral medications in athletes for pain management post-injury. Two reviewers screened the studies and measured their quality. To determine efficacy, we calculated the Hedges' g value. We created forest plots with 95% CI to graphically summarize the meta-analyses.

RESULTS

There was a significant pooled effect size reflecting a reduction in pain outcomes for the topical treatment versus placebo (g = -0.64; 95% CI [-0.89, -0.39]; p < 0.001). There was not a significant reduction in pain outcomes for the oral treatment versus placebo (g = -0.26; 95% CI [-0.60, 0.17]; p = 0.272).

CONCLUSION

Topical medications were significantly better at reducing pain compared to oral medications versus a placebo in injured athletes. These results are different when compared to other studies that used experimentally induced pain versus musculoskeletal injuries. The results from our study suggest that athletes should use topical medications for pain reduction, as it is more effective, and there are less reported adverse effects compared to oral medication.

The Biology of Placebo and Nocebo Effects on Experimental and Chronic Pain: State of the Art

(1) Background: In recent years, placebo and nocebo effects have been extensively documented in different medical conditions, including pain. The scientific literature has provided strong evidence of how the psychosocial context accompanying the treatment administration can influence the therapeutic outcome positively (placebo effects) or negatively (nocebo effects). (2) Methods: This state-of-the-art paper aims to provide an updated overview of placebo and nocebo effects on pain. (3) Results: The most common study designs, the psychological mechanisms, and neurobiological/genetic determinants of these phenomena are discussed, focusing on the differences between positive and negative context effects on pain in experimental settings on healthy volunteers and in clinical settings on chronic pain patients. Finally, the last section describes the implications for clinical and research practice to maximize the medical and scientific routine and correctly interpret the results of research studies on placebo and nocebo effects. (4) Conclusions: While studies on healthy participants seem consistent and provide a clear picture of how the brain reacts to the context, there are no unique results of the occurrence and magnitude of placebo and nocebo effects in chronic pain patients, mainly due to the heterogeneity of pain. This opens up the need for future studies on the topic.

Musculoskeletal practitioners' perceptions of contextual factors that may influence chronic low back pain outcomes: a modified Delphi study

BACKGROUND

Optimal shaping of contextual factors (CFs) during clinical encounters may be associated with analgesic responses in treatments for musculoskeletal pain. These CFs (i.e., the patient-practitioner relationship, patient's and practitioner's beliefs/characteristics, treatment characteristics, and environment) have not been widely evaluated by musculoskeletal practitioners. Understanding their views has the potential to improve treatment quality and effectiveness. Drawing on a panel of United Kingdom practitioners' expertise, this study aimed to investigate their perceptions of CFs during the management of patients presenting with chronic low back pain (LBP).

METHODS

A modified two-round online Delphi-consensus survey was conducted to measure the extent of panel agreement regarding the perceived acceptability and influence of five main types of CFs during clinical management of patients with chronic LBP. Qualified musculoskeletal practitioners in the United Kingdom providing regular treatment for patients with chronic LBP were invited to take part.

RESULTS

The successive Delphi rounds included 39 and 23 panellists with an average of 19.9 and 21.3 years of clinical experience respectively. The panel demonstrated a high degree of consensus regarding approaches to enhance the patient-practitioner relationship (18/19 statements); leverage their own characteristics/beliefs (10/11 statements); modify the patient's beliefs and consider patient's characteristics (21/25 statements) to influence patient outcomes during chronic LBP rehabilitation. There was a lower degree of consensus regarding the influence and use of approaches related to the treatment characteristics (6/12 statements) and treatment environment (3/7 statements), and these CFs were viewed as the least important. The patient-practitioner relationship was rated as the most important CF, although the panel were not entirely confident in managing a range of patients' cognitive and emotional needs.

CONCLUSION

This Delphi study provides initial insights regarding a panel of musculoskeletal practitioners' attitudes towards CFs during chronic LBP rehabilitation in the United Kingdom. All five CF domains were perceived as capable of influencing patient outcomes, with the patient-practitioner relationship being perceived as the most important CF during routine clinical practice. Musculoskeletal practitioners may require further training to enhance their proficiency and confidence in applying essential psychosocial skills to address the complex needs of patients with chronic LBP.

Single session of laser photobiomodulation for symptom management of oral lichen planus: a retrospective study

This study aimed to evaluate the effectiveness of a single session of laser photobiomodulation (PBM) with flat top handpiece in reducing painful symptoms in patients with Oral Lichen Planus (OLP). The clinical charts of 20 patients of the Dental Clinic of University of Padua (Italy) who underwent a single laser PBM to manage OLP symptomatology were retrospectively analyzed. A 980 nm diode laser and a flat top handpiece with a 1-cm2 spot area were employed to perform the PBM with a single session protocol. VAS pain scores were assessed before and after the laser PBM, the day after, and on the 7th and 30th days after the treatment. No adverse effects occurred within 30 days after treatment. The mean VAS-pain score was 3.8 (SD 2.3) before PBM; 2.6 (SD 2.0) after PBM; 1.9 (SD 2.2) on day 1; 2.0 (SD 2.3) on day 7; and 1.5 (SD 2.2) on day 30. VAS pain decreased significantly over time (p < 0.0001). A single session of laser PBM may be safe and effective in reducing pain for symptomatic OLP patients. Further investigations are required to include placebo or topical corticosteroids as comparators.

