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

Opioid-induced constipation in patients with cancer: a “real-world,” multicentre, observational study of diagnostic criteria and clinical features
The aim of this study was to investigate opioid-induced constipation (OIC) in a large cohort of “real-world” patients with cancer; the objectives were to determine the prevalence of OIC, the utility of a simple screening question, the accuracy of the Rome IV diagnostic criteria, the clinical features of OIC (physical and psychological), and the impact of OIC (quality of life). One thousand patients with cancer were enrolled in the study, which involved completion of the Rome IV diagnostic criteria for OIC, the Bowel Function Index, the Patient Assessment of Constipation Quality of Life questionnaire, and the Me...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

GABA and glutamate in pediatric migraine
Migraine is one of the top 5 most prevalent childhood diseases; however, effective treatment strategies for pediatric migraine are limited. For example, standard adult pharmaceutical therapies are less effective in children and can carry undesirable side effects. To develop more effective treatments, improved knowledge of the biology underlying pediatric migraine is necessary. One theory is that migraine results from an imbalance in cortical excitability. Magnetic resonance spectroscopy (MRS) studies show changes in GABA and glutamate levels (the primary inhibitory and excitatory neurotransmitters in the brain, respectivel...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

An experimental investigation into the mediating role of pain-related fear in boosting nocebo hyperalgesia
Nocebo hyperalgesia refers to increases in perceived pain that putatively result from negative expectations regarding a nocebo stimulus (eg, an inert treatment, compared with no treatment). The precise cognitive-emotional factors contributing to the origins of nocebo effects are poorly understood. We aimed to test the effects of experimentally induced pain-related fear on the acquisition and extinction of nocebo hyperalgesia in healthy participants (N = 72). Acquisition and extinction of nocebo hyperalgesia were compared between a group receiving standard nocebo conditioning (Control group) and 2 groups receiving distinct ...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Modality-specific facilitation of noninjurious sharp mechanical pain by topical capsaicin
We had previously shown that a “blunt blade” stimulator can mimic the noninjurious strain phase of incisional pain, but not its sustained duration. Here, we tested whether acute sensitization of the skin with topical capsaicin can add the sustained phase to this noninvasive surrogate model of intraoperative pain. Altogether, 110 healthy volunteers (55 male and 55 female; 26 ± 5 years) participated in several experiments using the “blunt blade” (0.25 × 4 mm) on normal skin (n = 36) and on skin pretreated by a high-concentration capsaicin patch (8%, Qutenza; n = 36). These data were compa...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Activation of the Notch signaling pathway in the anterior cingulate cortex is involved in the pathological process of neuropathic pain
Plastic changes in the anterior cingulate cortex (ACC) are critical in pain hypersensitivity caused by peripheral nerves injury. The Notch signaling pathway has been shown to regulate synaptic differentiation and transmission. Therefore, this study was to investigate the function of the Notch signaling pathway in the ACC during nociceptive transmission induced by neuropathic pain. We adopted Western blotting, N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT) microinjections, RNA interference targeting Notch1, Hairy and enhancer of split (Hes) 1 or Hes5, electrophysiological recordings, and behavi...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Effect of combined pharmacological, behavioral, and physical interventions for procedural pain on salivary cortisol and neurobehavioral development in preterm infants: a randomized controlled trial
This study examined (1) the efficacy and safety of sucrose combined with massage, music, non-nutritive sucking, and gentle human touch to treat preterm infants with repeated procedural pain; (2) the cortisol level at discharge from the neonatal intensive care unit (NICU); (3) neurobehavioral development at 40 weeks' corrected gestational age; and (4) the potential mediating effect of the cortisol level in the combined interventions on neurobehavioral development. Stable preterm infants (n = 76) were randomized to receive routine care or combined interventions across repeated painful procedures throughout their NICU stay. T...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

