Methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system: a systematic review

Methods to Discriminate Between Nociceptive, Neuropathic and Nociplastic in Children & Adolescents: A Systematic Review of Psychometric Properties and Feasibility

The aim of this systematic review was to identify and critically analyse the tools available for categorising pain as nociceptive, neuropathic and nociplastic pain in children and adolescents. Studies were included if they (i) included children and adolescents with a mean age of 0-24 years old, (ii) examined assessment tools that categorise pain as nociceptive, neuropathic or nociplastic, and (iii) examined the psychometric properties of the tools. Sensitive searches were conducted in five online databases in March 2024. Eligible studies were assessed for risk of bias and quality by two authors using COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) criteria. The search yielded 26 studies for 11 tools. No assessment tool had evidence for all nine recommended psychometric properties. Quantitative Sensory Testing, a tool used to identify signs and symptoms of nociplastic and neuropathic pain, was the most studied tool and had moderate evidence for construct validity, criterion validity and reliability. Three self-reported questionnaires, the Self-reported Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS), Central Sensitisation Inventory (CSI) and PainDETECT, had moderate evidence for construct validity and show promise as preliminary tools to identify possible neuropathic or nociplastic pain. However, they had low specificity when used in isolation. All assessment methods would benefit from further psychometric evaluation and validation in children and adolescents. PERSPECTIVE: This systematic review highlights the limited validation of pain assessment tools for children and adolescents. While Quantitative Sensory Testing and self-reported questionnaires show promise in identifying pain mechanisms, their applicability remains uncertain. Further psychometric validation is crucial to improve pain assessment and guide personalized treatment in young populations.

Rehabilitation Management of Neck Pain-Development of a Diagnostic Framework Based on the Pain and Disability Drivers Management Model

RATIONALE

Neck pain is a major cause of disability worldwide, and current rehabilitation strategies show limited effectiveness. Subgrouping patients by their primary pain and disability drivers can help tailor treatments. At this end, the Pain and Disability Drivers Management (PDDM) was developed and has demonstrated preliminary effectiveness in the management of low back pain. Nevertheless, the PDDM model was only validated for this population. Adapting this framework to patients with neck pain would provide a more global view of the patient's experience of pain and support a genuine biopsychosocial intervention.

AIMS AND OBJECTIVES

The aim of this study was to develop and validate the content of the PDDM model for patients living with neck pain.

METHODS

Through a modified DELPHI study design, participants with clinical and research expertize in rehabilitation of neck pain were invited to participate. A questionnaire was developed using literature reviews and endorsed by a steering committee. The relevance of each element of the newly adapted model was evaluated on a 4-point Likert scale. An item reached consensus if it obtained the predefined threshold of > 78% "relevant" and "very relevant." Participants left comments on terminology and recommended items to add in early rounds. Quantitative and qualitative analyses were performed.

RESULTS

An invitation was sent to 1650 potential participants, from which 155 accessed the survey, 64 completed the first round and 55 the second round. A total of 70 elements met consensus and were distributed across six domains: "Nociceptive pain drivers", "nociplastic pain drivers," "drivers associated with neuropathic pain", "comorbidity drivers", "cognitive-emotional drivers" and "environmental or lifestyle drivers, and social determinants of health."

CONCLUSION

Through a modified DELPHI study, the PDDM model was updated and adapted to people with neck pain. Subsequent steps include clinical integration and measures of efficacy when used for assessment/treatment.

An exploratory data-driven approach to classify subgroups of patients with temporomandibular disorders based on pain mechanisms

Temporomandibular disorders (TMDs) are a common musculoskeletal condition, presenting treatment challenges due to their non-specific nature. Categorizing patients with TMDs into clusters based on neurobiological pain mechanisms could provide a promising approach to facilitate targeted treatments. This observational study (1) used a network analysis (NA) to explore the complexity of TMDs by investigating relationships among biopsychosocial variables, and (2) validated potential TMD subgroups based on mechanism-specific pain categories. One hundred and two patients with TMD were included. Biopsychosocial variables covered: general health, psychosocial features, TMD pain, and TMD characteristics. A NA evaluated the associations between variables and determined the role of each feature within the network. Hierarchical clustering was used to identify TMD subgroups. The NA revealed significant correlations primarily within the same feature domains, indicating a strong interplay between symptoms and psychological factors. Cluster analysis identified two subgroups driven by nociceptive and nociplastic pain mechanisms; the nociplastic group exhibited higher levels of anxiety, depression, pain catastrophization, central sensitization, pain duration, and more pain locations, along with poorer sleep quality, quality of life, and health status. In contrast, the nociceptive group exhibited restricted maximal mouth opening (MMO), heightened pain during TMJ palpation and mouth opening, and a greater positive response to manual therapy. Across all features, psychological factors, pain locations, and MMO primarily contributed to the separation of subgroups. By adopting a data-driven approach, these results support the significant role of considering the neurobiological basis of pain to improve patient classification. This knowledge may facilitate clinical reasoning and personalized treatments. PERSPECTIVE: This study used a network analysis to explore the complex biopsychosocial interactions present in people with TMDs, identifying important variables such as the Central Sensitization Inventory and pain-free maximal mouth opening. The findings distinguish potential nociceptive and nociplastic pain subgroups, offering important insights for targeted therapeutic strategies.