The effects of cannabidiol and analgesic expectancies on experimental pain reactivity in healthy adults: A balanced placebo design trial

Despite its frequent use for pain relief, no experimental pain research has tested the analgesic effects of cannabidiol (CBD) in humans. The goal of this study was to experimentally test the effects of CBD and expectancies for receiving CBD on human pain reactivity. Using a crossover, 2 × 2 factorial balanced placebo design, drug administration (given inactive substance or given active CBD) and verbal instruction sets (told inactive substance or told active CBD) were experimentally manipulated. Fifteen healthy adults each completed four separate experimental sessions. Participants were randomly assigned to different counterbalanced manipulation conditions at each session: control (told inactive-given inactive); expectancy (told active CBD-given inactive); drug (told inactive-given active CBD); and expectancy + drug (told active CBD-given active CBD). Primary outcomes were pain threshold, tolerance, intensity, unpleasantness, conditioned pain modulation (CPM), and offset analgesia (OA). There was a significant main effect of instructions on OA, such that the OA response was significantly larger when participants were told that they received CBD, regardless of drug content. Pain unpleasantness was significantly reduced in the drug, expectancy, and expectancy + drug conditions, relative to the control condition. The drug and expectancy conditions separately improved CPM, whereas the expectancy + drug and control conditions produced the lowest CPM change scores. We did not detect significant effects for pain threshold, tolerance, or intensity. Our results indicated that separate pain outcomes can be differentially affected by CBD and/or expectancies for receiving CBD. Future investigations of the psychological and pharmacological mechanisms underlying CBD analgesia are warranted. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The analgesic effect of nostalgia elicited by idiographic and nomothetic approaches on thermal stimulus

Nostalgia is shown to relieve an individual's perception of pain evoked by cold water, pressure, and thermal stimuli. However, there is no direct evidence to show the analgesic effects of different nostalgia-inducing methods on various stimulus intensities. We conducted two studies to examine the analgesic effect, at different pain intensities, after inducing nostalgia either idiographically or nomothetically. Study 1 (N = 118) induced nostalgia through an idiographic approach (i.e., event reflection task) and found that nostalgia relieved both high and low thermal pain. Study 2 (N = 66) induced nostalgia through a nomothetic approach (i.e., viewing nostalgic pictures) and found that nostalgia relieved low but not high thermal pain. The findings verify the analgesic effect of nostalgia on thermal pain and suggest the potential moderating role of the nostalgia induction approach and pain intensity. Practically, these findings have implications for using nostalgia as a nonpharmacological treatment for pain.

Systematic review and meta-analysis of the placebo effect in panic disorder: Implications for research and clinical practice

OBJECTIVE

This review aimed to measure the degree of placebo response in panic disorder.

DATA SOURCES

We searched major databases up to 31 January 2021, for randomized pharmacotherapy trials published in English.

STUDY SELECTION

A total of 43 studies met inclusion criteria to be in the analysis (with 174 separate outcome measurements).

DATA EXTRACTION

Changes in outcome measures from baseline in the placebo group were used to estimate modified Cohen's d effect size.

RESULTS

A total of 43 trials (2392 subjects, 174 outcomes using 27 rating scales) were included in the meta-analysis. Overall placebo effect size was 0.57 (95% confidence interval = [0.50, 0.64]), heterogeneity (I²: 96.3%). Higher placebo effect size was observed among clinician-rated scales compared to patient reports (0.75 vs 0.35) and among general symptom and anxiety scales compared to panic symptoms and depression scales (0.92 and 0.64 vs 0.56 and 0.54, respectively). There was an upward trend in effect size over the publication period (r = 0.02, p = 0.002) that was only significant among clinician-rated scales (r = 0.02, p = 0.011). There was no significant publication bias, Egger's test (p = 0.08).

CONCLUSION

We observed a substantial placebo effect size in panic disorder. This effect was more prominent for some aspects of panic disorder psychopathology than for others and was correlated with the source of the assessment and publication year. This finding has implications both for research design, to address the heterogeneity and diversity in placebo responses, and for clinical practice to ensure optimal quality of care.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO, CRD42019125979.

Experiences of Patients Taking Conditioned Open-Label Placebos for Reduction of Postoperative Pain and Opioid Exposure After Spine Surgery

BACKGROUND

Pain after spine surgery is difficult to manage, often requiring the use of opioid analgesics. While traditional "deceptive" or concealed placebo has been studied in trials and laboratory experiments, the acceptability and patient experience of taking honestly prescribed placebos, such as "open-label" placebo (non-deceptive placebo), or conditioned placebo (pairing placebo with another active pharmaceutical) is relatively unexamined.

METHODS

Qualitative thematic analysis was performed using semi-structured, post-treatment interviews with spine surgery patients (n = 18) who had received conditioned open-label placebo (COLP) during the first 2-3 weeks after surgery as part of a RCT. Interview transcripts were reviewed by 3 investigators using an immersion/crystallization approach, followed by iterative large-group discussions with additional investigators, to identify, refine, and codify emergent themes.

RESULTS

Patients' experiences and perceptions of COLP efficacy varied widely. Some emergent themes included the power of the mind over pain, how COLP might provide distraction from or agency over pain, bandwidth required and engagement with COLP, and its modulation of opioid tapering, as well as negative attitudes toward opioids and pill taking in general. Other themes included uncertainty about COLP efficacy, observations of how personality may relate to COLP efficacy, and a recognition of the greater impact of COLP on reduction of opioid use rather than on pain itself. Interestingly, participant uncertainty, disbelief, and skepticism were not necessarily associated with greater opioid consumption or worse pain.

CONCLUSION

Participants provided insights into the experience of COLP which may help to guide its future utilization to manage acute pain and tapering from opioids.

The pain conductor: brainstem modulation in acute and chronic pain

PURPOSE OF REVIEW

It is well established in experimental settings that brainstem circuits powerfully modulate the multidimensional experience of pain. This review summarizes current understanding of the roles of brainstem nuclei in modulating the intensity of pain, and how these circuits might be recruited therapeutically for pain relief in chronic and palliative settings.

RECENT FINDINGS

The development of ultra-high field magnetic resonance imaging and more robust statistical analyses has led to a more integrated understanding of brainstem function during pain. It is clear that a number of brainstem nuclei and their overlapping pathways are recruited to either enhance or inhibit incoming nociceptive signals. This review reflects on early preclinical research, which identified in detail brainstem analgesic function, putting into context contemporary investigations in humans that have identified the role of specific brainstem circuits in modulating pain, their contribution to pain chronicity, and even the alleviation of palliative comorbidities.

SUMMARY

The brainstem is an integral component of the circuitry underpinning pain perception. Enhanced understanding of its circuitry in experimental studies in humans has, in recent years, increased the possibility for better optimized pain-relief strategies and the identification of vulnerabilities to postsurgical pain problems. When integrated into the clinical landscape, these experimental findings of brainstem modulation of pain signalling have the potential to contribute to the optimization of pain management and patient care from acute, to chronic, to palliative states.

