Not as “blurred” as expected? Acuity and spatial summation in the pain system
Spatial acuity measured by 2-point discrimination (2PD) threshold and spatial summation of pain (SSp) are useful paradigms to probe the pain system in humans. Whether the results of these paradigms are influenced by different stimulus modalities and intensities is unclear. The aim of this study was to test 2PD controlling the stimulus modality and the intensity and to investigate the effect of modality on SSp. Thirty-seven healthy volunteers were tested for 2PDs with 2 stimulus modalities (electrocutaneous and mechanical) and intensity (noxious and innocuous). For each condition, participants received stimuli to either 1 o...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Patients' perceptions of the pathways linking chronic pain with problematic substance use
Approximately one-half of patients with substance use disorders (SUDs) experience chronic pain. Yet, how patients perceive the relationship between their substance use and chronic pain remains poorly understood. We sought to identify how patients with comorbid SUD and chronic pain describe the relationship between, and mechanisms linking, these conditions. We conducted qualitative interviews with 34 patients engaged in SUD treatment who were also diagnosed with chronic pain. Interviews were transcribed verbatim and coded by both primary and secondary coders. Qualitative content analysis guided coding and analysis. Patient ...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Increased peptidergic fibers as a potential cutaneous marker of pain in diabetic small fiber neuropathy
In this study, we performed a detailed skin biopsy analysis in a well-characterized group of DPN patients with primarily small fiber involvement, with and without pain, and in healthy controls and test for correlation between skin biopsy findings and pain intensity and quantitative sensory testing. We found that although there was no difference in intraepidermal nerve fiber density using protein gene product 9.5 between patients with and without pain, patients with pain had increased density of dermal peptidergic fibers containing substance P and calcitonin gene-related peptide compared with patients with painless DPN and ...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Evolution of doctor shopping for oxycodone in the 67 million inhabitants in France as a proxy for potential misuse or abuse
This study is a cross-sectional comparative analysis of doctor shopping based on all dispensings of oxycodone in France, in 2010 and 2016. Dispensings of oxycodone were extracted from the Système national des données de santé, which covers the 67 million inhabitants in France. Quantification of doctor shopping relies on an algorithm accounting for overlapping prescriptions, which is a proxy for potential misuse or abuse. The number of subjects who received oxycodone increased by 214% from 67,838 subjects in 2010 to 212,753 subjects in 2016, and the number of subjects with doctor-shopping behavior incre...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

When pain becomes uncontrollable: an experimental analysis of the impact of instructions on pain-control attempts
Abstract: Under some conditions, people persist in their attempts to control their pain even when no such control is possible. Theory suggests that such pain-control attempts arise from actual pain experiences. Across 3 experiments we examined how (1) losing control over pain and (2) instructions concerning pain, moderated pain-control attempts. In each experiment, participants completed a learning task. Before the task, one group of participants received instructions outlining a strategy through which they could control pain, whereas another group had to develop such a strategy through trial-and-error learning. During...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Antenatal pain, intimate partner violence, and maternal bonding disorder: data from the Japan Environment and Children's Study
This prospective study examined (1) whether antenatal pain is associated with postnatal maternal bonding disorder (MBD) through postnatal depression and (2) whether intimate partner violence (IPV) has a moderating effect on the association between antenatal pain and postnatal MBD. We analyzed 77,326 pregnancies of women who completed self-report questionnaires including the SF-8 bodily pain item, the Edinburgh Postnatal Depression Scale, the Mother-to-Infant Bonding Scale, and an assessment of IPV. We conducted a mediation analysis to assess whether postnatal depression mediated the association between antenatal pain and M...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Prolonged opioid use among opioid-naive individuals after prescription for nonspecific low back pain in the emergency department
Low back pain is a leading cause of disability globally. It is a common reason for presentation to the emergency department where opioids are commonly prescribed. This is a retrospective cohort study of opioid-naive adults with low back pain presenting to 1 of 4 emergency departments in Nova Scotia. We use routinely collected administrative clinical and drug-use data (July 2010-November 2017) to investigate the prevalence of prolonged opioid use and associated individual and prescription characteristics. In total, 23,559 eligible individuals presented with nonspecific low back pain, with 84.4% being opioid-naive. Our study...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Optimized acupuncture treatment (acupuncture and intradermal needling) for cervical spondylosis–related neck pain: a multicenter randomized controlled trial
Cervical spondylosis (CS)-related neck pain is difficult to treat because of its degenerative nature. The aim of this 9-center, single-blinded, randomized controlled trial was to evaluate the efficacy of optimized acupuncture for CS-related neck pain. Participants who met the inclusion criteria were randomized to optimized, shallow, and sham acupuncture groups (1:1:1). The primary outcome was the change from baseline in the Northwick Park Neck Pain Questionnaire score at week 4. Participants were followed up until week 16. Of the 896 randomized participants, 857 received ≥1 intervention session; 280, 286, and 291 receiv...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

