Pain
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Evidence-based medicine is replete with studies assessing quality and bias, but few evaluating research integrity or trustworthiness. A recent Cochrane review of psychological interventions for chronic pain identified trials with a shared lead author with highly divergent results. We sought to systematically identify all similar trials from this author to explore their risk of bias, governance procedures, and trustworthiness. ⋯ We discuss the findings within the context of methods for establishing the trustworthiness of research findings generally. Important concerns regarding the trustworthiness of these trials reduce our confidence in them. They should probably not be used to inform the results and conclusions of systematic reviews, in clinical training, policy documents, or any relevant instruction regarding adult chronic pain management.
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Ambroxol is a multifaceted drug with primarily mucoactive and secretolytic actions, along with anti-inflammatory, antioxidant, and local anaesthetic properties. It has a long history of use in the treatment of respiratory tract diseases and has shown to be efficacious in relieving sore throat. In more recent years, ambroxol has gained interest for its potential usefulness in treating neuropathic pain. ⋯ With its well-established safety profile, extensive preclinical and clinical drug data, and early evidence of clinical effectiveness, ambroxol is an old drug worthy of further investigation for repurposing. As a patent-expired drug, a push is needed to progress the drug to clinical trials for neuropathic pain. We encourage the pharmaceutical industry to look at patented drug formulations and take an active role in bringing an optimized version for neuropathic pain to market.
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Randomized Controlled Trial
The effects of pain science education plus exercise on pain and function in chronic Achilles tendinopathy: a blinded, placebo-controlled, explanatory, randomized trial.
Exercise is the standard of care for Achilles tendinopathy (AT), but 20% to 50% of patients continue to have pain following rehabilitation. The addition of pain science education (PSE) to an exercise program may enhance clinical outcomes, yet this has not been examined in patients with AT. Furthermore, little is known about how rehabilitation for AT alters the fear of movement and central nervous system nociceptive processing. ⋯ After rehabilitation, performance-based function improved (number of heel raises: 5.2 [1.6-8.8]), central nervous system nociceptive processing remained the same (conditioned pain modulation: -11.4% [0.2 to -17.3]), and fear of movement decreased (Tampa Scale of Kinesiophobia, TSK-17: -6.5 [-4.4 to -8.6]). Linear regression models indicated that baseline levels of pain and function along with improvements in self-efficacy and knowledge gain were associated with a greater improvement in pain and function, respectively. Thus, acquiring skills for symptom self-management and the process of learning may be more important than the specific educational approach for short-term clinical outcomes in patients with AT.
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Processing spatially distributed nociceptive information is critical for survival. The conditioned pain modulation (CPM) response has become a common psychophysical test to examine pain modulation capabilities related to spatial filtering of nociceptive information. Neuroimaging studies have been conducted to elucidate the neural mechanisms underlying the CPM response in health and chronic pain states, yet their findings have not been critically reviewed and synthesized before. ⋯ The summary includes functional MRI studies assessing CPM responses during scanning as well as functional and structural MRI studies correlating indices with CPM responses assessed outside of the scanner. The findings are discussed in relation to the suggested mechanisms for the CPM response. A better understanding of neural mechanisms underlying spatial processing of nociceptive information could advance both pain research and clinical use of the CPM response as a marker or a treatment target.
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Meta Analysis
Structural imaging studies of patients with chronic pain: an anatomic likelihood estimate meta-analysis.
Neuroimaging is a powerful tool to investigate potential associations between chronic pain and brain structure. However, the proliferation of studies across diverse chronic pain syndromes and heterogeneous results challenges data integration and interpretation. We conducted a preregistered anatomical likelihood estimate meta-analysis on structural magnetic imaging studies comparing patients with chronic pain and healthy controls. ⋯ However, exploratory analyses using threshold-free cluster enhancement revealed several spatially distributed clusters showing structural alterations in chronic pain. Most of the clusters coincided with regions implicated in nociceptive processing including the amygdala, thalamus, hippocampus, insula, anterior cingulate cortex, and inferior frontal gyrus. Taken together, these results suggest that chronic pain is associated with subtle, spatially distributed alterations of brain structure.