Pain
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Randomized Controlled Trial Comparative Study
Motor cortex stimulation for long-term relief of chronic neuropathic pain: a 10 year experience.
Chronic subthreshold stimulation of the contralateral precentral gyrus is used in patients with intractable neuropathic pain for more than 15 years. The aim of this study was to analyse retrospectively our own patient group with long term follow-up of 10 years. Seventeen patients with chronic neuropathic pain were treated with contralateral epidural stimulation electrodes. ⋯ Double-blind testing can identify non-responders. Patients with TNP profit more than patients with PSP. The positive effect can last for ten years in long-term follow-up.
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Randomized Controlled Trial Comparative Study Clinical Trial
Loss of expectation-related mechanisms in Alzheimer's disease makes analgesic therapies less effective.
Expectation/placebo-related mechanisms and specific effects of therapies show additive effects, such that a therapy is less effective if the placebo component is absent. So far, the placebo component has been disrupted experimentally by using covert administrations of treatments. Here, we show for the first time that disruption of expectation/placebo-related analgesic mechanisms may occur in a clinical condition, Alzheimer's disease (AD). ⋯ We also found that the disruption of the placebo component occurred when reduced connectivity of the prefrontal lobes with the rest of the brain was present. Remarkably, the loss of these placebo-related mechanisms reduced treatment efficacy, such that a dose increase was necessary to produce adequate analgesia. These findings highlight the active role of cognition and prefrontal lobes in the therapeutic outcome and underscore the need of considering a possible revision of the therapeutic approach in Alzheimer patients in order to compensate for the loss of the endogenous expectation and placebo mechanisms.
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It is frequently necessary for patients to undergo multiple painful medical interventions as part of their diagnosis and care. Predictors of future pain report have yet to be established although initial pain level, affect, and memory of the procedure are often implicated. The purpose of this research was to establish a predictive model of future pain reporting using a standardized experimental pain stimulus. ⋯ An additional 13% of the variance was shared between Session 1 maximum pain intensity and remembered maximum pain intensity. The level of remembered Session 1 pain was significantly exaggerated from the initial pain report (p < or = .05) but not significantly different from the level of pain reported at Session 2. These findings provide strong evidence for a post-pain modulation phenomenon in which cognitive processes influence both pain recall and future pain reporting.
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Comparative Study
Glucocorticoid inhibition of vascular abnormalities in a tibia fracture rat model of complex regional pain syndrome type I.
Tibia fracture in rats evokes chronic hindpaw warmth, spontaneous extravasation, edema, allodynia, and periarticular bone loss, a syndrome resembling complex regional pain syndrome type I (CRPS I). Glucocorticoids such as methylprednisolone (MP) are probably effective analgesic and anti-edematous agents in patients suffering from CRPS and this study examined the effects of chronic MP treatment in the rat CRPS I model. Bilateral hindpaw thickness, temperature, and nociceptive thresholds were determined, and the hindlimb bone density was measured using dual-energy X-ray absorptiometry (DXA). ⋯ Furthermore, there was an increase in spontaneous protein extravasation and an enhanced substance P evoked extravasation and edema response in the hindpaw at 4 weeks that was inhibited by MP infusion. Glucocorticoid treatment had no effect on the allodynia, hindpaw unweighting, or the periarticular bone loss observed after tibia fracture. We postulate that post-junctional facilitation of substance P signaling contributes to the hindpaw warmth, edema, and the enhanced spontaneous protein extravasation observed in this CRPS I model, and that the anti-edematous effects of glucocorticoid treatment are due to inhibition of post-junctional neuropeptide signaling.
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Comparative Study
Synergism between paracetamol and nonsteroidal anti-inflammatory drugs in experimental acute pain.
The antinociception induced by the intraperitoneal coadministration of combinations of paracetamol with the nonsteroidal anti-inflammatory drugs (NSAIDs) diclofenac, ibuprofen, ketoprofen, meloxicam, metamizol, naproxen, nimesulide, parecoxib and piroxicam was studied by isobolographic analysis in the acetic acid abdominal constriction test of mice (writhing test). The effective dose that produced 50% antinociception (ED50) was calculated from the log dose-response curves of fixed ratio combinations of paracetamol with each NSAID. ⋯ As shown by isobolographic analysis, all the combinations were synergistic, the experimental ED50s being significantly smaller than the theoretically calculated ED50s. The results of this study demonstrate potent interactions between paracetamol and NSAIDs and validate the clinical use of combinations of these drugs in the treatment of pain conditions.