The IASP classification of chronic pain for ICD-11: chronic neuropathic pain

CD28 Superfamily Costimulatory Molecules in Chronic Pain: Focus on Immunomodulation

Chronic pain has substantial effects on patients' quality of life and psychological well-being. It does not respond satisfactorily to available medicinal therapeutics because its mechanism remains unclear. Recent studies have shown a strong relationship between chronic pain and immunomodulation. As important members of the immune response, CD28 superfamily costimulatory molecules were demonstrated to have an analgesic effect on chronic pain. Based on research on the role of these molecules in chronic pain, new and highly effective analgesic medicines are anticipated that could be used in combination with some previous analgesic medicines to reduce substance abuse and side effects. This review of the literature will examine the pain-regulating mechanisms of CD28 superfamily costimulatory molecules, focusing on immunomodulation. In addition, this review will discuss the potential and difficulties of developing novel analgesic medicines targeting CD28 superfamily costimulatory molecules.

Exploratory study on the ascending pain pathway in patients with chronic neck and shoulder pain based on combined brain and spinal cord diffusion tensor imaging

Objective

To explore the changes in the white matter microstructure of the ascending pain conduction pathways in patients with chronic neck and shoulder pain (CNSP) using combined brain and spinal cord diffusion tensor imaging techniques, and to assess its correlation with clinical indicators and cognitive functions.

Materials and methods

A 3.0T MRI scanner was used to perform combined brain and spinal cord diffusion tensor imaging scans on 31 CNSP patients and 24 healthy controls (HCs), extracting the spinothalamic tract (STT) and quantitatively analyzing the fractional anisotropy (FA) and mean diffusivity (MD) which reflect the microstructural integrity of nerve fibers. Additionally, these differences were subjected to partial correlation analysis in relation to Visual Analog Scale (VAS) scores, duration of pain, Self-Rating Anxiety Scale (SAS), and Self-Rating Depression Scale (SDS).

Results

Compared to HCs, CNSP patients showed decreased mean FA values and increased mean MD values in bilateral intracranial STT compared to the HC group, but two-sample t-test results indicated no statistically significant differences (p > 0.05). FA values of the left STT (C2 segment, C5 segment) and right STT (C1 segment, C2 segment) were significantly decreased in bilateral cervical STTs of CNSP patients; MD values of the left STT (C1 segment, C2 segment, C5 segment) and right STT (C1 segment, C5 segment) were significantly increased (p < 0.05). Partial correlation analysis results showed that FA values of STT in CNSP patients were negatively correlated with VAS scores, duration of pain, SAS scores, and SDS scores, while MD values were positively correlated with VAS scores and duration of pain (Bonferroni p < 0.05).

Conclusion

This research identified that patients with CNSP exhibited reduced mean FA and increased mean MD in the bilateral intracranial STT, although these differences were not statistically significant (p > 0.05). Conversely, significant abnormalities were observed in specific segments of the bilateral cervical STT (p < 0.05), which were also correlated with variations in pain intensity, illness duration, and levels of anxiety and depression. These findings contribute a novel neuroimaging perspective to the evaluation and elucidation of the pathophysiological mechanisms underlying chronic pain in the ascending conduction pathways.

Association between C-reactive protein and chronic pain in US adults: A nationwide cross-sectional study

BACKGROUND

Chronic pain has emerged as a significant global public health concern. Hence, it is imperative to acquire a more comprehensive comprehension of these characteristics in the adult population of the United States in order to facilitate the development of effective interventions. The objective of this study is to ascertain the prevalence of chronic pain among people in the United States and investigate its association with C-reactive protein (CRP) levels.

METHODS

The present study employed a cross-sectional design and utilized data from three cycles of the National Health and Nutrition Examination Survey (NHANES). The study aimed to investigate the relationship between chronic pain status, CRP levels, and potential confounding factors. The study incorporated individuals who successfully fulfilled chronic questionnaires and had CRP assays. Weighted univariate and multivariate logistic regression analyses were performed to examine the correlation between chronic pain and CRP levels. To explore the non-linear relationship, weighted restricted cubic spline (RCS) with three knots coupled with a weighted logistic regression model to assess the dose-response relationship between CRP (continuous variables) and chronic pain.

RESULTS

A total of 10,680 (Weighted 250,814,660.8) adult participants with complete information were included in the analysis and 2612 (Weighted 67978784.88, 27.1%) subjects met the definition of chronic pain. Compared with participants without chronic pain, those with chronic pain had a higher CRP level (P < 0.001). The results of the multivariable adjusted logistic regression model suggested that the highest CRP quartile (CRP >  0.52 mg/dL) was associated with a 32% increase in the risk of chronic pain compared with the lowest CRP quartile (CRP ≤  0.09 mg/dL). The RCS result showed that the OR of chronic pain and CRP displayed a linear relationship (P = 0.027, Non-linear P = 0.541).

CONCLUSIONS

The study found a significant correlation between CRP levels and the presence of chronic pain among people in the United States. Individuals exhibiting elevated levels of CRP demonstrated a heightened propensity for experiencing chronic pain in comparison to individuals with lower CRP levels. Additional investigation is necessary to explore the presence of a causal association between the two variables, as well as the potential underlying mechanisms.

Purinergic signaling in the battlefield of viral infections

Purinergic signaling has been associated with immune defenses against pathogens such as bacteria, protozoa, fungi, and viruses, acting as a sentinel system that signals to the cells when a threat is present. This review focuses on the roles of purinergic signaling and its therapeutic potential for viral infections. In this context, the purinergic system may play potent antiviral roles by boosting interferon signaling. In other cases, though, it can contribute to a hyperinflammatory response and disease severity, resulting in poor outcomes, such as during flu and potentially COVID-19. Lastly, a third situation may occur since viruses are obligatory intracellular parasites that hijack the host cell machinery for their infection and replication. Viruses such as HIV-1 use the purinergic system to favor their infection and persistence within the host cell. Therefore, understanding the particular nuances of purinergic signaling in each viral infection may contribute to designing proper therapeutic strategies to treat viral diseases.

Exploring Chronic Pain in Hemodialysis Patients: An Observational Study Based on the New IASP Classification for ICD-11

INTRODUCTION

Pain is one of the most frequently reported symptoms in hemodialyzed (HD) patients, with prevalence rates between 33% and 82%. Risk factors for chronic pain in HD patients are older age, long-lasting dialysis history, several concomitant diseases, malnutrition, and others. However, chronic pain assessment in HD patients is rarely performed by specialists in pain medicine, with relevant consequences in terms of diagnostic and treatment accuracy. Furthermore, no study has used the recently introduced International Association for the Study of Pain (IASP) pathophysiological classification.

METHODS

In this observational, cross-sectional study in a tertiary HD center in Northern Italy, we analyzed data regarding HD patients, evaluated for 5 months in 2021 by specialists in pain medicine and aimed to identify and characterize chronic pain according to the IASP definition and the last 2019 classification of chronic pain for ICD-11. Pain severity was evaluated by the pain severity score of the brief pain inventory tool.

RESULTS

Among 213 patients, 65 (31%) suffered from chronic pain. The average age was 73.1 years; 55.5% of the patients were male; 53.7% had diabetes, and 39.2% had arterial hypertension. Of the 54 patients subjected to an in-depth evaluation, data regarding 113 pain diagnoses were extracted, particularly related to osteoarthritis, obliterating arterial disease, and low back pain with or without radiculopathy. On the basis of these diagnoses, the pain classification according to the IASP pathophysiological definition highlighted a predominant nociceptive pain type (53.9% of all the diagnoses), followed by neuropathic (22.1%), mixed (22.1%), nociplastic (2.6%), and idiopathic (2.6%) pain. According to the IASP classification for ICD-11, the clinical diagnosis of chronic pain secondary to obliterating arterial disease and diabetes-related foot ulcers could not be assigned to any diagnostic category as a result of the lack of a specific item in the aforementioned classification.

CONCLUSION

This study confirmed that chronic pain is a common, burdening issue in hemodialysis patients and that it is of a prevalent nociceptive nature. Our study highlights some limitations of the last IASP ICD-11 classification, especially the lack of specific items for some pain features that are very frequent in hemodialysis patients, and not only in that population. Finally, this study underlines the importance of mutual collaboration between pain physicians and nephrologists for the well-being of patients of high clinical complexity, such as those undergoing chronic hemodialysis.

Spinal AT1R contributes to neuroinflammation and neuropathic pain via NOX2-dependent redox signaling in microglia

Microglia-mediated neuroinflammation demonstrates a crucial act in the progression of neuropathic pain. Oxidative damage induced by reactive oxygen species (ROS) derived from NADPH oxidase (NOX) in microglia drives proinflammatory microglia activation. Recent evidence points to the central renin angiotensin system (RAS) is involved in oxidative stress and neuroinflammation, with the angiotensin converting enzyme/angiotensin II/angiotensin receptor-1 (ACE/Ang II/AT1R) axis promoting inflammation through increased ROS production, counteracted by the ACE2/Ang (1-7)/Mas receptor (MasR) axis. While interventions targeting spinal AT1R have been shown to alleviate nociceptive hypersensitivity; yet the mechanisms remain elusive. Here, we discovered that spared nerve injury (SNI)-induced mechanical allodynia in rats were associated with M1-like microglia activation, oxidative stress and overactivity of ACE/Ang II/AT1R axis in the spinal cord. Increased AT1R and NOX2 expression were observed in activated dorsal horn microglia following SNI. Blockade of AT1R with losartan potassium (LOP) suppressed NOX2-mediated oxidative stress, and promoted a shift in microglia from the proinflammatory M1 phenotype to the anti-inflammatory M2 phenotype in LPS-treated BV-2 cells. Additionally, NOX2 overexpression triggered the activation of the high-mobility group box 1/nuclear factor-kappa B (HMGB1/NF-κB) signaling pathway. Intrathecal administration of LOP effectively inhibited SNI-induced NOX2 overactivation in microglia and suppressed the HMGB1/NF-kB pathway, reducing oxidative stress and shifting the microglia polarization from M1 to M2 in the spinal cord, thereby attenuating neuroinflammation and pain hypersensitivity. Collectively, these findings underscore the neuroimmune-modulating effects of spinal AT1R in neuropathic pain, highlighting the regulation of redox homeostasis in microglia via a NOX2 dependent mechanism.

