The journal of pain : official journal of the American Pain Society
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The objective was to perform an economic evaluation comparing spinal cord stimulation (SCS) in combination with best medical treatment (BMT) with BMT in painful diabetic peripheral neuropathy patients. Alongside a prospective 2-center randomized controlled trial, involving 36 painful diabetic peripheral neuropathy patients with severe lower limb pain not responding to conventional therapy, an economic evaluation was performed. Incremental cost-effectiveness ratios were based on: 1) societal costs and quality-adjusted life years (QALYs), and 2) direct health care costs and the number of successfully treated patients, respectively, both with a time horizon of 12 months. ⋯ Secondary analyses showed that cost-effectiveness of SCS became more favorable after correcting for baseline cost imbalance between the 2 groups, extending the depreciation period of SCS material to 4 years, and extrapolation of the data up to 4 years. Although SCS was considerably more effective compared with BMT, the substantial initial investment that is required resulted in SCS not being cost-effective in the short term. Cost-effectiveness results were sensitive to baseline cost imbalances between the groups and the depreciation period of the SCS material.
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Pain catastrophizing has emerged as one of the most robust predictors of child pain outcomes. Although assessments of state (ie, situation-specific) pain catastrophizing in children and parents are often used, their psychometric properties are unknown. This study aimed to assess factor structure, reliability, and predictive validity of state versions of Pain Catastrophizing Scales for children and parents relative to corresponding trait versions for child and parental pain-related outcomes. ⋯ Hierarchical linear regression analyses were used to examine relative influence of state versus trait catastrophizing on child and parent pain-related outcomes. Child and parent state catastrophizing were significantly associated with child pain intensity, child state anxiety and parental distress. State catastrophizing scores showed stronger associations than trait scores for most outcomes.
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Incongruence of pain severity ratings among people experiencing pain and their observers has been linked to psychological distress. Previous studies have measured pain rating congruence through static self-report, involving a single rating of pain; however, this method does not capture changes in ratings over time. The present study examined the extent to which partners were congruent on multiple ratings of a participants' pain severity during the cold pressor task. ⋯ On average, observers rated participants' pain as less severe than participants' rated their own pain. In addition, congruence between partners increased over time because of observers' ratings becoming more similar to participant's ratings. Finally, pain catastrophizing and perceived threat independently and jointly influenced the degree to which partners similarly rated the participant's pain.
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We have recently shown that spinal sigma-1 receptor (Sig-1R) activation facilitates nociception via an increase in phosphorylation of the N-methyl-D-aspartate (NMDA) receptor GluN1 subunit (pGluN1). The present study was designed to examine whether the Sig-1R-induced facilitative effect on NMDA-induced nociception is mediated by D-serine, and whether D-serine modulates spinal pGluN1 expression and the development of neuropathic pain after chronic constriction injury (CCI) of the sciatic nerve. Intrathecal administration of the D-serine degrading enzyme, D-amino acid oxidase attenuated the facilitation of NMDA-induced nociception induced by the Sig-1R agonist, 2-(4-morpholinethyl)1-phenylcyclohexane carboxylate. Exogenous D-serine increased protein kinase C (PKC)-dependent (Ser896) pGluN1 expression and facilitated NMDA-induced nociception, which was attenuated by preteatment with the PKC inhibitor, chelerythrine. In CCI mice, administration of the serine racemase inhibitor, L-serine O-sulfate potassium salt or D-amino acid oxidase on postoperative days 0 to 3 suppressed CCI-induced mechanical allodynia (MA) and pGluN1 expression on day 3 after CCI surgery. Intrathecal administration of D-serine restored MA as well as the GluN1 phosphorylation on day 3 after surgery that was suppressed by the Sig-1R antagonist, N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(dimethylamino)ethylamine dihydrobromide or the astrocyte inhibitor, fluorocitrate. In contrast, D-serine had no effect on CCI-induced thermal hyperalgesia or GluN1 expression. These results indicate that spinal D-serine: 1) mediates the facilitative effect of Sig-1R on NMDA-induced nociception, 2) modulates PKC-dependent pGluN1 expression, and 3) ultimately contributes to the induction of MA after peripheral nerve injury. ⋯ This report shows that reducing D-serine suppresses central sensitization and significantly alleviates peripheral nerve injury-induced chronic neuropathic pain and that this process is modulated by spinal Sig-1Rs. This preclinical evidence provides a strong rationale for using D-serine antagonists to treat peripheral nerve injury-induced neuropathy.
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Bone fracture with subsequent immobilization of the injured limb can cause complex regional pain syndrome (CRPS) in humans. Mechanisms of CRPS are still not completely understood but bone fracture with casting in mice leads to a similar post-traumatic inflammation as seen in humans and might therefore be an analog to human CRPS. In this article we report behavioral and spinal electrophysiological changes in mice that developed swelling of the paw, warming of the skin, and pain in the injured limb after bone fracture. ⋯ In all mice tested, all signs subsided 12 weeks after trauma. Our data suggest a significant reorganization of spinal circuitry after limb trauma, in a degree more comprehensive than most models of neuropathies. This process seems to be reversible in the rodent.