Effectiveness of Pain Neuroscience Education in Patients with Fibromyalgia: A Systematic Review and Meta-Analysis

PURPOSE

To assess the effects of pain neuroscience education (PNE) on patients with fibromyalgia (FM) in terms of pain intensity, fibromyalgia impact, anxiety, and pain catastrophizing.

METHODS

A systematic review and meta-analysis of randomized controlled trials was conducted. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated with RStudio software for relevant outcomes and were pooled in a meta-analysis using the random effects model.

RESULTS

A total of 8 studies were included. The meta-analysis showed statistically significant differences in the pain intensity with a moderate clinical effect in 7 studies in the post-intervention assessment (SMD:-0.76; 95% CI:-1.33- -0.19; p < 0.05) with evidence of significant heterogeneity (p < 0.05, I2=92%) but not in fibromyalgia impact, anxiety, and pain catastrophizing (p > 0.05). Regarding the follow-up assessment, only the fibromyalgia impact showed significant improvements with a very small clinical effect in 9 studies (SMD:-0.44; 95% CI:-0.73- -0.14; p < 0.05) with evidence of significant heterogeneity (p < 0.05, I2 = 80%). Applying a sensitivity analysis with the PNE face-to-face interventions, the meta-analysis showed a significant decrease of pain intensity with a moderate clinical effect at post-intervention and follow-up without evidence of significant heterogeneity (p < 0.05, I2=10%).

CONCLUSIONS

There is low quality evidence that in patients with FM, PNE can decrease the pain intensity post-intervention and also the fibromyalgia impact in the follow-up. However, it appears that PNE showed no effect on anxiety and pain catastrophizing.

Psycho-Neuro-Endocrine-Immunological Basis of the Placebo Effect: Potential Applications beyond Pain Therapy

The placebo effect can be defined as the improvement of symptoms in a patient after the administration of an innocuous substance in a context that induces expectations regarding its effects. During recent years, it has been discovered that the placebo response not only has neurobiological functions on analgesia, but that it is also capable of generating effects on the immune and endocrine systems. The possible integration of changes in different systems of the organism could favor the well-being of the individuals and go hand in hand with conventional treatment for multiple diseases. In this sense, classic conditioning and setting expectations stand out as psychological mechanisms implicated in the placebo effect. Recent advances in neuroimaging studies suggest a relationship between the placebo response and the opioid, cannabinoid, and monoaminergic systems. Likewise, a possible immune response conditioned by the placebo effect has been reported. There is evidence of immune suppression conditioned through the insular cortex and the amygdala, with noradrenalin as the responsible neurotransmitter. Finally, a conditioned response in the secretion of different hormones has been determined in different studies; however, the molecular mechanisms involved are not entirely known. Beyond studies about its mechanism of action, the placebo effect has proved to be useful in the clinical setting with promising results in the management of neurological, psychiatric, and immunologic disorders. However, more research is needed to better characterize its potential use. This review integrates current knowledge about the psycho-neuro-endocrine-immune basis of the placebo effect and its possible clinical applications.

Analgetische Placeboeffekte und Implikationen für die Behandlung chronischer Schmerzen

Die Behandlung von chronischen Schmerzen kann langwierig sein. Erste Ansätze zur Nutzung von Placeboeffekten bei der Behandlung von chronischen Schmerzen zeigen erfolgversprechende Ergebnisse und können dazu beitragen, die z. T. frustranen Therapieoptionen zu verbessern. Daher sollten Placeboeffekte zur verbesserten Behandlung genutzt werden. Im derzeitigen Modell zur Entstehung von Placeboeffekten spielt die Erwartung eine zentrale Rolle. Eine positive oder negative Erwartung wird durch psychologische und biologische „State“- und „Trait“-Faktoren der Patient:innen sowie die früheren Lernerfahrungen, die der:die Patient:in mitbringt, beeinflusst. Aus diesem Modell ergeben sich Implikationen für die klinische Praxis: Positive Erwartungen sollten unterstützt werden, wobei unrealistische Erwartungen wiederum den Placeboeffekt reduzieren. Negative Erwartungen sollten kritisch diskutiert werden. Es sollte im interdisziplinären Team eine gemeinsame Botschaft an die Patient:innen vermittelt werden. Open-Label-Placebos können als Intervention genutzt werden, um die Selbstwirksamkeit zu steigern.

Optimising treatment expectations in chronic lower back pain through observing others: a study protocol for a randomised clinical trial

INTRODUCTION

Chronic lower back pain (CLBP) is a frequent cause of medical consultations worldwide, and it results in decreased quality of life and disability. Current treatments for CLBP are often not effective, and alternatives are urgently needed. Three promising possibilities have emerged: (1) open-label placebo treatment reduces chronic pain, (2) placebo treatment is as efficacious as opioid treatment with a high correlation between patient expectation and treatment outcome, and (3) observing positive effects in another patient can improve functional capacity. We hypothesise that treatment expectations can be positively influenced through social observation and improve treatment outcome.

METHODS AND ANALYSIS

In our clinical trial, we will randomise patients with CLBP into five groups. Two groups receive either a 3 week course of treatment with an analgesic (ANA) (metamizole/dipyrone) or with open-label placebos (OLP). For one of each group, we will build treatment expectations through observational learning and assess its impact on the treatment. For this purpose, one group each will watch either a positive or a neutral video. The intervention groups will be compared with a control group that will not be given any medication or observational learning. Participants will be recruited via all institutions in the Hamburg metropolitan area that treat patients with CLBP. Patients are eligible for inclusion if they are at least 18 years or older, have CLBP (of at least 3 months duration), and agree to potentially receive an active ANA or an OLP. Patients with pain-related "red flags" will be excluded. The study requires 150 participants (30 participants per group) to assess the differences in the primary outcome, pain intensity. Secondary outcomes include changes in treatment expectations, anxiety, comorbid depression, stress-related neuroendocrine measures, functional and structural connectivity, functional capacity, and ANA consumption. All outcomes and treatment expectations will be measured before and after the intervention and 3 months post-intervention.