Involvement of the astroglial glutamate-glutamine cycle in the analgesic effects of electroacupuncture in a rat model of chronic neuropathic pain

OBJECTIVE

Our previous study found that astrocytes are involved in cumulative analgesia; however, the underlying mechanism remains unclear. The aim of this study was to further explore the potential role of astrocytes in the effects of electroacupuncture (EA) on neuropathic pain by focusing on the glutamate-glutamine cycle.

METHODS

69 male Sprague-Dawley (SD) rats were randomly divided into a normal control group, untreated chronic constriction injury (CCI) model group and EA-treated model (CCI + EA) group. EA was applied bilaterally at ST36 and GB34. Pain thresholds were assessed using behavioral tests and thermal stimuli. We examined the co-expression of glutamate/aspartate transporter (GLAST) via immunofluorescence and measured the expression levels of GLAST, glutamate transporter (GLT)-1 and glutamine synthetase (GS) using Western blotting and polymerase chain reaction (PCR). Glutamate (Glu) and gamma-aminobutyric acid (GABA) levels were detected by high-performance liquid chromatography (HPLC). To validate the impact of GLAST/GLT-1 in the analgesic effect of EA, an additional 30 SD male rats were divided into groups receiving intrathecal saline, GLAST antagonist or GLT-1 antagonist alongside EA.

RESULTS

Post-CCI, pain thresholds were decreased, GLAST expression was diminished, and spinal Glu levels were increased. EA treatment reversed these effects, improved pain thresholds and GLAST/GLT-1 expression in astrocytes, and reduced Glu levels. Antagonist administration negated the analgesic effects of EA.

CONCLUSION

Repeated EA administration inhibited CCI-induced chronic neuropathic pain in rats, corresponding to a reversal of decreased expression of GLAST and GLT-1, which may have accelerated the clearance of Glu and thereby reduced its concentration. Regulation of the astroglial glutamate-glutamine cycle is a potential target of EA.

Upregulation of FMRP Is Involved in Neuropathic Pain by Regulating GluN2B Activation in Rat Spinal Cord

Fragile X mental retardation protein (FMRP) has been proposed to play a potential role in the pathogenesis of autonomy and nociceptive paresthesia. However, the involvement of spinal FMRP in neuropathic pain remains unexplored. Using a rat model of neuropathic pain induced by chronic constriction injury (CCI), our investigation demonstrated an upregulation of FMRP at 3, 7, and 14 days post-CCI operation in the spinal dorsal horn (SDH). Immunofluorescence staining revealed predominant FMRP expression in spinal neurons, which colocalized with Glutamate Ionotropic Receptor NMDA Type Subunit 2B (GluN2B). The Co-immunoprecipitation results suggested an interaction between spinal FMRP and GluN2B. Genetic knockout of the Fmr1 gene or transient interference with the FMRP protein alleviated CCI-induced pain hypersensitivity and suppressed the increase in spinal GluN2B expression. Conversely, intrathecal administration of the GluN2B-specific inhibitor Ifenprodil significantly suppressed the CCI-induced increase in spinal FMRP expression. In conclusion, our findings highlight the pivotal role of spinal FMRP in developing neuropathic pain and modulating GluN2B levels within the SDH. Furthermore, our results suggest a reciprocal regulatory relationship, indicating that GluN2B may also influence FMRP expression. This study provides insights into the molecular mechanisms underlying neuropathic pain, suggesting the potential for therapeutic intervention targeting the FMRP-GluN2B axis in pain management.

Nociceptor-localized KCC2 suppresses brachial plexus avulsion-induced neuropathic pain and related central sensitization

Lack in understanding of the mechanism on brachial plexus avulsion (BPA)-induced neuropathic pain (NP) is the key factor restricting its treatment. In the current investigation, we focused on the nociceptor-localized K+-Cl- cotransporter 2 (KCC2) to investigate its role in BPA-induced NP and related pain sensitization. A novel mice model of BPA on the middle trunk (C7) was established, and BPA mice showed a significant reduction in mechanical withdrawal threshold of the affected fore- and hind- paws without affecting the motor function through CatWalk Gait analysis. Decreased expression of KCC2 in dorsal root ganglion (DRG) was detected through Western blot and FISH technology after BPA. Overexpression of KCC2 in DRG could reverse the hyperexcitability of DRG neurons and alleviate the pain of BPA mice synchronously. Meanwhile, the calcium response signal of the affected SDH could be significantly reduced through above method using spinal cord fiber photometry. The synthesis and release of brain-derived neurotrophic factor (BDNF) was also proved reduction through overexpression of KCC2 in DRG, which indicates BDNF can also act as the downstream role in this pain state. As in human-derived tissues, we found decreased expression of KCC2 and increased expression of BDNF and TrκB in avulsed roots of BPA patients compared with normal human DRGs. Our results indicate that nociceptor-localized KCC2 can suppress BPA-induced NP, and peripheral sensitization can be regulated to reverse central sensitization by targeting KCC2 in DRG at the peripheral level through BDNF signaling. The consistent results in both humanity and rodents endow great potential to future transformation of clinical practice.

Exploring the Pain Situation, Pain Impact, and Educational Preferences of Pain Among Adults in Mainland China, a Cross-Sectional Study

OBJECTIVES

This study aimed to investigate the pain situation, functional limitations, treatment used, care-seeking behaviors, and educational preferences of adults with pain in mainland China.

METHODS

An online questionnaire was developed through expert validation, and participants were recruited via social media platforms. Inclusion criteria required having access to the Internet and smartphones, while individuals with significant cognitive impairments or severe mental illness were excluded.

RESULTS

1566 participants, predominantly male (951) with a mean age of 30.24, were included. A total of 80.1% of the respondents reported experiencing pain, with over half suffering from chronic pain. Pain primarily affects the neck, lower back, and upper back, especially chronic low back pain. Pain significantly impacted various aspects of life, including mood, physical activity, work performance, family dynamics, and social relationships, particularly among chronic pain sufferers (p-value: < 0.001). Analgesics (66.9%) and self-management (80-94.3%) were the most used pain management strategies, with respondents with chronic pain reporting higher usage and effectiveness of medication than those with acute pain (p-value: < 0.001). Participants also expressed a greater interest in online education and psychotherapy interventions, especially through mobile applications.

CONCLUSIONS

Chronic pain is highly prevalent in mainland China, leading to emotional distress, decreased work competency, and social isolation, with a strong demand for pain education through smartphone applications.

The Challenge of Managing Neuropathic Pain in Children and Adolescents with Cancer

Neuropathic pain (NP) is a common complication associated with some types of childhood cancer, mainly due to nerve compression, chronic post-surgical pain, chemotherapy, and radiotherapy. NP is usually less responsive to traditional analgesics, and there is generally a lack of evidence on its management in cancer patients, leading to recommendations often based on clinical trials conducted on other forms of non-malignant NP. In pediatric oncology, managing NP is still very challenging for physicians. Different factors contribute to increasing the risk of undertreatment: (a) children may be unable to describe the quality of pain; therefore, the risk for NP to be underestimated or remain unrecognized; (b) specific tools to diagnose NP have not been validated in children; (c) there is a lack of randomized clinical trials involving children, with most evidence being based on case series and case reports; (d) most drugs used for adult patients are not approved for childhood cancers, and drug regulation varies among different countries; (e) recommendations for pediatric pain treatment are still not available. In this paper, a multidisciplinary team will review the current literature regarding children with cancer-related NP to define the best possible diagnostic strategies (e.g., clinical and instrumental tests) and propose a therapeutic care pathway, including both non-pharmacological and pharmacological approaches, which could help pediatricians, oncologists, neurologists, and pain therapists in designing the most effective multidisciplinary approach.

Perceptual Disturbances and Disorders in the ICD-11: An Overview and a Proposal for Systematic Classification

The International Classification of Diseases (ICD) has been developed and edited by the World Health Organisation and represents the global standard for recording health information and causes of death. The ICD-11 is the eleventh revision and came into effect on 1 January 2022. Perceptual disturbances refer to abnormalities in the way sensory information is interpreted by the brain, leading to distortions in the perception of reality. These can manifest as distorted perceptions or as phantom perceptions and can occur in all sensory modalities as visual, auditory, olfactory, gustatory tactile, vestibular, proprioceptory or interoceptory disturbances. There are similar brain mechanisms involved in the generation of these analogous perceptual disturbances and disorders, and they are treated with similar approaches. Perceptual disturbances are highly prevalent, with large variations across the different sensory modalities. They can be associated with significant suffering and cause a high socioeconomic burden. Perceptual disturbances can be symptoms of another disease or disease entities on their own. In the context of pain, this is reflected by the distinction between secondary pain (pain as a symptom of another underlying condition) and primary pain (a disease in its own right, rather than being a symptom of another underlying condition) in the ICD-11. Such a clear distinction is not found in an entirely consistent way across the various sensory modalities. By using the example of auditory phantom perceptions, we propose a framework for the classification of sensory disorders in alignment with the classification of pain in the ICD-11. The descriptions of the sensory disturbances should include (1) a causal aspect (primary versus secondary), (2) a temporal aspect (acute vs. chronic and persistent vs. intermittent), (3) a cognitive, emotional and autonomic interpretation aspect (=suffering) and (4) a social aspect (=disability). If the latter two aspects are present, we propose that the sensory disturbance is called a sensory disorder.

