Pain
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Randomized Controlled Trial Comparative Study Clinical Trial
Is there a right treatment for a particular patient group? Comparison of ordinary treatment, light multidisciplinary treatment, and extensive multidisciplinary treatment for long-term sick-listed employees with musculoskeletal pain.
In general, randomized controlled studies concerning return to work have failed to demonstrate significant treatment effects for long-lasting musculoskeletal pain, and most treatments examined have not been economically beneficial. Individuals (n=654) sick-listed for at least 8 weeks with musculoskeletal pain, selected from the Norwegian mandatory sickness insurance system and volunteering to participate, were categorized into three groups differing in a prognosis score (good, medium, poor) for return to work, based on a brief, standardized screening of psychological and physiotherapy findings. They were then randomly assigned to three outpatient treatments with three different levels of intensity (ordinary treatment, light multidisciplinary, and extensive multidisciplinary treatment). ⋯ Measures of pain or quality of life are not included in this study. The cost-benefit analysis of the economic returns of the light multidisciplinary and the extensive multidisciplinary treatment programs yields a positive net present social value of the treatment. A simple, standardized, screening instrument including only psychological and physiotherapeutic observations may be a useful clinical tool for allocating patients with musculoskeletal pain to the right level of treatment.
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Comparative Study
Complex regional pain syndrome: are there distinct subtypes and sequential stages of the syndrome?
This study tested for evidence supporting the clinical lore of three sequential stages of complex regional pain syndrome (CRPS) and examined the characteristics of possible CRPS subtypes. A series of 113 patients meeting IASP criteria for CRPS underwent standardized history and physical examinations to assess CRPS signs and symptoms in four domains identified in previous research: pain/sensory abnormalities, vasomotor dysfunction, edema/sudomotor dysfunction, and motor/trophic changes. K-Means cluster analysis was used to derive three relatively homogeneous CRPS patient subgroups based on similarity of sign/symptom patterns in these domains. ⋯ EMG/NCV testing suggests that Subtype 2 may reflect CRPS-Type 2 (causalgia). Overall, these results are consistent with limited previous work that argues against three sequential stages of CRPS. However, several distinct CRPS subtypes are suggested, and these could ultimately have utility in targeting treatment more effectively.
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We identified long-term (up to 12 weeks), bilateral changes in spontaneous and evoked pain behavior and baseline forebrain activity following a chronic constriction injury (CCI) of the sciatic nerve. The long-term changes in basal forebrain activation following CCI were region-specific and can be divided into forebrain structures that showed either: (1) no change, (2) an increase, or (3) a decrease in activity with regard to the short-term (2 weeks) changes we previously reported. All the rats showed spontaneous pain behaviors that persisted throughout the 12-week observation period, resembling the pattern of change found in four limbic system structures: the anterior dorsal thalamus, habenular complex, and the cingulate and retrosplenial cortices. ⋯ Finally, mechanical allodynia, which was maximal during the first 2 weeks following nerve injury and gradually recovered by the seventh post-operative week uniquely matches the time course of changes in ventrolateral and ventroposterolateral thalamic activity. Our results indicate that peripheral nerve damage results in persistent changes in behavior and resting forebrain systems that modulate pain perception. The persistent abnormalities in the somatosensory cortex and thalamus suggest that the sensory thalamocortical axis is functionally deranged in certain chronic pain states.
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The role of operant conditioning for the development and maintenance of chronic pain was examined in 30 chronic back pain patients (CBP) and 30 matched healthy controls. Half of each group was reinforced for increased, half for decreased pain reports while EEG, EOG, heart rate, skin conductance and muscle tension levels were recorded. ⋯ In addition, the CBP group displayed prolonged elevated electromyogram levels to the task. These data suggest that CBP patients are more easily influenced by operant conditioning factors than healthy controls and this susceptibility may add to the maintenance of the chronic pain problem.