ETHICS AND DISSEMINATION

Ethical approval was obtained in January 2020 from the Hamburg Medical Ethics Council (ref number PV7067). Outcomes will be disseminated through publications in peer-reviewed journals and presentations at national and international conference meetings.

TRIAL REGISTRATION NUMBER

The approved trial protocol was registered at the German Clinical Trials Register (DRKS) and can be found at drks.de (Identifier: DRKS00024418).

Peri-Operative Pain and Opioid Use in Opioid-Naïve Patients Following Inpatient Head and Neck Surgery

Pain management is an important consideration for Head and Neck Cancer (HNC) patients as they are at an increased risk of developing chronic opioid use, which can negatively impact both quality of life and survival outcomes. This retrospective cohort study aimed to evaluate pain, opioid use and opioid prescriptions following HNC surgery. Participants included patients undergoing resection of a head and neck tumor from 2019-2020 at a single academic center with a length of admission (LOA) of at least 24 h. Exclusion criteria were a history of chronic pain, substance-use disorder, inability to tolerate multimodal analgesia or a significant post-operative complication. Subjects were compared by primary surgical site: Neck (neck dissection, thyroidectomy or parotidectomy), Mucosal (resection of tumor of upper aerodigestive tract, excluding oropharynx), Oropharyngeal (OP) and Free flap (FF). Average daily pain and total daily opioid consumption (as morphine milligram equivalents, MME) and quantity of opioids prescribed at discharge were compared. A total of 216 patients met criteria. Pain severity and daily opioid consumption were comparable across groups on post-operative day 1, but both metrics were significantly greater in the OP group on the day prior to discharge (DpDC) (5.6 (1.9-8.6), p < 0.05; 49 ± 44 MME/day, p < 0.01). The quantity of opioids prescribed at discharge was associated with opioid consumption on the DpDC only in the Mucosal and FF groups, which had longer LOA (6-7 days) than the Neck and OP groups (1 day, p < 0.001). Overall, 65% of patients required at least one dose of an opioid on the DpDC, yet 76% of patients received a prescription for an opioid medication at discharge. A longer LOA (aOR = 0.82, 95% CI: 0.63-0.98) and higher Charlson Comorbidity Index (aOR = 0.08, 95% CI: 0.01-0.48) were negatively associated with receiving an opioid prescription at the time of discharge despite no opioid use on the DpDC, respectively. HNC patients, particularly those with shorter LOA, may be prescribed opioids in excess of their post-operative needs, highlighting the need the for improved pain management algorithms in this patient population. Future work aims to use prospective surveys to better define post-operative and outpatient pain and opioid requirements following HNC surgery.

The Influence of Preoperative Mood and Treatment Expectations on Early Postsurgical Acute Pain After a Total Knee Replacement

BACKGROUND

Reducing postoperative pain immediately after surgery is crucial because severe postoperative pain reduces quality of life and increases the likelihood that patients develop chronic pain. Even though postoperative pain has been widely studied and there are national guidelines for pain management, the postoperative course is differently from one patient to the next. Different postoperative courses could be explained by factors related to the treatment context and the patients. Preoperative emotional states and treatment expectations are significant predictors of postoperative pain. However, the interaction between emotional states and preoperative treatment expectations and their effect on postoperative pain have not yet been studied. The aim of our study was to identify the interaction between emotional states, treatment expectation and early postsurgical acute pain.

METHODS

In this prospective clinical trial, we enrolled patients who had received a TKR at a German hospital between October 2015 and March 2019. Patients rated their preoperative pain on a numeric rating scale (NRS) 0-10 (0 = no pain and 10 = worst pain imaginable), their emotional states preoperatively on the Pain and State of Health Inventory (PHI), their preoperative treatment expectations on the Stanford Expectation of Treatment Scale (SETS), and their postoperative level of pain on a NRS 0-10.

FINDINGS

The questionnaires were completed by 122 patients (57% female). Emotional states predict negative treatment expectation F(6, 108) = 8.32, p < 0.001, with an excellent goodness-of-fit, R² = 0.31. Furthermore, a mediator analysis revealed that the indirect effects and therefore relationship between the emotional states sad (ab = 0.06, 95% CI[0.01, 0.14]), anxious (ab = 0.13, 95% CI[0.04, 0.22]), and irritable (ab = 0.09, 95% CI[0.03, 0.17]) and postoperative pain is fully mediated by negative treatment expectations. Whereas the emotional states tired (ab = 0.09, 95% CI[0.03, 0.17]), dizzy/numb (ab = 0.07, 95% CI[0.01, 0.20]), weak (ab = 0.08, 95% CI[0.03, 0.16] are partially mediated by negative treatment expectations.

CONCLUSION

The relationship between emotional states and postoperative pain is mediated by negative treatment expectations. Therefore, innovative treatment strategies to reduce postoperative pain should focus on eliminating negative treatment expectation through establishing a differentiated preoperative expectation management program that also focuses on emotional states.

Placebo and hypnosis in the clinical setting: Contextual factors in hypnotic analgesia

The assumption that hypnotic analgesia produces placebo effects is controversial. The cognitive dimension that can distinguish hypnosis from placebo analgesia has been suggested as hypnotic susceptibility. The aim of this study is to investigate the role of the relationship between patient and therapist, assumed to produce the placebo effect, in the clinical context of hypnotic treatment for pain. Seventy subjects were given hypnosis administered by the therapist in person (Group A) and 37 practiced self-hypnosis (Group B) for 8 weeks. The Somatosensory Amplification Scale (SSAS), Stanford hypnotic susceptibility scale type A, Cold pressor test (CPT) and SCL-90 were administered at baseline, and Italian Pain Questionnaire (IPQ) dimensions were used as outcome measures. The SSAS did appear to reflect the efficacy of hypnotic analgesia in all pain variables explored, but only in Group B. An improvement in pain intensity and all IPQ dimensions were found at 8 weeks. In particular, an improvement in the affective dimension of pain, with a medium-high effect size (η2 = .774), was recorded after hypnotic analgesia, with the outcome being better in Group A than in Group B (p = .001). This outcome was independent of hypnotic susceptibility in both groups. Considering our hypothesis that, given the administration of the same suggestions, the therapist could promote the placebo response, contributing to the improvement in the affective dimension of pain outcome, which exhibited a response to the hypnotic treatment independently of hypnotic susceptibility.