Local abnormal white matter microstructure in the spinothalamic tract in people with chronic neck and shoulder pain

Objective

To investigate differences in the microstructure of the spinothalamic tract (STT) white matter in people with chronic neck and shoulder pain (CNSP) using diffusion tensor imaging, and to assess its correlation with pain intensity and duration of the pain.

Materials and methods

A 3.0T MRI scanner was used to perform diffusion tensor imaging scans on 31 people with CNSP and 24 healthy controls (HCs), employing the Automatic Fiber Segmentation and Quantification (AFQ) method to extract the STT and quantitatively analyze the fractional anisotropy (FA) and mean diffusivity (MD), reflecting the microstructural integrity of nerve fibers. Correlations of these differences with duration of pain and visual analog scale (VAS) scores were analyzed.

Results

No significant differences in the mean FA or MD values of the bilateral STT were observed between people with CNSP and HCs (p > 0.05), as indicated by the two-sample t test. Further point-by-point comparison along 100 equidistant nodes within the STT pathway revealed significant reductions in FA values in the left (segments 12-18, 81-89) and right (segments 9-19, 76-80) STT in the CNSP group compared to HCs; significant increases in MD values were observed in the left (segments 1-13, 26-30, 71-91) and right (segments 8-17, 76-91) STT (p < 0.05, FWE corrected). Partial correlation analysis indicates that in people with CNSP, the FA values of the STT in regions with damaged white matter structure show a negative correlation with VAS scores and duration of pain, whereas MD values show a positive correlation with VAS scores and duration of pain.

Conclusion

This study found that people with CNSP exhibit white matter microstructural abnormalities in the specific segments of STT. These abnormalities are associated with the patient's pain intensity and disease duration. The findings offer a new neuroimaging perspective on the pathophysiological basis of chronic pain in the ascending conduction process and its potential role in developing targeted intervention strategies. However, due to the limited sample size and the lack of statistical significance when analyzing the entire spinothalamic tract, these conclusions should be interpreted with caution. Further research with larger cohorts is necessary to validate these results.

The Role of Alpha-7 Nicotinic Acetylcholine Receptors in Pain: Potential Therapeutic Implications

Chronic pain represents a prevalent and costly medical challenge globally. Nicotinic acetylcholine receptors (nAChRs), one type of ligand-gated ion channels found extensively in both the central and peripheral nervous systems, have emerged as promising therapeutic targets for chronic pain. Although there are currently no FDA-approved analgesics specifically targeting nAChRs, accumulating preclinical and clinical evidence suggest that selective ligands for alpha 7 (α7) nAChRs show potential for treating chronic pain, boasting a reduced incidence of side effects compared with other nicotinic receptor types. The recent structural resolution of human α7 nAChRs has confirmed their negative association with heightened pain, providing a valuable foundation for the development of targeted medications. This review presents a comprehensive overview, encompassing insights into the roles of α7 nAChRs derived from structural and functional studies, recent advancements in pharmacology, and investigations into their involvement in the pathophysiology of chronic pain. Moreover, the review addresses the variability in analgesic effects based on the type of receptor agonist and highlights the current research limitations. As such, this review offers potential therapeutic approaches for the development of innovative strategies for chronic pain management.

N-Demethylsinomenine Relieves Neuropathic Pain in Male Mice Mainly via Regulating α2-Subtype GABAA Receptors

AIMS

N-Demethylsinomenine (NDSM) demonstrates good analgesic efficacy in preclinical pain models. However, how NDSM exerts analgesic actions remains unknown.

METHODS

We examined the analgesic effects of NDSM using both pain-evoked and pain-suppressed behavioral assays in two persistent pain models. Then western blot assay and immunofluorescence staining were used to investigate the effects of NDSM on the expression of the GABAA receptor α2 subunit (GABRA2) and inflammatory factors in the spinal cord and brain tissues of male spared nerve injury (SNI) mice. Finally, the individual subtypes of GABAARs (α1, α2, α3, and α5) were respectively silenced by viral-mediated knockdown to explore the involvement of subtypes of GABAARs in the effects of NDSM on the pain-like behaviors in male SNI mice.

RESULTS

NDSM demonstrated significant analgesic effects against chronic pain both in pain-evoked and pain-suppressed behavioral assays. NDSM treatment significantly reversed the SNI induced down-regulation of GABRA2 and up-regulation of TNF-α and IL-1β. The analgesic effects of NDSM were completely blocked by silencing GABRA2 or partially blocked by silencing GABRA3.

CONCLUSION

This study provided the first evidence that the analgesic effects of NDSM are mediated primarily by GABRA2 and partially by GABRA3, and the inhibition of neuroinflammation also contributes to the analgesic effects of NDSM.

Impact of chronic low back pain on implicit motor imagery assessed by a new laterality judgment task

It is clear that implicit motor imagery (IMI) is impaired by chronic pain in peripheral regions (hand, feet), but unclear in axial regions (neck, shoulder, back). Previous IMI tasks displayed small-amplitude movements of axial regions, which limits person-centered IMI processes mobilization. This study aimed to assess the impact of chronic low back pain (CLBP) on IMI processes with a new task displaying large-amplitude whole-body movements mobilizing the lumbar spine. Twenty patients with CLBP and twenty age-matched controls performed a laterality judgment task on four distinct whole-body movements (trunk flexion, trunk rotation, capoeira, kickboxing). Participants viewed images from four different body viewpoints (back, left, right and front), randomly presented. Mixed ANOVAs were used to compare judgment accuracy and response times between groups and conditions. In participants with CLBP, response times were longer than in controls. The response times of participants with CLBP were also associated with DN4 scores, a self-reported questionnaire assessing neuropathic pain. We validated the use of a person-centered IMI because, for all participants, the accuracy decreased and the response times increased for images presented in the front viewpoint, i.e. when a 180° turn in IMI was required, compared to other viewpoints. The laterality judgment task proposed here confirmed that CLBP impacts IMI processes, and that the nature of pain (neuropathic or mechanical) needs to be considered because it seems to modulate IMI processes. PERSPECTIVE: A laterality judgment task with large-amplitude lumbar movements is key to show that CLBP alters processing speed of sensorimotor information originating from the painful region. This task could become an objective tool, transferable in clinical settings, for assessing the impact and the progression of CLBP on motor control processes.

The use of abstract animations and a graphical body image for assessing pain outcomes among adults with sickle cell disease

Painimation, a novel digital pain assessment tool, allows patients to communicate their pain quality, intensity, and location using abstract animations (painimations) and a paintable body image. This study determined the construct validity of painimations and body image measures by testing correlations with validated pain outcomes in adults with sickle cell disease (SCD). Analyses used baseline data from a multisite randomized trial of 359 adults with SCD and chronic pain. Participants completed questionnaires on demographics, pain severity, frequency and interference, catastrophizing, opioid use, mood and quality of life, plus the Painimation app. Participants were categorized by selected painimations, and were split into groups based on the proportion of painted body image. Potential confounding was evaluated by age, gender, race, education, disability, site, depression, and anxiety. The 'shooting' painimation was strongly associated with daily pain intensity, pain interference, frequency, and severity. 'Electrifying' was associated with daily pain and opioid misuse, while greater body area in pain correlated with worse outcomes across all pain measures. Both painimations and body image measures correlated with validated pain outcomes, quality of life and mental health measures. This demonstrates animations and body image data can assess SCD pain severity, potentially with more accuracy than a 0-10 scale. Future research will explore whether Painimation can differentiate biological and psychosocial pain components. PERSPECTIVE: This article presents the preliminary construct validity of Painimation in SCD by examining the associations of "painimations" and body area image data with daily e-diary and traditional self-report pain outcomes.

Patterns of antidepressant use in people with low back pain: A retrospective study using workers' compensation data

BACKGROUND

Antidepressants are commonly used to treat low back pain (LBP), but little is known about patterns of antidepressant use in this population. This study aimed to identify patterns of antidepressant dispensing and switching in Australian workers with an accepted workers' compensation claim for LBP, and to investigate factors associated with dispensing and switching.

METHODS

This retrospective study included data from accepted workers' compensation time loss claims for LBP between 2010 and 2018 with a 2-year follow-up. We described the type of antidepressant dispensed, the time for the index antidepressant to be dispensed, and whether people in the study switched to a different antidepressant. Logistic regression models investigated factors associated with antidepressants being dispensed for the first time and for switching to a different antidepressant.

RESULTS

Antidepressants were dispensed to 2476 people with LBP (14%) at least once after a median (IQR) of 28 (10.9-54.7) weeks. Amitriptyline was the most dispensed antidepressant at any one point (47.8%), and the most common index antidepressant (42.9%). Also, 32.7% of people switched to a different antidepressant at least once. Sex, age, having been dispensed opioids, gabapentinoids or diazepam prior to antidepressants being dispensed, having used psychological services, and socioeconomic disadvantage were associated with antidepressant dispensing.

CONCLUSION

One in seven people with LBP were dispensed an antidepressant, most commonly amitriptyline. Antidepressants were commonly used in combination with other pain medicines such as opioids, gabapentinoids and diazepam.