Comparisons of the effects of psychologically-informed and usual physiotherapy on pain sensitivity in chronic low back pain: an exploratory randomized controlled trial

Introduction

The presence of altered central pain processing and modulation, as well as negative psychological factors, have been suggested to impede recovery in chronic low back pain (CLBP). Psychologically-informed physiotherapy (PiP) aims to specifically address the latter factors-in addition to physical factors-to improve treatment effects. This study aims to determine if the effect of PiP is superior to usual physiotherapy (UP) on pain sensitivity and modulation in participants with CLBP and if changes in these variables were associated with changes in clinical outcomes.

Methods

Forty participants with CLBP were randomly allocated to PiP or UP. Seven physiotherapy sessions over 6 weeks plus a booster session at an 11-week follow-up were delivered. Pressure pain threshold (PPT), temporal summation of pain (TSP), and exercise-induced hypoalgesia were assessed on lumbar, upper, and lower limb sites at baseline and after 6 weeks. Linear mixed models tested if PiP was superior to UP on pain sensitivity/modulation. Linear regressions tested if pain sensitivity/modulation changes were associated with changes in clinical outcomes (pain intensity, physical functioning, symptoms of central sensitization).

Results

PiP was not superior to UP to modulate pain sensitivity/modulation variables. All PPTs increased after 6 weeks regardless of the approach. Lumbar PPT and lumbar and lower limb TSP changes were associated with physical functioning changes.

Conclusion

Although our study suggests that neither approach has a superiority to impact on pain sensitivity, both approaches elicited widespread hypoalgesia. Future powered trials should verify if pain sensitivity can be a mediator of physical functioning improvement, as suggested by our results.

The Impact of Autonomic Nervous System Modulation on Heart Rate Variability and Musculoskeletal Manifestations in Chronic Neck Pain: A Double-Blind Randomized Clinical Trial

Background: The role of autonomic nervous system (ANS) modulation in chronic neck pain remains elusive. Transcutaneous vagus nerve stimulation (t-VNS) provides a novel, non-invasive means of potentially mitigating chronic neck pain. This study aimed to assess the effects of ANS modulation on heart rate variability (HRV), pain perception, and neck disability. Methods: In this double-blind randomized clinical trial, 102 participants with chronic neck pain were randomly allocated to one of three groups: t-VNS plus standard-care physiotherapy (SC-PT), heart rate variability biofeedback (HRV-BF) with SC-PT, or SC-PT alone. Interventions were administered three times weekly for 6 weeks. The following outcome measures were assessed at baseline and after 6 weeks: HRV, the visual analog scale (VAS), the pressure pain threshold (PPT), and the neck disability index (NDI). Results: The t-VNS group exhibited significant improvements compared to the HRV-BF and SC-PT groups. Specifically, t-VNS increased the RR interval (mean difference [MD] = 35.0 ms; p = 0.037) and decreased the average heart rate (MD = -5.4 bpm; p = 0.039). Additionally, t-VNS reduced the VAS scores (versus HRV-BF: MD = -0.8 cm, p = 0.044; SC-PT: MD = -0.9 cm, p = 0.018), increased the PPT (versus HRV-BF: MD = 94.4 kPa, p < 0.001; SC-PT (MD = 56.2 kPa, p = 0.001)), and lowered the NDI scores (versus HRV-BF: MD = -4.0, p = 0.015; SC-PT: MD = -5.9, p < 0.001). Conclusions: t-VNS demonstrated superior effectiveness compared to HRV-BF and SC-PT in regulating HRV, alleviating pain, and enhancing functional capabilities in individuals with chronic neck pain.

Development of a comprehensive clinical assessment protocol for low back and hip pain in powerlifters: a feasibility study

BACKGROUND

Low back and hip pain problems are frequent in powerlifting. There is a lack of information on the specific pain phenotypes and specific impairments in body function associated with these pain problems, as well as how to reach a clinical diagnosis relevant for powerlifters' pain problems. Therefore, the aim was to develop a comprehensive clinical assessment protocol for pain and function in powerlifters with low back and/or hip pain and evaluate its feasibility for use in further epidemiological or clinical studies of powerlifters.

