Pain
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Cognitive-behavioral factors are considered important in the development of chronic disability and pain in patients with low back pain. In a prospective cohort study of 277 patients undergoing surgery for lumbosacral radicular syndrome, the predictive value of preoperatively measured cognitive-behavioral factors (fear of movement/(re)injury, passive pain coping, and negative outcome expectancies) for disability and pain intensity at 6 weeks and 6 months after surgery was investigated, taking into account the effect of possible confounding variables. Higher levels of cognitive-behavioral factors were found to be associated with a worse outcome at both 6 weeks and 6 months. ⋯ In multiple regression analyses, the cognitive-behavioral factors independently predicted different outcomes. Fear of movement/(re)injury predicted more disability and more severe pain at 6 weeks and more severe pain at 6 months; passive pain-coping strategies predicted more disability at 6 months; and negative outcome expectancies predicted more disability and more severe pain at both 6 weeks and 6 months. The findings support the potential utility of preoperative screening measures that include cognitive-behavioral factors for predicting surgical outcome, as well as studies to examine the potential benefits of cognitive-behavioral treatment to improve surgical outcome.
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Randomized Controlled Trial Comparative Study
A comparative study of oxycodone and morphine in a multi-modal, tissue-differentiated experimental pain model.
Visceral pain can be difficult to treat with classical mu-opioid agonists and it has been suggested to use opioids with distinct pharmacological profiles. In animal experiments, oxycodone has shown different effects compared to morphine, and clinical observations have shown that oxycodone may occasionally be superior to, e.g., morphine in the treatment of visceral pain. In the current study, we randomised 24 healthy subjects to treatment with either morphine (30 mg), oxycodone (15 mg) or placebo in a crossover study. ⋯ Morphine and oxycodone were equipotent in pain modulation of the skin and muscles, but oxycodone had superior analgesic effect to both morphine and placebo on the mechanical (P<0.001) and thermal (P<0.001) stimulations of the oesophagus. In conclusion, the multi-modal and tissue-differentiated pain model could link findings from animal experiments to clinical findings. A different pharmacological profile of oxycodone compared to that of morphine was shown, and thus oxycodone may be a useful alternative to morphine in the treatment of visceral pain syndromes.
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Past research has shown that pain catastrophizing contributes to heightened pain experience. The hypothesis advanced in this study was that individuals who score high on measures of pain catastrophizing would also perceive more intense pain in others. The study also examined the role of pain behaviour as a determinant of the relation between catastrophizing and estimates of others' pain. ⋯ Catastrophizing was associated with more accurate pain inferences on only one of three indices of inferential accuracy. The pattern of findings suggests that increasing reliance on pain behaviour as a means of inferring others' pain will not necessarily yield more accurate estimates. Discussion addresses the processes that might underlie the propensity to attend more to others' pain behaviour, and the clinical and interpersonal consequences of perceiving more pain in others.
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Rare patients are left with chronic pain, vasodysregulation, and other symptoms that define complex regional pain syndrome (CRPS), after limb traumas. The predisposing factors are unknown. Genetic factors undoubtedly contribute, but have not yet been identified. ⋯ All had sustained joint injury; in three this had been surgically treated. The association of these two diagnoses leads us to hypothesize that EDS might contribute to the development of CRPS in one or more of the following ways: via stretch injury to nerves traversing hypermobile joints, increased fragility of nerve connective tissue, or nerve trauma from more frequent surgery. We review the clinical presentation of the different Ehlers Danlos syndromes and provide clinical criteria that can be used to screen CRPS patients for EDS for clinical or research purposes.
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Osteoarthritis (OA) is a debilitating disease in which primarily weight-bearing joints undergo progressive degeneration. Despite the widespread prevalence of OA in the adult population, very little is known about the factors responsible for the generation and maintenance of OA pain. Vasoactive intestinal peptide (VIP) was identified in the synovial fluid of arthritis patients nearly 20 years ago and the aim of this study was to examine whether VIP could be involved in the generation of OA pain. ⋯ Treatment of OA knees with a single injection of VIP6-28 diminished hindlimb incapacitance while increasing paw withdrawal threshold. This study showed for the first time that peripheral application of VIP causes increased knee joint allodynia and secondary hyperalgesia. Furthermore, antagonists that inhibit VIP activity may prove beneficial in the alleviation of OA pain.