Conditioning to Enhance the Effects of Repetitive Transcranial Magnetic Stimulation on Experimental Pain in Healthy Volunteers

OBJECTIVE

In this proof-of-concept study we sought to explore whether the combination of conditioning procedure based on a surreptitious reduction of a noxious stimulus (SRPS) could enhance rTMS hypoalgesic effects [i.e., increase heat pain threshold (HPT)] and augment intervention expectations in a healthy population.

METHODS

Forty-two healthy volunteers (19-35 years old) were enrolled in a randomized crossover-controlled study and were assigned to one of two groups: (1) SRPS and (2) No SRPS. Each participant received two consecutive sessions of active or sham rTMS over the M1 area of the right hand on two visits (1) active, (2) sham rTMS separated by at least one-week interval. HPT and the temperature needed to elicit moderate heat pain were measured before and after each rTMS intervention on the right forearm. In the SRPS group, conditioning consisted of deliberately decreasing thermode temperature by 3°C following intervention before reassessing HPT, while thermode temperature was held constant in the No SRPS group. Intervention expectations were measured before each rTMS session.

RESULTS

SRPS conditioning procedure did not enhance hypoalgesic effects of rTMS intervention, neither did it modify intervention expectations. Baseline increases in HPT were found on the subsequent intervention session, suggesting variability of this measure over time, habituation or a possible "novelty effect."

CONCLUSION

Using a SRPS procedure in healthy volunteers did not enhance rTMS modulating effects on experimental pain sensation (i.e., HPT). Future studies are therefore needed to come up with a conditioning procedure which allows significant enhancement of rTMS pain modulating effects in healthy volunteers.

What Should Clinicians Tell Patients about Placebo and Nocebo Effects? Practical Considerations Based on Expert Consensus

INTRODUCTION

Clinical and laboratory studies demonstrate that placebo and nocebo effects influence various symptoms and conditions after the administration of both inert and active treatments.

OBJECTIVE

There is an increasing need for up-to-date recommendations on how to inform patients about placebo and nocebo effects in clinical practice and train clinicians how to disclose this information.

METHODS

Based on previous clinical recommendations concerning placebo and nocebo effects, a 3-step, invitation-only Delphi study was conducted among an interdisciplinary group of internationally recognized experts. The study consisted of open- and closed-ended survey questions followed by a final expert meeting. The surveys were subdivided into 3 parts: (1) informing patients about placebo effects, (2) informing patients about nocebo effects, and (3) training clinicians how to communicate this information to the patients.

RESULTS

There was consensus that communicating general information about placebo and nocebo effects to patients (e.g., explaining their role in treatment) could be beneficial, but that such information needs to be adjusted to match the specific clinical context (e.g., condition and treatment). Experts also agreed that training clinicians to communicate about placebo and nocebo effects should be a regular and integrated part of medical education that makes use of multiple formats, including face-to-face and online modalities.

CONCLUSIONS

The current 3-step Delphi study provides consensus-based recommendations and practical considerations for disclosures about placebo and nocebo effects in clinical practice. Future research is needed on how to optimally tailor information to specific clinical conditions and patients' needs, and on developing standardized disclosure training modules for clinicians.

Placebo Effect of Sham Spine Procedures in Chronic Low Back Pain: A Systematic Review

Background

The literature lacks information about the characteristics of the placebo effect following sham spine procedures for chronic low back pain. We aim to evaluate the effect using pain score data from the sham arms of published trials.

Methods

Relevant trials were selected and reviewed. Baseline and post-procedure pain scores were collected. Each follow up pain score was considered an episode and compared to its baseline for significance. Patients and episodes were pooled and analyzed using three parameters: patient reported outcome measures (PROMs) (Oswestry Disability Index [ODI], Visual Analog Scale [VAS], Numerical Rating Scale [NRS] and Short Form-36 [SF]), anatomical targets (disc, facet, sacroiliac joint [SIJ], ramus communicans nerve [RCN], basivertebral nerve [BVN], and caudal) and follow up periods (early: 0–2, intermediate: >2–4 and late: >4–6) in months. The percentage of pooled patients in the episodes that had significant reduction in pain scores was termed placebo effect. The outcome was defining the magnitude of the placebo effect and determining if it was influenced by the three parameters.

Results

Seventeen studies that reported 535 patients and 55 pain scoring episodes were considered eligible. Significant reduction in pain scores was reported in 21 episodes. The overall placebo effect among the patients during the studied period was 53.2%. The rate ranged according to PROMs from 42.4% to 72.1%, anatomical targets from 11.1% to 100% and follow up periods from 47.9% to 59%. The placebo effect differed significantly between the various domains in the three parameters.

Conclusion

Placebo effect was observed in nearly half of the patients during the first 6 months following a sham spine procedure. The effect was influenced by utilized PROMs, anatomical target and follow up period. The findings should be considered in the design of new sham spine procedure trials. Further research is required to delineate the effect of bias on the findings.

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.

Evaluating cannabidiol (CBD) expectancy effects on acute stress and anxiety in healthy adults: a randomized crossover study

RATIONALE

Cannabidiol (CBD) has been reported to attenuate stress and anxiety, but little is known about the extent to which such effects result from pharmacological versus expectancy factors.

OBJECTIVES

We evaluated whether CBD expectancy alone could influence stress, anxiety, and mood, and the extent to which beliefs regarding CBD effects predicted these responses.

METHODS

In this randomized crossover study, 43 health adults (23 women) attended two experimental laboratory sessions, where they self-administered CBD-free hempseed oil sublingually. During one session, they were (incorrectly) informed that the oil contained CBD and in the other session, that the oil was CBD-free. Following administration, participants engaged in the Maastricht Acute Stress Test (MAST). Heart rate variability (HRV) was assessed continuously, and subjective state was assessed at baseline, 90-min following oil administration, immediately following the MAST, and after a 10-min recovery period.

