Pain
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Randomized Controlled Trial Multicenter Study
Group cognitive behavioural interventions for low back pain in primary care: extended follow-up of the Back Skills Training Trial (ISRCTN54717854).
Group cognitive behavioural intervention (CBI) is effective in reducing low back pain and disability over a 12-month period, in comparison to best practice advice in primary care. The aim was to study the effects of this CBI beyond 12 months. We undertook an extended follow-up of our original randomised, controlled trial of a group CBI and best practice advice in primary care, in comparison to best practice advice alone. ⋯ There was no between-group difference in Modified von Korff Scale pain outcomes. The results suggest that the effects of a group CBI are maintained up to an average of 34 months. Although pain improves in response to best practice advice, longer-term recovery of disability remains substantially less.
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We performed a prospective study in 32 patients with Guillain-Barré syndrome (GBS) or its variants to correlate intraepidermal nerve fiber density (IENFD) at the distal leg and lumbar region with pain, autonomic dysfunction, and outcome. In the acute phase, IENFD was reduced in 60% and 61.9% of patients at the distal leg and lumbar region, respectively. In the acute phase, 43.7% of patients complained of neuropathic pain. ⋯ Double and triple staining confocal microscope studies showed diffuse damage of myelinated dermal nerves along with axonal degeneration, and mononuclear cell infiltration. Unmyelinated and myelinated skin nerves are diffusely affected in GBS and its variants, including the pure motor form. IENFD declines early, remains low over time, correlates with pain severity in the acute phase, and may predict long-term disability.
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The facial expression of pain plays a crucial role in pain communication and pain diagnostics. Despite its importance, it has remained unknown which dimensions of pain (sensory and/or affective) are encoded in the face. To answer this question, we used a well-established cognitive strategy (suggestions) to differentially modulate the sensory and affective dimensions of pain and investigate the effect of this manipulation on facial responses to experimental pain. ⋯ Furthermore, suggestions for either increased pain affect or pain sensation produced selective modulations in facial response patterns, with facial movements around the eyes mostly encoding sensory aspects, whereas movements of the eyebrows and of the upper lip were closely associated with the affective pain dimension. The facial expression of pain is a multidimensional response system that differentially encodes affective and sensory pain qualities. This differential encoding might have evolved to guarantee that the specific characteristics of one's pain experience are facially communicated, thereby ensuring adequate help and support from others.
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The complement system is an important part of innate immunity. Complement activation generates a set of effector molecules with diverse biological functions. C5a is a crucial terminal component of the complement cascade. ⋯ The main findings were: (1) Heat vs mechanical nociceptive sensitization after incision were differentially reduced in C5aR(-/-) mice, with thermal sensitization affected throughout the postincisional period but mechanical sensitization affected only at later time points; (2) Edema developed after incision in wild-type mice but only slightly and transiently in C5aR(-/-) mice, and (3) Deletion of C5aR blocked interleukin-1β and nerve growth factor production near the wound site. These findings demonstrate that the complement system component C5a is a novel biomarker and mediator associated with postsurgical nociceptive processing. C5aR may provide a novel target for the control of pain and inflammation after surgery.