The journal of pain : official journal of the American Pain Society
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Comparative Study
Mild social stress in mice produces opioid-mediated analgesia in visceral but not somatic pain states.
Visceral pain has a greater emotional component than somatic pain. To determine if the stress-induced analgesic response is differentially expressed in visceral versus somatic pain states, we studied the effects of a mild social stressor in either acute visceral or somatic pain states in mice. We show that the presence of an unfamiliar conspecific mouse (stranger) in an adjacent cubicle of a standard transparent observation box produced elevated plasma corticosterone levels compared with mice tested alone, suggesting that the mere presence of a stranger is stressful. ⋯ Compared with mice tested alone, the presence of a stranger produced a dramatic opioid-dependent reduction in pain behavior associated with visceral but not somatic pain. This social stress-induced reduction of visceral pain behavior relied on visual but not auditory/olfactory cues. These findings suggest that visceral pain states may provoke heightened responsiveness to mild stressors, an effect that could interfere with testing outcomes during simultaneous behavioral testing of multiple rodents.
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Review Meta Analysis
Prevalence and predictors of chronic postsurgical pain in children: A systematic review and meta-analysis.
Emerging research suggests that pain may persist longer-term for many children after major surgery, with significant effects on their health outcomes. This systematic review identified the prevalence of chronic postsurgical pain (CPSP) in children after surgery, and determined presurgical biomedical and psychosocial risk factors associated with CPSP prevalence or severity. Prospective studies assessing CPSP 3 to 12 months after surgery in children 6 to 18 years of age published in English in MedLine, EMBASE, PsycINFO, and Cochrane Database of Systematic Reviews since 1996 were eligible for inclusion. Of 16,084 abstracts yielded by the search, 123 full articles were assessed for eligibility, and 12 studies were included in the review. Overall quality of included studies assessed using the Quality in Prognostic Studies tool was low. On the basis of 4 studies with a total of 628 participants across all surgery types, median prevalence of CPSP across studies was 20% (25th percentile = 14.5%, 75th percentile = 38%) at 12 months after surgery. Presurgical pain intensity, child anxiety, child pain coping efficacy, and parental pain catastrophizing were the only presurgical factors identified as predictive of CPSP. Biological and medical factors assessed were not associated with CPSP in any study. Well designed studies examining prevalence and predictors of CPSP are critically needed in children. ⋯ In this systematic review, the median prevalence of CPSP in children was 20% across studies. Presurgical pain intensity, and child and parent psychosocial factors predicted CPSP. Additional resources and interventions are needed for youth who report persistent pain after surgery.
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Comparative Study
The Value of Prognostic Screening for Patients With Low Back Pain in Secondary Care.
Prognostic screening in patients with low back pain (LBP) offers a practical approach to guiding clinical decisions. Whether screening is helpful in secondary care is unclear. This prospective cohort study in adults with LBP placed on outpatient clinic waiting lists, compared the performance of the short-form Orebro Musculoskeletal Pain Screening Questionnaire, the Predicting the Inception of Chronic Pain Tool, and the STarT Back Tool. ⋯ All instruments were miscalibrated and underestimated risk. The decision curve analysis indicated that, in this setting, prognostic screening does not add value over and above a treat-all approach. The potential for LBP patients to be misclassified using screening and the high incidence of nonrecovery indicate that care decisions should be made with the assumption that all patients are 'at risk.'
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Most previous transient receptor potential vanilloid subtype 1 (TRPV1) antagonist programs have been put on hold, mainly because of on-target adverse events: hyperthermia and impaired noxious heat sensation. NEO6860 is a TRPV1 antagonist, blocking capsaicin activation of the target, with little or no effect against pH or heat activation. The hypothesis is that this pharmacological profile will translate into analgesia without undesired effects on the body temperature or heat-pain threshold. ⋯ Unlike other TRPV1 antagonists, no clinically significant increase in temperature or heat pain threshold/tolerance was noted despite thorough and specific monitoring of these parameters. At all doses, most subjects reported a sensation of "feeling hot," with a rapid onset and transient. NEO6860 showed an improvement in the pharmacodynamics parameters (evoked pain and secondary hyperalgesia) at 3 and 8 hours post NEO6860 dosing.
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Approximately 20% of children develop persistent pain after major surgery. Sleep disruption has been implicated as a predictor of children's acute postsurgical pain. However, perioperative sleep patterns have not been longitudinally assessed, and the role of sleep in persistence of postsurgical pain has not been explored. ⋯ Poorer night-time sleep quality was significantly associated with greater next day pain intensity (B = -.15, P = .005). Sleep duration and efficiency were not associated with subsequent pain; daytime pain was not associated with subsequent sleep. Findings suggest sleep quality may be an important target for intervention after surgery in children; research is needed to understand how other sleep parameters may relate to recovery.