Pain: an overview

Social Determinants and Consequences of Pain: Toward Multilevel, Intersectional, and Life Course Perspectives

Despite wide endorsement of a biopsychosocial framework for pain, social aspects of pain remain rarely addressed in the context of pain prevention and management. In this review, we aim to 1) examine the broad scope of social determinants and consequences of pain and their interactions across multiple levels of organization, and 2) provide a framework synthesizing existing concepts and potential areas for future work on social aspects of pain, drawing upon socioecological, intersectional, and life course approaches. Integrating interdisciplinary theory and evidence, we outline pathways through which multilevel social factors and pain may affect each other over time. We also provide a brief summary of intrapersonal aspects of pain, which are thought to operate at the interface between individuals and the social context. Progressing from micro- to macrolevel factors, we illustrate how social determinants of pain can directly or indirectly contribute to pain experiences, expression, risk, prognosis, and impact across populations. We consider 1) at the interpersonal level, the roles of social comparison, social relatedness, social support, social exclusion, empathy, and interpersonal conflict; 2) at the group or community level, the roles of intimacy groups, task groups, social categories, and loose associations; and 3) at the societal level, the roles of political, economic, and cultural systems, as well as their policies and practices. We present examples of multilevel consequences of pain across these levels and discuss opportunities to reduce the burden and inequities of pain by expanding multilevel social approaches in pain research and practice. PERSPECTIVE: Despite wide endorsement of a biopsychosocial framework for pain, social aspects of pain are often unclearly defined, hindering their use in pain prevention, management, and research. We summarize the scope of social aspects of pain and provide a framework synthesizing existing concepts and potential areas for future work.

Impact of Preoperative Symptom Duration on Patient-Reported Outcomes Following Cervical Disc Replacement for Cervical Radiculopathy

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

To determine the impact of preoperative symptom duration on postoperative functional outcomes after cervical disc replacement (CDR) for radiculopathy.

SUMMARY OF BACKGROUND DATA

CDR has emerged as a reliable and efficacious treatment option for degenerative cervical spine pathologies. The relationship between preoperative symptom duration and outcomes after CDR is not well established.

METHODS

Patients with radiculopathy without myelopathy who underwent primary 1- or 2-level CDRs were included and divided into shorter (<6 mo) and prolonged (≥6 mo) cohorts based on preoperative symptom duration. Patient-reported outcome measures (PROMs) included neck disability index (NDI), visual analog scale (VAS) neck and arm. Changes in PROM scores and minimal clinically important difference (MCID) rates were calculated. Analyses were conducted on the early (within 3 mo) and late (6 mo-2 y) postoperative periods.

RESULTS

A total of 201 patients (43.6±8.7 y, 33.3% female) were included. In both early and late postoperative periods, the shorter preoperative symptom duration cohort experienced significantly greater change from preoperative PROM scores compared with the prolonged symptom duration cohort for NDI, VAS-Neck, and VAS-Arm. The shorter symptom duration cohort achieved MCID in the early postoperative period at a significantly higher rate for NDI (78.9% vs. 54.9%, P =0.001), VAS-Neck (87.0% vs. 56.0%, P <0.001), and VAS-Arm (90.5% vs. 70.7%, P =0.002). Prolonged preoperative symptom duration (≥6 mo) was identified as an independent risk factor for failure to achieve MCID at the latest timepoint for NDI (OR: 2.9, 95% CI: 1.2-6.9, P =0.016), VAS-Neck (OR: 9.8, 95% CI: 3.7-26.0, P <0.001), and VAS-Arm (OR: 7.5, 95% CI: 2.5-22.5, P <0.001).

CONCLUSIONS

Our study demonstrates improved patient-reported outcomes for those with shorter preoperative symptom duration undergoing CDR for radiculopathy, suggesting delayed surgical intervention may result in poorer outcomes and greater postoperative disability.

LEVEL OF EVIDENCE

Level III.

Diminished pain sensitivity mediates the relationship between psychopathic traits and reduced learning from pain

Individuals with elevated psychopathic traits exhibit decision-making deficits linked to a failure to learn from negative outcomes. We investigated how reduced pain sensitivity affects reinforcement-based decision-making in individuals with varying levels of psychopathic traits, as measured by the Self-Report Psychopathy Scale-Short Form. Using computational modelling, we estimated the latent cognitive processes in a community non-offender sample (n = 111) that completed a task with choices leading to painful and non-painful outcomes. Higher psychopathic traits were associated with reduced pain sensitivity and disturbances in reinforcement learning from painful outcomes. In a Structural Equation Model, a superordinate psychopathy factor was associated with a faster return to original stimulus-outcome associations as pain tolerance increased. This provides evidence directly linking reduced pain sensitivity and learning from painful outcomes with elevated psychopathic traits. Our results offer insights into the computational mechanisms of maladaptive decision-making in psychopathy and antisocial behavior.

Abscisic acid, an evolutionary conserved hormone: Biosynthesis, therapeutic and diagnostic applications in mammals

Abscisic acid (ABA), a phytohormone traditionally recognized for its role in plant stress responses, has recently emerged as a significant player in mammalian defense mechanisms. Like plants, various mammalian cell types synthesize ABA in response to specific health challenges, although the precise pathways remain not fully elucidated. ABA is associated with the regulation of inflammation and insulin signaling, prompting extensive research into its potential as a therapeutic agent for various diseases. ABA exerts its effects through its receptors, particularly PPAR-γ and LANCL-2, which serve as signaling hubs regulating numerous pathways. Through these interactions, ABA profoundly impacts mammalian health, and new ABA targets continue to be identified. Numerous studies in animal models demonstrate ABA's benefit in managing conditions such as neurological and psychiatric disorders, cancer, and malaria infections, all of which involve significant inflammatory dysregulation. In this manuscript we review the studies covering ABA synthesis and release in cell cultures, the signaling pathways regulated by ABA, and how these impact health in preclinical models. Furthermore, we highlight recent research suggesting that measuring ABA levels in human body fluids could serve as a useful biomarker for pathological conditions, providing insights into disease progression and treatment efficacy. This comprehensive review outlines the current understanding of ABA in mammalian pathophysiology, identifying gaps in knowledge, particularly concerning ABA biosynthesis and metabolism in mammals. In addition, this study emphasizes the need for clinical trials to validate the effectiveness of ABA-based therapies and its reliability as a biomarker for various diseases.

Unpacking the relationship between Big Five personality traits and experimental pain: A systematic review and meta-analysis

Pain is essential for survival, but individual responses to painful stimuli vary, representing a complex interplay between sensory, cognitive, and affective factors. Individual differences in personality traits and in pain perception covary but it is unclear which traits play the most significant role in understanding the pain experience and whether this depends on pain modality. A systematic search identified 1534 records (CINAHL, MEDLINE, PsycInfo, PubMed and Web of Science), of which 22 were retained and included in a systematic review. Only studies from the pressure pain domain (n=6) could be compared in a formal meta-analysis to evaluate the relationship between Big Five traits and experimental pain. Pressure pain tolerance correlated positively with Extraversion and negatively with Neuroticism with a trivial effect size (<0.1). While these findings suggest personality might be only weakly related to pain in healthy individuals, we emphasize the need to consider standardization, biases, and adequate sample sizes in future research, as well as additional factors that might affect experimental pain sensitivity.

A challenging diagnosis of chronic osteomyelitis in a child with congenital insensitivity to pain: a case report

Introduction

Congenital insensitivity to pain (CIP) is a rare condition where individuals are born with an inability to perceive pain. This can lead to various complications in the skin, skeletal system, and other bodily systems. Chronic osteomyelitis is one of the possible manifestations of CIP, which can be difficult to diagnose and treat due to the lack of pain as a diagnostic criterion.

Presentation

A 5-year-old boy with CIP developed chronic osteomyelitis in his right leg, presented with fever, claudication, swelling, and local heat for 2 months. He had a history of CIP since birth, diagnosed at 18 months of age. He also had a family history of CIP. He had previously suffered a shoulder fracture and had taken asthma medication for 1 year. He had experienced tonsillitis 2 months ago. On examination, he had hepatomegaly, enlarged lymph nodes in the groin, and a minor swelling on the right knee. He had an audible snapping sound during knee flexion. Blood tests showed increased inflammatory markers. Imaging studies confirmed presence of osteomyelitis, and bone biopsy revealed infection with Staphylococcus aureus. Treatment included vancomycin and cefotaxime.

