Pain
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Meta Analysis
Pain mechanisms in carpal tunnel syndrome: a systematic review and meta-analysis of quantitative sensory testing outcomes.
Carpal tunnel syndrome (CTS) is the most common nerve compression in the arm. A mix of peripheral and central contributions on quantitative sensory testing (QST) has been reported in the literature. Thus, this systematic review or meta-analysis aimed to identify the dominant sensory phenotype and draw conclusive evidence about the presence of central sensitization (CS) in CTS. ⋯ Furthermore, there was a significant increase in mechanical pain sensitivity in median nerve territories and remotely in the forearm ( P < 0.05) and a significant gain in pressure and heat pain thresholds in the carpal area ( P < 0.05). Conditioned pain modulation was impaired in CTS. Hypoesthesia and increased thermal and mechanical pain ratings are the dominant sensory phenotype with inconclusive evidence about CS in CTS due to the heterogenous results of thermal and mechanical pain thresholds.
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Musculoskeletal pain is a global health concern, and work-related psychosocial stress might be a potential contributing factor. This cross-sectional study investigates whether job stress is associated with chronic and widespread musculoskeletal pain in 2051 Brazilian active civil servants included in the Brazilian Longitudinal Study of Adult Health Musculoskeletal (ELSA-Brasil MSK). Job stress was assessed using the Effort-Reward Imbalance (ERI) questionnaire. ⋯ Chronic musculoskeletal pain according to body regions, especially generalized pain, was also associated with ERI domains effort (OR = 2.06; 95%CI = 1.33-3.21), overcommitment (OR = 3.44; 95%CI = 2.20-5.39), and effort-reward imbalance ratio (OR = 2.06; 95%CI = 1.30-3.27). Results reveal an association between job stress not only with CMP at any site but notably with the pain spread to other body sites or regions. Our findings suggest that lowering stress at work and discouraging overcommitment may help reduce the CMP burden, including reduction of CMP spread from one site or region of the body to another.
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Despite being involved in a number of functions, such as nociception and locomotion, spinal lamina X remains one of the least studied central nervous system regions. Here, we show that Aδ- and C-afferent inputs to lamina X neurons are presynaptically inhibited by homo- and heterosegmental afferents as well as by descending fibers from the corticospinal tract, dorsolateral funiculus, and anterior funiculus. Activation of descending tracts suppresses primary afferent-evoked action potentials and also elicits excitatory (mono- and polysynaptic) and inhibitory postsynaptic responses in lamina X neurons. Thus, primary afferent input to lamina X is subject to both spinal and supraspinal control being regulated by at least 5 distinct pathways.