No pain, still gain (of function): the relation between sensory profiles and the presence or absence of self-reported pain in a large multicenter cohort of patients with neuropathy
The pathophysiology of pain in neuropathy is complex and may be linked to sensory phenotypes. Quantitative sensory testing, a standardized method to evaluate sensory profiles in response to defined stimuli, assesses functional integrity of small and large nerve fiber afferents and central somatosensory pathways. It has revealed detailed insights into mechanisms of neuropathy, yet it remains unclear if pain directly affects sensory profiles. The main objective of this study was to investigate sensory profiles in patients with various neuropathic conditions, including polyneuropathy, mononeuropathy, and lesions to the centra...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Cell–cell interactions in joint pain: rheumatoid arthritis and osteoarthritis
No abstract available (Source: Pain)
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: PAIN Pictured Source Type: research

An unusual complication of quadriparesis after trigger point injection: a case report
Abstract: Quadriparesis after intramuscular trigger point injections for myofascial pain syndrome has been rarely reported in the literature. A 37-year-old male patient presented with myofascial pain syndrome and was given trigger point injections in trapezius muscles under ultrasound guidance. The patient noticed weakness in all the 4 limbs at approximately 12 hours after the procedure, which gradually progressed to functional quadriplegia at the time of presentation to the emergency department. On examination, he had quadriparesis with no sensory involvement and superficial reflexes were normal. MRI screening of the ...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Clinical Note Source Type: research

The STarT Back stratified care model for nonspecific low back pain: a model-based evaluation of long-term cost-effectiveness
This study therefore produces a de novo decision model of this stratified care approach for LBP management to estimate the long-term cost-effectiveness and address methodological concerns in LBP modelling. A cost-utility analysis from the National Health Service perspective compared stratified care with usual care in patients consulting in primary care with nonspecific LBP. A Markov state-transition model was constructed where patient prognosis over 10 years was dependent on physical function achieved at 12 months. Data from the clinical trial and implementation study provided short-term model parameters, with extrapolatio...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Systematic Review and Meta-Analysis Source Type: research

The time course of attentional biases in pain: a meta-analysis of eye-tracking studies
Previous meta-analyses investigating attentional biases towards pain have used reaction time measures. Eye-tracking methods have been adopted to more directly and reliably assess biases, but this literature has not been synthesized in relation to pain. This meta-analysis aimed to investigate the nature and time course of attentional biases to pain-related stimuli in participants of all ages with and without chronic pain using eye-tracking studies and determine the role of task parameters and theoretically relevant moderators. After screening, 24 studies were included with a total sample of 1425 participants. Between-group ...
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Systematic Review and Meta-Analysis Source Type: research

Relationship between psychological factors and spinal motor behaviour in low back pain: a systematic review and meta-analysis
In conclusion, the very small effect sizes found in the meta-analyses question the role of psychological factors as major causes of spinal movement avoidance in low back pain. Experimental studies with more specific and individualized measures of psychological factors, pain intensity, and spinal motor behaviour are recommended. (Source: Pain)
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Systematic Review and Meta-Analysis Source Type: research