Clinical discussion

Genetic factors behind CIP were discussed, highlighting challenges in diagnosis. Manifestations of CIP, diverse and age-related, include orthopaedic issues, ophthalmological effects, and thermoregulation disturbances. The patient's case is presented with unique features, necessitating a comprehensive diagnostic approach.

Conclusion

This case highlights the challenges faced in diagnosing osteomyelitis among CIP patients and emphasizes the need for other diagnostic criteria apart from pain.

Acupoint Selection in Postoperative Ophthalmic Pain Management: A Data Mining Protocol

Background

Postoperative ophthalmic pain not only induces anxiety and depression among patients, but also prolongs the recovery cycle. However, the management of postoperative pain in ophthalmology is still not standardized. The effectiveness of acupuncture in treating postoperative pain has been validated based on numerous clinical trials and meta-analysis. Our study is to conduct the first data mining analysis to identify the most effective acupoints selection and combinations for treating postoperative ophthalmic pain, inform.

Methods

We will search bibliographic databases from inception to November 2023. Clinical trials evaluating the effectiveness of acupuncture therapy in the management of postoperative ophthalmic pain will be selected. Reviews, protocols, animal studies, case reports, systematic evaluations and Meta-analyses will be excluded. Primary outcome indicators will be clinical outcomes related to postoperative ophthalmic pain. Descriptive statistics will be performed in Excel 2019. Association rule analysis will be performed in SPSS Modeler 18.0. Exploratory factor analysis and cluster analysis will be performed in SPSS Statistics 25.0.

Results

This study will investigate the most effective point selection and combination of acupuncture points for the treatment of postoperative ophthalmic pain.

Conclusion

Our findings will provide evidence for the effectiveness and potential therapeutic prescription of acupuncture for postoperative ophthalmologic pain, helping clinicians and patients work together to make more informed decisions.

Comparison of the Effectiveness of Different Methods for Pain Reduction During Injection Procedures in the Frontalis Muscle

BACKGROUND

Forehead aesthetic injections are a well-known source of discomfort, and many analgesic non-invasive techniques have been proposed to ameliorate pain. However, no study has compared all these techniques for aesthetic purposes. Therefore, this study aimed to compare the effectiveness of topical cream anesthesia, vibratory stimulus, cryotherapy, pressure, and even no intervention, on pain during and immediately after injection, when considering aesthetic injections in the forehead.

METHODS

Seventy patients were selected and had their foreheads divided into 5 parts, which received four different analgesic techniques, and one control zone was added. A numeric rating scale was used to assess pain, two direct questions were asked to evaluate patients' preference and discomfort with the techniques, and the adverse events were quantified. The injections were performed in the same sequence, with three minutes of rest between them and in a single session. Comparisons among analgesic methods for pain relief were performed by the one-way analysis of variance (ANOVA), considering a significance level of 5%.

RESULTS

No significant differences were found among the analgesic methods, and between the methods and the control zone, both during and immediately after the injections (p > 0.05). The preferred method for pain relief was the use of topical anesthetic cream (47%), while the most uncomfortable technique was manual distraction (pressure) (36%). Only one patient reported an adverse event.

CONCLUSIONS

No analgesic method to diminish pain was superior to the others or was better than no method. Nevertheless, the topical anesthetic cream was the preferred technique, causing less discomfort.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Effect of Needle Gauge Size on Pain During Intravitreal Anti-VEGF Injection: A Systematic Review and Network Meta-Analysis

INTRODUCTION

Concerns related to pain from intravitreal injections are one of the key factors mentioned by patients when asked about therapy. In this systematic review and network meta-analysis, we evaluate the literature of comparative clinical trials on the relationship between needle gauge size and pain experience during intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy.

METHODS

We searched 12 literature databases on 14 October 2023 for comparative studies of gauge sizes for intravitreal anti-VEGF injections. The primary outcome of interest was the reported pain experience immediately after the injection. All outcomes of pain were transformed into standardized effect sizes using Cohen's d. Using a network meta-analysis approach, we were able to compare all gauge sizes and rank them according to the reported pain experience.

RESULTS

We identified nine eligible studies with data on a total of 998 patients and 1004 eyes. Needle sizes studied were 26-gauge, 27-gauge, 29-gauge, 30-gauge, 32-gauge, 33-gauge, and 34-gauge. A complete network was present, which allowed for a network meta-analysis. We used the thickest (26-gauge) needle as the reference group and observed a clear trend of lower pain experience with thinner gauge sizes (d: -0.4, d: -2.7, d: -3.8, d: -4.8, d: -4.5, and d: -5.3; respectively, for 27-gauge, 29-gauge, 30-gauge, 32-gauge, 33-gauge, and 34-gauge).

CONCLUSION

A gauge size of 30 or thinner may minimize patient discomfort related to intravitreal anti-VEGF therapy.

Pain symptoms and physical performance in older adults: cross-sectional findings from the International Mobility in Aging Study (IMIAS)

PURPOSE

To analyze the associations between pain and physical performance in different aging contexts.

METHODS

Data from 1725 older adults from Canada, Brazil, Colombia, and Albania from the 2014 wave of the IMIAS were used to assess the associations between Back Pain (BP) or Lower Limb Pain (LLP) and physical performance by the Short Physical Performance Battery (SPPB). Three binary logistic regression models adjusted for sex, age, study site, education, income sufficiency, BMI, depressive symptoms, and chronic conditions were used to estimate the associations between LLP or BP and SPPB. The SPPB was classified into good performance (8 points or more) and poor physical performance (< 8 points).

RESULTS

The mean age of the older men was 71.2 (± 3.0) and the mean age of the women was 71.2 (± 2.8) years. Older men (72.8%, p < 0.05) and women (86.1%, p-value < 0.05) from Albania had the highest frequencies of self-reported general pain. Older women in Colombia had the highest frequencies of LLP or BP (33.5%, p-value < 0.05). In the fully adjusted logistic regression model, LLP or BP was significantly associated with poor SPPB (OR = 0.48, 0.35 to 0.66 95% CI, p < 0.01).

CONCLUSIONS

Pain symptoms are associated with reduced physical performance in older people, even when adjusted for other clinical and sociodemographic factors. Protocols for aiming to increase the level of physical activity to manage pain should be incorporated into health care strategies.

Prediction of pain using electrocardiographic-derived autonomic measures: A systematic review

BACKGROUND AND OBJECTIVE

Pain is a major clinical challenge, and understanding the pathophysiology is critical for optimal management. The autonomic nervous system reacts to pain stimuli, and autonomic dysfunction may predict pain sensation. The most used assessment of autonomic function is based on electrocardiographic measures, and the ability of such measures to predict pain was investigated.

DATABASES AND DATA TREATMENT

English articles indexed in PubMed and EMBASE were reviewed for eligibility and included when they reported electrocardiographic-derived measures' ability to predict pain response. The quality in prognostic studies (QUIPS) tool was used to assess the quality of the included articles.

RESULTS

The search revealed 15 publications, five on experimental pain, five on postoperative pain, and five on longitudinal clinical pain changes, investigating a total of 1069 patients. All studies used electrocardiographically derived parameters to predict pain assessed with pain thresholds using quantitative sensory testing or different scales. Across all study modalities, electrocardiographic measures were able to predict pain. Higher parasympathetic activity predicted decreased experimental, postoperative, and long-term pain in most cases while changes in sympathetic activity did not consistently predict pain.

CONCLUSIONS

Most studies demonstrated that parasympathetic activity could predict acute and chronic pain intensity. In the clinic, this may be used to identify which patients need more intensive care to prevent, for example postoperative pain and develop personalized chronic pain management.

SIGNIFICANCE

Pain is a debilitating problem, and the ability to predict occurrence and severity would be a useful clinical tool. Basal autonomic tone has been suggested to influence pain perception. This systematic review investigated electrocardiographic-derived autonomic tone and found that increased parasympathetic tone could predict pain reduction in different types of pain.

