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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This study reports the results of a researcher-administered survey with 115 patients receiving chronic opioid therapy (>90 days) to obtain information regarding how chronic opioid therapy was started. Chronic opioids were started after surgery (27.0%, 95% confidence interval [CI], 18.5-35.5) or for the treatment of acute injury-related pain (27.0%, 95% CI, 18.5-35.5). Many who initiated opioid therapy after surgery reported postoperative complications (61.3%, 95% CI, 50.8-71.8) and many with injury-related pain reported follow-up corrective surgery (58.1%, 95% CI, 47.5-68.7), which led to the continuation of opioids. ⋯ Patients receiving long-term opioid therapy often transitioned to chronic use after starting opioids for the short-term treatment of postoperative or injury-related pain. It is not evident if a clear decision to continue opioids on a chronic basis was made. This survey provides insight as to how chronic opioid therapy is started, and may suggest opportunities for improved patient selection for opioid therapy.
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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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Migraine with aura is a subtype of migraine characterized by transient neurological disturbances that usually precede headache. Cortical spreading depression (CSD) is the likely pathophysiological correlate of the aura phase of migraine, found in common and rare forms of migraine, such as familial hemiplegic migraine. CSD is a depolarization wave that propagates across the cerebral gray matter transiently suppressing neuronal activity. ⋯ In brainstem, CSD with and without treatment, although to a lesser extent, also induced gene expression changes involving genes related to apoptosis. Half of the genes altered in brainstem after CSD were also differentially expressed in the same direction in cortex. No differences in gene expression were identified after CSD as a consequence of the treatments, neither in cortex nor in brainstem.