Pain
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Musculoskeletal disorders (MSDs) are highly prevalent, painful, and costly disorders. The MSD Cohort was created to characterize variation in pain, comorbidities, treatment, and outcomes among patients with MSD receiving Veterans Health Administration care across demographic groups, geographic regions, and facilities. We searched electronic health records to identify patients treated in Veterans Health Administration who had ICD-9-CM codes for diagnoses including, but not limited to, joint, back, and neck disorders, and osteoarthritis. ⋯ Nontraumatic joint disorder (27%), back disorder (25%), and osteoarthritis (21%) were the most common MSD diagnoses. Patients entering the cohort in recent years had more concurrent MSD diagnoses and higher NRS scores. The MSD Cohort is a rich resource for collaborative pain-relevant health service research.
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Pain behaviors are shaped by social demands and learning processes, and chronic pain has been previously suggested to affect their meaning. In this study, we combined functional magnetic resonance imaging with in-scanner video recording during thermal pain stimulations and use multilevel mediation analyses to study the brain mediators of pain facial expressions and the perception of pain intensity (self-reports) in healthy individuals and patients with chronic back pain (CBP). Behavioral data showed that the relation between pain expression and pain report was disrupted in CBP. ⋯ Stronger activity was observed in CBP specifically during pain facial expressions in several nonmotor brain regions such as the medial prefrontal cortex, the precuneus, and the medial temporal lobe. In sharp contrast, no moderating effect of chronic pain was observed on brain activity associated with pain intensity ratings. Our results demonstrate that pain facial expressions and pain intensity ratings reflect different aspects of pain processing and support psychosocial models of pain suggesting that distinctive mechanisms are involved in the regulation of pain behaviors in chronic pain.
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The fear avoidance model (FAM) has been proposed to explain the development of chronic disability in a variety of conditions including whiplash-associated disorders (WADs). The FAM does not account for symptoms of posttraumatic stress and sensory hypersensitivity, which are associated with poor recovery from whiplash injury. The aim of this study was to explore a model for the maintenance of pain and related disability in people with WAD including symptoms of PTSD, sensory hypersensitivity, and FAM components. ⋯ Mixed-model analysis using Neck Disability Index (NDI) scores and average 24-hour pain intensity as the dependent variables revealed that overall model fit was greatest when measures of fear of movement, posttraumatic stress, and sensory hypersensitivity were included. The interactive effects of time with catastrophising and time with fear of activity of the cervical spine were also included in the best model for disability. These results provide preliminary support for the addition of neurobiological and stress system components to the FAM to explain poor outcome in patients with WAD.
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Limited research suggests that there may be Warm complex regional pain syndrome (CRPS) and Cold CRPS subtypes, with inflammatory mechanisms contributing most strongly to the former. This study for the first time used an unbiased statistical pattern recognition technique to evaluate whether distinct Warm vs Cold CRPS subtypes can be discerned in the clinical population. An international, multisite study was conducted using standardized procedures to evaluate signs and symptoms in 152 patients with clinical CRPS at baseline, with 3-month follow-up evaluations in 112 of these patients. ⋯ A derived total inflammatory score was significantly (P < 0.001) elevated in the Warm CRPS group (compared with Cold CRPS) at baseline but diminished significantly (P < 0.001) over the follow-up period, whereas this score did not diminish in the Cold CRPS group (time × subtype interaction: P < 0.001). Results support the existence of a Warm CRPS subtype common in patients with acute (<6 months) CRPS and a relatively distinct Cold CRPS subtype most common in chronic CRPS. The pattern of clinical features suggests that inflammatory mechanisms contribute most prominently to the Warm CRPS subtype but that these mechanisms diminish substantially during the first year postinjury.