METHODS

The study was conducted in two phases. In phase one, the protocol was developed according to literature regarding musculoskeletal assessment and sports injuries, and in phase two, feasibility was evaluated. Eight powerlifters with low back/hip pain were included in phase two. Four of them were examined independently by two physical therapists, and the other four were examined by one of the physical therapists. The time spent on the examination, whether the physical therapists could reach a clinical diagnosis without adding items to the protocol, and whether the two physical therapists were consistent in terms of the clinical diagnosis, were evaluated.

RESULTS

The protocol was developed including subjective examination, physical examination, and a clinical diagnosis based mainly on signs and symptoms of associated neurophysiological pain mechanisms and the specific impairments in body functions associated with the powerlifter's pain problem. The protocol met the feasibility criteria. The examination lasted approximately 1 h, no items needed to be added, and both physical therapists were able to make a consistent clinical diagnosis. Visual observation and alteration of movement strategy of the squat/deadlift were thought to be crucial for assessing the powerlifters' pain problem.

CONCLUSIONS

This is the first comprehensive clinical assessment protocol developed to describe powerlifters' pain problems/injuries with a clinical diagnosis based on the dominating neurophysiological pain mechanism and impairments in body functions. However, before use in larger studies, it is recommended that the protocol be further evaluated by a larger number of physical therapists and powerlifters to evaluate its reliability and whether the content of the protocol should be further expanded.

Neuroinflammatory activation in sensory and motor regions of the cortex is related to sensorimotor function in individuals with low back pain maintained by nociplastic mechanisms: A preliminary proof-of-concept study

BACKGROUND

Chronic pain involves communication between neural and immune systems. Recent data suggest localization of glial (brain immune cells) activation to the sensorimotor regions of the brain cortex (S1/M1) in chronic low back pain (LBP). As glia perform diverse functions that impact neural function, activation might contribute to sensorimotor changes, particularly in LBP maintained by increased nervous system sensitivity (i.e., nociplastic pain). This preliminary proof-of-concept study aimed to: (i) compare evidence of neuroinflammatory activation in S1/M1 between individuals with and without LBP (and between nociceptive and nociplastic LBP phenotypes), and (ii) evaluate relationships between neuroinflammatory activation and sensorimotor function.

METHODS

Simultaneous PET-fMRI measured neuroinflammatory activation in functionally defined S1/M1 in pain-free individuals (n = 8) and individuals with chronic LBP (n = 9; nociceptive: n = 4, nociplastic: n = 5). Regions of S1/M1 related to the back were identified using fMRI during motor tasks and thermal stimuli. Sensorimotor measures included single and paired-pulse transcranial magnetic stimulation (TMS) and quantitative sensory testing (QST). Sleep, depression, disability and pain questionnaires were administered.

RESULTS

Neuroinflammatory activation was greater in the lower back cortical representation of S1/M1 of the nociplastic LBP group than both nociceptive LBP and pain-free groups. Neuroinflammatory activation in S1/M1 was positively correlated with sensitivity to hot (r = 0.52) and cold (r = 0.55) pain stimuli, poor sleep, depression, disability and BMI, and negatively correlated with intracortical facilitation (r = -0.41).

CONCLUSION

This preliminary proof-of-concept study suggests that neuroinflammation in back regions of S1/M1 in individuals with nociplastic LBP could plausibly explain some characteristic features of this LBP phenotype.

SIGNIFICANCE STATEMENT

Neuroinflammatory activation localized to sensorimotor areas of the brain in individuals with nociplastic pain might contribute to changes in sensory and motor function and aspects of central sensitization. If cause-effect relationships are established in longitudinal studies, this may direct development of therapies that target neuroinflammatory activation.

Application of the IASP Grading System to Identify Underlying Pain Mechanisms in Patients With Knee Osteoarthritis: A Prospective Cohort Study

OBJECTIVES

This study aimed to apply the International Association for the Study of Pain (IASP) grading system for identifying nociplastic pain in knee osteoarthritis (KOA) awaiting total knee arthroplasty (TKA) and propose criteria to fine-tune decision-making. In addition, the study aimed to characterize a "probable" versus "no or possible" nociplastic pain mechanism using biopsychosocial variables and compare both groups in their 1-year post-TKA response.

METHODS

A secondary analysis of baseline data of a longitudinal prospective study involving 197 patients with KOA awaiting total TKA in Belgium and the Netherlands was performed. Two approaches, one considering 4 and the other 3 pain locations (step 2 of the grading system), were presented. Linear mixed model analyses were performed to compare the probable and no or possible nociplastic pain mechanism groups for several preoperative biopsychosocial-related variables and 1-year postoperative pain. Also, a sensitivity analysis, comparing 3 pain mechanism groups, was performed.

