Pain
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Observational Study
The responsiveness of quantitative sensory testing-derived sensory phenotype to disease-modifying intervention in patients with entrapment neuropathy: a longitudinal study.
The German Research Network on Neuropathic Pain (DFNS) quantitative sensory testing (QST) method for sensory phenotyping is used to stratify patients by mechanism-associated sensory phenotype, theorised to be predictive of intervention efficacy. We hypothesised that change in pain and sensory dysfunction would relate to change in sensory phenotype. We investigated the responsiveness of sensory phenotype to surgery in patients with an entrapment neuropathy. ⋯ Quantitative sensory testing-derived sensory phenotype is sensitive to clinically important change. In an entrapment neuropathy model, sensory phenotype was associated with patient-reported symptoms and demonstrated statistically significant, clinically relevant change after disease-modifying intervention. Sensory phenotype was independent of disease severity and may reflect underlying neuropathophysiology.
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Meta Analysis
Effectiveness of placebo interventions for patients with non-specific low back pain: a systematic review.
Little is known about the effectiveness of placebo interventions in patients with nonspecific low back pain (LBP). This systematic review assessed the magnitude of the effects of placebo interventions as compared to no intervention in randomized controlled trials (RCTs) including patients with LBP. Embase, MEDLINE (Ovid), and Cochrane CENTRAL databases were searched from inception to December 5, 2019. ⋯ These results show placebo interventions are more effective than no intervention at short-term follow-up in patients with chronic LBP. However, the magnitude of the effects is probably not clinically relevant (approximately 8 points on a 0-100 pain scale). Future research should identify effect modifiers and causal mechanisms explaining the short-term effects of placebo interventions in patients with chronic LBP.
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This study investigated the association between COVID-related myalgia experienced by patients at hospital admission and the presence of post-COVID symptoms. A case-control study including patients hospitalised due to COVID-19 between February 20 and May 31, 2020, was conducted. Patients reporting myalgia and patients without myalgia at hospital admission were scheduled for a telephone interview 7 months after hospital discharge. ⋯ The presence of myalgia at hospital admission was associated with preexisting history of musculoskeletal pain (OR 1.62, 95% confidence interval 1.10-2.40). In conclusion, myalgia at the acute phase was associated with musculoskeletal pain as long-term post-COVID sequelae. In addition, half of the patients with preexisting pain conditions experienced a persistent exacerbation of their previous syndromes.
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Dorsal root ganglion field stimulation (GFS) relieves evoked and spontaneous neuropathic pain by use-dependent blockade of impulse trains through the sensory neuron T-junction, which becomes complete within less than 1 minute for C-type units, also with partial blockade of Aδ units. We used this tool in the spinal nerve ligation (SNL) rat model to selectively block sensory neuron spontaneous activity (SA) of axotomized neurons at the fifth lumbar (L5) level vs blockade of units at the L4 level that remain uninjured but exposed to inflammation. In vivo dorsal root single-unit recordings after SNL showed increased SA in L5 units but not L4 units. ⋯ In addition, L5 GFS, but not L4 GFS, increased mechanical threshold of DH units during cutaneous mechanical stimulation, while L5 GFS exceeded L4 GFS in reducing evoked firing rates. Our results indicate that SA in injured neurons supports increased firing of DH wide-dynamic-range neurons, contributing to hyperalgesia, allodynia, and ongoing pain. Ganglion field stimulation analgesic effects after nerve injury are at least partly attributable to blocking propagation of this SA.
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Randomized Controlled Trial
Internet-delivered cognitive behavioral therapy for youth with functional abdominal pain: a randomized clinical trial testing differential efficacy by patient subgroup.
Inconsistent results of psychological treatments for pediatric functional abdominal pain (FAP) may be due to heterogeneity of patients' pain-related psychological characteristics. This randomized controlled trial tested whether statistically derived patient subgroups (high pain dysfunctional [HPD], high pain adaptive [HPA], and low pain adaptive [LPA]) moderated response to cognitive behavior therapy (CBT) for adolescents with FAP and their parents (n = 278 dyads; patients were 66% female, mean [SD] age was 14.62 [1.88] years, and parents were 95% female). Randomization to Internet-delivered CBT vs Internet-delivered pain education (EDU) was stratified by patient subgroup. ⋯ Furthermore, among all patients assigned to CBT, HPD youth demonstrated significantly greater reductions in GI symptoms compared with HPA and LPA youth and greater reductions in abdominal pain compared with LPA youth. All subgroups maintained symptom reductions throughout the follow-up period. Results suggest that subgrouping FAP patients may inform treatment allocation and optimize treatment response.