Pain
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Peripheral nerve regeneration is associated with pain in several preclinical models of neuropathic pain. Some neuropathic pain conditions and preclinical neuropathic pain behaviors are improved by sympathetic blockade. In this study, we examined the effect of a localized "microsympathectomy," ie, cutting the gray rami containing sympathetic postganglionic axons where they enter the L4 and L5 spinal nerves, which is more analogous to clinically used sympathetic blockade compared with chemical or surgical sympathectomy. ⋯ Microsympathectomy reduced functional regeneration as measured by myelinated action potential propagation through the injury site and denervation-induced atrophy of the tibial-innervated gastrocnemius muscle at day 10. Microsympathectomy plus CCL2 knockdown had behavioral effects similar to microsympathectomy alone. The results show that local sympathetic effects on neuropathic pain may be mediated in a large part by the effects on expression of CCL2, which in turn regulates the regeneration process.
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Prescription opioids remain an important driver of the opioid crisis in the United States. The purpose of this study was to examine recent changes in opioid prescribing patterns in the Military Health System (MHS) which is a nationwide health system service active duty military personnel and civilian beneficiaries. All patients prescribed opioid analgesics by MHS providers and filled at MHS pharmacies between 2014 and 2018 were identified. ⋯ The proportion of prescriptions written for >90 OMEs per day declined 21%. Declines in opioid prescriptions and quantities were observed in nearly all specialties over the study period. The results of this study suggest a broad-based shift towards less opioid prescribing.
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Clinical models of chronic low back pain (cLBP) highlight the role of excessive attention to pain and kinesiophobia on the origin of disability. At the motor control level, various mechanisms are involved in the impairments observed in patients with cLBP. We aimed to assess the role of maladaptative attentional behaviors by using a complex systems approach and a visual display as a distraction during walking. ⋯ Post hoc analysis showed that, without distraction, patients with cLBP had significantly lower ST complexity than controls, but when distracted, they regained gait complexity, recovering the level of controls. Our results suggest that excessive attention to pain causes loss of complexity and adaptability in cLBP and explain alterations of motor control with pain. Fractal analysis seems to be a promising method to explore movement variability and individual adaptability in musculoskeletal disorders.
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In 2019, the American College of Rheumatology conditionally recommended tramadol and conditionally recommended against nontramadol opioids for patients with hip and knee osteoarthritis. Although tramadol is known to be less prone to opioid use disorders, little is known about the differing magnitude of negative clinical outcomes, health care resource utilization, and costs of tramadol relative to nontramadol opioids. Administrative claims records for commercially insured patients with osteoarthritis who were prescribed opioids were used to compare clinical and cost outcomes during a 3-year follow-up period by conducting a pre-post analysis and a matched case-cohort analysis. ⋯ Finally, in both analyses, the nontramadol cohort incurred higher levels of inpatient and emergency department visits and all-cause costs during the 3-year follow-up period. However, tramadol patients incur a higher incremental change (+$24,013) in costs relative to their pretreatment baseline compared with nontramadol (+$18,191). These real-world findings demonstrated lower risks with tramadol relative to other opioids, albeit risks and increased health care costs were present with tramadol, highlighting the need for further strategies to improve outcomes.
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Pain-induced negative affect reduces life quality of patients by increasing psychiatric comorbidities, including alcohol use disorders (AUDs). Indeed, clinical data suggest pain as a risk factor to suffer AUDs, predicting relapse drinking in abstinent patients. Here, we analyse the impact of pain on alcohol relapse and the role of kappa opioid receptor (KOR) activation in mediating these pain-induced effects because KORs play an important role in pain-driven negative affect and AUD. ⋯ Finally, KOR antagonist norbinaltorphimine was administered in the nucleus accumbens shell during abstinence to prevent a pain-induced alcohol deprivation effect, a phenomenon observed in CFA-female rats. The administration of norbinaltorphimine effectively blocked a pain-induced alcohol deprivation effect in female rats. Our data evidenced that inflammatory pain constitutes a risk factor to increase alcohol consumption during a reintroduction phase only in female rats by the rise and maintenance of stress probably mediated by KOR signalling in the nucleus accumbens.