RESULTS

Thirty (15.22%-approach 4 pain locations) and 46 (23.35%-approach 3 pain locations) participants were categorized under probable nociplastic pain. Irrespective of the pain location approach or sensitivity analysis, the probable nociplastic pain group included more woman, was younger, exhibited worse results on various preoperative pain-related and psychological variables, and had more pain 1-year post-TKA compared with the other group.

DISCUSSION

This study proposed additional criteria to fine-tune the grading system for nociplastic pain (except for discrete/regional/multifocal/widespread pain) and characterized a subgroup of patients with KOA with probable nociplastic pain. Future research is warranted for further validation.

Evaluating Sensitization-associated, Neuropathic-like Symptoms and Psychological Factors in Patients With Interstitial Lung Disease

The aims of this study were to phenotype pain in patients with interstitial lung disease (ILD) by investigating the association between sensitization-associated symptoms with quality of life, anxiety/depression, pain catastrophizing, and kinesiophobia levels and identifying those risk factors explaining the variance of quality of life in individuals with ILD and pain. One hundred and thirty-two (38.6% women, mean age: 70, standard deviation: 10.5 years) patients with ILD completed clinical (age, sex, height, weight), psychological (Hospital Anxiety and Depression Scale [HADS] and the Pittsburgh Sleep Quality Index), and health-related quality of life (EQ-5D-5L) variables, as well as the Central Sensitization Inventory (CSI), the Self-Report Leeds Assessment of Neuropathic Symptoms (S-LANSS), Pain Catastrophizing Scale, and Tampa Scale for Kinesiophobia (TSK-11) questionnaires. The prevalence of sensitization-associated symptomatology (CSI), neuropathic-like features (S-LANSS), anxiety symptoms, depressive symptoms, or poor sleep was 20.5%, 23.5%, 23.6%, 22.9%, or 51.6%. Significant associations between CSI, S-LANSS, HADS-A, HADS-D, Pain Catastrophizing Scale, TSK-11, and EQ-5D-5L (.220 < r < .716) were found. The regression analysis revealed that CSI, TSK-11, and HADS-D explained 44.8% of the variance of EQ-5D-5L (r2 adjusted: .448). This study found the presence of sensitization-associated and neuropathic-like symptoms as well as other central nervous system-derived symptoms, such as anxiety, depression, poor sleep, pain catastrophizing, and kinesiophobia in 25% of ILD patients with pain. Sensitization-associated symptoms, depression, and kinesiophobia were associated with a worse quality of life. These findings would support that individuals with ILD can exhibit different pain phenotypes, including nociplastic-like pain phenotype based on self-reported measurements. PERSPECTIVE: Pain in patients with ILD can fulfill features of different phenotypes, including nociplastic pain, when sensory, emotional, and cognitive mechanisms are involved at the same time.

Rethinking neck-related arm pain: hypothetical clinical scenarios to differentiate the underlying IASP-defined pain mechanisms

Neck-related arm pain is frequently encountered in clinical settings, yet its underlying pain mechanisms remain elusive. While such pain radiating from the neck to the arm is often attributed to injuries or diseases of the nervous system (neuropathic pain), it can also arise from nociceptive (referred) or nociplastic sources. Regrettably, patients exhibiting this specific pain distribution are frequently diagnosed with varying terms, including 'cervicobrachialgia', 'cervicobrachial neuralgia', 'cervicobrachial pain syndrome', and 'cervical radiculopathy'. The ambiguity surrounding these diagnostic labels complicates the clinical reasoning process. It is imperative for clinicians to discern and comprehend the dominant pain mechanism. Three distinct hypothetical clinical scenarios depict patients with almost identical pain distribution but divergent dominant pain mechanisms. Within these scenarios, both subjective and objective examinations are employed to elucidate the dominant pain mechanism associated with neck-related arm pain: nociceptive, neuropathic, and nociplastic. Furthermore, clinicians must remain aware that the dominant pain mechanism can evolve over time.

