Normality Analysis of Numeric Rating Scale Scores in Patients with Chronic Axial Spine Pain Before and After Medial Branch Blocks: a Multicenter Study.

OBJECTIVE: The statistical analysis typically employed to compare pain both before and after interventions assumes scores are normally distributed. The present study evaluates whether Numeric Rating Scale (NRS), specifically the NRS-11, scores are indeed normally distributed in a clinically-relevant cohort of adults with chronic axial spine pain pre- and post-analgesic intervention. METHODS: Retrospective review from four academic medical centers of prospectively collected data from a uniform pain diary administered to consecutive patients after undergoing medial branch blocks. The pain diary assessed NRS-11 scores immediately pre-injection and at 12 different time points post-injection up to 48 hours. D'Agostino-Pearson tests were used to test normality at all time points. RESULTS: One hundred fifty pain diaries were reviewed and despite normally distributed pre-injection NRS-11 scores (K2 = 0.655, p = 0.72), all post-injection NRS-11 data was not normally distributed (K2 = 9.70- 17.62, p = 0.0001-0.008). CONCLUSIONS: Although the results of parametric analyses of NRS-11 scores are commonly reported in pain research, some properties of NRS-11 do not satisfy the assumptions required for these analyses. The data demonstrate non-normal distributions in post-intervention NRS-11 scores, thereby violating a key requisite for parametric analysis. We urge pain researchers to consider appropriate statistical analysis and reporting for non-normally distributed NRS-11 scores to ensure accurate interpretation and communication of these data. Practicing pain physicians should similarly recognize that parametric post-intervention pain score statistics may not accurately describe the data and should expect manuscripts to utilize measures of normality to justify the selected statistical methods.

Impact of Shared Decision-Making on Opioid Prescribing Among Patients With Chronic Pain: A Retrospective Cohort Study.

Shared decision-making (SDM) involving patient and physician is a desirable goal that is recommended in chronic pain management guidelines. This study measured whether SDM affects opioid prescribing frequency for chronic low back pain. A retrospective cohort study involving 1,478 participants was conducted within a national pain research registry. The patient participation and patient orientation (PPPO) scale of the Communication Behavior Questionnaire was used to measure SDM, including the classification of greater SDM (PPPO scale score ≥ 80) or lesser SDM (PPPO scale score < 80). Opioid prescribing frequency was measured at quarterly intervals from enrollment through 12 months. Baseline and longitudinal covariates were collected to adjust for potential confounding using generalized estimating equations. The mean age of participants was 53.1 (SD, 13.2) years, and 1,098 (74.3%) were female. A total of 473 (32.0%) participants were prescribed opioids at baseline. Participants completed 5,968 encounters wherein multivariable analyses demonstrated that PPPO scale scores were associated with more frequent opioid prescribing (ß = .013; 95% CI, .005-.021; P < .001). Greater SDM was associated with more frequent opioid prescribing than lesser SDM (ß = .441; 95% CI, .160-.722; P = .002). Opioids were prescribed in 34.3% versus 25.2% of encounters with greater versus lesser SDM (OR, 1.55; 95% CI, 1.17-2.06). SDM remained associated with more frequent opioid prescribing in a series of sensitivity analyses. Although SDM is desirable in chronic pain management, complex issues and challenging patient conversations may arise during serial assessments of the appropriateness of opioid therapy. Physicians need better education and training to address such difficult situations. PERSPECTIVE: The more frequent use of opioid therapy among patients who reported greater SDM with their physicians underscores the need for better medical education and training in dealing with the complex issues and challenges pertaining to serial assessments of the appropriateness of opioid therapy for chronic pain.

Pain catastrophizing and risk of progression to widespread pain among patients with chronic low back pain: A retrospective cohort study.