RESULTS

The CBD expectancy condition was associated with increased sedation as well as with changes in HRV that were consistent with heightened anticipatory stress regulation. Overall, there were no systematic changes in subjective stress, or anxiety, according to expectancy condition. However, participants who endorsed strong a priori beliefs that CBD has anxiolytic properties reported significantly diminished anxiety in the CBD expectancy condition.

CONCLUSIONS

CBD expectancy alone impacted several subjective and physiological responses. Additionally, expectancy-related factors were implicated in anxiolytic effects of CBD for those who believed it was helpful for such purposes, emphasizing the need to measure and control for CBD-related expectancies in clinical research that involves the administration of CBD.

Targeted Use of Placebo Effects Decreases Experimental Itch in Atopic Dermatitis Patients: A Randomized Controlled Trial

Evidence from pain research shows that the effectiveness of active pharmacological treatments can be enhanced by placebo effects. The "open drug administration" is superior to "hidden drug administration.​" In a randomized controlled trial, we aimed to show that the targeted use of placebo effects increases the efficacy of an antihistamine (dimetindene) infusion in participants with atopic dermatitis. We openly infused dimetindene (drug) in full sight with information (intervention group 1: OPEN-DRUG+INST), openly infused drug with an additional classical conditioning learning experience (intervention group 2: OPEN-DRUG+INST+COND) or infused drug without any information or sight (i.e., hidden administration (control group 1: HIDDEN-DRUG)). Control group 2 received a placebo infusion (saline) declared as dimetindene and also experienced the conditioning experience (PLAC+INST+COND). Itch was experimentally induced with histamine via a skin prick test. Outcome was assessed at the subjective (primary end point: experimental itch intensity, numeric rating scale), and objective level (secondary end point: wheal size, mm² ). Experimental-induced itch intensity decreased in all groups but at different rates (P < 0.001). The groups with the open administration, whether it was dimetindene or placebo, had significantly stronger reductions in itch compared to the HIDDEN-DRUG group (OPEN-DRUG+INST+COND: P < 0.001; OPEN-DRUG+INST: P = 0.009; and PLAC+INST+COND: P < 0.001). Additional drug conditioning mediated via expectation led to a stronger reduction of itching (P = 0.001). Results on wheal size were similar (P = 0.048), however, no significant difference between the HIDDEN-DRUG group and the PLAC+INST+COND group (P = 0.967) was found. We conclude that specifically generated targeted placebo effects can significantly increase the action of a drug (dimetindene) and should be used in clinical practice.

Preoperative analgesic instruction and prescription reduces early home pain after outpatient surgery: a randomized controlled trial

BACKGROUND

Home pain remains the most common complication in outpatient surgery. Optimal management requires good information and early availability of analgesics. The main objective of this randomized controlled trial was to compare the effects of pre- vs postoperative analgesic instruction and prescription on postoperative home pain.

METHODS

Patients were randomized into an anesthesia consultation group (AC group) and a standard postoperative group (POP group). The AC group and the POP group received analgesic prescription and instruction during the anesthesia consultation and after surgery, respectively. The primary outcome was the incidence of home pain on postopertive day one (D1). Home pain was defined by at least one episode with a numeric rating scale score > 3/10 at rest. Treatment compliance and postoperative nausea and vomiting (PONV) were also assessed on D1 and postoperative day 7 (D7).

RESULTS

One hundred and eighty-six patients were included between May 2017 and May 2018 at Rouen University Hospital, France. Ninety-four patients were randomized to the AC group and 92 to the POP group. On D1, the incidence of pain was 23/94 (24%) in the AC group and 44/92 (48%) in the POP group (P < 0.001). On D1, the rate of treatment compliance was significantly higher in the AC group than in the POP group (85% vs 69%; P = 0.02). There was no statistically significant difference in the incidence of pain or treatment compliance between groups on D7 or in PONV on D1 and on D7.

CONCLUSIONS

Preoperative analgesic instruction and prescription during anesthesia consultation reduces the incidence of early postoperative home pain in outpatient surgery.

TRIAL REGISTRATION

www.clinicaltrialsgov (NCT03205189); registered 2 July 2017.

Pectoral nerve blocks for breast surgery: A meta-analysis

BACKGROUND

Pectoral nerve blocks (PECS block) might be an interesting new regional anaesthetic technique in patients undergoing breast surgery.

OBJECTIVE

The aim of this meta-analysis was to investigate postoperative pain outcomes and adverse events of a PECS block compared with no treatment, sham treatment or other regional anaesthetic techniques in women undergoing breast surgery.

DESIGN

We performed a systematic review of randomised controlled trials (RCT) with meta-analysis and risk of bias assessment.

DATA SOURCES

The databases MEDLINE, CENTRAL (until December 2019) and clinicaltrials.gov were systematically searched.

ELIGIBILITY CRITERIA

All RCTs investigating the efficacy and adverse events of PECS compared with sham treatment, no treatment or other regional anaesthetic techniques in women undergoing breast surgery with general anaesthesia were included.

RESULTS

A total of 24 RCTs (1565 patients) were included. PECS (compared with no treatment) block might reduce pain at rest [mean difference -1.14, 95% confidence interval (CI), -2.1 to -0.18, moderate quality evidence] but we are uncertain regarding the effect on pain during movement at 24 h after surgery (mean difference -1.79, 95% CI, -3.5 to -0.08, very low-quality evidence). We are also uncertain about the effect of PECS block on pain at rest at 24 h compared with sham block (mean difference -0.83, 95% CI, -1.80 to 0.14) or compared with paravertebral block (PVB) (mean difference -0.18, 95% CI, -1.0 to 0.65), both with very low-quality evidence. PECS block may have no effect on pain on movement at 24 h after surgery compared with PVB block (mean difference -0.56, 95% CI, -1.53 to 0.41, low-quality evidence). Block-related complications were generally poorly reported.

CONCLUSION

There is moderate quality evidence that PECS block compared with no treatment reduces postoperative pain intensity at rest. The observed results were less pronounced if patients received a sham block. Furthermore, PECS blocks might be equally effective as PVBs. Due to mostly low-quality or very low-quality evidence level, further research is warranted.

