The journal of pain : official journal of the American Pain Society
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Review Meta Analysis
Effects of yoga interventions on pain and pain-associated disability: a meta-analysis.
We searched databases for controlled clinical studies, and performed a meta-analysis on the effectiveness of yoga interventions on pain and associated disability. Five randomized studies reported single-blinding and had a higher methodological quality; 7 studies were randomized but not blinded and had moderate quality; and 4 nonrandomized studies had low quality. In 6 studies, yoga was used to treat patients with back pain; in 2 studies to treat rheumatoid arthritis; in 2 studies to treat patients with headache/migraine; and 6 studies enrolled individuals for other indications. All studies reported positive effects in favor of the yoga interventions. With respect to pain, a random effect meta-analysis estimated the overall treatment effect at SMD = -.74 (CI: -.97; -.52, P < .0001), and an overall treatment effect at SMD = -.79 (CI: -1.02; -.56, P < .0001) for pain-related disability. Despite some limitations, there is evidence that yoga may be useful for several pain-associated disorders. Moreover, there are hints that even short-term interventions might be effective. Nevertheless, large-scale further studies have to identify which patients may benefit from the respective interventions. ⋯ This meta-analysis suggests that yoga is a useful supplementary approach with moderate effect sizes on pain and associated disability.
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The qualities of chronic neuropathic pain (NeP) may be informative about the different mechanisms of pain. We previously developed a 2-factor model of NeP that described an underlying structure among sensory descriptors on the Short-Form McGill Pain Questionnaire. The goal of this study was to confirm the correlated 2-factor model of NeP. Individual descriptive scores from the Short-Form McGill Pain Questionnaire were analyzed. Confirmatory factor analysis was used to test a correlated 2-factor model. Factor 1 (stabbing pain) was characterized by high loadings on stabbing, sharp, and shooting sensory items; factor 2 (heavy pain) was characterized by high loadings on heavy, gnawing, and aching items. Results of the confirmatory factor analysis strongly supported the correlated 2-factor model. ⋯ This article validates a model that describes the qualities of neuropathic pain associated with diabetic peripheral neuropathy and postherpetic neuralgia. These data suggest that specific pain qualities may be associated with pain mechanisms or may be useful for predicting treatment response.
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Recent reports suggest deficits in conditioned pain modulation (CPM) and enhanced suprathreshold heat pain response (SHPR) potentially play a role in the development of chronic pain. The purpose of this study was to investigate whether central pain processing was altered in 2 musculoskeletal shoulder pain models. The goals of this study were to determine whether central pain processing: 1) differs between healthy subjects and patients with clinical shoulder pain; 2) changes with induction of exercise-induced muscle pain; and 3) changes 3 months after shoulder surgery. Fifty-eight patients with clinical shoulder pain and 56 age- and sex-matched healthy subjects were included in these analyses. The healthy cohort was examined before inducing EIMP, and 48 and 96 hours later. The clinical cohort was examined before shoulder surgery and 3 months later. CPM did not differ between the cohorts, however; SHPR was elevated for patients with shoulder pain compared to healthy controls. Induction of acute shoulder pain with EIMP resulted in increased shoulder pain intensity but did not change CPM or SHPR. Three months following shoulder surgery, clinical pain intensity decreased but CPM was unchanged from preoperative assessment. In contrast, SHPR was decreased and showed values comparable with healthy controls at 3 months. Therefore, the present study suggests that: 1) clinical shoulder pain is associated with measurable changes in central pain processing; 2) exercise-induced shoulder pain did not affect measures of central pain processing; and 3) elevated SHPR was normalized with shoulder surgery. Collectively our findings support neuroplastic changes in pain modulation were associated with decreases in clinical pain intensity only, and could be detected more readily with thermal stimuli. ⋯ Longitudinal studies involving quantitative sensory testing are rare. In exploring 2 musculoskeletal shoulder pain models (exercise-induced muscle pain and surgical pain), conditioned pain modulation was unchanged from pre- to post-assessment in both models. Suprathreshold heat pain response decreased after shoulder surgery and was comparable to healthy controls, suggesting this measure may be sensitive to decreases in clinical pain intensity.
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Complex Regional Pain Syndrome (CRPS) is a chronic and often disabling pain disorder. There is evidence demonstrating that neurogenic inflammation and activation of the immune system play a significant role in the pathophysiology of CRPS. This study evaluated the plasma levels of cytokines, chemokines, and their soluble receptors in 148 subjects afflicted with CRPS and in 60 gender- and age-matched healthy controls. Significant changes in plasma cytokines, chemokines, and their soluble receptors were found in subjects with CRPS as compared with healthy controls. For most analytes, these changes resulted from a distinct subset of the CRPS subjects. When the plasma data from the CRPS subjects was subjected to cluster analysis, it revealed 2 clusters within the CRPS population. The category identified as most important for cluster separation by the clustering algorithm was TNFα. Cluster 1 consisted of 64% of CRPS subjects and demonstrated analyte values similar to the healthy control individuals. Cluster 2 consisted of 36% of the CRPS subjects and demonstrated significantly elevated levels of most analytes and in addition, it showed that the increased plasma analyte levels in this cluster were correlated with disease duration and severity. ⋯ The identification of biomarkers that define disease subgroups can be of great value in the design of specific therapies and of great benefit to the design of clinical trials. It may also aid in advancing our understanding of the mechanisms involved in the pathophysiology of CRPS, which may lead to novel treatments for this very severe condition.
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Randomized Controlled Trial
Training for general practitioners in opioid prescribing for chronic pain based on practice guidelines: a randomized pilot and feasibility trial.
This study is a pilot and feasibility study that compares 2 training experiences to improve appropriate opioid prescribing for chronic pain. Both training conditions included education in relation to opioid guidelines. Following education, 1 condition included training aimed at improving psychological flexibility and the other included training in practical knowledge and skills related to pain management. Eighty-one general practitioners (GPs) took part in the study, each having been randomly assigned to 1 of the training conditions. It proved easy to recruit GPs to the training. Overall, GPs demonstrated increased knowledge of opioid prescribing for chronic pain and decreases in concerns related to prescribing following training. However, there were no changes observed in reported prescribing practices or in secondary measures of well-being. There were also no significant differences between the training conditions, other than a greater increase in intention to use prescribing guidelines in the psychological flexibility condition. Feasibility and acceptability of the training methods were generally rated high. The psychological flexibility condition was rated higher than the comparison condition in terms of interest and satisfaction. Finally, processes of psychological flexibility before and after training significantly correlated with measures of GP well-being, providing partial support for the relevance of these processes as a focus in GP training. ⋯ A training intervention for GPs including education on opioid guidelines for chronic pain and psychological flexibility training increased knowledge of prescribing and reduced concerns but did not change prescribing behavior or well-being. The training was highly acceptable to GPs but may have been too short to produce other effects.