SIGNIFICANCE

Antidepressants were dispensed to one in seven people with low back pain, most commonly amitriptyline followed by duloxetine. Antidepressants were typically dispensed after 6 months and after other medicines such as opioids, gabapentinoids and diazepam had been dispensed. Due to the administrative nature of the data, the study cannot infer whether antidepressants were dispensed to treat pain or other health problems, such as a mental health condition.

Management of Central Poststroke Pain: Systematic Review and Meta-analysis

Central poststroke pain (CPSP) is a neuropathic pain condition prevalent in 8 to 35% of stroke patients. This systematic review and meta-analysis aimed to provide insight into the effectiveness of available pharmacological, physical, psychological, and neuromodulation interventions in reducing pain in CPSP patients (PROSPERO Registration: CRD42022371835). Secondary outcomes included mood, sleep, global impression of change, and physical responses. Data extraction included participant demographics, stroke etiology, pain characteristics, pain reduction scores, and secondary outcome metrics. Forty-two original studies were included, with a total of 1,451 participants. No studies providing psychological therapy to CPSP patients were identified. Twelve studies met requirements for a random-effects meta-analyses that found pharmacological therapy to have a small effect on mean pain score (SMD = -.36, 96.0% confidence interval [-.68, -.03]), physical interventions did not show a significant effect (SMD = -.55 [-1.28, .18]), and neuromodulation treatments had a moderate effect (SMD = -.64 [-1.08, -.19]). Fourteen studies were included in proportional meta-analysis with pharmacological studies having a moderate effect (58.3% mean pain reduction [-36.51, -80.15]) and neuromodulation studies a small effect (31.1% mean pain reduction [-43.45, -18.76]). Sixteen studies were included in the narrative review, the findings from which largely supported meta-analysis results. Duloxetine, amitriptyline, and repetitive transcranial magnetic stimulation had the most robust evidence for their effectiveness in alleviating CPSP-induced pain. Further multicenter placebo-controlled research is needed to ascertain the effectiveness of physical therapies, such as acupuncture and virtual reality, and invasive and noninvasive neuromodulation treatments. PERSPECTIVE: This article presents a top-down and bottom-up overview of evidence for the effectiveness of different pharmacological, physical, and neuromodulation treatments of CPSP. This review could provide clinicians with a comprehensive understanding of the effectiveness and tolerability of different treatment types.

Sex-Specific White Matter Abnormalities Across the Dynamic Pain Connectome in Neuropathic Pain: A Fixel-Based Analysis Study

A fundamental issue in neuroscience is a lack of understanding regarding the relationship between brain function and the white matter architecture that supports it. Individuals with chronic neuropathic pain (NP) exhibit functional abnormalities throughout brain networks collectively termed the "dynamic pain connectome" (DPC), including the default mode network (DMN), salience network, and ascending nociceptive and descending pain modulation systems. These functional abnormalities are often observed in a sex-dependent fashion. However, the enigmatic white matter structural features underpinning these functional networks and the relationship between structure and function/dysfunction in NP remain poorly understood. Here we used fixel-based analysis of diffusion weighted imaging data in 80 individuals (40 with NP [21 female, 19 male] and 40 sex- and age-matched healthy controls [HCs]) to evaluate white matter microstructure (fiber density [FD]), macrostructure (fiber bundle cross section) and combined microstructure and macrostructure (fiber density and cross section) within anatomical connections that support the DPC. We additionally examined whether there are sex-specific abnormalities in NP white matter structure. We performed fixel-wise and connection-specific mean analyses and found three main ways in which individuals with NP differed from HCs: (1) people with NP exhibited abnormally low FD and FDC within the corona radiata consistent with the ascending nociceptive pathway between the sensory thalamus and primary somatosensory cortex (S1). Furthermore, the entire sensory thalamus-S1 pathway exhibited abnormally low FD and FDC in people with NP, and this effect was driven by the females with NP; (2) females, but not males, with NP had abnormally low FD within the cingulum consistent with the right medial prefrontal cortex-posterior cingulate cortex DMN pathway; and (3) individuals with NP had higher connection-specific mean FDC than HCs in the anterior insula-temporoparietal junction and sensory thalamus-posterior insula pathways. However, sex-specific analyses did not corroborate these connection-specific findings in either females or males with NP. Our findings suggest that females with NP exhibit microstructural and macrostructural white matter abnormalities within the DPC networks including the ascending nociceptive system and DMN. We propose that aberrant white matter structure contributes to or is driven by functional abnormalities associated with NP. Our sex-specific findings highlight the utility and importance of using sex-disaggregated analyses to identify white matter abnormalities in clinical conditions such as chronic pain.

The Importance of Bright Spotty Lesions on Magnetic Resonance Imaging in Predicting Chronic Neuropathic Pain in Myelitis

Background/Objectives: Chronic neuropathic pain (CNP) stands as one of the most debilitating complications in patients with myelitis owing to its challenging management. Bright spotty lesions (BSLs) are frequently observed in neuromyelitis optica spectrum disorder (NMOSD), but few reports have discussed CNP in myelitis. We aim to demonstrate that BSLs could be one of the potential prognostic factors for CNP development in myelitis. Methods: We examined 63 patients diagnosed with myelitis. Patients were categorized into CNP and non-CNP groups. We assessed the severity of clinical symptoms and the oral steroid dose administered after pulse therapy. Spine magnetic resonance imaging (MRI) of each patient was reviewed to analyze the characteristics of myelitis. Serological and cerebrospinal fluid (CSF) findings were also examined to confirm the etiology. Results: CNP was observed in 27 patients (42.9%). The mean onset age of patients with CNP was 45.26 ± 14.16 years. The MRI lesions exhibited more enhanced features and bright spotty lesions (BSLs) in the CNP group (χ2 test, p < 0.05). Patients with CNP received a lower oral steroid dose during the first month after symptom onset (χ2 test, p < 0.05). Multivariate logistic regression analysis revealed that patients with CNP exhibited significant BSLs in their myelitis lesions on spine MRI (OR 4.965; 95% CI, 1.282 to 19.235, p = 0.02). Conclusions: Although the exact mechanism remains unknown, the presence of BSLs on spine MRI could serve as an independent prognostic factor for CNP development. Additionally, our study suggests that lower oral steroid doses administered immediately after symptom onset are associated with CNP development. Further investigation with a larger cohort is warranted to validate our findings.

A scoping review of mind-body therapies for people with persistent pain after stroke

PURPOSE

Persistent pain post-stroke is common; however, non-medical management options remain under-researched. This scoping review sought to identify and summarise existing literature regarding mind-body therapies for people with persistent pain post-stroke, examine pain and pain-related biopsychosocial outcomes, and identify areas for future research.

MATERIALS AND METHODS

This review followed PRISMA and JBI guidelines; the protocol was registered on Open Science Framework. Five electronic databases (PubMed, EMBASE, CINAHL, PsycINFO, Web of Science) were searched from 1992 until 19th August 2024. Primary studies of any design evaluating mind-body therapies in adults with persistent pain post-stroke, published in English in peer-reviewed journals, were eligible. Findings were narratively summarised by study, sample, and mind-body therapy characteristics.

RESULTS

Twenty-one studies comprising 458 adults with various post-stroke pain presentations were included. Only 10 studies specifically targeted stroke pain; the remainder primarily incorporated pre-post measures of pain in a heterogenous stroke sample (with and without pain). Studies varied in their levels of evidence, sample characteristics, mind-body therapies, and biopsychosocial outcome measurement. Nonetheless, improvements in pain and pain-related biopsychosocial outcomes were consistently reported.

CONCLUSION

Limited, lower-quality research suggests improved pain and biopsychosocial outcomes. However, further rigorous research exploring feasibility, safety, efficacy, optimal dosage, format, and setting is recommended.

The Diagnosis and Treatment of Neuropathic Pain

BACKGROUND

The reported prevalence of neuropathic pain in the general population in Germany is from 6.9% to 10%. There are both medical and surgical treatment options.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed, with consideration of clinical trials, meta-analyses, and guidelines.

RESULTS

Neuropathic pain is diagnosed when pain of the appropriate character is accompanied by further features such as hypesthesia/anesthesia, allodynia, or hyperalgesia. It is generally treated initially with drugs (antidepressant drugs, anticonvulsant drugs, opioids, topical agents, and others); the number needed to treat (NNT) is between 7 and 8 for gabapentin and 3.6 for amitryptiline, as estimated in meta-analyses. For nerve compression and entrapment syndromes, surgical decompression is a treatment directed against the cause of the problem, which can therefore be curative. Microvascular decompression (MVD) is often used to treat supposed compression syndromes of cranial nerves, above all classic trigeminal neuralgia; according to a meta-analysis, MVD brings about a pain-free state in 92.9% [89.1; 96.8] of patients after 5 months to 5 years of follow-up. Ablative surgical procedures are used for symptom control in patients with refractory and/or cancer-related pain. Further symptomdirected treatment options for medically intractable neuropathic pain include neuromodulatory techniques, which involve minimally invasive electrical stimulation of neural structures, and the chronic intrathecal application of drugs such as opioids and ziconotide.

CONCLUSION

The treatment of neuropathic pain can be either cause-directed or symptom-directed, depending on its origin. Multidisciplinary collaboration can facilitate both the diagnostic evaluation and the selection of the optional modality and timing of treatment.