PROTOCOL REGISTRATION

CRD42019126733.

Efficacy and Safety of Pregabalin for Fibromyalgia in a Population of Chinese Subjects

PURPOSE

Fibromyalgia (FM) may go underdiagnosed and untreated in China in part due to a lack of awareness and understanding of the condition, and limited available treatments.

PATIENTS AND METHODS

This randomized, double-blind, Phase III local registration trial compared the efficacy and safety of pregabalin (flexibly dosed 300-450 mg/day) versus placebo for the management of pain in Chinese adults diagnosed with FM according to American College of Rheumatology 1990 criteria, across 22 centers within China. Patients reported pain score of ≥40 mm on 100-mm scale (from 0 "no pain" to 100 "worst possible pain"). The primary efficacy endpoint was change from baseline to Week 14 in mean pain score (MPS). Secondary endpoints included measures of sleep and sleep interference. Safety and tolerability were monitored throughout.

RESULTS

Median pregabalin dose was 335 mg/day. A significant reduction from baseline to Week 14 in weekly MPS was seen for patients treated with pregabalin (n=170) versus placebo (n=164) (least-squares mean difference [95% confidence interval]: -0.73 [-1.10 to -0.36]; P=0.0001). Significantly greater proportions of patients experienced ≥30% and ≥50% reductions in MPS at Week 14 with pregabalin versus placebo. Pregabalin-treated subjects demonstrated improvements in measures of sleep and sleep interference. Pregabalin was generally well tolerated. The most common adverse events were dizziness and somnolence; no serious adverse events (SAEs) occurred in pregabalin-treated subjects. Nine placebo-treated subjects experienced SAEs.

CONCLUSION

Pregabalin (300-450 mg/day) is a safe and effective treatment for reducing pain and improving sleep in native Chinese subjects with FM.

CLINICALTRIALSGOV IDENTIFIER

NCT01387607.

A Meta-Analysis of Group-Based Pain Management Programs: Overall Effect on Quality of Life and Other Chronic Pain Outcome Measures, with an Exploration into Moderator Variables that Influence the Efficacy of Such Interventions

OBJECTIVES

Group-based pain management programs (GPMPs) have been found to significantly improve quality of life and other pain outcome measures in patients with chronic musculoskeletal pain. The aims of this meta-analysis were to reevaluate the overall effect of GPMPs on various pain outcomes for individuals experiencing chronic musculoskeletal conditions and to explore moderator variables that potentially contribute to the overall efficacy of GPMPs.

METHODS

Using the R package called metaphor and RevMan, we estimated the overall effectiveness of GPMPs on various pain outcome measures. The differential effectiveness of GPMPs was examined by conducting a mixed-effects meta-analytic model using various study-level characteristics. Moderator analyses included three content moderator variables and seven format moderator variables. Receiver operating characteristic curves investigated optimal points in some of the moderator variable analysis results.

RESULTS

Significant overall main effects of GPMPs were found on all the explored outcome measures in this study (P < 0.05). In moderator analyses, it was found that the structure of GPMPs, rather than the content, significantly improved outcomes (P < 0.05). Receiver operating characteristic curve analyses identified the optimal number of GPMP sessions and number of participants per group.

DISCUSSION AND CLINICAL RELEVANCE

GPMPs have a statistically significant overall effect on all explored pain outcome measures. The investigation into content and structural moderators suggests that certain GPMP design factors have a greater effect on pain outcomes than do content factors. Therefore, GPMP structural designs appear to be important in reducing pain and improving quality of life for patients with chronic pain and warrant further investigation.

Non-invasive neuromodulation effects on painful diabetic peripheral neuropathy: a systematic review and meta-analysis

Diabetic Peripheral Neuropathy (DPN) typically is accompanied by painful symptoms. Several therapeutic agents have been tried for symptomatic relief, but with varying results. The use of non-invasive neuromodulation (NINM) is a potential treatment option for DPN. The objective of our study is to evaluate NINM effects on pain rating and nerve conduction velocity in DPN patients. The search was carried out in seven databases until Aug 30th, 2019. Finally, twenty studies met the inclusion criteria. We found a significant reduction of pain scores by central NINMs (effect size [ES] =  - 0.75, 95% CI =  - 1.35 to - 0.14), but not by the overall peripheral techniques (electrical and electromagnetic) (ES =  - 0.58, 95% CI =  - 1.23 to 0.07). However, the subgroup of peripheral electrical NINMs reported a significant higher effect (ES =  - 0.84, 95% CI =  - 1.57 to - 0.11) compared to electromagnetic techniques (ES = 0.21; 95% CI =  - 1.00 to 1.42, I2 = 95.3%) . Other subgroup analysis results show that NINMs effects are higher with intensive protocols and in populations with resistant symptoms or intolerance to analgesic medications. Besides, NINMs can increase motor nerves velocity (ES = 1.82; 95% CI = 1.47 to 2.17), and there were no effects on sensory nerves velocity (ES = 0.01, 95% CI =  - 0.79 to 0.80). The results suggest that central and peripheral electrical NINMs could reduce neuropathic pain among DPN patients, without reported adverse events. Well-powered studies are needed to confirm that NINM techniques as an alternative effective and safe treatment option.

A Meta-Analysis of Therapeutic Pain Neuroscience Education, Using Dosage and Treatment Format as Moderator Variables

OBJECTIVES

This meta-analysis aimed to assess the overall effect of therapeutic pain neuroscience education (TPNE) on chronic musculoskeletal pain and to further assess whether such an effect differs by TPNE dosage as well as other treatment format components. Dosage included the number of TPNE sessions provided as well as the amount of time per TPNE session. Structural components included TPNE provided alone as treatment or combined with other pain management modalities, as well as the inclusion of group-based treatment sessions.

METHODS

Electronic databases were utilized to search for randomized controlled trials that included TPNE. The overall effectiveness of TPNE was estimated on 4 pain outcome measures, including kinesiophobia, pain intensity, pain disability, and pain catastrophizing. The differential effectiveness of TPNE was examined using a mixed-methods moderator analysis on various study-level characteristics to identify potential moderators affecting the overall results.