Altered interoception and its role for the co-occurrence of chronic primary pain and mental health problems in children
No abstract available (Source: Pain)
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Topical Review Source Type: research

What can we learn from the failure of quantitative sensory testing?
No abstract available (Source: Pain)
Source: Pain - February 25, 2021 Category: Anesthesiology Tags: Commentary Source Type: research

Intergenerational transmission of chronic pain-related disability: the explanatory effects of depressive symptoms
Parents with chronic pain have a higher likelihood of having depression and anxiety and more often have children with these conditions. Depressive and anxious symptoms in children worsen pain-related disability and may be derived from exposure to their parents' symptoms. We assessed a model of intergenerational chronic pain-related disability that relies upon depressive and anxious symptoms of a mother and their child. Adolescents in grades 5 to 10 from 5 schools, and their mothers, completed standardized electronic questionnaires about pain. In maternal-offspring dyads (n = 1179), the mean offspring age was 12.7 years (SD...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Neural effects of placebo analgesia in fibromyalgia patients and healthy individuals
Placebo analgesia is hypothesized to involve top-down engagement of prefrontal regions that access endogenous pain inhibiting opioid pathways. Fibromyalgia (FM) patients have neuroanatomical and neurochemical alterations in pathways relevant to placebo analgesia. Thus, it remains unclear whether placebo analgesic mechanisms would differ in FM patients compared to healthy controls (HCs). Here, using placebo-analgesia-inducing paradigms that included verbal suggestions and conditioning manipulations, we examined whether behavioral and neural placebo analgesic responses differed between 32 FM patients and 46 age- and sex-matc...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Relationship of prosthesis ownership and phantom limb pain: results of a survey in 2383 limb amputees
Phantom limb pain (PLP) accounts for a significant reduction in quality of life and is difficult to treat. Prosthesis use has been shown to negatively covary with PLP. Recent research on body perception in amputees suggest that prosthesis ownership, defined as the extent to which a prosthesis is experienced as being part of the body rather than an artificial device foreign to the body, might interact with PLP. We used survey data from 2383 unilateral prosthesis-using upper-limb or lower-limb amputees and performed regression analyses to determine the relationship between prosthesis ownership and PLP. To test for specificit...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Cross-sectional study of psychosocial and pain-related variables among patients with chronic pain during a time of social distancing imposed by the coronavirus disease 2019 pandemic
The COVID-19 pandemic has had a tremendous impact, including on individuals with chronic pain. The social distancing policies necessary to slow the spread of SARS-CoV-2 have involved increased levels of social isolation. This cross-sectional survey study examined pain severity and interference among individuals with chronic pain during an early phase of social distancing mandates and identified characteristics of individuals who were most impacted. Approximately 4 to 8 weeks after social distancing mandates commenced in the state of Massachusetts, 150 patients with fibromyalgia, chronic spine, and postsurgical pain complet...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Nociceptive afferent phenotyping reveals that transient receptor potential ankyrin 1 promotes cold pain through neurogenic inflammation upstream of the neurotrophic factor receptor GFRα3 and the menthol receptor transient receptor potential melastatin 8
The proper detection and behavioral response to painfully cold temperatures is critical for avoiding potentially harmful tissue damage. Cold allodynia and hyperalgesia, pain associated with innocuous cooling and exaggerated pain with noxious cold, respectively, are common in patients with chronic pain. In peripheral somatosensory afferents, the ion channels transient receptor potential melastatin 8 (TRPM8) and transient receptor potential ankyrin 1 (TRPA1) are candidate receptors for innocuous and noxious cold temperatures, respectively. However, the role of TRPA1 as a cold sensor has remained controversial, and recent evi...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Metabolomic analysis coupled with extreme phenotype sampling identified that lysophosphatidylcholines are associated with multisite musculoskeletal pain
Musculoskeletal pain often occurs simultaneously at multiple anatomical sites. The aim of the study was to identify metabolic biomarkers for multisite musculoskeletal pain (MSMP) by metabolomics with an extreme phenotype sampling strategy. The study participants (n = 610) were derived from the Newfoundland Osteoarthritis Study. Musculoskeletal pain was assessed using a self-reported pain questionnaire where painful sites were circled on a manikin by participants and the total number of painful sites were calculated. Targeted metabolomic profiling on fasting plasma samples was performed using the Biocrates AbsoluteIDQ p180 ...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Differential actions of indomethacin: clinical relevance in headache
Nonsteroidal anti-inflammatory drugs, cyclooxygenase inhibitors, are used routinely in the treatment of primary headache disorders. Indomethacin is unique in its use in the diagnosis and treatment of hemicrania continua and paroxysmal hemicrania. The mechanism of this specific action is not fully understood, although an interaction with nitric oxide (NO) signaling pathways has been suggested. Trigeminovascular neurons were activated by dural electrical stimulation, systemic administration of an NO donor, or local microiontophoresis of L-glutamate. Using electrophysiological techniques, we subsequently recorded the activati...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