BACKGROUND: Chronic low back pain often progresses to widespread pain. Although many factors are associated with progression, their roles in contributing to chronic widespread pain (CWP) are often unclear. OBJECTIVE: To determine if pain catastrophizing is an independent risk factor for CWP. DESIGN: Retrospective cohort study within a national pain research registry from April 2016 through August 2022. METHODS: A total of 1111 participants with chronic low back pain, but without CWP, were included. Participants were followed at quarterly intervals for up to 48 months to measure CWP risk. Survival analyses involved Kaplan-Meier plots and the Cox proportional hazards model to measure CWP risk according to pain catastrophizing and subscale scores for rumination, magnification, and helplessness. RESULTS: Crude CWP risks for moderate pain catastrophizing (HR, 2.13; 95% CI, 1.54-2.95; P < 0.001) and high pain catastrophizing (HR, 3.98; 95% CI, 2.95-5.35; P < 0.001) were each elevated in comparison with low pain catastrophizing. Adjusted CWP risks for moderate pain catastrophizing (HR, 1.80; 95% CI, 1.27-2.53; P < 0.001) and high pain catastrophizing (HR, 2.82; 95% CI, 1.98-4.02; P < 0.001) remained elevated in analyses that controlled for potential confounders. Corresponding results were observed in the survival analyses involving rumination, magnification, and helplessness. CONCLUSIONS: Pain catastrophizing appears to be an independent risk factor for progression to CWP among patients with chronic low back pain. These findings provide a rationale for interventions aimed at reducing pain catastrophizing, including rumination, magnification, and helplessness, among patients with chronic low back pain.

Sex Differences in Pain and Its Treatment.

Pain is a highly personal experience. Pain is often considered to be a purely neurologic phenomenon, but in actuality, it is a combination of both sensory and emotional experiences. This has sometimes been translated clinically toward a more mechanistic approach to the assessment and treatment of pain instead of one that does not discount pain mechanisms, but also is more inclusive of the need for humanism - considering the individual. In today's medical environment, more than ever before there is a significant amount of attention being paid to educating clinicians to better understand that several physiological, neurophysiological, and psychosocial factors can significantly impact responses to pain. The composition of these factors will be unique to that individual's life narrative, context, sex, and prior life experiences. Thus, the concept that a templated approach to pain assessment and pharmacotherapeutic treatment planning should not be expected to provide optimal patient satisfaction and treatment outcomes in the majority. The hypotheses that there may be sex-based differences in the pain experience in a variety of ways including pain sensitivity, tolerance to pain, threshold at which something becomes painful, and the effectiveness of endogenous pain modulation systems are not new and have been well represented in the literature. This chapter reviews important key findings in the scientific literature with respect to sex-based differences in pain and pain responses to experimentally induced painful stimuli, pain experienced in commonly occurring painful medical conditions, and variations in responses to pain treatments. Possible explanations to account for observed differences or similarities will also be discussed.

INDIVIDUALIZED RISK ASSESSMENT OF PREOPERATIVE OPIOID USE BY INTERPRETABLE NEURAL NETWORK REGRESSION.

Preoperative opioid use has been reported to be associated with higher preoperative opioid demand, worse postoperative outcomes, and increased postoperative healthcare utilization and expenditures. Understanding the risk of preoperative opioid use helps establish patient-centered pain management. In the field of machine learning, deep neural network (DNN) has emerged as a powerful means for risk assessment because of its superb prediction power; however, the blackbox algorithms may make the results less interpretable than statistical models. Bridging the gap between the statistical and machine learning fields, we propose a novel Interpretable Neural Network Regression (INNER), which combines the strengths of statistical and DNN models. We use the proposed INNER to conduct individualized risk assessment of preoperative opioid use. Intensive simulations and an analysis of 34,186 patients expecting surgery in the Analgesic Outcomes Study (AOS) show that the proposed INNER not only can accurately predict the preoperative opioid use using preoperative characteristics as DNN, but also can estimate the patient-specific odds of opioid use without pain and the odds ratio of opioid use for a unit increase in the reported overall body pain, leading to more straight-forward interpretations of the tendency to use opioids than DNN. Our results identify the patient characteristics that are strongly associated with opioid use and is largely consistent with the previous findings, providing evidence that INNER is a useful tool for individualized risk assessment of preoperative opioid use.

A historical review of pain disparities research: Advancing toward health equity and empowerment.

BACKGROUND AND PURPOSE: This theory-guided review draws on 30 years of published data to examine and interrogate the current and future state of pain disparities research. METHODS: Using the Hierarchy of Health Disparity Research framework, we synthesize and present an overview of "three generations" of pain disparities scholarship, while proposing directions for adopting a "fourth generation" that redefines, explains, and theorizes future pain disparities research in a diverse society. DISCUSSION: Prior research has focused on describing the scope of disparities, and throughout the historical context of human existence, racialized groups have been subjected to inadequate pain care. It is imperative that research not only illuminates existing problems but also provides solutions that can be implemented and sustained across varying social milieus. CONCLUSION: We must invest in new theoretical models that expand on current perspectives and ideals that position all individuals at the forefront of justice and equity in their health.