Reduction of Chronic Primary Low Back Pain by Spinal Manipulative Therapy is Accompanied by Decreases in Segmental Mechanical Hyperalgesia and Pain Catastrophizing: A Randomized Placebo-controlled Dual-blind Mixed Experimental Trial

Chronic primary low back pain (CPLBP) refers to low back pain that persists over 3 months, that cannot be explained by another chronic condition, and that is associated with emotional distress and disability. Previous studies have shown that spinal manipulative therapy (SMT) is effective in relieving CPLBP, but the underlying mechanisms remain elusive. This randomized placebo-controlled dual-blind mixed experimental trial (NCT05162924) aimed to investigate the efficacy of SMT to improve CPLBP and its underlying mechanisms. Ninety-eight individuals with CPLBP and 49 controls were recruited. Individuals with CPLBP received SMT (n = 49) or a control intervention (n = 49), 12 times over 4 weeks. The primary outcomes were CPLBP intensity (0-100 on a numerical rating scale) and disability (Oswestry Disability Index). Secondary outcomes included pressure pain thresholds in 4 body regions, pain catastrophizing, Central Sensitization Inventory, depressive symptoms, and anxiety scores. Individuals with CPLBP showed widespread mechanical hyperalgesia (P < .001) and higher scores for all questionnaires (P < .001). SMT reduced pain intensity compared with the control intervention (mean difference: -11.7 [95% confidence interval, -11.0 to -12.5], P = .01), but not disability (P = .5). Similar mild to moderate adverse events were reported in both groups. Mechanical hyperalgesia at the manipulated segment was reduced after SMT compared with the control intervention (P < .05). Pain catastrophizing was reduced after SMT compared with the control intervention (P < .05), but this effect was not significant after accounting for changes in clinical pain. Although the reduction of segmental mechanical hyperalgesia likely contributes to the clinical benefits of SMT, the role of pain catastrophizing remains to be clarified. PERSPECTIVE: This randomized controlled trial found that 12 sessions of SMT yield greater relief of CPLBP than a control intervention. These clinical effects were independent of expectations, and accompanied by an attenuation of hyperalgesia in the targeted segment and a modulation of pain catastrophizing.

Latent Profile Analysis of Canadian Military Veterans With Chronic Pain Identifies 5 Meaningful Classes Through Self-Report Measures

The purpose of this study was to identify meaningful response patterns in self-report survey data collected from Canadian military veterans with chronic pain and to create an algorithm intended to facilitate triage and prioritization of veterans to the most appropriate interventions. An online survey was presented to former members of the Canadian military who self-identified as having chronic pain. Variables collected were related to pain, physical and mental interference, prior traumatic experiences, and indicators from each of the 7 potential drivers of the pain experience. Maximum likelihood estimation-based latent profile analysis was used to identify clinically and statistically meaningful profiles using the 7-axis variables, and classification and regression tree (CRT) analysis was then conducted to identify the most parsimonious set of indicators that could be used to accurately classify respondents into the most relevant profile group. Data from N = 322 veterans were available for analysis. The results of maximum likelihood estimation-based latent profile analysis indicated a 5-profile structure was optimal for explaining the patterns of responses within the data. These were: Mood-Dominant (13%), Localized Physical (24%), Neurosensory-Dominant (33%), Central-Dominant with complex mood and neurosensory symptoms (16%), and Trauma- and mood-dominant (14%). From CRT analysis, an algorithm requiring only 3 self-report tools (central symptoms, mood screening, bodily coherence) achieved 83% classification accuracy across the 5 profiles. The new classification algorithm requiring 16 total items may be helpful for clinicians and veterans in pain to identify the most dominant drivers of their pain experience that may be useful for prioritizing intervention strategies, targets, and relevant health care disciplines. PERSPECTIVE: This article presents the results of latent profile (cluster) analysis of responses to standardized self-report questionnaires by Canadian military veterans with chronic pain. It identified 5 clusters that appear to represent different drivers of the pain experience. The results could be useful for triaging veterans to the most appropriate pain care providers.

Biopsychosocial contributors to irritability in individuals with shoulder or low back pain

OBJECTIVES

Irritability is a foundational clinical reasoning concept in rehabilitation to evaluate reactivity of the examination and treatment. While originally theorized to reflect tissue damage, a large body of evidence supports pain is a biopsychosocial experience impacted by pain sensitivity and psychological factors. Therefore, the purpose of this study was to examine biopsychosocial contributors to irritability.

METHODS

40 patients with shoulder (n = 20) and low back (n = 20) pain underwent Quantitative Sensory Testing (QST) (Pressure Pain Threshold, Heat Pain Threshold, Conditioned Pain Modulation, Temporal Summation), completed pain-related psychological questionnaires, an Exercise-Induced Hypoalgesia protocol, and standardized irritability assessment based on Clinical Practice Guidelines. Participants were then categorized as irritable or not irritable based on Maitland's criteria and by irritability level based on Clinical Practice Guidelines. An independent samples t-test examined for differences in QST and psychological factors by irritability category. A MANOVA examined for differences in QST and psychological factors by irritability level (high, moderate, low).