High-dose spinal cord stimulation for patients with failed back surgery syndrome: a multicenter effectiveness and prediction study
The use of high-dose spinal cord stimulation (HD-SCS) has increased drastically during the past few years, with positive results. However, there remains a deficit of real-world data of the effectiveness of HD-SCS. Therefore, the primary aim was to evaluate the effectiveness of HD-SCS in patients with failed back surgery syndrome (FBSS). The second aim was to develop a prediction model for a holistic responder. One hundred ninety-four patients were recruited to a multicenter real-world registry. Self-reporting outcome variables were evaluated at baseline (before SCS) and at 1, 3, and 12 months of HD-SCS implant. Outcome mea...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

A spider-venom peptide with multitarget activity on sodium and calcium channels alleviates chronic visceral pain in a model of irritable bowel syndrome
Chronic pain is a serious debilitating condition that affects ∼20% of the world's population. Currently available drugs fail to produce effective pain relief in many patients and have dose-limiting side effects. Several voltage-gated sodium (NaV) and calcium (CaV) channels are implicated in the etiology of chronic pain, particularly NaV1.1, NaV1.3, NaV1.7–NaV1.9, CaV2.2, and CaV3.2. Numerous NaV and CaV modulators have been described, but with few exceptions, they display poor potency and/or selectivity for pain-related channel subtypes. Here, we report the discovery and characterization of 2 novel tarantula-veno...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Double-blind, randomized, placebo-controlled crossover trial of alpha-lipoic acid for the treatment of fibromyalgia pain: the IMPALA trial
Fibromyalgia is a common and challenging chronic pain disorder with few, if any, highly effective and well-tolerated treatments. Alpha-lipoic acid (ALA) is a nonsedating antioxidant with evidence of efficacy in the treatment of symptomatic diabetic neuropathy that has not been evaluated in the setting of fibromyalgia treatment. Thus, we conducted a single-centre, proof-of-concept, randomized, placebo-controlled, crossover trial of ALA for the treatment of fibromyalgia. Twenty-seven participants were recruited, and 24 participants completed both treatment periods of the trial. The median maximal tolerated dose of ALA in thi...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Association between chronic pain and long-term cognitive decline in a population-based cohort of elderly participants
Chronic pain (CP) was associated with impaired cognitive performance in several cross-sectional studies conducted in older adults; however, fewer longitudinal studies assessed this link that remains still debated. With a prospective design, the present analysis was aimed at evaluating the relationship between CP and the change in several tests assessing memory, attention, verbal fluency, and processing speed. The study population was selected from the PAQUID study, a cohort of community dwellers aged 65 years and older; 693 subjects receiving a pain assessment were included. Chronic pain was evaluated using a questionnaire...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