Pain and functional recovery from chronic low back pain over 12 months: implications for osteopathic medicine.

CONTEXT: Although low back pain is a common medical condition that often progresses to become a chronic problem, little is known about the likelihood of recovery from chronic low back pain (CLBP). OBJECTIVES: This study aimed to measure the risk of recovery from CLBP based on low back pain intensity and back-related functioning measures reported by participants within a pain research registry over 12 months of observation and to consider the implications for osteopathic medicine. METHODS: A total of 740 participants with CLBP in the Pain Registry for Epidemiological, Clinical, and Interventional Studies and Innovation in the United States were studied between April 2016 and October 2021. Inception cohorts for pain recovery and functional recovery were assembled from the participants who did not meet the recovery criteria at registry enrollment. The pain recovery criterion was having a score of ≤1/10 on a numerical rating scale for low back pain intensity, and the functional recovery criterion was having a score of ≤4/24 on the Roland-Morris Disability Questionnaire. A total of 737 and 692 participants were included in the inception cohorts for pain recovery and functional recovery, respectively. Participants provided follow-up data at quarterly encounters over 12 months to determine if they achieved and maintained a pain or functional recovery from CLBP over the entire period of observation. Logistic regression was utilized to identify factors associated with recovery. RESULTS: The mean age of the participants at baseline was 52.9 years (SD, 13.1 years) and 551 (74.5%) were female. No participant reported a pain recovery that was maintained over all four quarterly encounters, whereas 16 participants (2.3%; 95% CI, 1.2-3.4%) maintained a functional recovery. Having high levels of pain self-efficacy (OR, 17.50; 95% CI, 2.30-133.23; p=0.006) and being Hispanic (OR, 3.55; 95% CI, 1.11-11.37; p=0.03) were associated with functional recovery, and high levels of pain catastrophizing (OR, 0.15; 95% CI, 0.03-0.65; p=0.01) and having chronic widespread pain (OR, 0.23; 95% CI, 0.08-0.66; p=0.007) were inversely associated with functional recovery. The findings for pain self-efficacy and Hispanic ethnicity remained significant in the multivariate analysis that adjusted for potential confounders. CONCLUSIONS: The absence of pain recovery and the low likelihood of functional recovery observed in our study suggests that osteopathic physicians should embrace a biopsychosocial approach to CLBP management and work with patients to set realistic expectations based on more pragmatic outcome measures, such as those that address health-related quality of life. The findings also suggest the potential importance of patient education and counseling to enhance pain self-efficacy.

Persistent and Chronic Perioperative Pain After Cancer Surgery.

PURPOSE OF REVIEW: Persistent and chronic pain after cancer surgery is a complex clinical problem. The etiology of pain in these cases is often multifactorial and, in addition to the surgery itself, can include or overlap with other painful syndromes such as direct effects of tumors, neuropathic pain, and pain syndromes secondary to chemotherapy and/or radiation. RECENT FINDINGS: There is a growing body of literature which suggests that treating pain in the acute and subacute periods can prevent chronic pain, an important step in reducing the morbidity of this clinical problem. This review describes the incidence of persistent pain after cancer surgery, its pathophysiology, and treatment considerations. Additional research on diagnostic criteria, pathophysiology, and novel medications, restorative therapies, and interventional treatments will be essential to continue to reduce the clinical burden of persistent and chronic perioperative pain after cancer surgery.

Exploring the Abilities of Peripheral Autonomic Parameters to Describe Pain: Another Dead End?

