Pain
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Traumatic peripheral nerve injuries are at high risk of neuropathic pain for which novel effective therapies are urgently needed. Preclinical models of neuropathic pain typically involve irreversible ligation and/or nerve transection (neurotmesis). However, translation of findings to the clinic has so far been unsuccessful, raising questions on injury model validity and clinically relevance. ⋯ The partially crushed nerve was characterized by the sparing of small-diameter myelinated axons and intraepidermal nerve fibers, fewer dorsal root ganglia expressing the injury marker activating transcription factor 3, and lower serum levels of neurofilament light chain. By day 30, axons showed signs of reduced myelin thickness. In summary, the escape of small-diameter axons from Wallerian degeneration is likely a determinant of chronic pain pathophysiology distinct from the general response to complete nerve injury.
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Inconsistent reporting of outcomes in clinical trials of treatments for whiplash associated disorders (WAD) hinders effective data pooling and conclusions about treatment effectiveness. A multidisciplinary International Steering Committee recently recommended 6 core outcome domains: Physical Functioning, Perceived Recovery, Work and Social Functioning, Psychological Functioning, Quality of Life and Pain. This study aimed to reach consensus and recommend a core outcome set (COS) representing each of the 6 domains. ⋯ No PROMs had undergone evaluation of content validity in patients with WAD, but some had moderate-to-high-quality evidence for sufficient internal structure. Based on these results, the International Steering Committee reached 100% consensus to recommend the following COS: Neck Disability Index or Whiplash Disability Questionnaire (Physical Functioning), the Global Rating of Change Scale (Perceived Recovery), one of the Pictorial Fear of Activity Scale-Cervical, Pain Self-Efficacy Questionnaire, Pain Catastrophizing Scale, Harvard Trauma Questionnaire, or Posttraumatic Diagnostic Scale (Psychological Functioning), EQ-5D-3L or SF-6D (Quality of Life), numeric pain rating scale or visual analogue scale (Pain), and single-item questions pertaining to current work status and percent of usual work (Work and Social Functioning). These recommendations reflect the current status of research of PROMs of the 6 core outcome domains and may be modified as evidence grows.
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Juvenile fibromyalgia (JFM) is a chronic widespread pain condition that primarily affects adolescent girls. Previous studies have found increased sensitivity to noxious pressure in adolescents with JFM. However, the underlying changes in brain systems remain unclear. ⋯ The JFM group showed augmented right primary somatosensory cortex (S1) activation to 4 kg/cm 2 (Z > 3.1, cluster-corrected P < 0.05), and the peak S1 activation magnitudes significantly correlated with the scores on the Widespread Pain Index ( r = 0.35, P = 0.048) with higher activation associated with more widespread pain. We also found that greater primary sensorimotor cortex activation in response to 4 kg/cm 2 mediated the between-group differences in pain intensity ratings ( P < 0.001). In conclusion, we found heightened sensitivity to noxious pressure stimuli and augmented pain-evoked sensorimotor cortex responses in adolescent girls with JFM, which could reflect central sensitization or amplified nociceptive input.