The journal of pain : official journal of the American Pain Society
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Evidence suggests that the effect of cigarette smoking on chronic pain is stronger in younger than older adults. This case-control study investigated whether age modified an effect of smoking on temporomandibular disorder (TMD) in 299 females aged 18 to 60 years. It also investigated the extent to which this relationship was explained by psychological profile, inflammatory response, and allergy. Cases were defined using the Research Diagnostic Criteria for Temporomandibular Disorders based on clinical examination. Psychological profile was evaluated using standardized instruments. Inflammatory response was evaluated with 11 cytokines isolated in plasma. History of allergy conditions was self-reported. Odds ratios (ORs) for the effect of smoking were calculated using binary logistic regression. Stratified analyses and the likelihood ratio test examined effect modification by smoking. Compared with nonsmokers, ever smokers aged <30 years had higher odds of TMD (OR = 4.14, 95% CI: 1.57, 11.35) than older adults (OR = 1.23, 95% CI: .55, 2.78) (P (effect modification) = .038). Adjustment for psychological profile, cytokines, and history of allergy-like conditions attenuated the effect by 45% to statistical nonsignificance. The main finding was reproduced with secondary analyses of 2 nationally representative surveys of adults conducted in the US and Australia. ⋯ This study showed that smoking was associated with TMD risk in females, but only in young adulthood. It replicated this finding in 2 nationally representative surveys of females in the US and Australia. Findings may alert clinicians to recognize that smoking is a concern for TMD in younger female patients.
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Randomized Controlled Trial
Test order of quantitative sensory testing facilitates mechanical hyperalgesia in healthy volunteers.
Quantitative sensory testing (QST) has become a widely used method to evaluate different submodalities of the somatic sensory system (predominantly) in patients with neuropathic pain. QST consists of 7 tests measuring 13 parameters in order to assess and quantify the perception of temperature, touch, pain, pressure, and vibration. The German Research Network on Neuropathic Pain implemented a standardized QST protocol including a defined testing order of the measurements. Accordingly, subjects tested with QST undergo thermal before mechanical testing. In the present study, we investigated the effect of testing order on the results of QST. Twenty healthy subjects were tested twice, 1 week apart with 2 different QST testing orders: the standardized testing order according to the German Research Network on Neuropathic Pain and a modified testing order in which mechanical stimuli were applied before thermal stimuli. For the test protocol that began with thermal testing, subjects exhibited signs of an increased mechanical perception: The mechanical pain sensitivity was significantly increased (P = .001, Wilcoxon test) for each pinprick stimulator and the mechanical pain threshold was lowered by a factor of 2 when compared with the modified testing order in which mechanical parameters were tested at the beginning of the session without prior thermal stimulation. Thermal parameters were the same for both test-order paradigms. These data indicate that preceding mild thermal stimulation might lead to a sensitization to mechanical stimuli and thus to mechanical hyperalgesia. Alternative habituation mechanisms in the modified testing order resulting from repeated pinprick stimulation at the beginning should also be debated. QST is a helpful diagnostic tool but interpretation should be done with consideration of interaction between test parameters. Reference data are only valid in the testing order from which they are obtained. ⋯ Present data showed that mechanical hyperalgesia followed thermal testing. This article demonstrates that the test order of quantitative sensory testing is relevant in interpreting the results obtained. Reference values are suitable in the test order from which they are obtained.
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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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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.
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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.