BACKGROUND: Pain is essential for survival, but it is also a major clinical, social, and economic problem that demands adequate management. The latter involves timely and accurate assessment, so several efforts have been made to develop accurate and reliable pain assessment tools. Advances in objective pain assessment include a large body of work focused on determining whether autonomic-mediated peripheral responses can be used to predict pain intensity. However, there is still no clinically validated autonomic marker for objective pain assessment. OBJECTIVES: In order to identify possible causes of this situation, the present study reviews the most recent advances examining peripheral autonomic markers' ability to describe pain intensity. STUDY DESIGN: Systematic literature review. METHODS: We conducted an online search on PubMed using terms such as "pain assessment," "experimental pain," "autonomic arousal," "heart rate," "heart rate variability," "electrodermal activity," "pupillary diameter," and "blood pressure." Articles published from 2010 through 2020 examining the abilities of peripheral autonomic markers to describe experimental pain intensity were collected and reviewed. From each of the included studies, we extracted information regarding autonomic parameters and stimulation modalities used by experimenters, as well as the sample size, gender, and health condition of the patients. RESULTS: Twenty-six articles were included for analysis, from which only 2 studies reported the use of multiple modalities. Half of the documents reported sample sizes ranging from 20 to 50 patients, and only 3 studies used formal power calculation to determine the sample size. Most of the articles included only healthy patients, so the influence of age, gender, and pre-existing health conditions on the autonomic peripheral parameters' capabilities to reflect the experience of pain remains unexplored. LIMITATIONS: It is possible that several documents were not retrieved due to a potential search engine bias or the use of very specific terms. Furthermore, only studies reporting pain intensity as a unique measure of its severity were included. CONCLUSION: The measurement of autonomic responses elicited by experimentally induced pain is one crucial step toward the development of reliable pain assessment tools. Still, several issues need to be addressed before continuing to explore the use of autonomic parameters for the assessment of pain. It is also recommended that future research endeavors in capturing the singularity of the pain experience involve the measurement of both peripheral (end organs) and central (brain) autonomic responses to pain.

Calcium imaging for analgesic drug discovery.

Somatosensation and pain are complex phenomena involving a rangeofspecialised cell types forming different circuits within the peripheral and central nervous systems. In recent decades, advances in the investigation of these networks, as well as their function in sensation, resulted from the constant evolution of electrophysiology and imaging techniques to allow the observation of cellular activity at the population level both in vitro and in vivo. Genetically encoded indicators of neuronal activity, combined with recent advances in DNA engineering and modern microscopy, offer powerful tools to dissect and visualise the activity of specific neuronal subpopulations with high spatial and temporal resolution. In recent years various groups developed in vivo imaging techniques to image calcium transients in the dorsal root ganglia, the spinal cord and the brain of anesthetised and awake, behaving animals to address fundamental questions in both the physiology and pathophysiology of somatosensation and pain. This approach, besides giving unprecedented details on the circuitry of innocuous and painful sensation, can be a very powerful tool for pharmacological research, from the characterisation of new potential drugs to the discovery of new, druggable targets within specific neuronal subpopulations. Here we summarise recent developments in calcium imaging for pain research, discuss technical challenges and advances, and examine the potential positive impact of this technique in early preclinical phases of the analgesic drug discovery process.

Preventing progression from chronic to widespread pain and its impact on health-related quality of life: a historical cohort study of osteopathic medical care.

CONTEXT: It is generally acknowledged that osteopathic physicians take a holistic approach to patient care. This style may help prevent the progression of painful musculoskeletal conditions, particularly if combined with osteopathic manipulative treatment (OMT). OBJECTIVES: The study aimed to determine if osteopathic medical care lowers the risk of progression from localized chronic low back pain to widespread pain and lessens the impact of pain on health-related quality of life. METHODS: A historical cohort study was conducted within the Pain Registry for Epidemiological, Clinical, and Interventional Studies and Innovation (PRECISION Pain Research Registry) using data acquired from April 2016 through March 2021. Registry participants aged 21-79 years with chronic low back pain at the baseline encounter were potentially eligible for inclusion if they had a treating physician, completed all four quarterly follow-up encounters, and did not report physician crossover at the final 12-month encounter. Eligible participants were classified according to the type of physician provider at baseline and thereby into osteopathic or allopathic medical care groups. Participants were also classified according to prior use of OMT at the final encounter. Widespread pain was measured at baseline and each quarterly encounter to determine the period prevalence rate of widespread pain and its severity over 12 months using the Minimum Dataset for Chronic Low Back Pain recommended by the National Institutes of Health. Participants who reported "not being bothered at all" by widespread pain during each encounter were classified as not having widespread pain, whereas those who were bothered "a little" or "a lot" at any quarterly encounter were classified as having widespread pain. The severity of widespread pain was measured by summing participant responses at each encounter. The Patient-Reported Outcomes Measurement Information System was used at each encounter to measure health-related quality-of-life (HRQOL) scores for physical function, anxiety, depression, fatigue, sleep disturbance, participation in social roles and activities, and pain interference with activities. RESULTS: A total of 462 participants were studied, including 101 (21.9%) in the osteopathic medical care group and 73 (15.8%) who used OMT. The mean age of participants at baseline was 52.7 ± 13.2 years (range, 22-79 years) and 336 (72.7%) were female. A lower period prevalence rate of widespread pain was observed in the osteopathic medical care group (OR, 0.47; 95% CI, 0.27-0.81; p=0.006) and in the OMT group (OR, 0.40; 95% CI, 0.21-0.75; p=0.004), although the latter finding did not persist after adjustment for potential confounders. The osteopathic medical care and OMT groups both reported lower widespread pain severity. The osteopathic medical care group also reported better age- and sex-adjusted outcomes for each of the seven HRQOL dimensions throughout the study. The OMT group reported better outcomes in five of the HRQOL dimensions. CONCLUSIONS: This study supports the view that osteopathic physicians practice a holistic approach to medical care that manifests itself through a lower risk of progression from chronic low back pain to widespread pain, lower widespread pain severity, and lesser deficits in HRQOL. Similar findings were generally associated with OMT use.