Overexpression of miR-133a-3p reduces microglia activation by binding to GCH1, alleviating neuroinflammation and neuropathic pain

Neuropathic pain is a chronic pain condition that is primarily caused by underlying neurological damage and dysfunction. Recent studies have identified microRNAs (miRNAs) as a key factor in the treatment of neuropathic pain. To explore the effects of miR-133a-3p on neuroinflammation and neuropathic pain via GTP cyclohydrolase (GCH1), and its underlying mechanisms. In vitro models were constructed using BV-2 cells that had been treated with lipopolysaccharide, followed by treatment with either miR-133a-3p mimic or GCH1 viral knockdown/overexpression. The expression of miR-133a-3p and GCH1 in BV-2 cells was quantified by RT-qPCR. The degree of neuroinflammation was quantified using an enzyme-linked immunosorbent assay (ELISA). The targeting relationship between miR-133a-3p and GCH1 was confirmed by western blot and dual luciferase reporter assay. A chronic constriction injury model was employed to induce neuropathic pain in rats, and the mechanical withdrawal threshold (MWT) was quantified. Immunofluorescence was used to demonstrate alterations in microglial cells. The expression of miR-133a-3p was found to be decreased in lipopolysaccharide-induced BV-2 cells. The overexpression of miR-133a-3p was observed to inhibit the expression of IL-1β, IL-6, TNF-α and iNOS, which was attributed to a reduction in GCH1.Nevertheless, OE-GCH1 could partially reverse the downregulation by miR-133a-3p of the expression of inflammatory factors. In animal experiments, intrathecal injection of AVV-miR-133a-3p was observed to alleviate mechanical nociceptive abnormalities induced by activated microglia. Furthermore, miR-133a-3p ameliorated neuroinflammation in the spinal cord of chronic constriction injury rats. In summary, miR-133a-3p improves neuroinflammation and neuropathic pain by binding to GCH1. The binding of miR-133a-3p to GCH1 has been demonstrated to improve neuroinflammation and neuropathic pain.This insight will facilitate the development of new methods to effectively treat neuropathic pain.

The Role of Mechanosensitive Piezo Channels in Chronic Pain

Purpose of Review

Mechanosensitive Piezo channels are ion channels activated by mechanical stimuli, playing a crucial role in mechanotransduction processes and mechanical hypersensitivity. When these channels are subjected to mechanical loading, membrane currents rise instantaneously, depolarizing and activating voltage-gated calcium channels. This results in an increase in intracellular Ca2+, which contributes to heightened sensitivity to mechanical stimuli. This review delves into the characteristics and mechanisms of Piezo channels in chronic pain.

Recent Findings

The findings suggest that Piezo channels are integral to the occurrence and development of chronic pain, including neuropathic pain, visceral pain, musculoskeletal pain, headache or orofacial pain, and inflammatory pain. Piezo channels significantly impact pain perception and transmission. These channels' critical involvement in various pain types highlights their potential as promising targets for chronic pain therapy.

Summary

This review discusses the role of Piezo channels in chronic pain. By understanding these pain mechanisms, new therapeutic strategies can be developed to alleviate chronic pain, offering hope for patients suffering from these debilitating conditions.

Elevated plasma CXCL12 leads to pain chronicity via positive feedback upregulation of CXCL12/CXCR4 axis in pain synapses

BACKGROUND

Chronic pain poses a clinical challenge due to its associated costly disability and treatment needs. Determining how pain transitions from acute to chronic is crucial for effective management. Upregulation of the chemokine C-X-C motif ligand 12 (CXCL12) in nociceptive pathway is associated with chronic pain. Our previous study has reported that elevated plasma CXCL12 mediates intracerebral neuroinflammation and the comorbidity of cognitive impairment in neuropathic pain, but whether it is also involved in the pathogenesis of pathologic pain has not been investigated.

METHODS

Intravenous or intrathecal injection (i.v. or i.t.) of recombinant mouse CXCL12, neutralizing antibody (anti-CXCL12) or AMD3100 [an antagonist of its receptor C-X-C chemokine receptor type 4 (CXCR4)] was used to investigate the role of CXCL12 signaling pathway in pain chronicity. Two behavioral tests were used to examine pain changes. ELISA, immunofluorescence staining, Western blot, quantitative Real Time-PCR and Cytokine array were applied to detect the expressions of different molecules.

RESULTS

We found that increased plasma CXCL12 was positively correlated with pain severity in both chronic pain patients and neuropathic pain model in mice with spared nerve injury (SNI). Neutralizing plasma CXCL12 mitigated SNI-induced hyperalgesia. A single i.v. injection of CXCL12 induced prolonged mechanical hyperalgesia and activation of the nociceptive pathway. Multiple intravenous CXCL12 caused persistent hypersensitivity, enhanced structural plasticity of nociceptors and up-regulation of the CXCL12/CXCR4 axis in the dorsal root ganglion (DRG) and spinal dorsal horn (SDH). However, intrathecal blocking of CXCL12/CXCR4 pathway by CXCL12 antibody or CXCR4 antagonist AMD3100 significantly alleviated CXCL12-induced pain hypersensitivity and pathological changes.

CONCLUSIONS

Our study provides strong evidence that a sustained increase in plasma CXCL12 contributes to neuropathic pain through a positive feedback loop that enhances nociceptor plasticity, and suggests that targeting CXCL12/CXCR4 axis in plasma or nociceptive pathways has potential value in regulating pain chronicity.

Peripheral Nerve Stimulation for Neuropathic Pain Management: A Narrative Review

This narrative review examines the therapeutic efficacy of peripheral nerve stimulation (PNS) in the treatment of neuropathic pain (NP), a type of pain arising from lesions or diseases of the somatosensory system with a global prevalence ranging from 6.90% to 10.00%. Traditional pharmacological interventions often fall short for many persons, highlighting the need for alternative treatments such as PNS, which has demonstrated significant promise with minimal side effects. The review summarizes the effectiveness of PNS in various NP conditions, including trigeminal neuralgia and postherpetic neuralgia, and underscores the need for further research to refine treatment approaches. The mechanism of PNS is discussed, involving the activation of non-nociceptive Aβ fibers and modulation of neurotransmitters, and offering pain relief through both peripheral and central pathways. Despite the proven efficacy of PNS, challenges remain, including the need for randomized controlled trials and the optimization of stimulation parameters. The review concludes that PNS is a promising treatment modality for NP, warranting additional high-quality trials to solidify its role in clinical practice.

Astilbin exerts anti-hypersensitivity by regulating metabolic demand and neuronal activity in rodent model of neuropathic pain

OBJECTIVE

Astilbe chinensis, is a traditional Chinese medicine commonly employed for pain management. However, its primary active ingredient remains a subject of debate.

METHODS

Spinal nerve ligation (SNL) and formalin-induced pain models were employed. Network pharmacology and bioinformatics were utilized to identify targets. Verification was performed through spinal cord double immunofluorescence staining, quantitative PCR and whole-cell recording techniques.

RESULTS

In experiments conducted on neuropathic rats, both systemic and intrathecal administration of astilbin, an essential constituent, exhibited a noteworthy and dose-dependently decrease in chronic and acute pain behaviours. The ED50 value, which represents the dose at which 50% effectiveness is achieved, was measure at 7.59 μg, while the Emax value, indicating the maximum attainable effect, was found to be 60% of the maximal possible effect (% MPE). Forty-two shared targets were identified, enriching the metabolic and synaptic pathways in the network pharmacology analysis, as confirmed by transcriptomic analysis. Weighted gene co-expression network analysis (WGCNA) revealed a strong correlation between the anti-nociceptive effects of astilbin and neuronal metabolic processes. Spinal functional ultrasound (FUS) analysis indicated increased spinal blood flow intensity and changes in metabolism-related enzyme activity, including stearoyl-CoA desaturase (Scd), 17beta-hydroxysteroid dehydrogenase (Hsd17b7) and sterol 14alpha-demethylase (Cyp51) in neuropathic rats, pretreatment with astilbin decreased formalin-induced blood flow in acute pain. Bath application of astilbin dose-dependently inhibited neuronal activity by reducing the frequency and amplitude of miniature excitatory postsynaptic currents (mEPSCs) without affecting miniature inhibitory postsynaptic currents (mIPSCs).

CONCLUSIONS

In summary, this study provides evidence that astilbin alleviates pain by modulating neuronal metabolic processes and synaptic homeostasis.

Discordant dry eye disease and chronic pain: A systematic review and meta-analysis

PURPOSE

To evaluate the relative contributions of objective and subjective indicators of dry eye disease (DED) in individuals with chronic pain conditions compared with controls.

METHODS

A systematic review and meta-analysis was conducted of studies that reported the signs and symptoms of DED and/or their prevalence in individuals with chronic pain compared with controls. International Association for the Study of Pain (IASP) International Classification of Diseases (ICD)-11 codes for chronic pain conditions were applied, and outcomes defined as DED signs and symptoms. A search strategy utilised the EMBASE, Web of Science, Cochrane Library and MEDLINE databases. Risk of bias assessment was performed with the Newcastle-Ottawa scale. Random effects meta-analysis calculated mean differences (MD) and odds ratios (OR), while subgroup analysis of different chronic pain conditions explored their relative association with the signs and symptoms of DED. Evidence certainty was evaluated using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE).

RESULTS

Fourteen observational studies comprising 3,281,882 individuals were included. Meta-analysis found high quality evidence that individuals with chronic pain were more likely to experience symptoms of DED than controls (OR = 3.51 [95 %CI: 3.45,3.57]). These symptoms were more severe (MD = 18.53 [95 %CI: 11.90, 25.15]) than controls with a clinically meaningful effect size. Individuals with chronic pain had more rapid tear film disruption (MD = -2.45 [95 %CI: -4.20, -0.70]) and reduced tear production (MD = -5.57 [95 %CI: -9.56, -1.57]) compared with controls (with moderate evidence quality). High quality evidence revealed individuals with chronic pain had lower basal tear production (anaesthetised) than controls (MD = -2.59 [95 %CI: -3.60, -1.58]). Tear film osmolarity showed no significant differences between the chronic pain and pain-free groups. Group differences for DED signs were not considered clinically meaningful.