A combination of pain indices based on momentary assessments can predict placebo response in patients with fibromyalgia syndrome
In conclusion, profiles of pain characteristics derived from baseline EMA may be useful for detecting patient subgroups with enhanced placebo responses that can diminish assay sensitivity in pain clinical trials. (Source: Pain)
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Effects of sex on placebo effects in chronic pain participants: a cross-sectional study
Sex-related differences can influence outcomes of randomized clinical trials and may jeopardize the effectiveness of pain management and other therapeutics. Thus, it is essential to understand the mechanistic and translational aspects of sex differences in placebo outcomes. Recently, studies in healthy participants have shed light on how sex-related placebo effects might influence outcomes, yet no research has been conducted in a patient population. Herein, we used a tripartite approach to evaluate the interaction of prior therapeutic experience (eg, conditioning), expectations, and placebo effects in 280 chronic (orofacia...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Acupuncture alleviates chronic pain and comorbid conditions in a mouse model of neuropathic pain: the involvement of DNA methylation in the prefrontal cortex
We examined whether acupuncture can restore epigenetic changes caused by chronic pain, and identified the underlying mechanisms in neuropathic pain mice. Acupuncture treatment for 6 months (3 days/week) improved mechanical/cold allodynia and the emotional/cognitive dysfunction caused by left partial sciatic nerve ligation (PSNL)-induced neuropathic pain. The effects of acupuncture were associated with global DNA methylation recovery in the prefrontal cortex (PFC). Analysis of DNA methylation patterns in PFC indicated that 1364 overlapping genes among 4442 and 4416 methylated genes in the PSNL vs sham and PSNL vs acupunctur...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Prevalence and predictors of burnout symptoms in multidisciplinary pain clinics: a mixed-methods study
Frequent exposure to patient distress is associated with a higher prevalence of clinician distress and burnout. Patients with chronic pain often present with high levels of emotional distress. The current study examined the prevalence of burnout symptoms among a multidisciplinary sample of pain clinicians in Australia, the relationship between clinician confidence managing emotions and symptoms of burnout, and clinicians' perspectives on sources of stress and wellbeing at work. One hundred seventy-six clinicians from 58 multidisciplinary pain clinics across Australia completed a survey including the 22-item Maslach Burnout...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Foxo1 selectively regulates static mechanical pain by interacting with Nav1.7
Mechanical allodynia is a debilitating condition for millions of patients with chronic pain. Mechanical allodynia can manifest in distinct forms, including brush-evoked dynamic and filament-evoked static allodynia. In the nervous system, the forkhead protein Foxo1 plays a critical role in neuronal structures and functions. However, the role of Foxo1 in the somatosensory signal remains unclear. Here, we found that Foxo1 selectively regulated static mechanical pain. Foxo1 knockdown decreased sensitivity to static mechanical stimuli in normal rats and attenuated static mechanical allodynia in rat models for neuropathic, infla...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Prism adaptation treatment for upper-limb complex regional pain syndrome: a double-blind randomized controlled trial
We examined the effects of prism adaptation vs sham treatment on current pain intensity and the CRPS symptom severity score (primary outcomes), as well as sensory, motor, and autonomic functions, self-reported psychological functioning, and experimentally tested neuropsychological functions (secondary outcomes). We found no evidence that primary or secondary outcomes differed between the prism adaptation and sham treatment groups when tested at either time point after treatment. Overall, CRPS severity significantly decreased over time for both groups, but we found no benefits of prism adaptation beyond sham treatment. Our ...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Sex- and cell-dependent contribution of peripheral high mobility group box 1 and TLR4 in arthritis-induced pain
In this study, we addressed the role of peripheral HMGB1 and explored if sex contributes differentially to nociception in arthritis. We found Hmgb1 expression to be elevated in the ankle joints of male and female mice subjected to collagen antibody-induced arthritis. Blocking the action of peripheral HMGB1, however, only reversed collagen antibody-induced arthritis-mediated hypersensitivity in males. Intra-articular injection of the toll-like receptor (TLR)4-activating, partially reduced disulfide, but not the fully reduced all-thiol, HMGB1 evoked mechanical hypersensitivity in both sexes. A sex-dependent temporal profile ...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Sex-dependent role of microglia in disulfide high mobility group box 1 protein-mediated mechanical hypersensitivity
High mobility group box 1 protein (HMGB1) is increasingly regarded as an important player in the spinal regulation of chronic pain. Although it has been reported that HMGB1 induces spinal glial activation in a Toll-like receptor (TLR)4-dependent fashion, the aspect of sexual dimorphisms has not been thoroughly addressed. Here, we examined whether the action of TLR4-activating, partially reduced disulfide HMGB1 on microglia induces nociceptive behaviors in a sex-dependent manner. We found disulfide HMGB1 to equally increase microglial Iba1 immunoreactivity in lumbar spinal dorsal horn in male and female mice, but evoke high...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Novel bifunctional hybrid compounds designed to enhance the effects of opioids and antagonize the pronociceptive effects of nonopioid peptides as potent analgesics in a rat model of neuropathic pain
The purpose of our work was to determine the role of nonopioid peptides derived from opioid prohormones in sensory hypersensitivity characteristics of neuropathic pain and to propose a pharmacological approach to restore the balance of these endogenous opioid systems. Nonopioid peptides may have a pronociceptive effect and therefore contribute to less effective opioid analgesia in neuropathic pain. In our study, we used unilateral chronic constriction injury (CCI) of the sciatic nerve as a neuropathic pain model in rats. We demonstrated the pronociceptive effects of proopiomelanocortin- and proenkephalin-derived nonopioid ...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