RESULTS

Significantly lower heat and pressure pain thresholds at multiple locations (p < 0.05), as well as less efficient conditioned pain modulation (p = 0.02), were demonstrated in individuals categorized as irritable. Heat and pressure pain thresholds were also significantly lower in patients with high irritability compared to other levels. Significantly higher depression and anger, as well as lower self-efficacy, were reported in individuals with an irritable presentation.

DISCUSSION/CONCLUSION

Biopsychosocial factors, including widespread hyperalgesia and elevated psychological factors, may contribute to an irritable presentation.

Chronic neuropathic pain components in whiplash-associated disorders correlate with metabolite concentrations in the anterior cingulate and dorsolateral prefrontal cortex: a consensus-driven MRS re-examination

Introduction

Whiplash injury (WHI) is characterised by a forced neck flexion/extension, which frequently occurs after motor vehicle collisions. Previous studies characterising differences in brain metabolite concentrations and correlations with neuropathic pain (NP) components with chronic whiplash-associated disorders (WAD) have been demonstrated in affective pain-processing areas such as the anterior cingulate cortex (ACC). However, the detection of a difference in metabolite concentrations within these cortical areas with chronic WAD pain has been elusive. In this study, single-voxel magnetic resonance spectroscopy (MRS), following the latest MRSinMRS consensus group guidelines, was performed in the anterior cingulate cortex (ACC), left dorsolateral prefrontal cortex (DLPFC), and occipital cortex (OCC) to quantify differences in metabolite concentrations in individuals with chronic WAD with or without neuropathic pain (NP) components.

Materials and methods

Healthy individuals (n = 29) and participants with chronic WAD (n = 29) were screened with the Douleur Neuropathique 4 Questionnaire (DN4) and divided into groups without (WAD-noNP, n = 15) or with NP components (WAD-NP, n = 14). Metabolites were quantified with LCModel following a single session in a 3 T MRI scanner within the ACC, DLPFC, and OCC.

Results

Participants with WAD-NP presented moderate pain intensity and interference compared with the WAD-noNP group. Single-voxel MRS analysis demonstrated a higher glutamate concentration in the ACC and lower total choline (tCho) in the DLPFC in the WAD-NP versus WAD-noNP group, with no intergroup metabolite difference detected in the OCC. Best fit and stepwise multiple regression revealed that the normalised ACC glutamate/total creatine (tCr) (p = 0.01), DLPFC n-acetyl-aspartate (NAA)/tCr (p = 0.001), and DLPFC tCho/tCr levels (p = 0.02) predicted NP components in the WAD-NP group (ACC r 2 = 0.26, α = 0.81; DLPFC r 2 = 0.62, α = 0.98). The normalised Glu/tCr concentration was higher in the healthy than the WAD-noNP group within the ACC (p < 0.05), but not in the DLPFC or OCC. Neither sex nor age affected key normalised metabolite concentrations related to WAD-NP components when compared to the WAD-noNP group.

Discussion

This study demonstrates that elevated glutamate concentrations within the ACC are related to chronic WAD-NP components, while higher NAA and lower tCho metabolite levels suggest a role for increased neuronal-glial signalling and cell membrane dysfunction in individuals with chronic WAD-NP components.

Fatigue can influence the development of late-onset pain in post-COVID-19 syndrome: An observational study

BACKGROUND

Late-onset pain is frequent following COVID-19, and many pathogenetic mechanisms have been proposed. Identifying the main features of patients may help in designing tailored rehabilitative interventions.

METHODS

We enrolled post-COVID-19 patients with an increase in pain intensity of two points on the COVID-19 Yorkshire Rehabilitation Scale (C19-YRS) at 52 weeks compared to the pre-COVID-19 condition. All subjects were retrospectively monitored at 12, 26, and 52 weeks. A specific pain assessment was performed to determine the characteristics and mechanisms of pain. Catastrophizing, kinesiophobia, and other psychological symptoms were evaluated. The pressure pain threshold (PPT) and temporal summation (TS) were measured and compared in age- and sex-matched healthy controls to analyse pain characteristics.

RESULTS

A total of 67 patients were recruited, with 20 of them presenting an increase in pain at 52 weeks. Subjects of the two subgroups were similar in demographic and clinical characteristics at baseline; significant differences in fatigue, anxiety, mobility, ability to perform daily activities, and general health perception were recorded at 26 weeks. Fatigue significantly predicted pain onset (β = 0.54, p = 0.002). Sixteen different body regions were identified as painful, with a pain intensity of 6.0 ± 1.9. Most of the samples did not show neuropathic or nociplastic mechanisms. No differences in PPT and TS were recorded between patients and healthy controls.