CONCLUSION

More severe, clinically meaningful symptoms of DED were reported in individuals with chronic pain than controls, however group differences for the signs of DED were typically of limited or questionable clinical relevance. This ocular phenotype where DED is felt more than it is seen in chronic pain may reflect underlying sensory hypersensitivity, shared by both conditions and contributing to their frequent comorbidity. Advancing understanding of this potential pathophysiological mechanism may guide clinical management.

The analgesic effect of acupuncture in neuropathic pain: regulatory mechanisms of DNA methylation in the brain

Recent research has demonstrated that chronic pain, resulting from peripheral nerve injury, leads to various symptoms, including not only allodynia and hyperalgesia but also anxiety, depression, and cognitive impairment. These symptoms are believed to arise due to alterations in gene expression and neural function, mediated by epigenetic changes in chromatin structure. Emerging evidence suggests that acupuncture can modulate DNA methylation within the central nervous system, contributing to pain relief and the mitigation of comorbidities. Specifically, acupuncture has been shown to adjust the DNA methylation of genes related to mitochondrial dysfunction, oxidative phosphorylation, and inflammation pathways within cortical regions, such as the prefrontal cortex, anterior cingulate cortex, and primary somatosensory cortex. In addition, it influences the DNA methylation of genes associated with neurogenesis in hippocampal neurons. This evidence indicates that acupuncture, a treatment with fewer side effects compared with conventional medications, could offer an effective strategy for pain management.

Transcutaneous Electrical Nerve Stimulation and Aerobic Exercise for Alcohol-Related Peripheral Neuropathy: A Case Report

Alcohol use disorders can cause peripheral and central neurological disorders with symptoms such as pain, numbness, paresthesia, and dysesthesia, often impairing walking ability. However, effective treatments for alcohol-related peripheral neuropathy are yet to be identified. This case report highlights the successful use of dysesthesia-matched transcutaneous electrical nerve stimulation (DM-TENS) and aerobic exercise in a 53-year-old woman with alcohol-related peripheral neuropathy who presented with severe pain and walking difficulties. Initially, her pain and numbness were scored 8-9 on the numerical rating scale (NRS), and her timed up-and-go test (TUG) time was 23.00 seconds. DM-TENS reduced her symptoms (NRS: 3), and the introduction of aerobic exercise further enhanced her recovery. After six days, her pain and numbness improved (NRS: 5), and her walking ability markedly increased (TUG: 10.94 s). By day 10, her symptoms had significantly resolved (NRS: 1). This case suggests that combining DM-TENS and aerobic exercise can effectively reduce pain, improve mobility, and offer a promising therapeutic approach to alcohol-related peripheral neuropathy.

An Update on Emerging Regenerative Medicine Applications: The Use of Extracellular Vesicles and Exosomes for the Management of Chronic Pain

PURPOSE OF REVIEW

Chronic pain affects nearly two billion people worldwide, surpassing heart disease, diabetes, and cancer in terms of economic costs. Lower back pain alone is the leading cause of years lived with disability worldwide. Despite limited treatment options, regenerative medicine, particularly extracellular vesicles (EVs) and exosomes, holds early promise for patients who have exhausted other treatment options. EVs, including exosomes, are nano-sized structures released by cells, facilitating cellular communication through bioactive molecule transfer, and offering potential regenerative properties to damaged tissues. Here, we review the potential of EVs and exosomes for the management of chronic pain.

RECENT FINDINGS

In osteoarthritis, various exosomes, such as those derived from synovial mesenchymal stem cells, human placental cells, dental pulp stem cells, and bone marrow-derived mesenchymal stem cells (MSCs), demonstrate the ability to reduce inflammation, promote tissue repair, and alleviate pain in animal models. In intervertebral disc disease, Wharton's jelly MSC-derived EVs enhance cell viability and reduce inflammation. In addition, various forms of exosomes have been shown to reduce signs of inflammation in neurons and alleviate pain in neuropathic conditions in animal models. Although clinical applications of EVs and exosomes are still in the early clinical stages, they offer immense potential in the future management of chronic pain conditions. Clinical trials are ongoing to explore their therapeutic potential further, and with more research the potential applicability of EVs and exosomes will be fully understood.

Pharmacological Pain Treatment in Older Persons

Pharmacological pain treatment in older persons is presented by a multi-disciplinary group of European pain experts. Drugs recommended for acute or chronic nociceptive pain, also for neuropathic pain and the routes of administration of choice are the same as those prescribed for younger persons but comorbidities and polypharmacy in older persons increase the risk of adverse effects and drug interactions. Not all drugs are available or authorised in all European countries. For mild-to-moderate pain, non-opioids including paracetamol and non-steroidal anti-inflammatory drugs are first-line treatments, followed by nefopam and metamizole. Codeine, dihydrocodeine and tramadol are prescribed for moderate to severe pain and 'strong' opioids, including morphine, hydromorphone, oxycodone, fentanyl, buprenorphine, methadone and tapentadol, for severe pain. Chronic neuropathic pain treatment relies on coanalgesics, including anti-epileptics (gabapentinoids) and anti-depressants with additional option of topical lidocaine and capsaicine. The choice of analgesic(s) and the route of administration should be guided by the pain characteristics, as well as by the patient's comorbidities, organ function and medications. Several directions have been highlighted to optimise pharmacological pain management in older individuals: (1) before starting pain treatment adequately detect and assess pain and always perform a full geriatric assessment, (2) consider kidney function systematically to adjust the doses of analgesics and avoid the risks of overdose, (3) start with the lowest dose of an analgesic and increase it gradually under the control of the effect, (4) involve the older persons and family in their treatment, (5) reevaluate pain regularly during treatment and (6) combine pharmacological treatment with non-pharmacological approaches.

Impact of Erector Spinae Plane Blocks on Pain Management and Postoperative Outcomes in Patients with Chronic Pain Undergoing Spine Fusion Surgery: A Retrospective Cohort Study

PURPOSE

To evaluate the impact of bilateral ultrasound-guided erector spinae plane blocks (ESPBs) on pain and opioid-related outcomes in a surgical population with chronic pain.

METHODS

A retrospective, observational cohort study. Clinical data were extracted from the electronic medical records of patients who underwent lumbar fusion (February 2018 - July 2020). Eligible patients had a confirmed history/diagnosis of chronic pain starting >3 months before surgery and received either bilateral ESPBs or no ESPBs. Patients were matched on demographic variables (sex, age, race, BMI, ASA Classification, and preoperative opioid use) in a 1:1 ratio. The primary outcome was median opioid consumption (morphine equivalent dose, MED) 24 hours post-surgery (hydromorphone iv-PCA and oral). Secondary outcomes included Numeric Rating Scale (NRS) pain scores, opioid consumption up to 48 hours post-surgery, and hospital length of stay (LOS). Group differences were analyzed using bivariable and multivariable regression.

RESULTS

Of 72 patients, 36 received ultrasound-guided ESPBs and 36 did not. Baseline demographics showed no significant differences. On bivariable analysis, ESPBs were associated with significantly lower 24-hour opioid consumption (79 mg MED vs 116 mg MED, p=0.024) and shorter LOS (82 hours, 95% CI 51-106 vs 126 hours, 95% CI 101-167, p<0.001). No significant differences in NRS pain scores were found up to 48 hours post-surgery. Multivariable analysis confirmed significant reductions in 24-hour opioid consumption (-44, 95% CI -1.06 - -87.55, p=0.044), IV-PCA use (-22, 95% CI -1.59 - -56.77, p=0.038), and LOS (-38, 95% CI -10.074 - -66.22, p=0.008) in the ESPB group without differences in NRS pain scores.

CONCLUSION

ESPBs were associated with statistically and clinically significant reductions in 24-hour opioid consumption and LOS, without differences in NRS pain scores after spinal fusion in a chronic pain surgical cohort. Given these effects, patients with chronic pain may disproportionately benefit from ESPBs for spine surgery.

Mirogabalin as a novel calcium channel α2δ ligand for the treatment of neuropathic pain: a review of clinical update

Neuropathic pain (NP) is often caused by diabetic neuropathy, chemotherapy, or spinal cord lesions and is associated with significant economic burden and poor quality of life. Sophisticated etiology and pathology recognized different pharmacologic interventions, and hitherto, the reported analgesic efficacy and safety of guideline-recommended drugs are not satisfactory. Overall, this article reviews the mechanism of α2δ ligand, the clinical pharmacokinetics, efficacy, safety and cost-effectiveness of mirogabalin for the treatment of NP, offering clinical perspectives into potential benefits of NP-related syndrome or comorbidities. Mirogabalin, a novel voltage-gated Ca2+ channel (VGCC) α2δ ligand with selective binding affinities to α2δ-1 than α2δ-2 subunit, exhibited a wider safety margin and a relatively lower incidence of adverse events compared with other gabapentinoids. Randomized-controlled trials and open-label studies have demonstrated the efficacy and long-term safety of mirogabalin in Asian patients with diabetic peripheral neuropathic pain (DPNP), postherpetic neuralgia (PHN), and central NP. Analgesic effects of mirogabalin for the single or add-on treatment on chemotherapy-induced peripheral neuropathy and orthopedic disease/postoperation-related NP were also evidenced. To date, mirogabalin is approved for the general indication of NP in Japan, PNP in South Korea, and DPNP in the Chinese Mainland and DPNP, PHN in Taiwan (China). In summary, mirogabalin emerges as a promising option for NP; further research is warranted to refine wider treatment strategies, flexible dosing in real-world setting.