Studies on Pain Associated with Anxiety or Depression in the Last 10 Years: A Bibliometric Analysis

Background

The prevalence of pain comorbid and anxiety/depression in clinical observations has been high, and the number of related publications has increased in recent years. Nevertheless, few studies have used bibliometric methods to analyze the scientific research on comorbid pain and depression/anxiety. The aim of this study was to systematically examine the trends in global scientific research on comorbid pain and depression/anxiety from 2012 to 2022.

Methods

Papers published between 2012 and 2022 were identified in the Web of Science database. Publications that examined comorbid pain and depression/anxiety were included. The language was limited to English. CiteSpace, Excel and VOSviewer were used to analyze the volume of publications, countries, institutions, authors, cocited authors, and keywords.

Results

A total of 30,290 papers met the inclusion criteria of the study. Using CiteSpace, VOSviewer and Excel, the results showed that the United States (10,614 publications), Harvard University (1195 publications), and Jensen, Mark P. (77 publications) were the most productive country, institution, and author, respectively. The hotspots and frontiers were "relationship between depression and pain", "gender differences in pain and depression/anxiety domains", "study of specific pain types with depression/anxiety", "treatment of pain combined with anxiety/depression", and "effects of COVID-19 on patients with pain combined with depression/anxiety".

Conclusion

These findings indicate a growing interest in the field of comorbid pain and depression/anxiety. The research has been broad and deep, but there is still much room for growth. Furthermore, there is a need for more mature global collaborative networks as well as more high-quality research results in the future.

Stem cells and pain

Pain can be defined as an unpleasant sensory and emotional experience caused by either actual or potential tissue damage or even resemble that unpleasant experience. For years, science has sought to find treatment alternatives, with minimal side effects, to relieve pain. However, the currently available pharmacological options on the market show significant adverse events. Therefore, the search for a safer and highly efficient analgesic treatment has become a priority. Stem cells (SCs) are non-specialized cells with a high capacity for replication, self-renewal, and a wide range of differentiation possibilities. In this review, we provide evidence that the immune and neuromodulatory properties of SCs can be a valuable tool in the search for ideal treatment strategies for different types of pain. With the advantage of multiple administration routes and dosages, therapies based on SCs for pain relief have demonstrated meaningful results with few downsides. Nonetheless, there are still more questions than answers when it comes to the mechanisms and pathways of pain targeted by SCs. Thus, this is an evolving field that merits further investigation towards the development of SC-based analgesic therapies, and this review will approach all of these aspects.

The role of pain modulation pathway and related brain regions in pain

Pain is a multifaceted process that encompasses unpleasant sensory and emotional experiences. The essence of the pain process is aversion, or perceived negative emotion. Central sensitization plays a significant role in initiating and perpetuating of chronic pain. Melzack proposed the concept of the "pain matrix", in which brain regions associated with pain form an interconnected network, rather than being controlled by a singular brain region. This review aims to investigate distinct brain regions involved in pain and their interconnections. In addition, it also sheds light on the reciprocal connectivity between the ascending and descending pathways that participate in pain modulation. We review the involvement of various brain areas during pain and focus on understanding the connections among them, which can contribute to a better understanding of pain mechanisms and provide opportunities for further research on therapies for improved pain management.

Cebranopadol for the Treatment of Chronic Pain

PURPOSE OF REVIEW

Regardless of the etiology, if pain persists chronically, it can detrimentally impact multiple aspects of a patient's well-being. Both physical and psychological effects are significant in many chronic pain patients. In this regard, psychological consequences can alter a patient's quality of life, functionality, and social functioning. Opioids have been the long-established gold standard for acute pain treatment in settings such as the postoperative period. An alternative to opioids in pain management has been highly sought after. Through a non-selective mechanism, cebranopadol is a first-in-class oral drug which combines agonism of the mu and nociceptin opioid peptide (NOP) receptors to provide improved analgesia, while reducing the occurrence of many typically opioid side effects. This manuscript is a narrative review of the possible use of cebranopadol in pain management.

RECENT FINDINGS

In pre-clinical studies, cebranopadol was similar to morphine in its pain control efficacy. In a phase IIa trial, cebranopadol was superior to placebo in reducing pain. In a randomized clinical trial, cebranopadol was superior to morphine. Another study concluded that cebranopadol had a lower misuse potential when compared to hydromorphone. In summary, cebranopadol offers new opportunities in treating chronic moderate to severe pain, while also countering risks of addiction. Additional studies are warranted to further evaluate the safety and efficacy of cebranopadol. In this regard, cebranopadol could prove to be a promising alternative to current pain treatment options.

Tramadol for chronic pain in adults: protocol for a systematic review with meta-analysis and trial sequential analysis of randomised clinical trials

BACKGROUND

Chronic pain in adults is a frequent clinical symptom with a significant impact on patient well-being. Therefore, sufficient pain management is of utmost importance. While tramadol is a commonly used pain medication, the quality of evidence supporting its use has been questioned considering the observed adverse events. Our objective will be to assess the benefits and harms of tramadol compared with placebo or no intervention for chronic pain.

METHODS/DESIGN

We will conduct a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis to assess the beneficial and harmful effects of tramadol in any dose, formulation, or duration. We will accept placebo or no intervention as control interventions. We will include adult participants with any type of chronic pain, including cancer-related pain. We will systematically search the Cochrane Library, MEDLINE, EMBASE, Science Citation Index, and BIOSIS for relevant literature. We will follow the recommendations by Cochrane and the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. The risk of systematic errors ('bias') and random errors ('play of chance') will be assessed. The certainty of evidence will be evaluated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

DISCUSSION

Although tramadol is often being used to manage chronic pain conditions, the beneficial and harmful effects of this intervention are unknown. The present review will systematically assess the current evidence on the benefits and harms of tramadol versus placebo or no intervention to inform clinical practice and future research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019140334.

Preoperative Pain Facilitates Postoperative Cognitive Dysfunction via Periaqueductal Gray Matter-Dorsal Raphe Circuit

Postoperative cognitive dysfunction (POCD) is a medically induced, rapidly occurring postoperative disease, which is hard to recover and seriously threatens the quality of life, especially for elderly patients, so it is important to identify the risk factors for POCD and apply early intervention to prevent POCD. As we have known, pain can impair cognition, and many surgery patients experience different preoperative pain, but it is still unknown whether these patients are vulnerable for POCD. Here we found that chronic pain (7 days, but not 1 day acute pain) induced by Complete Freund's Adjuvant (CFA) injected in the hind paw of rats could easily induce spatial cognition and memory impairment after being exposed to sevoflurane anesthesia. Next, for the mechanisms, we focused on the Periaqueductal Gray Matter (PAG), a well-known pivotal nucleus in pain process. It was detected the existence of neural projection from ventrolateral PAG (vlPAG) to adjacent nucleus Dorsal Raphe (DR), the origin of serotonergic projection for the whole cerebrum, through virus tracing and patch clamp recordings. The Immunofluorescence staining and western blot results showed that Tryptophan Hydroxylase 2 (TPH2) for serotonin synthesis in the DR was increased significantly in the rats treated with CFA for 7 days and sevoflurane for 3 hours, while chemo-genetic inhibition of the vlPAG-DR projection induced obvious spatial learning and memory impairment. Our study suggests that preoperative chronic pain may facilitate cognitive function impairment after receiving anesthesia through the PAG-DR neural circuit, and preventative analgesia should be a considerable measure to reduce the incidence of POCD.

Layered Double Hydroxides: A Novel Promising 2D Nanomaterial for Bone Diseases Treatment

Bone diseases including bone defects, bone infections, osteoarthritis, and bone tumors seriously affect life quality of the patient and bring serious economic burdens to social health management, for which the current clinical treatments bear dissatisfactory therapeutic effects. Biomaterial-based strategies have been widely applied in the treatment of orthopedic diseases but are still plagued by deficient bioreactivity. With the development of nanotechnology, layered double hydroxides (LDHs) with adjustable metal ion composition and alterable interlayer structure possessing charming physicochemical characteristics, versatile bioactive properties, and excellent drug loading and delivery capabilities arise widespread attention and have achieved considerable achievements for bone disease treatment in the last decade. However, to the authors' best knowledge, no review has comprehensively summarized the advances of LDHs in treating bone disease so far. Herein, the advantages of LDHs for orthopedic disorders treatment are outlined and the corresponding state-of-the-art achievements are summarized for the first time. The potential of LDHs-based nanocomposites for extended therapeutics for bone diseases is highlighted and perspectives for LDHs-based scaffold design are proposed for facilitated clinical translation.

