Pain
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Randomized Controlled Trial Clinical Trial
The cyclooxygenase isozyme inhibitors parecoxib and paracetamol reduce central hyperalgesia in humans.
Non-steroidal antiinflammatory drugs (NSAIDs) are known to induce analgesia mainly via inhibition of cyclooxygenase (COX). Although the inhibition of COX in the periphery is commonly accepted as the primary mechanism, experimental and clinical data suggest a potential role for spinal COX-inhibition to produce antinociception and reduce hypersensitivity. We used an experimental model of electrically evoked pain and hyperalgesia in human skin to determine the time course of central analgesic and antihyperalgesic effects of intravenous parecoxib and paracetamol (acetaminophen). ⋯ In conclusion, our results provide clear experimental evidence for the existence of central antihyperalgesia induced by intravenous infusion of two COX inhibitors, parecoxib and paracetamol. Since the electrical current directly stimulated the axons, peripheral effects of the COX inhibitors on nociceptive nerve endings cannot account for the reduction of hyperalgesia. Thus, besides its well-known effects on inflamed peripheral tissues, inhibition of central COX provides an important mechanism of NSAID-mediated antihyperalgesia in humans.
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We conducted a systematic review of the literature on the effectiveness of spinal cord stimulation (SCS) in relieving pain and improving functioning for patients with failed back surgery syndrome and complex regional pain syndrome (CRPS). We also reviewed SCS complications. Literature searches yielded 583 articles, of which seven met the inclusion criteria for the review of SCS effectiveness, and 15 others met the criteria only for the review of SCS complications. ⋯ Although life-threatening complications with SCS are rare, other adverse events are frequent. On average, 34% of patients who received a stimulator had an adverse occurrence. We conclude with suggestions for methodologically stronger studies to provide more definitive data regarding the effectiveness of SCS in relieving pain and improving functioning, short- and long-term, among patients with chronic pain syndromes.
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The SF-36 is a well-validated health status instrument measuring eight different health concepts. One aim of this study was to compare health status as measured by SF-36 in subjects from the general population with no chronic pain (NCP), chronic regional pain (CRP), and chronic widespread pain (CWP). A second aim was to assess if SF-36 could reflect changes in pain status over time. ⋯ Changes in SF-36 over the 3-year follow up time coincided with improvement or deterioration of pain status. Baseline SF-36 scores predicted pain outcome 3 years later. These results support that both physical and mental aspects of health status as measured by SF-36 are affected by the burden of musculoskeletal pain, are sensitive to changes in pain status, and also predict the further development of pain.
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Clinical Trial
Lowering fear-avoidance and enhancing function through exposure in vivo. A multiple baseline study across six patients with back pain.
This study investigated the effects of an exposure in vivo treatment for chronic pain patients with high levels of fear and avoidance. The fear-avoidance model offers an enticing explanation of why some back pain patients develop persistent disability, stressing the role of catastrophic interpretations; largely fueled by beliefs and expectations that activity will cause injury and will worsen the pain problem. Recently, an exposure in vivo treatment was developed that aims to enhance function by directly addressing these fears and expectations. ⋯ These improvements were observed even though rated pain intensity actually decreased somewhat. Thus, the results replicate and extend the findings of previous studies to a new setting, with other therapists and a new research design. These results, together with the initial studies, provide a basis for pursuing and further developing the exposure technique and to test it in group designs with larger samples.
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The 'nociceptive' blink reflex is a method of examining human trigeminal pain pathways. We explored temporal summation of this reflex by using a train of pulses, rather than a single pulse, and remote activation of diffuse noxious inhibitory control (DNIC), to improve reliability, flexibility and nociceptive specificity of this technique. The R2 component of the nociceptive blink reflex response (nR2) was assessed in 28 healthy volunteers using between 1 and 7 pulses per stimulus train (inter-pulse interval 5 ms). ⋯ Activation of the DNIC system using heterotopic pain suppressed the nR2 evoked by double and triple stimulation by 16 and 42%, respectively, but not the nR2 from a single pulse. Stimulation with double and triple pulses may be more suitable to study influences on nociceptive pathways than single pulses and may widen the methodological flexibility of the nociceptive blink reflex technique. This technique may be useful in studying the trigeminal nociceptive system with particular reference to primary headache disorders and their neuropharmacology.