RESULTS

Significant effects of TPNE were found on all the outcome measures. The only moderator that displayed a significant effect was group-based treatment on kinesiophobia (z = -2.23, P < 0.05, 95% confidence interval [CI] -2.70 to -0.20). Between-group analysis revealed that only interventions that included group sessions were found to be statistically significant (z = 2.20, P < 0.05) and displayed a large effect size (d = 0.80, 95% CI 0.09 to 1.50).

DISCUSSION

Therapeutic pain neuroscience education had a statistically significant impact on all the explored pain outcome measures. However, when investigating the treatment dosage and format moderator variables, they appeared to not have a statistically significant effect except for group-based interventions on kinesiophobia levels.

CONCLUSION

This meta-analysis examined the efficacy of TPNE for patients with chronic pain. It assessed various pain outcome measures following intervention. In addition, this research identified that various moderator variables do not have and do have an impact on the treatment modality of TPNE.

The evolution of temporomandibular disorders: A shift from experience to evidence

After over 80 years of much obsession as well as avoidance of the subject of temporomandibular disorders (TMDs), the dental profession is still divided over what they are and how to deal with them. Over this period, nearly every discipline in dentistry has played some role in the development of this field. Unfortunately, a significant amount of this information has been based on personal opinion, experience-based philosophies, or poorly conducted research. Furthermore, each dental specialty has been responsible for contributing to the concepts of the etiology and management of TMDs with their own professional bias; for example, orthodontists describe these problems in orthodontic terms and offer orthodontic treatments or solutions for their patients. As various treatment approaches were found to be effective at least some of the time, this has further led to misinformation and confusion within the profession. Advances in research from diverse fields, including neurophysiology, pain pathophysiology, genetics, endocrinology, behavioral sciences, and psychology, have significantly altered our understanding of TMDs and how they should be managed. The rigid mechanical and dental-based model of the past has been gradually replaced by a biopsychosocial medical model for the diagnosis and treatment of TMDs as well as other acute and chronic pain disorders. This paper discusses the evolution of our understanding of TMDs since they were first described 85 years ago. Contemporary scientific findings and their implications are presented in some detail for clinicians who wish to provide the appropriate management for their orofacial pain patients.

Context matters: the psychoneurobiological determinants of placebo, nocebo and context-related effects in physiotherapy

Background

Placebo and nocebo effects embody psychoneurobiological phenomena where behavioural, neurophysiological, perceptive and cognitive changes occur during the therapeutic encounter in the healthcare context. Placebo effects are produced by a positive healthcare context; while nocebo effects are consequences of negative healthcare context. Historically, placebo, nocebo and context-related effects were considered as confounding elements for clinicians and researchers. In the last two decades this attitude started to change, and the understanding of the value of these effects has increased. Despite the growing interest, the knowledge and the awareness of using the healthcare context to trigger placebo and nocebo effects is currently limited and heterogeneous among physiotherapists, reducing their translational value in the physiotherapy field.

Objectives

To introduce the placebo, nocebo and context-related effects by: (1) presenting their psychological models; (2) describing their neurophysiological mechanisms; (3) underlining their impact for the physiotherapy profession; and (4) tracing lines for future researches.

Conclusion

Several psychological mechanisms are involved in placebo, nocebo and context-related effects; including expectation, learning processes (classical conditioning and observational learning), reinforced expectations, mindset and personality traits. The neurophysiological mechanisms mainly include the endogenous opioid, the endocannabinoid and the dopaminergic systems. Neuroimaging studies have identified different brain regions involved such as the dorsolateral prefrontal cortex, the rostral anterior cingulate cortex, the periaqueductal gray and the dorsal horn of spine. From a clinical perspective, the manipulation of the healthcare context with the best evidence-based therapy represents an opportunity to trigger placebo effects and to avoid nocebo effects respecting the ethical code of conduct. From a managerial perspective, stakeholders, organizations and governments should encourage the assessment of the healthcare context aimed to improve the quality of physiotherapy services. From an educational perspective, placebo and nocebo effects are professional topics that should be integrated in the university program of health and medical professions. From a research perspective, the control of placebo, nocebo and context-related effects offers to the scientific community the chance to better measure the impact of physiotherapy on different outcomes and in different conditions through primary studies.

Definitions of blinding in randomised controlled trials of interventions published in high-impact anaesthesiology journals: a methodological study and survey of authors

OBJECTIVES

To analyse the completeness of reporting of blinding in randomised controlled trials (RCTs) of interventions in anaesthesiology, the actual blinding status of various persons associated with an RCT and trial authors' interpretation of blinding terminology related to RCTs.

METHODS

This was a methodological study and a cross-sectional survey. We analysed reporting related to blinding in published RCTs of interventions published in seven highly cited anaesthesiology journals from 2014 to 2016 and registered protocols in ClinicalTrials.gov. We surveyed corresponding authors of included RCTs about their definitions of blinding. The primary outcome was the number of RCTs that explicitly described who was blinded in a trial. Secondary outcomes were definitions of blinding terminology in the trials; trial authors' interpretation of blinding terminology; discrepancies in the blinding description within registered protocols and between registered protocols and publications.

RESULTS

Out of 622 analysed RCTs, 38% were not explicitly described as either open label or blinded studies and 10% did not report any information about blinding or lack of blinding. Only one manuscript fully reported the status of blinding for various individuals that may be involved with a trial. The most common descriptor was that a trial was double-blind. We found discrepant information regarding blinding in the majority of registered protocols. Even when there were no discrepancies in the registration, we found discrepancies in the reporting of blinding between the majority of registered protocols and published manuscripts. The survey of authors (40 responses from 231 eligible authors; 17% response rate) of analysed RCTs showed that they differed in how they defined different levels of blinding in trials.

CONCLUSIONS

Reporting of the blinding status of key individuals involved in analysed anaesthesiology RCTs was insufficient. For reporting guidelines, peer reviewers and editors should insist on clear information on who was blinded in a trial instead of using the term 'double-blind' for different blinding practices.