Obesity in Nursing Home Patients: Association with Common Care Problems

(1) Background: There is not much research about obesity in nursing homes although knowledge will help us to develop customized treatment plans and prevention strategies, which may help to decrease the burden for all persons involved. The objective of conducting this study was to describe the prevalence of obesity and the association between obesity and care problems in nursing home patients. (2) Methods: This study is a secondary data analysis of data collected in an annually performed cross-sectional study called "Nursing Quality Measurement 2.0". A standardized and tested questionnaire was used to collect data. (3) Results: In total, 1236 nursing home patients took part, and 16.7% of them were obese. The multivariate logistic regression analysis results show that urinary incontinence is significantly associated with the presence of obesity (OR 2.111). The other care problems of pressure injuries, fecal and double incontinence, physical restraints, falls, and pain were not associated with obesity. (4) Conclusions: The results indicate that, in the nursing home setting, healthcare staff should pay special attention to the patients' nutritional status and help patients to maintain a healthy weight and prevent a loss of muscle mass and function. Conducting more studies with larger sample sizes is recommended, as this will allow for differentiation among different obesity classes.

Reminders of Mortality: Investigating the Effects of Different Mortality Saliences on Somatosensory Neural Activity

The Terror Management Theory (TMT) offered a great deal of generative hypotheses that have been tested in a plethora of studies. However, there is a still substantive lack of clarity about the interpretation of TMT-driven effects and their underlying neurological mechanisms. Here, we aimed to expand upon previous research by introducing two novel methodological manipulations aimed to enhance the effects of mortality salience (MS). We presented participants with the idea of the participants' romantic partner's death as well as increased the perceived threat of somatosensory stimuli. Linear mixed modelling disclosed the greater effects of MS directed at one's romantic partner on pain perception (as opposed to the participant's own mortality). The theta event-related oscillatory activity measured at the vertex of the scalp was significantly lower compared to the control condition. We suggest that MS aimed at one's romantic partner can result in increased effects on perceptual experience; however, the underlying neural activities are not reflected by a classical measure of cortical arousal.

TRP (transient receptor potential) ion channel family: structures, biological functions and therapeutic interventions for diseases

Transient receptor potential (TRP) channels are sensors for a variety of cellular and environmental signals. Mammals express a total of 28 different TRP channel proteins, which can be divided into seven subfamilies based on amino acid sequence homology: TRPA (Ankyrin), TRPC (Canonical), TRPM (Melastatin), TRPML (Mucolipin), TRPN (NO-mechano-potential, NOMP), TRPP (Polycystin), TRPV (Vanilloid). They are a class of ion channels found in numerous tissues and cell types and are permeable to a wide range of cations such as Ca²⁺, Mg²⁺, Na⁺, K⁺, and others. TRP channels are responsible for various sensory responses including heat, cold, pain, stress, vision and taste and can be activated by a number of stimuli. Their predominantly location on the cell surface, their interaction with numerous physiological signaling pathways, and the unique crystal structure of TRP channels make TRPs attractive drug targets and implicate them in the treatment of a wide range of diseases. Here, we review the history of TRP channel discovery, summarize the structures and functions of the TRP ion channel family, and highlight the current understanding of the role of TRP channels in the pathogenesis of human disease. Most importantly, we describe TRP channel-related drug discovery, therapeutic interventions for diseases and the limitations of targeting TRP channels in potential clinical applications.

Hierarchical Classification Strategy for Mitigating the Impact of The Presence of Pain in fNIRS-based BCIs

Brain computer interfaces (BCIs) can find applications in assistive systems for patients who experience conditions that impede their motor abilities. A BCI uses signals acquired from the brain to control external devices. As physical pain influences cortical signals, the presence of pain can negatively impact the performance of the BCI. In this work, we propose a strategy to mitigate this negative impact. Cortical signals are acquired from test subjects while they performed two mental arithmetic tasks, in the presence and the absence of painful stimuli. The task of the BCI is to reliably classify the two mental arithmetic tasks from the cortical recordings, irrespective of the presence or the absence of pain. We propose to do this classification, hierarchically, in two levels. In the first level, the data is classified into those captured in the presence and the absence of pain. Depending on the results of the classification from the first level, in the second level, the BCI performs the classification of tasks using a classifier trained either in the presence or the absence of pain. A 1-dimensional convolutional neural network (1D-CNN) is used for classification at both levels. It is observed that using this hierarchical strategy, the BCI is able to classify the tasks with an accuracy greater than 90%, irrespective of the presence or the absence of pain. Given that the presence of physical pain has shown previously to reduce the classification accuracy of a BCI to almost chance levels, this mitigation strategy will be a significant step towards enhancing the performance of BCIs when they are used in assistive systems for patients.

5-Alkoxy-1-aryl-3-polyfluoroalkylpyrazoles with Antinociceptive Activity: Partial Agonists of TRPV1 Ion Channels

Chemoselective O-alkylation of 1-aryl-3-polyfluoroalkylpyrazol-5-oles under basic conditions resulted in a series of 5-alkoxypyrazoles (26 derivatives). They showed an acceptable ADME profile (in silico) and can be considered as drug-like. In experiments in vivo (CD-1 mice), it was found that the obtained compounds do not have toxic properties at a dose of more than 150 mg/kg (for most compounds at a dose of >300 mg/kg, and for lead compounds - >600 mg/kg). 22 Compounds from this series demonstrated from moderate to high analgesic effects (28-104 % at 1 h and 37-109 % at 2 h after administration) in vivo in the hot plate test (SD rats, 15 mg/kg, intraperitoneal (ip)). The lead compound was 4-([1-phenyl-3-(trifluoromethyl)pyrazol-5-yl]oxy)butan-1-ol, which not only increased the latent period in the hot plate test by 103 % at both measurement points but also showed a pronounced analgesic effect under conditions of capsaicin-induced nociception (CD-1 mice, 15 mg/kg, ip). According to molecular modeling, all synthesized compounds can interact with the TRPV1 ion channel. This biological target was confirmed in in vitro experiments on Chinese hamster ovary cells expressing rTRPV1. 5-Alkoxypyrazoles were partial agonists of the TRPV1 ion channel in various degree, and the most active was the same pyrazole as in in vivo tests.

Data showing that post-traumatic stress symptoms and defense mechanisms change based on perceived stress levels: A multivariate analysis of variance approach during the COVID-19 pandemic

The present research article provides data about the differences in post-traumatic stress symptoms, and defense mechanisms based on the levels of perceived stress (low, average, high), using a large national sample of 1100 Italian individuals, collected during the first wave of the COVID-19 pandemic. Participants completed an online survey through the Google Form platform, where the Ten-Item Perceived Stress Scale, Impact of Event Scale - Revised, and Forty Item Defense Style Questionnaire were included. First, the cut-offs of the perceived stress scale were calculated by determining the 25^th and 75^th percentile scores for the sample of this survey. Then, MANOVA analyses were performed, together with ANOVAs and the Bonferroni Post hoc analyses as a follow-up. The dataset (.xlsx) includes the survey scores, while the tables and figures provide the analysed data, where the differences are shown. This data article may provide useful bases for future research on perceived stress and for suggesting associated factors on which focus clinical intervention and preventive programs.

Yarning about pain: Evaluating communication training for health professionals at persistent pain services in Queensland, Australia

Background

Providing cultural education to health professionals is essential in improving the quality of care and outcomes for Aboriginal and Torres Strait Islander patients. This study reports the evaluation of a novel training workshop used as an intervention to improve communication with Aboriginal and Torres Strait Islander patients of persistent pain services.

Methods

In this single-arm intervention study, health professionals undertook a one-day workshop, which included cultural capability and communication skills training based on a clinical yarning framework. The workshop was delivered across three adult persistent pain clinics in Queensland. At the end of the training, participants completed a retrospective pre/post evaluation questionnaire (5 points Likert scale, 1 = very low to 5 = very high), to rate their perceived importance of communication training, their knowledge, ability and confidence to communicate effectively. Participants also rated their satisfaction with the training and suggested improvements for future trainings.