The relationship between neuropathic pain and lower urinary tract symptom scores in patients with primary Sjögren's syndrome

OBJECTIVE

To evaluate the effect of neuropathic pain on lower urinary tract symptoms (LUTS) scores in patients with primary Sjögren's syndrome (pSS).

METHODS

Seventy-two patients diagnosed with pSS were included in the study. The patients with pSS were divided into two groups according to the presence/absence of neuropathic pain. The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) questionnaire was recorded assess neuropathic pain. LUTS was evaluated using the International Prostate Symptom Score (IPSS), International Incontinence Consultation Questionnaire Short Form (ICIQ-SF) and Overactive Bladder Questionnaire (OAB-V8).

RESULTS

The mean age of the patients was 52.4 ± 11.2 years. Neuropathic pain was recorded in 21 (29.2%) patients. Among the patients, the number of patients with mild symptoms was recorded as 41 (56.9%), moderate symptoms in 25 (34.7%), and severe symptoms in 6 (8.3%) according to IPSS. IPSS and IPSS voiding subscores were statistically significantly higher in patients with neuropathic pain than non-neuropathic pain group (p = 0.035; p = 0.001, respectively). Although ICIQ-SF, OAB-V8 and IPSS storage subscores were found to be higher in patients with neuropathic pain group, there was no statistically significant difference between the groups (p = 0.299; p = 0.283; p = 0.237, respectively).

CONCLUSION

Neuropathic pain concomitant with PSS patients may negatively affect bladder voiding functions.

Clinical pharmacology of neuropathic pain

This chapter aims to review the current pharmacological options for neuropathic pain treatment, their mechanisms of action, and future directions for clinical practice. Achieving pain relief in neuropathic pain conditions remains a challenge in clinical practice. The field of pharmacotherapy for neuropathic pain has encountered significant difficulties in translating substantial advances in our understanding of the underlying pathophysiological mechanisms into clinically effective therapies. This chapter presents the drugs recommended for the pharmacotherapy of neuropathic pain, based on the widely accepted treatment guidelines formulated by the Neuropathic Pain Special Interest Group of the International Association for the Study of Pain. In addition to discussing how the evidence base is created as part of international consortia, the drugs are also examined in terms of their putative molecular mechanisms as well as pharmacological pleiotropy, i.e., their potential unspecific and multi-target effects resulting in modulation of neuronal hyperexcitability. The chapter closes with a discussion of potential future developments in the field.

Neuropathic pain - A clinical primer

Neuropathic pain is used both as a mechanistic descriptor and a classification category of pain caused by a lesion or disease of the somatosensory nervous system and encompasses a vast array of possible diagnoses. The identification of neuropathic pain and diagnosis of specific syndromes relies on a detailed patient history. Standardized pain questionnaires can capture the patient`s symptoms, while the anatomical distribution of pain is often documented using pain drawings. Following this, a thorough clinical neurological examination is conducted to identify distinct sensory abnormalities, specifically sensory deficits and signs of increased sensitivity such as allodynia and hyperalgesia, within the pain-affected areas. Regardless of whether the lesion or disease is in the peripheral or central somatosensory nervous system, the presence of clinically overt sensory abnormalities is a key feature, distinguishing neuropathic pain from other types of pain, such as nociceptive pain, which likely coexist in neurological disorders. Extensive sensory deficits, as seen in certain stroke syndromes or following spinal cord injuries, may increase the likelihood of concomitant non-neuropathic pain within the same area of sensory loss. For this reason, differential diagnosis is essential when assessing patients with suspected neuropathic pain. Further diagnostic tests, including imaging or specific neurophysiological methods that assess nociceptive pathways, can provide objective evidence of a lesion or disease within the somatosensory nervous system. However, the causality between the lesion and the presence of neuropathic pain cannot be established definitively and always requires clinical judgment and interpretation within the broader context of the neurological disorder.

Exploring neuroinflammation: A key driver in neuropathic pain disorders

Inflammation is a fundamental part of the body's natural defense mechanism, involving immune cells and inflammatory mediators to promote healing and protect against harm. In the event of a lesion or disease of the somatosensory nervous system, inflammation, however, triggers a cascade of changes in both the peripheral and central nervous systems, ultimately contributing to chronic neuropathic pain. Substantial evidence links neuroinflammation to various conditions associated with neuropathic pain. This chapter will explore the role of neuroinflammation in the initiation, maintenance, and resolution of peripheral and central neuropathic pain. Additionally, biomarkers of neuroinflammation in humans will be examined, emphasizing their relevance in different neuropathic pain disorders.

Pre-treatment DTI markers: predicting clinical outcomes in microvascular decompression for classic trigeminal neuralgia - a systematic review

BACKGROUND AND PURPOSE

Trigeminal neuralgia (TN) is a severe chronic pain condition, typically affecting patients over 50-year-old, caused by the compression of the nerve at the root entry zone (REZ) by blood vessels. While the diagnosis is clinical, advanced imaging like diffusion tensor imaging (DTI) is crucial to identify underlying causes and assessing nerve damage. DTI may help develop neuroimaging markers to improve understanding of TN and predict surgical outcomes. The goal of the present systematic review is to evaluate the effectiveness of DTI and tractography in order to better assess treatment planning and outcome prediction through the analysis of trigeminal nerve alterations.

METHODS

The authors conducted a systematic review and meta-analysis of the literature to compare radiological parameters identified in pre- and post-operative MRI with DTI sequences, including fractional anisotropy (FA), quantity of anisotropy (QA), radial diffusivity (RD), and to correlate these findings with post-operative clinical outcomes. A comprehensive search of the PubMed and Scopus databases was carried out for studies published between April 2010 and January 2024.

RESULTS

This review included 11 studies and 603 patients. Of the 363 patients with trigeminal neuralgia (TN), 193 underwent microvascular decompression (MVD), with 72.5% showing clinical improvement and 27.5% not improving, possibly due to chronic nerve damage. Four studies assessed radiological parameters before and after MVD, while two focused only on post-MVD data. The mean fractional anisotropy (FA) in affected nerves increased from 0.328 before MVD to 0.382 afterward. Five studies did not report postoperative outcomes, just comparing radiological parameters in TN patients versus healthy controls.

CONCLUSIONS

Recent studies show that MRI-DTI parameters, including FA, RD, and QA, are useful for diagnosing trigeminal neuralgia and predicting treatment outcomes. Lower FA and higher RD values indicate better results after surgery. More research is mandatory to guide treatment decisions and enhance patients' care.

Molecular mechanisms of neuropathic pain

Peripheral neuropathic pain, which occurs after a lesion or disease affecting the peripheral somatosensory nervous system, is a complex and challenging condition to treat. This chapter will cover molecular mechanisms underlying the pathophysiology of peripheral neuropathic pain, focusing on (1) sensitization of nociceptors, (2) neuro-immune crosstalk, and (3) axonal degeneration and regeneration. The chapter will also emphasize the importance of identifying novel therapeutic targets in non-neuronal cells. A comprehensive understanding of how changes at both neuronal and non-neuronal levels contribute to peripheral neuropathic pain may significantly improve pain management and treatment options, expanding to topical application that bypass the side effects associated with systemic administration.

Regional and interregional functional and structural brain abnormalities in neuropathic pain

Neuropathic pain is a severe form of chronic pain due to a lesion or disease of the somatosensory nervous system. Here we provide an overview of the neuroimaging approaches that can be used to assess brain abnormalities in a chronic pain condition, with particular focus on people with neuropathic pain and then summarize the findings of studies that applied these methodologies to study neuropathic pain. First, we review the most commonly used approaches to examine grey and white matter abnormalities using magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) and then review functional neuroimaging techniques to measure regional activity and inter-regional communication using functional MRI, electroencephalography (EEG) and magnetoencephalography (MEG). In neuropathic pain the most prominent structural abnormalities have been found to be in the primary somatosensory cortex, insula, anterior cingulate cortex and thalamus, with differences in volume directionality linked to neuropathic pain symptomology. Functional connectivity findings related to treatment outcome point to a potential clinical utility. Some prominent abnormalities in neuropathic pain identified with EEG and MEG throughout the dynamic pain connectome are slowing of alpha activity and higher regional oscillatory activity in the theta and alpha band, lower low beta and higher high beta band power. Finally, connectivity and coupling findings placed into context how regional abnormalities impact the networks and pathways of the dynamic pain connectome. Overall, functional and structural neuroimaging have the potential to identify predictive biomarkers that can be used to guide development of personalized pain management of neuropathic pain.

Cannabis constituents for chronic neuropathic pain; reconciling the clinical and animal evidence

Chronic neuropathic pain is a debilitating pain syndrome caused by damage to the nervous system that is poorly served by current medications. Given these problems, clinical studies have pursued extracts of the plant Cannabis sativa as alternative treatments for this condition. The vast majority of these studies have examined cannabinoids which contain the psychoactive constituent delta-9-tetrahydrocannabinol (THC). While there have been some positive findings, meta-analyses of this clinical work indicates that this effectiveness is limited and hampered by side-effects. This review focuses on how recent preclinical studies have predicted the clinical limitations of THC-containing cannabis extracts, and importantly, point to how they might be improved. This work highlights the importance of targeting channels and receptors other than cannabinoid CB1 receptors which mediate many of the side-effects of cannabis.

Sensitization-associated and neuropathic-associated symptoms in patients with unilateral lateral elbow tendinopathy: an exploratory study

OBJECTIVES

We evaluate the presence of sensitization-associated symptoms and neuropathic pain features and identify if there is an association between these symptoms and pressure pain sensitivity, pain, and related-disability in lateral elbow tendinopathy.