Whiplash-Associated Disorders. Biopsychosocial Profiles of Pain Perception in Forensic Cases of Victims of Motor Vehicle Accidents.

In order to make a complete diagnosis of all the factors influencing whiplash associated disorders (WAD), the evidence suggests that the condition evaluation should follow an integrated biopsychosocial model. This perspective would offer a fuller view of it, recognizing the interplay between the medical, biomechanical, social, and psychological factors. Despite the progress made in the subject, evidence of which psychosocial factors influence the experience of pain in litigant WAD patients is limited. A cross-sectional design and a cluster analysis was used to study the experience of pain and the psychosocial factors included therein in 249 patients with WAD assessed after suffering a motor vehicle accident. Three clusters were obtained: C1, with low scores of pain and a slight-moderate alteration of the Health-Related Quality of Life (HRQoL); C2, with medium scores of pain, alteration of HRQoL and a perception of moderate disability; and C3, with medium-high scores of pain, alteration of the HQoL, perception of moderate disability, presence of anxious-depressive symptomatology, poorer comprehension of the condition suffered, and the belief that it will extend over a long period of time. The results show a heterogeneous experience of pain in WAD, compatible with the biopsychosocial model of disease and the multidimensional approach to pain. The role of the psychologist in the evaluation of the condition could be useful to obtain a complete view of the condition, thus ensuring that the treatment is adapted to the needs of the patient.

Behavioral phenotyping of cancer pain in domesticated cats with naturally occurring squamous cell carcinoma of the tongue: initial validation studies provide evidence for regional and widespread algoplasticity.

Feline oral squamous cell carcinoma (FOSCC) is a common and naturally occurring condition that recapitulates many features of human head and neck cancer (HNC). In both species, there is need for improved strategies to reduce pain caused by HNC and its treatment. Research to benefit both species could be conducted using pet cats as a comparative model, but this prospect is limited by lack of validated methods for quantifying FOSCC-associated pain. A prospective non-randomized pilot study was performed for initial validation of: (1) a pet owner administered quality of life questionnaire and visual assessment scoring tool (FORQ/CLIENT); (2) a clinician assessment questionnaire (UFEPS/VET); (3) electronic von Frey testing [EVF]; and (4) Cochet-Bonnet (COBO) aesthesiometry. To assess intra-rater reliability, discriminatory ability, and responsiveness of each assay, 6 cats with sublingual SCC and 16 healthy control cats were enrolled. The intra-rater reliability was moderate-to-good for the clinical metrology instruments and EVF (intraclass correlation coefficient [ICC] ≥ 0.68), but poor for COBO (ICC = 0.21). FORQ/CLIENT scores were higher (worse quality of life) in FOSCC cats vs healthy controls. The internal reliability of FORQ/CLIENT scoring was high (Cronbach α = 0.92); sensitivity and specificity were excellent (100% when using cut-offs determined using receiver operating characteristic [ROC] curves). For the FORQ/CLIENT, there was strong and inverse correlation between scores from the questions and visual assessment (r =  - 0.77, r 2 = 0.6, P < 0.0001). For the UFEPS/VET, Cronbach's α was 0.74 (high reliability). Sensitivity and specificity were 100% and 94%, respectively, when using a cut-off score (3.5) based on ROC curves (Youden index of 0.94). Total UFEPS/VET scores were positively correlated with FORQ/CLIENT scores (r 2 = 0.72, P < 0.0001). Sensitivity of EVF and COBO ranged from 83 to 100% and specificity ranged from 56 to 94%. Cats with cancer were more sensitive around the face (lower response thresholds) and on the cornea (longer filament lengths) than control animals (P < 0.03). Reduced pressure response thresholds were also observed at a distant site (P = 0.0002) in cancer cats. After giving buprenorphine, EVF pressure response thresholds increased (P = 0.04) near the mandible of cats with OSCC; the length of filament required to elicit a response in the COBO assay also improved (shortened; P = 0.017). Based on these preliminary assessments, the assays described herein had reasonable inter-rater reliability, and they were able to both discriminate between cats with and without oral cancer, and respond in a predictable manner to analgesic therapy. In cats with tongue cancer, there was evidence for regional peripheral sensitization, and widespread somatosensory sensitization. These results provide a basis for multi-dimensional assessments of pain and sensitivity in cats with oral SCC.