Results

Fifty-seven health professionals were trained (N = 57/111; 51% participation rate), 51 completed an evaluation questionnaire (n = 51/57; 90% response rate). Significant improvements in the perceived importance of communication training, knowledge, ability and confidence to effectively communicate with Aboriginal and Torres Strait Islander patients were identified (p < 0.001). The greatest increase was in the perceived confidence pre-training mean of 2.96 (SE = 0.11) to the post-training mean of 4.02 (SE = 0.09).

Conclusion

This patient-centred communication training, delivered through a novel model that combines cultural capability and the clinical yarning framework applied to the pain management setting, was highly acceptable and significantly improved participants' perceived competence. This method is transferrable to other health system sectors seeking to train their clinical workforce with culturally sensitive communication skills.

Treatment of Acute Pain in Patients on Naltrexone: A Narrative Review

PURPOSE OF REVIEW

The tissue damage and trauma associated with surgery almost always result in acute postoperative pain. The intensity of postoperative pain can range from mild to severe. Naltrexone is suitable for patients who do not wish to be on an agonist treatment such as methadone or buprenorphine. However, naltrexone has been shown to complicate postoperative pain management.

RECENT FINDINGS

Multiple studies have found that the use of naltrexone can increase the opioid requirement for postoperative pain control. Other modalities exist that can help outside of opioids such as ketamine, lidocaine/bupivacaine, duloxetine, and non-pharmacological management can help manage pain. Multimodal pain regiments should also be employed in patients. In addition to traditional methods for postoperative pain management, other methods of acute pain control exist that can help mitigate opioid dependence and help control pain in patients who use naltrexone for their substance use disorders.

Understanding racial bias through electroencephalography

Research on racial bias in social and cognitive psychology has focused on automatic cognitive processes such as categorisation or stereotyping. Neuroimaging has revealed differences in the neural circuit when processing social information about one's own or another's ethnicity. This review investigates the influence of racial bias on human behaviour by reviewing studies that examined changes in neural circuitry (i.e. ERP responses) during automatic and controlled processes elicited by specific tasks. This systematic analysis of specific ERP components across different studies provides a greater understanding of how social contexts are perceived and become associated with specific stereotypes and behavioural predictions. Therefore, investigating these related cognitive and neurobiological functions can further our understanding of how racial bias affects our cognition more generally and guide more effective programs and policies aimed at its mitigation.

What is the role of interoception in the symptom experience of people with a chronic condition? A systematic review

BACKGROUND

Interoception, the ability of the organism to sense, interpret, and regulate signals originating from within the body, plays an important role in how individuals perceive and respond to symptoms. However, there is scarce evidence on the role of interoception in the symptom experience of people with chronic conditions.

AIM

To synthesize the role of interoception in the symptom experience of adults with a chronic condition.

METHODS

Systematic review. We searched PubMed, Psychinfo, Embase, CINAHL, and Science Citation Index-Expanded. We included primary research (all study designs) addressing our study aim, published between 2013-2021, and measuring at least one dimension of interoception. Any chronic condition and any symptom were included. No language limits were applied. Only the adult population was included.

RESULTS

We included 18 quantitative studies investigating the relationship between three interoceptive dimensions (i.e., accuracy, sensibility, awareness) and condition-specific symptoms in 10 chronic conditions. People with chronic conditions had lower interoceptive accuracy than healthy controls. Higher interoceptive sensibility was associated with lower symptom severity/frequency. Higher interoceptive accuracy was associated with lower symptom severity/frequency in half of the studies, while the other half reported the opposite. Only one study explored interoceptive awareness.

CONCLUSION

Interoceptive abilities are lower in patients with chronic conditions. Higher interoceptive sensibility is associated with lower symptom severity/frequency, but this relationship is unclear when it comes to interoceptive accuracy and awareness.

Doctor trustworthiness influences pain and its neural correlates in virtual medical interactions

Trust is an important component of the doctor-patient relationship and is associated with improved patient satisfaction and health outcomes. Previously, we reported that patient feelings of trust and similarity toward their clinician predicted reductions in evoked pain in response to painful heat stimulations. In the present study, we investigated the brain mechanisms underlying this effect. We used face stimuli previously developed using a data-driven computational modeling approach that differ in perceived trustworthiness and superimposed them on bodies dressed in doctors' attire. During functional magnetic resonance imaging, participants (n = 42) underwent a series of virtual medical interactions with these doctors during which they received painful heat stimulation as an analogue of a painful diagnostic procedure. Participants reported increased pain when receiving painful heat stimulations from low-trust doctors, which was accompanied by increased activity in pain-related brain regions and a multivariate pain-predictive neuromarker. Findings suggest that patient trust in their doctor may have tangible impacts on pain and point to a potential brain basis for trust-related reductions in pain through the modulation of brain circuitry associated with the sensory-discriminative and affective-motivational dimensions of pain.

Advances in the role and mechanism of miRNA in inflammatory pain

Pain is a distressing experience associated with tissue damage or potential tissue damage, and its occurrence is related to sensory, emotional, cognitive and social factors. Inflammatory pain is one of the chronic pains where pain hypersensitivity are functional features of inflammation used to protect tissues from further damage. Pain has a serious impact on people's lives and has become a social problem that cannot be ignored. MiRNAs are small non-coding RNA molecules that exert directing effects on RNA silencing by complementary binding to the 3'UTR of target mRNA. MiRNAs can target a number of protein-coding genes and participate in almost all developmental and pathological processes in animals. Growing studies have suggested that miRNAs have significant implications for inflammatory pain via participating in multiple processes during the occurrence and development, such as affecting the activation of glial cells, regulating pro-inflammatory cytokines and inhibiting central and peripheral sensitization. In this review, the advances in the role of miRNAs in inflammatory pain were discussed. miRNAs as a class of micro-mediators are potential biomarkers and therapeutic targets for inflammatory pain, which provides a better diagnostic and treatment approach for inflammatory pain.

Measuring pain and nociception: Through the glasses of a computational scientist. Transdisciplinary overview of methods

In a healthy state, pain plays an important role in natural biofeedback loops and helps to detect and prevent potentially harmful stimuli and situations. However, pain can become chronic and as such a pathological condition, losing its informative and adaptive function. Efficient pain treatment remains a largely unmet clinical need. One promising route to improve the characterization of pain, and with that the potential for more effective pain therapies, is the integration of different data modalities through cutting edge computational methods. Using these methods, multiscale, complex, and network models of pain signaling can be created and utilized for the benefit of patients. Such models require collaborative work of experts from different research domains such as medicine, biology, physiology, psychology as well as mathematics and data science. Efficient work of collaborative teams requires developing of a common language and common level of understanding as a prerequisite. One of ways to meet this need is to provide easy to comprehend overviews of certain topics within the pain research domain. Here, we propose such an overview on the topic of pain assessment in humans for computational researchers. Quantifications related to pain are necessary for building computational models. However, as defined by the International Association of the Study of Pain (IASP), pain is a sensory and emotional experience and thus, it cannot be measured and quantified objectively. This results in a need for clear distinctions between nociception, pain and correlates of pain. Therefore, here we review methods to assess pain as a percept and nociception as a biological basis for this percept in humans, with the goal of creating a roadmap of modelling options.

Pharmacokinetic and pharmacodynamic herb-drug interactions of common over-the-counter pain medications

Pain is one of the most common reasons for seeking medical intervention, and self-medication with over-the-counter medications and/or traditional herbal remedies has become increasingly popular. In this review, original articles on understanding possible herb-drug interactions between traditional herbs and four major pain medications-acetaminophen, aspirin, ibuprofen and naproxen-are compiled and analyzed. In terms of analytical methods, high-performance liquid chromatography using an isocratic eluent system coupled to biological sample clean-up is the most common, while a wide variety of detectors have been observed, including a photodiode array, variable wavelength detector, electrochemical detector and tandem mass spectrometer. Both synergistic and anti-synergistic effects were observed for acetaminophen and aspirin, while only synergistic effects have been found for naproxen. Currently, no interactions have been reported for ibuprofen.