METHODS

Thirty-seven (43% women, age: 45.5 ± 9.5 years) patients with lateral elbow tendinopathy completed: demographic (i.e. age, height, and weight); clinical (i.e. pain history, pain intensity, and Disabilities of the Arm, Shoulder and Hand); and psychophysical (i.e. pressure pain thresholds at the elbow, cervical spine, hand, and leg) outcomes, and the Central Sensitization Inventory and Self-administered Leeds Assessment of Neuropathic Symptoms and Signs questionnaires. Step-wise multiple linear regression models were performed to identify predictors of sensitization- or neuropathic-associated symptoms.

RESULTS

Six (16%) patients exhibited sensitization-associated symptoms (mean: 46.5, SD: 6.1), whereas 13 (35%) patients showed neuropathic-associated symptoms (mean: 13.5; SD: 1.4). Sensitization-associated symptoms were positively associated with neuropathic-associated symptoms (r = 0.538, P = .001) and negatively associated with pressure pain thresholds at the leg (r = -0.378, P = .021). Neuropathic-associated symptoms were positively associated with related-disability (r = 0.479, P = .003) and negatively associated with pressure pain threshold at the elbow (r = -0.394, P = .017). Stepwise regression analyses revealed that neuropathic-like symptoms explained 26.8% of the variance of sensitization symptoms (r2: 0.268), whereas pressure pain threshold at the elbow explained an additional 6.6% to neuropathic-like symptoms (r2: 0.334).

CONCLUSION

This explorative study identified sensitization- and neuropathic-associated symptoms in 16% and 35% of the people with lateral elbow tendinopathy. Sensitization- and neuropathic-associated symptoms were associated. Pressure pain sensitivity at the elbow (peripheral sensitization) was associated with neuropathic -associated symptoms.

Sinomenine Ameliorated Microglial Activation and Neuropathic Pain After Chronic Constriction Injury Via TGF-β1/ALK5/Smad3 Signalling Pathway

Sinomenine (SIN), a bioactive isoquinoline alkaloid extracted from the roots and stems of Sinomenium acutum, is efficacious against various chronic pain conditions. Inhibition of microglial activation at the spinal level contributes to the analgesic effects of SIN. Microglial activation in the spinal dorsal horn is key to sensitising neuropathic pain. Consequently, this study aimed to investigate whether the antinociceptive effects of SIN in neuropathic pain are induced through microglial inhibition and the underlying mechanisms. In this study, we observed that SIN alleviated chronic constriction injury (CCI)-induced pain hypersensitivity, spinal microglial activation and neuroinflammation. Consistently, SIN evoked the upregulation of transforming growth factor-beta1 (TGF-β1) and phosphorylated Smad3 in the L4-6 ipsilateral spinal dorsal horn of CCI mice. Intrathecal injection of TGF-β1 siRNA and an activin receptor-like receptor (ALK5) inhibitor reversed SIN's antinociceptive and antimicroglial effects on CCI mice. Moreover, targeting Smad3 in vitro with siRNA dampened the inhibitory effect of TGF-β1 on lipopolysaccharide-induced microglial activation. Finally, targeting Smad3 abrogated SIN-induced pain relief and microglial inhibition in CCI mice. These findings indicate that the TGF-β1/ALK5/Smad3 axis plays a key role in the antinociceptive effects of SIN on neuropathic pain, indicating its suppressive ability on microglia.

Activation of TGR5 in the injured nerve site according to a prevention protocol mitigates partial sciatic nerve ligation-induced neuropathic pain by alleviating neuroinflammation

ABSTRACT

Neuropathic pain is a pervasive medical challenge currently lacking effective treatment options. Molecular changes at the site of peripheral nerve injury contribute to both peripheral and central sensitization, critical components of neuropathic pain. This study explores the role of the G-protein-coupled bile acid receptor (GPBAR1 or TGR5) in the peripheral mechanisms underlying neuropathic pain induced by partial sciatic nerve ligation in male mice. TGR5 was upregulated in the injured nerve site and predominantly colocalized with macrophages. Perisciatic nerve administration of the TGR5 agonist, INT-777 according to a prevention protocol (50 μg/μL daily from postoperative day [POD] 0 to POD6) provided sustained relief from mechanical allodynia and spontaneous pain, whereas the TGR5 antagonist, SBI-115 worsened neuropathic pain. Transcriptome sequencing linked the pain relief induced by TGR5 activation to reduced neuroinflammation, which was further evidenced by a decrease in myeloid cells and pro-inflammatory mediators (eg, CCL3, CXCL9, interleukin [IL]-6, and tumor necrosis factor [TNF] α) and an increase in CD86-CD206+ anti-inflammatory macrophages at POD7. Besides, myeloid-cell-specific TGR5 knockdown in the injured nerve site exacerbated both neuropathic pain and neuroinflammation, which was substantiated by bulk RNA-sequencing and upregulated expression levels of inflammatory mediators (including CCL3, CCL2, IL-6, TNF α, and IL-1β) and the increased number of monocytes/macrophages at POD7. Furthermore, the activation of microglia in the spinal cord on POD7 and POD14 was altered when TGR5 in the sciatic nerve was manipulated. Collectively, TGR5 activation in the injured nerve site mitigates neuropathic pain by reducing neuroinflammation, while TGR5 knockdown in myeloid cells worsens pain by enhancing neuroinflammation.

Chinese national clinical practice guideline on diagnosis and treatment of biliary tract cancers

BACKGROUND

Biliary tract carcinoma (BTC) is relatively rare and comprises a spectrum of invasive tumors arising from the biliary tree. The prognosis is extremely poor. The incidence of BTC is relatively high in Asian countries, and a high number of cases are diagnosed annually in China owing to the large population. Therefore, it is necessary to clarify the epidemiology and high-risk factors for BTC in China. The signs associated with BTC are complex, often require collaborative treatment from surgeons, endoscopists, oncologists, and radiation therapists. Thus, it is necessary to develop a comprehensive Chinese guideline for BTC.

METHODS

This clinical practice guideline (CPG) was developed following the process recommended by the World Health Organization. The Grading of Recommendations Assessment, Development, and Evaluation approach was used to assess the certainty of evidence and make recommendations. The full CPG report was reviewed by external guideline methodologists and clinicians with no direct involvement in the development of this CPG. Two guideline reporting checklists have been adhered to: Appraisal of Guidelines for Research and Evaluation (AGREE) and Reporting Items for practice Guidelines in Healthcare (RIGHT).

RESULTS

The guideline development group, which comprised 85 multidisciplinary clinical experts across China. After a controversies conference, 17 clinical questions concerning the prevention, diagnosis, and treatment of BTC were proposed. Additionally, detailed descriptions of the surgical principles, perioperative management, chemotherapy, immunotherapy, targeted therapy, radiotherapy, and endoscopic management were proposed.

CONCLUSIONS

The guideline development group created a comprehensive Chinese guideline for the diagnosis and treatment of BTC, covering various aspects of epidemiology, diagnosis, and treatment. The 17 clinical questions have important reference value for the management of BTC.

Evaluation of somatosensory bedside testing and neurodynamics of the trigeminal nerve in craniofacial pain: A matched case-control study

OBJECTIVE

The objective of this study was to investigate whether trigeminal somatosensory function and mechanosensitivity differ between groups with craniofacial neuropathic pain (CNP), non-neuropathic craniofacial pain (NNP), and healthy controls (HC).

METHODS

Thirty-three participants were categorized into these groups, matched for age and sex. The study evaluated pain intensity, the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS), and various trigeminal somatosensory tests, including vibration, pressure pain, thermal detection, cold pain, and neurodynamic tests of the trigeminal nerve.

RESULTS

Cold pain thresholds differed significantly among the three groups CNP, NNP, and HC (p = .047). No difference was found in vibration detection, pressure pain threshold, and thermal detection. Trigeminal nerve mechanosensitivity was significantly different among the three groups (p = .03), particularly between groups CNP and HC (p = .01).

CONCLUSION

Differences in aspects of trigeminal somatosensory function, including cold pain and trigeminal mechanosensitivity, exist between subjects with chronic craniofacial pain and HC. This implies that a clinical classification system for neuromusculoskeletal rehabilitation could be valuable in evaluating patients.

Patients' perspective on the chronic pain classification in the 11th revision of the International Classification of Diseases (ICD-11): results from an international web-based survey

ABSTRACT

The 11th revision of the International Classification of Diseases and Related Health Problems (ICD-11) aims at improving the lives of persons with the lived experience of chronic pain by providing clearly defined and clinically useful diagnoses that can reduce stigma, facilitate communication, and improve access to pain management, among others. The aim of this study was to assess the perspective of people with chronic pain on these diagnoses. An international web-based survey was distributed among persons with the lived experience of chronic pain. After having seen an information video, participants rated the diagnoses on 8 endorsement scales (eg, diagnostic fit, stigma) that ranged from -5 to +5 with 0 representing the neutral point of no expected change. Overall ratings and differences between participants with chronic primary pain (CPP) and chronic secondary pain (CSP) were analyzed. N = 690 participants were included in the data analysis. The ratings on all endorsement scales were significantly higher than the neutral point of 0. The highest ratings were obtained for "openness" (2.95 ± 1.93) and "overall opinion" (1.87 ± 1.98). Participants with CPP and CSP did not differ in their ratings; however, those with CSP indicated an improved diagnostic fit of the new diagnoses, whereas participants with CPP rated the diagnostic fit of the new diagnoses similar to the fit of their current diagnoses. These results show that persons with the lived experience of chronic pain accept and endorse the new diagnoses. This endorsement is an important indicator of the diagnoses' clinical utility and can contribute to implementation and advocacy.