Pain
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Review Meta Analysis
Persistent postoperative pain after cardiac surgery: a systematic review with meta-analysis regarding incidence and pain intensity.
Persistent postoperative pain (PPP) has been described as a complication of cardiac surgery (CS). We aimed to study PPP after CS (PPPCS) by conducting a systematic review of the literature regarding its incidence, intensity, location, and the presence of neuropathic pain, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The review comprised 3 phases: a methodological assessment of 6 different databases identifying potential articles and screening for inclusion criteria by 2 independent reviewers; data extraction; and study quality assessment. ⋯ Chest is the main location of PPPCS followed by the leg; neuropathic pain is present in the majority of the patients. This is the first systematic review and meta-analysis to provide estimates regarding incidence and intensity of PPPCS, which elucidates its relevance. There is an urgent need for adequate treatment and follow-up in patients with PPPCS.
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Long noncoding RNAs have been implicated in neuropathy. Here, we identify and validate a long noncoding RNA, MRAK009713, as the primary regulator of neuropathic pain in chronic constriction injury (CCI) rats. MRAK009713 expression was markedly increased in CCI rats associated with enhanced pain behaviors, and small interfering RNA against MRAK009713 significantly reduced both mechanical and thermal hyperalgesia in the CCI rats. ⋯ Overexpression of MRAK009713 markedly increased expression of P2X3 in the dorsal root ganglia of the control rats, and MRAK009713 small interfering RNA significantly inhibited the P2X3 expression in the dorsal root ganglia of the CCI rats. MRAK009713 directly interacted with the P2X3 protein heterologously expressed in the human embryonic kidney (HEK) 293 cells and potentiated P2X3 receptor function. Thus, MRAK009713 is a novel positive regulator of neuropathic pain in rats through regulating the expression and function of the P2X3 receptor.
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Randomized Controlled Trial
Placebo effects of a sham opioid solution: a randomized controlled study in patients with chronic low back pain.
This study tested the experimental placebo effect in a group of chronic pain patients. Forty-eight patients having chronic back pain participated in a randomized clinical trial that tested the efficacy of a sham opioid solution (NaCl) compared with an alleged neutral, completely inactive solution (NaCl). We shaped the placebo effect by 2 interventions: verbal instruction and conditioning. ⋯ The inactive solution (NaCl), when presented as an effective treatment (sham "opioid" solution), induced placebo analgesia as evident in lower ratings of the patients' clinical back pain (F(3.12,144.21) = 25.05, P < 0.001), acute pain ratings (F(1.99,87.40) = 18.12, P < 0.01), and time needed to complete a series of daily activities exercises (F(1,44) = 8.51, P < 0.01) as well as increased functional capacity (F(1,44.00) = 19.42, P < 0.001). The 2 manipulations (instruction and conditioning) changed pain expectations, and they were maintained in both sham opioid groups. The results suggest that it may be clinically useful to explicitly integrate placebo analgesia responses into pain management.
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Child and parent pain catastrophizing are reported preoperative risk factors for children's acute and persistent postsurgical pain. This study examined dyadic relations between child and parent pain catastrophizing and child and parent ratings of child pain prior to (M = 4.01 days; "baseline") and following surgery (M = 6.5 weeks; "acute follow-up"), as well changes in pain catastrophizing during this time in 167 youth (86% female; Mage = 14.55 years) undergoing spinal fusion surgery and 1 parent (89% mothers). Actor-partner interdependence models assessed cross-sectional and longitudinal intra- and interpersonal effects. ⋯ Baseline child and parent pain catastrophizing did not predict child pain at acute follow-up. In conclusion, child, not parent, pain catastrophizing was associated with children's pre- and postsurgical pain, and showed significantly less stability over time. There is a need to better understand contributors to the stability or changeability of pain catastrophizing, the prospective relation of catastrophizing to pain, and contexts in which child vs parent pain catastrophizing is most influential for pediatric postsurgical pain.
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Multicenter Study
Brain signature and functional impact of centralized pain: a Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Network Study.
Chronic pain is often measured with a severity score that overlooks its spatial distribution across the body. This widespread pain is believed to be a marker of centralization, a central nervous system process that decouples pain perception from nociceptive input. Here, we investigated whether centralization is manifested at the level of the brain using data from 1079 participants in the Multidisciplinary Approach to the Study of Chronic Pelvic Pain Research Network (MAPP) study. ⋯ Widespread pain was also associated with reduced physical and mental function independent of pain severity. Brain pathology in patients with centralized pain is related to pain distribution throughout the body. These patients may benefit from interventions targeting the central nervous system.