The Relationship among Anxiety, Worry, Perceived Stress, Defense Mechanisms, and High Levels of Post-Traumatic Stress Symptoms: A Discriminant Analytic Approach

Post-traumatic stress disorder (PTSD) is a pathological condition that may lead to a significant deterioration in the quality of life over time. Therefore, the study of the elements that can characterize the disorder could be considered of great clinical interest and relevance. The aim of the present research was to empirically discriminate the influence of perceived stress, state anxiety, worry, and defense mechanisms (mature, neurotic, and immature) at different levels of post-traumatic stress symptoms. A sample of 1250 participants (69.5% women, 30.5% men; M_age = 34.52, SD = 11.857) completed an online survey including the Impact of Event Scale-Revised, Ten-Item Perceived Stress Scale, Penn State Worry Questionnaire, Forty Item Defense Style Questionnaire, and State-Trait Anxiety Inventory-Form X3. Data were analysed by implementing MANOVA and discriminant analysis. Results showed significant differences in the levels of perceived stress, state anxiety, and worry, as well as neurotic and immature defenses based on the levels of post-traumatic stress symptoms: F(12,2484) = 85.682, p < 0.001; Wilk's Λ = 0.430. Furthermore, these variables discriminate significant accuracy between participants who reported a mild psychological impact and those with a probable presence of PTSD, with perceived stress, which was found to be the best predictor. Classification results indicated that the original grouped cases were classified with 86.3% overall accuracy. Such findings may provide useful insight for clinical practice.

SCN9A variant in a family of mixed breed dogs with congenital insensitivity to pain

BACKGROUND

Congenital insensitivity to pain (CIP) and hereditary sensory and autonomic neuropathies (HSANs) are a rare group of genetic disorders causing inability to feel pain. Three different associated variants have been identified in dogs: 1 in Border Collies, 1 in mixed breed dogs, and 1 in Spaniels and Pointers.

OBJECTIVES

To clinically and genetically characterize CIP in a family of mixed breed dogs.

ANIMALS

Two mixed breed dogs from the same litter were independently presented: 1 for evaluation of painless fractures, and the other for chronic thermal skin injuries.

METHODS

Physical, neurological, and histopathological evaluations were performed. Whole genome sequencing of 1 affected dog was used to identify homozygous protein-changing variants that were not present in 926 control genomes from diverse dog breeds.

RESULTS

Physical and neurological examinations showed the absence of superficial and deep pain perception in the entire body. Histopathological evaluations of the brain, spinal cord and sensory ganglia were normal. Whole genome sequencing identified a homozygous missense variant in SCN9A, XM_038584713.1:c.2761C>T or XP_038440641.1:(p.Arg921Cys). Both affected dogs were homozygous for the mutant allele, which was not detected in 926 dogs of different breeds.

CONCLUSIONS AND CLINICAL IMPORTANCE

We confirmed the diagnosis of CIP in a family of mixed breed dogs and identified a likely pathogenic variant in the SCN9A gene. The clinical signs observed in these dogs mimic those reported in humans with pathogenic SCN9A variants causing CIP. This report is the first of a spontaneous pathogenic SCN9A variant in domestic animals.

Mechanism and effects of STING-IFN-I pathway on nociception: A narrative review

Since the discovery of STING in 2008, numerous studies have investigated its functions in immunity, inflammation, and cancer. STING activates downstream molecules including IFN-I, NLRP3, and NF-κB. The STING-IFN-I pathway plays a vital role in nociception. After receiving the upstream signal, STING is activated and induces the expression of IFN-I, and after paracrine and autocrine signaling, IFN-I binds to IFN receptors. Subsequently, the activity of ion channels is inhibited by TYK2, which induces an acute antinociceptive effect. JAK activates PIK3 and MAPK-MNK-eIF4E pathways, which sensitize nociceptors in the peripheral nervous system. In the mid-late stage, the STING-IFN-I pathway activates STAT, increases pro-inflammatory and anti-inflammatory cytokines, inhibits ER-phagy, and promotes microglial M1-polarization in the central nervous system, leading to central sensitization. Thus, the STING-IFN-I pathway may exert complex effects on nociception at various stages, and these effects require further comprehensive elucidation. Therefore, in this review, we systematically summarized the mechanisms of the STING-IFN-I pathway and discussed its function in nociception.

A brain-inspired robot pain model based on a spiking neural network

Introduction

Pain is a crucial function for organisms. Building a "Robot Pain" model inspired by organisms' pain could help the robot learn self-preservation and extend longevity. Most previous studies about robots and pain focus on robots interacting with people by recognizing their pain expressions or scenes, or avoiding obstacles by recognizing dangerous objects. Robots do not have human-like pain capacity and cannot adaptively respond to danger. Inspired by the evolutionary mechanisms of pain emergence and the Free Energy Principle (FEP) in the brain, we summarize the neural mechanisms of pain and construct a Brain-inspired Robot Pain Spiking Neural Network (BRP-SNN) with spike-time-dependent-plasticity (STDP) learning rule and population coding method.

Methods

The proposed model can quantify machine injury by detecting the coupling relationship between multi-modality sensory information and generating "robot pain" as an internal state.

Results

We provide a comparative analysis with the results of neuroscience experiments, showing that our model has biological interpretability. We also successfully tested our model on two tasks with real robots-the alerting actual injury task and the preventing potential injury task.

Discussion

Our work has two major contributions: (1) It has positive implications for the integration of pain concepts into robotics in the intelligent robotics field. (2) Our summary of pain's neural mechanisms and the implemented computational simulations provide a new perspective to explore the nature of pain, which has significant value for future pain research in the cognitive neuroscience field.

Communication and access to healthcare: Experiences of Aboriginal and Torres Strait Islander people managing pain in Queensland, Australia

Background

Pain management requires a multidisciplinary approach and a collaborative relationship between patient-provider in which communication is crucial. This study examines the communication experiences of Aboriginal and Torres Strait Islander patients and Aboriginal and Torres Strait Islander Hospital Liaison Officers (ATSIHLOs), to improve understanding of how pain is managed in and through patient-health professional communication.

Methods

This qualitative study involved a purposive sample of patients attending three persistent pain clinics and ATSIHLOs working in two hospitals in Queensland, Australia. Focus groups and in-depth interviews explored the communication experiences of patients managing pain and ATSIHLOs supporting patients with pain. This study adopted a descriptive phenomenological methodology, as described by Colaizzi (1978). Relevant statements (patient and ATSIHLOs quotes) about the phenomenon were extracted from the transcripts to formulate meanings. The formulated meanings were subsequently sorted into thematic clusters and then integrated into themes. The themes were then incorporated into a concise description of the phenomenon of communication within pain management. Findings were validated by participants.

Results

A total of 21 Aboriginal and Torres Strait Islander participants were involved in this study. Exploration of the communication experiences of patients and ATSIHLOs revealed overlapping themes of important barriers to and enablers of communication that affected access to care while managing pain. Acknowledging historical and cultural factors were particularly important to build trust between patients and health professionals. Some patients reported feeling stigmatized for identifying as Aboriginal and Torres Strait Islander, while others were reluctant to disclose their background for fear of not having the same opportunity for treatment. Differences in the expression of pain and the difficulty to use standard pain measurement scales were identified. Communication was described as more than the content delivered, it is visual and emotional expressed through body language, voice intonation, language and the speed of the conversation.

Conclusion

Communication can significantly affect access to pain management services. Aboriginal and Torres Strait Islander patients highlighted the burden of emotional pain caused by historical factors, negative stereotypes and the fear of discrimination. Pain management services and their health professionals need to acknowledge how these factors impact patients trust and care.

Comparison of the effect of psychosocial skills training on acute and chronic musculoskeletal pain intensity: The effectiveness of early intervention in the reduction of acute musculoskeletal pain

BACKGROUND

Pain, as a psychological experience, is caused by complex interactions among sensory-discriminative, motivational-affective, and cognitive-evaluative dimensions. The psychosocial approach is one of the important approaches in managing musculoskeletal pain in patients. Therefore, this study aimed to determine and compare the effects of psychosocial skills training on pain intensity in patients with acute and chronic musculoskeletal pain.

METHODS

In this quasi-experimental study, 64 patients with acute and chronic musculoskeletal pain were selected using convenience sampling. Both groups received psychosocial training in pain management in groups of 8-10 people over six 1-h sessions. The data were collected at baseline, after the intervention, and 3 months later using a numerical rating scale (NRS). Then, the data were entered into the SPSS 22 software and were analysed using descriptive and inferential statistics.