CONCLUSIONS

Almost one out of three patients hospitalized for COVID-19 developed pain 1 year later, and fatigue seems responsible for chronicity. An overlapping of conditions may explain late-onset post-COVID-19 pain, and a comprehensive approach must be considered for patient management.

SIGNIFICANCE

Late-onset pain is frequent in post-COVID-19 syndrome and an overlapping of different mechanisms seems to be responsible for its development. Among many predisposing factors, fatigue in the months before seems to be one of the primary causes of pain one year following infection and its management may help to identify new strategies for prevention and treatment of late-onset pain.

Deciphering nociplastic pain: clinical features, risk factors and potential mechanisms

Nociplastic pain is a mechanistic term used to describe pain that arises or is sustained by altered nociception, despite the absence of tissue damage. Although nociplastic pain has distinct pathophysiology from nociceptive and neuropathic pain, these pain mechanisms often coincide within individuals, which contributes to the intractability of chronic pain. Key symptoms of nociplastic pain include pain in multiple body regions, fatigue, sleep disturbances, cognitive dysfunction, depression and anxiety. Individuals with nociplastic pain are often diffusely tender - indicative of hyperalgesia and/or allodynia - and are often more sensitive than others to non-painful sensory stimuli such as lights, odours and noises. This Review summarizes the risk factors, clinical presentation and treatment of nociplastic pain, and describes how alterations in brain function and structure, immune processing and peripheral factors might contribute to the nociplastic pain phenotype. This article concludes with a discussion of two proposed subtypes of nociplastic pain that reflect distinct neurobiological features and treatment responsivity.

New clinical decision tool to assist physical therapists with joint mobilization application to the pediatric population

Joint mobilizations are well-established and extensively researched treatment modality for adults. However, it remains largely unexplored in the pediatric population. Physical therapists hesitate to perform joint mobilization on children because of lack of knowledge, concern for the developing skeletal system, and the paucity of research on the topic. The aim of this article is to present a decision tool created for a continuing education course with the purpose to instruct pediatric therapists in the safe and effective use of joint mobilizations in children. It is based on the pediatric paradigm of developmental and functional assessment to best address the concerns and preferences of physical therapists (PTs). To advance research in pediatric joint mobilization, PTs should listen to the concerns of pediatric therapists and respond to those concerns with effective, evidence-supported training. This decision tree will serve as a resource for the education of pediatric therapists in the safe and effective use of joint mobilizations.

Usefulness of the DN4, S-LANSS, and painDETECT screening questionnaires to detect the neuropathic pain components in people with acute whiplash-associated disorders: a cross-sectional study

OBJECTIVE

Although the presence of neuropathic pain (NP) components has been reported in whiplash-associated disorders (WAD), no studies have analyzed the usefulness of NP screening questionnaires to detect NP components in WAD. This study aimed to assess the usefulness of 3 NP screening tools (Douleur Neuropathique 4 [DN4], self-administered Leeds Assessment of Neuropathic Symptoms and Signs [S-LANSS], and painDETECT questionnaire [PDQ]) to detect the presence of NP components in acute WAD.

DESIGN

A cross-sectional study.

SETTING

Hospital.

SUBJECTS

Of 188 eligible individuals, 50 people (68% women, mean age = 40.3 ± 12.5 years) with acute WAD (52% Grade III) were included.

METHODS

Specialized physicians initially screened participants for the presence of NP components according to clinical practice and international recommendations. After physician assessment, blinded investigators used NP screening questionnaires (DN4, S-LANSS, and PDQ) to assess participants within 2 weeks of their accident. The diagnostic accuracy of these tools was analyzed and compared with the reference standard (physicians' assessments).

RESULTS

The 3 screening questionnaires showed excellent discriminant validity (area under the curve: ≥0.8), especially S-LANSS (area under the curve: 0.9; P < .001). DN4 demonstrated the highest sensitivity (87%), followed by S-LANSS (75%), while S-LANSS and PDQ showed the highest specificity (85% and 82%, respectively). These tools demonstrated a strong correlation with the reference standard (S-LANSS: rho = 0.7; PDQ: rho = 0.62; DN4: rho = 0.7; all, P < .001).

CONCLUSIONS

The DN4, S-LANSS, and PDQ show excellent discriminant validity to detect the presence of NP components in acute WAD, especially S-LANSS. Initial screening with these tools might improve management of WAD.

Psychological factors show limited association with the severity of Achilles tendinopathy

BACKGROUND

This study aimed to investigate the association between psychosocial factors and the severity of Achilles tendinopathy, along with exploring their potential link to the pain's duration.

METHODS

A cross-sectional study involving 111 individuals with Achilles tendon pain was conducted.