Patient-centered care or osteopathic manipulative treatment as mediators of clinical outcomes in patients with chronic low back pain.

CONTEXT: Patient-centered care is often considered a characteristic of osteopathic medicine, in addition to the use of osteopathic manipulative treatment (OMT) in such musculoskeletal conditions as low back pain. OBJECTIVES: This study aimed to determine if patient-centered care or OMT are mediators of the clinical outcomes of osteopathic medicine in patients with chronic low back pain. METHODS: A comparative effectiveness study was conducted within the Pain Registry for Epidemiological, Clinical, and Interventional Studies and Innovation (PRECISION Pain Research Registry). Eligible patients met the diagnostic criteria recommended by the National Institutes of Health Task Force on Research Standards for Chronic Low Back Pain and completed four consecutive quarterly encounters between April 2016 and November 2020. The Consultation and Relational Empathy instrument for patient-centered care was used at the baseline encounter and OMT use was measured at the final encounter. The clinical outcome measures included low back pain intensity on a numerical rating scale (NRS) from 0 to 10, back-related functioning on the Roland-Morris Disability Questionnaire (RMDQ), and pain impact on the National Institutes of Health Minimum Dataset for Chronic Low Back Pain (NIH-MDS). A parallel multiple mediator model was used to compute the direct and indirect effects of osteopathic medicine in achieving each of the three clinical outcomes. RESULTS: The 404 study patients had a mean age of 52.2 years (standard deviation, 13.1 years) and 288 (71.3%) were female. The 88 (21.8%) patients treated by osteopathic physicians reported more favorable scores for patient-centered care (mean, 41.3; 95% CI 39.0-43.5) than patients treated by allopathic physicians (mean, 38.0; 95% CI 36.8-39.3) (p=0.02). Fifty-six (63.6%) patients treated by osteopathic physicians used OMT. The age- and sex-adjusted outcomes for patients of osteopathic vs. allopathic physicians across all four encounters were: mean, 5.4; 95% CI 5.0-5.7 vs. mean, 5.9; 95% CI 5.7-6.1 on the NRS for pain intensity (p=0.01); mean, 11.3; 95% CI 10.1-12.6 vs. mean, 14.0; 95% CI 13.3-14.7 on the RMDQ for back-related disability (p<0.001); and mean, 26.8; 95% CI 24.9-28.7 vs. mean, 30.1; 95% CI 29.1-31.1 on the NIH-MDS for pain impact (p=0.002). Patient-centered care did not mediate any outcome of osteopathic medicine, whereas OMT mediated better outcomes in low back pain intensity. CONCLUSIONS: This appears to be the first study to simultaneously address both patient-centered care and OMT as potential mediators of the effect of osteopathic medicine in treating chronic pain. Patient-centered care did not mediate the effects of osteopathic medicine and OMT only mediated outcomes relating to low back pain intensity. More research is needed to identify other aspects of osteopathic medicine that mediate its beneficial effects in patients with chronic low back pain.

Identifying patients with chronic pain who respond to acupuncture: results from an individual patient data meta-analysis.