RESULTS

In this study, the mean age of the participants was 50.10 ± 10.63 years and 60.9% of them were female. Based on the results, time had a significant effect on pain intensity (p < 0.001), but the effect of group on pain intensity was not statistically significant (p = 0.07). The group × time effect on pain intensity was also statistically significant (p < 0.001).

CONCLUSION

Psychosocial training had a positive impact on the reduction of pain among the patients with acute and chronic musculoskeletal pain. Additionally, the training was more effective in patients with acute pain due to early training. These findings can help healthcare providers in the field of musculoskeletal pain management, especially in patients with acute pain.

The Social Legitimacy of Pain: Protocol for a Systematic Literature Review

Introduction: Pain is a perception conditioned both by the subjective experience of the sufferer and their social context. A preliminary literature search suggests that, today, information about the social legitimacy of pain is scarce, although it is known that this phenomenon is an element that is closely linked to the type of pain and contributes to the sufferer's experience. Thus, our objective is to explore how the social legitimacy of pain is tackled in the scientific literature. Methods: This study is a protocol for a systematic literature review where six databases were reviewed: Pubmed, Web of Science, Scielo, Scopus, PsycInfo, and CINAHL, were searched for papers dealing with the social legitimacy of pain from any discipline/study design. The obtained papers will be exported to Zotero, where the duplicates will be deleted. Later, the studies of interest will be selected, first on the basis of their titles/abstracts, and, later, on the complete text. This process will be carried out in pairs. Finally, the data of interest will be extracted, analyzing their quality, to finally make a qualitative analysis of the results. Discussion: This will be the first review to systematically explore the available evidence on the social legitimacy of pain. Therefore, it will be able, not only to extend the theoretical knowledge on this phenomenon, but also to extend its visibility, which will make it possible for the social legitimacy of pain to be studied from different disciplines and fields, thus improving the way it is approached.

Transcranial magnetic stimulation maps the neurophysiology of chronic noncancer pain: A scoping review

BACKGROUND

Chronic noncancer pain is a global public health challenge. It is imperative to identify biological markers ("biomarkers") to understand the mechanisms underlying chronic pain and to monitor pain over time and after interventions. Transcranial magnetic stimulation (TMS) is a promising method for this purpose.

OBJECTIVES

To examine differences in TMS-based outcomes between persons with chronic pain and healthy controls (HCs) and/or before versus after pain-modulating interventions and relationships between pain measures and TMS outcomes; To summarize the neurophysiological mechanisms underlying chronic pain as identified by TMS.

METHODS

We searched the PubMed database for literature from January 1, 1985, to June 9, 2020, with the keywords "pain" and "transcranial magnetic stimulation." Eligible items included original studies of adult human participants with pain lasting for ≥ 6 months. We completed a narrative synthesis of the study findings stratified by chronic pain etiology (primary pain, neuropathic pain, and secondary musculoskeletal pain).

RESULTS

The search yielded 1265 records. The final 12 articles included 244 patients with chronic pain (192 females, aged 35-65 years) and 169 HCs (89 females, aged 28-59 years). Abnormalities in TMS outcomes that reflect GABAergic and glutamatergic activities were associated with many of the disorders studied and were distinct for each pain etiology. Chronic primary pain is characterized by reduced intracortical inhibition and corticospinal excitability, chronic neuropathic pain shows evidence of increased excitation and disinhibition, and chronic secondary musculoskeletal pain involves low corticospinal excitability.

DISCUSSION

TMS could be a useful tool for delineating the neurophysiological underpinnings of chronic pain syndromes.

Opportunities and challenges of pain-related myocardial ischemia-reperfusion injury

Pain is one of the most serious problems plaguing human health today. Pain is not an independent pathophysiological condition and is associated with a high impact on elevated disability and organ dysfunction. Several lines of evidence suggested the associations of pain with cardiovascular diseases, especially myocardial ischemia-reperfusion (I/R) injury, while the role of pain in I/R injury and related mechanisms are not yet comprehensively assessed. In this review, we attempted to explore the role of pain in myocardial I/R injury, and we concluded that acute pain protects myocardial ischemia-reperfusion injury and chronic pain aggravates cardiac ischemia-reperfusion injury. In addition, the construction of different pain models and animal models commonly used to study the role of pain in myocardial I/R injury were discussed in detail, and the potential mechanism of pain-related myocardial I/R injury was summarized. Finally, the future research direction was prospected. That is, the remote regulation of pain to cardiac function requires peripheral pain signals to be transmitted from the peripheral to the cardiac autonomic nervous system, which then affects autonomic innervation during cardiac ischemia-reperfusion injury and finally affects the cardiac function.

Equitable Mindfulness: The practice of mindfulness for all

The benefits of mindfulness are well-documented; however, these benefits may not be evenly distributed across communities. Equitable Mindfulness aims to make these benefits accessible to a wider and more inclusive audience. The aim of this study was to investigate the applicability of Equitable Mindfulness and systemic barriers that prevent mindfulness programs from being equitably accessed across communities. Twenty-one participants were recruited for qualitative in-depth interviews during a 2-day mindfulness conference. The constant comparison method was used to iteratively identify and categorize themes that emerged within and across interviews. Five dominant themes emerged from the data as follows: inherent equitability, accessibility, inclusiveness, awareness and knowledge-sharing, and acknowledgement of multiple perspectives. Having an applicable and meaningful term to use when describing mindfulness as an inclusive and equitable practice can facilitate the exploration of a new area of research. There is a need for future initiatives aimed at making mindfulness trainings and programs more equitable and accessible to all, regardless of socioeconomic status, race/ethnicity, or abilities/disabilities.

Comparison of the postoperative analgesic effect of transversus abdominis plan block and quadratus lumborum block: A prospective randomized study

Background and Aims

In this study, we aimed to compare the transversus abdominis plan block (TAP) and quadratus lumborum block (QL) efficacy for postoperative analgesia in patients undergoing varicocelectomy under spinal anesthesia.

Methods

American Society of Anesthesiologists (ASA) 1 and 2 patients, aged 18-45 years, who underwent varicocelectomy operation under elective conditions, were included. Eighty patients were divided into three groups as TAP group, QL group, and control group by prospective randomization. The patients were operated under spinal anesthesia. At the end of the operation, TAP was applied to the TAP group with a posterior approach using ultrasound (USG) in the supine position. To the QL group, the patient was placed in the lateral decubitus position and the lateral QL was applied via USG. No block type was applied to the control group. Patient-controlled analgesia (PCA) device containing tramadol was administered intravenously at the end of the surgery in all groups. Visual analogue scale (VAS) score was questioned at 0, 2, 4, 6, 8, 10, 12, 18, 24 h in the follow-up of the patients. Intravenous 1 g paracetamol was given over VAS 4. PCA usage time and usage amounts were recorded.

Results

As a result of comparing the groups according to the VAS scores at all hours were significantly different between the three groups (p < 0.001). There was a significant difference between the groups when comparing the number of PCA bolus administrations (p < 0.001). TAP and QL blocks significantly reduced the number of PCA bolus when compared with the control group (p < 0.001) but the number of PCA bolus was found to be similar between TAP and QL blocks (p > 0.05).

Conclusion

TAP and QL, which are administered to evaluate the effectiveness of postoperative analgesia in patients undergoing varicocelectomy under spinal anesthesia, are both effective in reducing pain scores and the amount of analgesia consumption.

Rhodojaponin III-Loaded Chitosan Derivatives-Modified Solid Lipid Nanoparticles for Multimodal Antinociceptive Effects in vivo

Background

Rhodojaponin III (RJ-III) is a bioactive diterpenoid, which is mainly found in Rhododendron molle G. Don (Ericaceae), a potent analgesia in traditional Chinese medicine with several years of clinical applications in the country. However, its clinical use is limited by its acute toxicity and poor pharmacokinetic profiles. To reduce such limitations, the current study incorporated RJ-III into the colloidal drug delivery system of hydroxypropyl trimethyl ammonium chloride chitosan (HACC)-modified solid lipid nanoparticles (SLNs) to improve its sustained release and antinociceptive effects in vivo for oral delivery.