The α2/α3GABAA receptor modulator TPA023B alleviates not only the sensory but also the tonic affective component of chronic pain in mice
Diminished synaptic inhibition in the spinal dorsal horn is a major contributor to pathological pain syndromes of neuropathic or inflammatory origin. Drugs that enhance the activity of dorsal horn α2/α3GABAARs normalize exaggerated nociceptive responses in rodents with neuropathic nerve lesions or peripheral inflammation but lack most of the typical side effects of less specific GABAergic drugs. It is however still unknown whether such drugs also reduce the clinically more relevant conscious perception of pain. Here, we investigated the effects of the α2/α3GABAAR subtype-selective modulator TPA023B ...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Hyporesponsivity to mu-opioid receptor agonism in the Wistar-Kyoto rat model of altered nociceptive responding associated with negative affective state
Chronic pain is often comorbid with anxiety and depression, altering the level of perceived pain, which negatively affects therapeutic outcomes. The role of the endogenous mu-opioid receptor (MOP) system in pain–negative affect interactions and the influence of genetic background thereon are poorly understood. The inbred Wistar-Kyoto (WKY) rat, which mimics aspects of anxiety and depression, displays increased sensitivity (hyperalgesia) to noxious stimuli, compared with Sprague-Dawley (SD) rats. Here, we report that WKY rats are hyporesponsive to the antinociceptive effects of systemically administered MOP agonist mo...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Tapentadol vs oxycodone for postoperative pain treatment the first 7 days after total knee arthroplasty: a randomized clinical trial
This study compared the effectiveness of tapentadol extended-release (ER) 50 mg × 2, oxycodone controlled-release (CR) 10 mg × 2, and placebo, as added to a multimodal analgesic regime both in-hospital and at home the first week after total knee arthroplasty. The study was randomized and blinded for investigators, staff, outcome assessors, and patients. Follow-up included pain intensity on mobilization, pain at rest, worst pain in the previous 24 hours, and adverse effects measured on 0 to 10 numerical rating scales. A total of 134 patients in 3 study groups received their allocated intervention and were includ...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Histone deacetylase 3 in hippocampus contributes to memory impairment after chronic constriction injury of sciatic nerve in mice
Chronic neuropathic pain is frequently accompanied by memory impairment, yet the underlying mechanisms remain unclear. Here, we showed that mice displayed memory impairment starting at 14 days and lasting for at least 21 days after chronic constriction injury (CCI) of unilateral sciatic nerve in mice. Systemic administration of the pan histone deacetylase (HDAC) inhibitor sodium butyrate attenuated this memory impairment. More specifically, we found that hippocampus HDAC3 was involved in this process because the levels of its mRNA and protein increased significantly in the hippocampus at 14 and 21 days after CCI, but not s...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Identification of neural and psychophysical predictors of headache reduction after cognitive behavioral therapy in adolescents with migraine
Cognitive behavioral therapy (CBT) is a psychological intervention that involves development of coping strategies to reduce the experience of pain. Although CBT is a promising intervention to reduce headache days in patients with migraine, it may not be effective for all patients. Thus, there is a need to identify markers that could predict which patients will respond to CBT. We aimed to determine whether baseline brain function and amygdalar connectivity, assessed by functional magnetic resonance imaging, or pain modulation capacities, assessed by the conditioned pain modulation (CPM) response, can predict a reduction in ...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