BACKGROUND: In a recent individual patient data meta-analysis, acupuncture was found to be superior to sham and non-sham controls in patients with chronic pain. It has been suggested that a subgroup of patients has an exceptional response to acupuncture. We hypothesized the presence of exceptional acupuncture responders would lead to a different distribution of pain scores in acupuncture versus control groups, with the former being skewed to the right. METHODS: This individual patient data meta-analysis included 39 high-quality randomized trials of acupuncture for chronic headache, migraine, osteoarthritis, low back pain, neck pain and shoulder pain published before December 2015 (n = 20,827). In all, 25 involved sham acupuncture controls (n = 7097) and 25 non-acupuncture controls (n = 16,041). We analyzed the distribution of change scores and calculated the difference in the skewness statistic-which assesses asymmetry in the data distribution-between acupuncture and either sham or non-acupuncture control groups. We then entered the difference in skewness along with standard error into a meta-analysis. FINDINGS: Control groups were more right-skewed than acupuncture groups, although this difference was very small. The difference in skew was 0.124 for non-acupuncture-controlled trials (p = 0.047) and 0.141 for sham-controlled trials (p = 0.029). In a pre-specified sensitivity analysis excluding three trials with outlying results known a priori, the difference in skew between acupuncture and sham was no longer statistically significant (p = 0.2). CONCLUSION: We did not find evidence to support the notion that there are exceptional acupuncture responders. The challenge remains to identify features of chronic pain patients that can be used to distinguish those that have a good response to acupuncture treatment.

[Pain prevention: what is in the pipeline?] / Schmerzprävention ­ was ist in der Pipeline?

Approximately 10% of the German population report chronic pain that has at least a moderate influence on everyday life. For instance, patients in Germany often experience an oversupply of diagnostics and therapy when suffering from mild back pain, while the care of patients with severe, chronic pain remains insufficient. Multimodal and interdisciplinary therapies are generally too seldomly used. Potentially preventive procedures are insufficiently investigated and used in current clinical practice and little is known about the mechanisms underlying chronification processes. In Germany, pain is still largely neglected in current clinical and basic science, as well as research funding. Furthermore, existing projects are often insufficiently connected with each other, thereby missing the unique opportunity of building synergies. To improve medical pain care and to enable participation in activities of daily life with the maximum radius, interdisciplinary clinical programs and cross-linking of basic and clinical research is necessary. The main objectives are to: (1) Strengthen basic research to investigate the underlying mechanisms of pain development and maintenance as well as of chronification processes; (2) improve patient care by adequate application of diagnostic, therapeutic, and preventive procedures; (3) consolidate interdisciplinarity in pain research and patient care; (4) maintain participation of patients in social and in everyday life; and (5) achieve and maintain high quality standards in pain patient care. The following article provides an overview of the measures and advances currently being taken in pain research in Germany to close the above-mentioned gaps. The focus lies on current and future developments in the field of pain prevention.

Application of Referencing Techniques in EEG-Based Recordings of Contact Heat Evoked Potentials (CHEPS).

Evoked potentials in the amplitude-time spectrum of the electroencephalogram are commonly used to assess the extent of brain responses to stimulation with noxious contact heat. The magnitude of the N- and P-waves are used as a semi-objective measure of the response to the painful stimulus: the higher the magnitude, the more painful the stimulus has been perceived. The strength of the N-P-wave response is also largely dependent on the chosen reference electrode site. The goal of this study was to examine which reference technique excels both in practical and theoretical terms when analyzing noxious contact heat evoked potentials (CHEPS) in the amplitude-time spectrum. We recruited 21 subjects (10 male, 11 female, mean age of 55.79 years). We applied seven noxious contact heat stimuli using two temperatures, 51°C, and 54°C, to each subject. During EEG analysis, we aimed to identify the referencing technique which produces the highest N-wave and P-wave amplitudes with as little artifactual influence as possible. For this purpose, we applied the following six referencing techniques: mathematically linked A1/A2 (earlobes), average reference, REST, AFz, Pz, and mathematically linked PO7/PO8. We evaluated how these techniques impact the N-P amplitudes of CHEPS based on our data from healthy subjects. Considering all factors, we found that mathematically linked earlobes to be the ideal referencing site to use when displaying and evaluating CHEPS in the amplitude-time spectrum.