The journal of pain : official journal of the American Pain Society
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Review Meta Analysis
Systematic review and meta-analysis of genetic risk of developing chronic postsurgical pain.
Chronic postsurgical pain (CPSP) is a significant detriment to postsurgical recovery and a risk factor for prolonged opioid use. Emerging evidence suggests the estimated heritability for chronic pain is 45% and that genetic factors partially explain individual susceptibility to CPSP. The aim of this study was to systematically review, assess quality, and summarize the studies in humans that have investigated genetic factors associated with CPSP. ⋯ PERSPECTIVE: Our systematic review comprehensively describes 21 studies evaluating genetic association with CPSP, and limitations thereof. A meta-analysis of 6 variants (5 genes) found marginally increased risk for CPSP associated with rs734784 A>G of the potassium voltage-gated channel gene (KCNS1). Understanding genetic predisposition for CPSP will enable prediction and personalized management.
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Randomized Controlled Trial
Large treatment effect with extended home-based transcranial direct current stimulation over dorsolateral prefrontal cortex in fibromyalgia: A Proof of Concept Sham-Randomized Clinical Study.
This randomized, double-blind controlled trial tested the hypothesis that 60 sessions of home-based anodal (a)-transcranial direct current stimulation (tDCS) over dorsolateral prefrontal cortex (DLPFC) would be better than home-based sham-tDCS to improve the widespread pain and the disability-related to pain. The anodal-tDCS (2 mA for 30 minutes) over the left DLPFC was self-administered with a specially developed device following in-person training. Twenty women, 18 to 65 years old were randomized into 2 groups [active-(a)-tDCS (n = 10) or sham-(s)-tDCS (n = 10)]. ⋯ Higher serum levels of the brain-derived neurotrophic factor predicted higher decreases on the pain scores across of treatment. PERSPECTIVE: These findings bring 3 important insights: 1) show that an extended period of treatment (60 sessions, to date the largest number of tDCS sessions tested) for fibromyalgia induces large pain decreases (a large effect size of 1.59) and 2) support the feasibility of home-based tDCS as a method of intervention; 3) provide additional data on DLPFC target for the treatment of fibromyalgia. Finally, our findings also highlight that brain-derived neurotrophic factor to index neuroplasticity may be a valuable predictor of the tDCS effect on pain scores decreases across the treatment.
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Chemotherapy-induced peripheral neuropathy (CIPN) is a major, dose-limiting side effect of treatment with neurotoxic cancer treatments which can result in long-term impairment. Deficits often reflect a large fiber polyneuropathy, however small fiber involvement resulting in neuropathic pain and autonomic dysfunction can occur. Quantification of both CIPN and small fiber neuropathy (SFN) remains a challenge. ⋯ Accurately identifying subgroups of patients with neuropathic symptoms which may respond to existing pain medication may reduce the impact of CIPN and improve long-term quality of life as well as provide better categorization of patients for future clinical trials of neuroprotective and treatment strategies for CIPN. PERSPECTIVE: This review provides a critical analysis of SFN associated with neurotoxic cancer treatments and the assessment tools for evaluating small fiber dysfunction in cancer patients. Quantification of small fiber involvement in CIPN will assist in identifying subgroups of patients with neuropathic symptoms which may respond to existing pain medications.
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Chronic overlapping pain conditions (COPCs) are a set of painful chronic conditions characterized by high levels of co-occurrence. It has been hypothesized that COPCs co-occur in many cases because of common neurobiological vulnerabilities. In practice, most research on COPCs has focused upon a single index condition with little effort to assess comorbid painful conditions. ⋯ The codes presented can facilitate administrative database research on COPCs. PERSPECTIVE: This article presents a set of ICD-10 codes that researchers can use to explore the presence and overlap of COPCs in administrative databases. This may serve as a tool for estimating samples for research, exploring comorbidities, and treatments for individual COPCs, and identifying mechanisms associated with their overlap.