SARS-CoV-2 spike protein co-opts VEGF-A/neuropilin-1 receptor signaling to induce analgesia
Global spread of severe acute respiratory syndrome coronavirus 2 continues unabated. Binding of severe acute respiratory syndrome coronavirus 2's spike protein to host angiotensin-converting enzyme 2 triggers viral entry, but other proteins may participate, including the neuropilin-1 receptor (NRP-1). Because both spike protein and vascular endothelial growth factor-A (VEGF-A)—a pronociceptive and angiogenic factor, bind NRP-1, we tested whether spike could block VEGF-A/NRP-1 signaling. VEGF-A-triggered sensory neuron firing was blocked by spike protein and NRP-1 inhibitor EG00229. Pronociceptive behaviors of VEGF-A ...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Pharmacological modulation of voltage-gated sodium (NaV) channels alters nociception arising from the female reproductive tract
This study identifies potential molecular targets that can be used to modulate vaginal nociceptive signalling and aid in the development of approaches to manage endometriosis and vulvodynia-related dyspareunia. (Source: Pain)
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Assessing the validity of health administrative data compared to population health survey data for the measurement of low back pain
Low back pain (LBP) is a high-burden condition that lacks routine surveillance data. Health administrative data may be used for surveillance, but their validity for measuring LBP in the general population has not been established. We aimed to (1) determine the validity of health administrative data to measure LBP compared to self-reported LBP in a population-based sample of Ontario adults; and (2) describe the differences in characteristics of LBP cases based on data sources. Adult respondents (≥18 years) of the Canadian Community Health Survey (CCHS) from 2003 to 2012 were included (N = 150,695). Canadian Community Hea...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Single-nucleus characterization of adult mouse spinal dynorphin-lineage cells and identification of persistent transcriptional effects of neonatal hindpaw incision
Neonatal tissue damage can have long-lasting effects on nociceptive processing in the central nervous system, which may reflect persistent injury-evoked alterations to the normal balance between synaptic inhibition and excitation in the spinal dorsal horn. Spinal dynorphin-lineage (pDyn) neurons are part of an inhibitory circuit which limits the flow of nociceptive input to the brain and is disrupted by neonatal tissue damage. To identify the potential molecular underpinnings of this disruption, an unbiased single-nucleus RNAseq analysis of adult mouse spinal pDyn cells characterized this population in depth and then ident...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Prevalence of chronic pain in opioid-maintained patients using the capture–recapture method: a nationwide population-based study
This study sought to assess the prevalence of CP in the exhaustive population of OMPs using the capture–recapture method applied to the French nationwide health care database. Capture–recapture methods are increasingly used to estimate the prevalence of chronic conditions but have never been used in the specific context of CP in OMPs. Three large medical-administrative sources were used: the prescription drug database (A-list), the national hospital discharge database (M-list), and the pain center database (C-list). Between 2015 and 2016, 160,429 OMPs aged 15 years and older were identified and age- and sex-mat...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Cold pain hypersensitivity predicts trajectories of pain and disability after low back surgery: a prospective cohort study
Improving the ability to predict persistent pain after spine surgery would allow identification of patients at risk and guide treatment decisions. Quantitative sensory tests (QST) are measures of altered pain processes, but in our previous study, preoperative QST did not predict pain and disability at single time-points. Trajectory analysis accounts for time-dependent patterns. We hypothesized that QST predict trajectories of pain and disability during 1 year after low back surgery. We performed a trajectory analysis on the cohort of our previous study (n = 141). Baseline QST included electrical, pressure, heat, and cold s...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Intradural artery dilation during experimentally induced migraine attacks
The middle meningeal artery is a proposed surrogate marker for activation of trigeminal nociceptors during migraine. Previous studies focused on the extracranial part of the artery; hence, vasoreactivity in the intradural arteries during migraine is unknown. Thirty-four patients with migraine without aura were given sildenafil on one day and calcitonin gene-related peptide on another in double-blind crossover fashion. Patients were scanned with 3.0 T MR angiography before drug administration and again 6 hours later during induced attacks of migraine. We measured circumference of the intradural segment of the middle meninge...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Netrin-1 receptor DCC is required for the contralateral topography of lamina I anterolateral system neurons
Anterolateral system (AS) neurons relay nociceptive information from the spinal cord to the brain, protecting the body from harm by evoking a variety of behaviours and autonomic responses. The developmental programs that guide the connectivity of AS neurons remain poorly understood. Spinofugal axons cross the spinal midline in response to Netrin-1 signalling through its receptor deleted in colorectal carcinoma (DCC); however, the relevance of this canonical pathway to AS neuron development has only been demonstrated recently. Here, we disrupted Netrin-1:DCC signalling developmentally in AS neurons and assessed the conseque...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