Results

The optimized RJ-III@HACC-SLNs were close to spherical, approximately 134 nm in size, and with a positive zeta potential. In vitro experiments showed that RJ-III@HACC-SLNs were stable in the simulated gastric fluid and had a prolonged release in PBS (pH = 6.8). Pharmacokinetic results showed that after intragastric administration in mice, the relative bioavailability of RJ-III@HACC-SLNs was 87.9%. Further, it was evident that the peak time, half-time, and mean retention time of RJ-III@HACC-SLNs were improved than RJ-III after the administration. In addition, pharmacodynamic studies revealed that RJ-III@HACC-SLNs markedly reduced the acetic acid, hot, and formalin-induced nociceptive responses in mice (P < 0.001), and notably increased the analgesic time (P < 0.01). Moreover, RJ-III@HACC-SLNs not only showed good biocompatibility with Caco-2 cells in vitro but its LD₅₀ value was also increased by 1.8-fold as compared with that of RJ-III in vivo.

Conclusion

These results demonstrated that RJ-III@HACC-SLNs improved the pharmacokinetic characteristics of the RJ-III, thereby exhibiting toxicity-attenuating potential and antinociceptive enhancing properties. Consequently, HACC-SLNs loaded with RJ-III could become a promising oral formulation for pain management that deserves further investigation in the future.

Psychological therapies for temporomandibular disorders (TMDs)

BACKGROUND

Temporomandibular disorders (TMDs) are a group of musculoskeletal disorders affecting the jaw. They are frequently associated with pain that can be difficult to manage and may become persistent (chronic). Psychological therapies aim to support people with TMDs to manage their pain, leading to reduced pain, disability and distress.

OBJECTIVES

To assess the effects of psychological therapies in people (aged 12 years and over) with painful TMD lasting 3 months or longer.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched six bibliographic databases up to 21 October 2021 and used additional search methods to identify published, unpublished and ongoing studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of any psychological therapy (e.g. cognitive behaviour therapy (CBT), behaviour therapy (BT), acceptance and commitment therapy (ACT), mindfulness) for the management of painful TMD. We compared these against control or alternative treatment (e.g. oral appliance, medication, physiotherapy).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We reported outcome data immediately after treatment and at the longest available follow-up. We used the Cochrane RoB 1 tool to assess the risk of bias in included studies. Two review authors independently assessed each included study for any risk of bias in sequence generation, allocation concealment, blinding of outcome assessors, incomplete outcome data, selective reporting of outcomes, and other issues. We judged the certainty of the evidence for each key comparison and outcome as high, moderate, low or very low according to GRADE criteria.

MAIN RESULTS

We identified 22 RCTs (2001 participants), carried out between 1967 and 2021. We were able to include 12 of these studies in meta-analyses. The risk of bias was high across studies, and we judged the certainty of the evidence to be low to very low overall; further research may change the findings. Our key outcomes of interest were: pain intensity, disability caused by pain, adverse events and psychological distress. Treatments varied in length, with the shortest being 4 weeks. The follow-up time ranged from 3 months to 12 months. Most studies evaluated CBT.   At treatment completion, there was no evidence of a benefit of CBT on pain intensity when measured against alternative treatment (standardised mean difference (SMD) 0.03, confidence interval (CI) -0.21 to 0.28; P = 0.79; 5 studies, 509 participants) or control (SMD -0.09, CI -0.30 to 0.12; P = 0.41; 6 studies, 577 participants). At follow-up, there was evidence of a small benefit of CBT for reducing pain intensity compared to alternative treatment (SMD -0.29, 95% CI -0.50 to -0.08; 5 studies, 475 participants) and control (SMD -0.30, CI -0.51 to -0.09; 6 studies, 639 participants). At treatment completion, there was no evidence of a difference in disability outcomes (interference in activities caused by pain) between CBT and alternative treatment (SMD 0.15, CI -0.40 to 0.10; P = 0.25; 3 studies, 245 participants), or between CBT and control/usual care (SMD 0.02, CI -0.21 to 0.24; P = 0.88; 3 studies, 315 participants). Nor was there evidence of a difference at follow-up (CBT versus alternative treatment: SMD -0.15, CI -0.42 to 0.12; 3 studies, 245 participants; CBT versus control: SMD 0.01 CI - 0.61 to 0.64; 2 studies, 240 participants). There were very few data on adverse events. From the data available, adverse effects associated with psychological treatment tended to be minor and to occur less often than in alternative treatment groups. There were, however, insufficient data available to draw firm conclusions. CBT showed a small benefit in terms of reducing psychological distress at treatment completion compared to alternative treatment (SMD -0.32, 95% CI -0.50 to -0.15; 6 studies, 553 participants), which was maintained at follow-up (SMD -0.32, 95% CI -0.51 to -0.13; 6 studies, 516 participants). For CBT versus control, only one study reported results for distress and did not find evidence of a difference between groups at treatment completion (mean difference (MD) 2.36, 95% CI -1.17 to 5.89; 101 participants) or follow-up (MD -1.02, 95% CI -4.02 to 1.98; 101 participants). We assessed the certainty of the evidence to be low or very low for all comparisons and outcomes. The data were insufficient to draw any reliable conclusions about psychological therapies other than CBT.

AUTHORS' CONCLUSIONS

We found mixed evidence for the effects of psychological therapies on painful temporomandibular disorders (TMDs). There is low-certainty evidence that CBT may reduce pain intensity more than alternative treatments or control when measured at longest follow-up,  but not at treatment completion. There is low-certainty evidence that CBT may be better than alternative treatments, but not control, for reducing psychological distress at treatment completion and follow-up. There is low-certainty evidence that CBT may not be better than other treatments or control for pain disability outcomes.  There is insufficient evidence to draw conclusions about alternative psychological therapeutic approaches, and there are insufficient data to be clear about adverse effects that may be associated with psychological therapies for painful TMD.  Overall, we found insufficient evidence on which to base a reliable judgement about the efficacy of psychological therapies for painful TMD. Further research is needed to determine whether or not psychological therapies are effective, the most effective type of therapy and delivery method, and how it can best be targeted. In particular, high-quality RCTs conducted in primary care and community settings are required, which evaluate a range of psychological approaches against alternative treatments or usual care, involve both adults and adolescents, and collect measures of pain intensity, pain disability and psychological distress until at least 12 months post-treatment.

Pain and its associated factors in nursing home residents

This study examined the associated factors of pain in nursing home residents in Austria. A secondary data analysis was conducted with data collected in the 'Nursing Quality Measurement 2.0' study, which is conducted annually in Austrian healthcare institutions. Data from nursing homes from 2016 to 2019 were used. Of the 1,239 residents, 40.4% had experienced pain in the last 7 days and/or were experiencing pain at the time of the survey. The regression analysis showed that diseases of the musculoskeletal system, diseases of the skin and subcutaneous tissue, diseases of the circulatory system, pressure injuries, and a risk of malnutrition were statistically associated with pain (Χ2 (11) = 82,392, p < 0.000). Healthcare professionals working in nursing homes need to be aware of associated factors when treating pain in residents. This awareness is important because it enables professionals to identify high-risk groups and take appropriate steps.

Alternative Options for Complex, Recurrent Pain States Using Cannabinoids, Psilocybin, and Ketamine: A Narrative Review of Clinical Evidence

With emerging information about the potential for morbidity and reduced life expectancy with long-term use of opioids, it is logical to evaluate nonopioid analgesic treatments to manage pain states. Combinations of drugs can provide additive and/or synergistic effects that can benefit the management of pain states. In this regard, tetrahydrocannabinol (THC) and cannabidiol (CBD) modulate nociceptive signals and have been studied for chronic pain treatment. Psilocybin, commonly known as “magic mushrooms”, works at the serotonin receptor, 5-HT_2A. Psilocybin has been found in current studies to help with migraines since it has a tryptamine structure and works similarly to triptans. Psilocybin also has the potential for use in chronic pain treatment. However, the studies that have looked at alternative plant-based medications such as THC, CBD, and psilocybin have been small in terms of their sample size and may not consider the demographic or genetic differences in the population because of their small sample sizes. At present, it is unclear whether the effects reported in these studies translate to the general population or even are significant. In summary, additional studies are warranted to evaluate chronic pain management with alternative and combinations of medications in the treatment of chronic pain.