Trigeminal neuralgia diffusivities using Gaussian process classification and merged group tractography
Imaging of trigeminal neuralgia (TN) has demonstrated key diffusion tensor imaging-based diffusivity alterations in the trigeminal nerve; however, imaging has primarily focused on the peripheral nerve segment because of previous limitations in reliably segmenting small fiber bundles across multiple subjects. We used Selective Automated Group Integrated Tractography to study 36 subjects with TN (right-sided pain) and 36 sex-matched controls to examine the trigeminal nerve (fifth cranial nerve [CN V]), pontine decussation (TPT), and thalamocortical fibers (S1). Gaussian process classifiers were trained by scrolling a moving ...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Research Paper Source Type: research

The use and reporting of neonatal pain scales: a systematic review of randomized trials
The burden of pain in newborn infants has been investigated in numerous studies, but little is known about the appropriateness of the use of pain scales according to the specific type of pain or infant condition. This systematic review aimed to evaluate the reporting of neonatal pain scales in randomized trials. A systematic search up to March 2019 was performed in Embase, PubMed, PsycINFO, CINAHL, Cochrane Library, Scopus, and Luxid. Randomized and quasirandomized trials reporting neonatal pain scales were included. Screening of the studies for inclusion, data extraction, and quality assessment was performed independently...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Systematic Review and Meta-Analysis Source Type: research

Attentional bias to somatosensory stimuli in chronic pain patients: a systematic review and meta-analysis
This systematic review and meta-analysis aimed to evaluate the evidence pertaining to attentional bias for painful and nonpainful somatosensory stimuli in individuals with chronic pain. Eligible studies were identified through searches of Medline, PsycINFO, CINAHL, Web of Science, Scopus, and Cochrane Library databases. Search terms were words and phrases organised into 3 concept blocks: pain condition, cognitive process, and stimuli/paradigm. The search identified 29 eligible studies (reporting 32 eligible experiments), of which quantitative meta-analysis was possible for 16 studies (19 experiments). The meta-analysis fou...
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Systematic Review and Meta-Analysis Source Type: research

Virtual reality approaches to pain: toward a state of the science
No abstract available (Source: Pain)
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Topical Review Source Type: research

Unveiling new mechanisms for cold sensitization
No abstract available (Source: Pain)
Source: Pain - January 22, 2021 Category: Anesthesiology Tags: Commentary Source Type: research

Reply to Goebel and Molloy
No abstract available (Source: Pain)
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Correspondence Source Type: research

Diagnosis of chronic primary pain in the context of structural deformity needs better definition
No abstract available (Source: Pain)
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Correspondence Source Type: research

Is obesity associated with odds of prescription opioid use independent of depression?
No abstract available (Source: Pain)
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Correspondence Source Type: research