A longitudinal examination of the interpersonal fear avoidance model of pain: the role of intolerance of uncertainty
This study longitudinally examined major tenets of the Interpersonal Fear Avoidance Model of Pain and included parent and youth IU as key factors in the model. Participants included 152 youth with chronic pain (Mage = 14.23 years; 72% female) and their parents (93% female). At baseline, parents and youth reported on their IU and catastrophic thinking about youth pain; youth reported on their fear of pain, pain intensity, and pain interference; and parents reported on their protective responses to child pain. Youth reported on their pain interference 3 months later. Cross-lagged panel models, controlling for baseline pain i...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Nociceptor-localized cGMP-dependent protein kinase I is a critical generator for central sensitization and neuropathic pain
Patients with neuropathic pain often experience exaggerated pain and anxiety. Central sensitization has been linked with the maintenance of neuropathic pain and may become an autonomous pain generator. Conversely, emerging evidence accumulated that central sensitization is initiated and maintained by ongoing nociceptive primary afferent inputs. However, it remains elusive what mechanisms underlie this phenomenon and which peripheral candidate contributes to central sensitization that accounts for pain hypersensitivity and pain-related anxiety. Previous studies have implicated peripherally localized cGMP-dependent protein k...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Spinal caspase-6 regulates AMPA receptor trafficking and dendritic spine plasticity through netrin-1 in postoperative pain after orthopedic surgery for tibial fracture in mice
Chronic postoperative pain hinders functional recovery after bone fracture and orthopedic surgery. Recently reported evidence indicates that caspase-6 is important in excitatory synaptic plasticity and pathological pain. Meanwhile, netrin-1 controls postsynaptic recruitment of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) and synaptogenesis. The present work aimed to examine whether caspase-6 and netrin-1 contribute to fracture-induced postoperative allodynia. A mouse model of tibial fracture by intramedullary pinning was generated for inducing postoperative pain. Then, paw withdrawal threshol...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Machine learning suggests sleep as a core factor in chronic pain
Patients with chronic pain have complex pain profiles and associated problems. Subgroup analysis can help identify key problems. We used a data-based approach to define pain phenotypes and their most relevant associated problems in 320 patients undergoing tertiary pain management. Unsupervised machine learning analysis of parameters “pain intensity,” “number of pain areas,” “pain duration,” “activity pain interference,” and “affective pain interference,” implemented as emergent self-organizing maps, identified 3 patient phenotype clusters. Supervised analyses, imp...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research

Abnormal subgenual anterior cingulate circuitry is unique to women but not men with chronic pain
The subgenual anterior cingulate cortex (sgACC) plays an important role in pain modulation. We previously demonstrated sex differences in sgACC functional connectivity (FC) in healthy individuals. Given that many chronic pain conditions show sex differences in prevalence, here we tested the hypothesis that people with chronic pain exhibit a sex-specific pattern of abnormal sgACC FC. We acquired resting-state functional magnetic resonance imaging data from 156 (82 W: 74 M) healthy participants and 38 (19 W: 19 M) people with chronic low back pain resulting from ankylosing spondylitis, a condition that predominantly affects ...
Source: Pain - December 24, 2020 Category: Anesthesiology Tags: Research Paper Source Type: research