METHODS

A cross-sectional study involving 111 individuals with Achilles tendon pain was conducted. Various psychological factors were assessed using the Pain Catastrophizing Scale, Chronic Pain Self-Efficacy Scale (CPSS), Tampa Scale for Kinesiophobia, and Hospital Anxiety and Depression Scale (HAD). Additionally, the severity of Achilles tendon pain was evaluated using the Victorian Institute of Sport Assessment-Achilles questionnaire (VISA-A-Br). Regression analyses were employed to determine the association of these psychosocial factors with pain severity and duration.

RESULTS

Self-efficacy for chronic pain showed a slight association with Achilles tendon pain severity (β = 0.42 [95% CI: 0.06 to 0.16], p = 0.001), explaining only 19% of the dependent variable. The other variables, including anxiety, depression, pain catastrophizing, and fear of movement, did not exhibit significant associations.

CONCLUSION

The study suggests that psychological factors demonstrate limited association with the severity of Achilles tendinopathy. While self-efficacy for chronic pain was weakly associated, its clinical relevance remains uncertain. Future research, particularly longitudinal studies, should explore the influence of psychosocial factors on treatment adherence and response to enhance management strategies for Achilles tendon pain.

Cracking the Chronic Pain code: A scoping review of Artificial Intelligence in Chronic Pain research

OBJECTIVE

The aim of this review is to identify gaps and provide a direction for future research in the utilization of Artificial Intelligence (AI) in chronic pain (CP) management.

METHODS

A comprehensive literature search was conducted using various databases, including Ovid MEDLINE, Web of Science Core Collection, IEEE Xplore, and ACM Digital Library. The search was limited to studies on AI in CP research, focusing on diagnosis, prognosis, clinical decision support, self-management, and rehabilitation. The studies were evaluated based on predefined inclusion criteria, including the reporting quality of AI algorithms used.

RESULTS

After the screening process, 60 studies were reviewed, highlighting AI's effectiveness in diagnosing and classifying CP while revealing gaps in the attention given to treatment and rehabilitation. It was found that the most commonly used algorithms in CP research were support vector machines, logistic regression and random forest classifiers. The review also pointed out that attention to CP mechanisms is negligible despite being the most effective way to treat CP.

CONCLUSION

The review concludes that to achieve more effective outcomes in CP management, future research should prioritize identifying CP mechanisms, CP management, and rehabilitation while leveraging a wider range of algorithms and architectures.

SIGNIFICANCE

This review highlights the potential of AI in improving the management of CP, which is a significant personal and economic burden affecting more than 30% of the world's population. The identified gaps and future research directions provide valuable insights to researchers and practitioners in the field, with the potential to improve healthcare utilization.

Sensitization-Associated Symptoms and Neuropathic-like Features in Patients with Cervical Dystonia and Pain

Background: This exploratory study evaluated the presence of sensitization-associated and neuropathic-like symptoms and identified their association with pressure sensitivity, pain, and disability in patients with cervical dystonia (CD). Methods: Thirty-one patients with CD (74.2% women, age: 61.2 years, SD 10.1) participated. Data collected included clinical variables, the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS), the Central Sensitization Inventory (CSI), the Self-administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS), the Hospital Anxiety and Depression Scale (HADS) and the Pittsburgh Sleep Quality Index (PSQI), as well as widespread pressure pain thresholds (PPTs). Results: Patients with CD with pain (n = 20, 64.5%) showed higher scores on the TWSTRS disability subscale and the CSI (p < 0.001), and lower PPTs (p < 0.05). Fifteen patients (15/31, 48%) showed sensitization-associated symptoms (CSI ≥ 40), whereas five of the patients with pain (5/20, 25%) exhibited neuropathic-like symptoms (S-LANSS ≥ 12). The CSI and S-LANSS were positively associated with the TWSTRS, HADS-A and HADS-D, and negatively associated with PPTs. HADS-D and S-LANSS explained 72.5% of the variance of the CSI (r2: 0.725), whereas CSI explained 42.3% of the variance of the S-LANSS (r2: 0.423). Conclusions: Pain is an important source of disability in CD, and may be a consequence of different mechanisms, including sensitization.

Pain as a disease in the new International Classification of Diseases (ICD-11): Latin American expert consensus

Aims: Pain diagnoses in the 10th version of the International Classification of Diseases (ICD-10) did not adequately support the current management of pain. Therefore, we aimed to review the new 11th revision (ICD-11) in order to analyze its usefulness for the management, coding, research and education of chronic pain from a Latin American perspective. Methods: The Latin American Federation of Associations for the Study of Pain convened a meeting of pain experts in Lima, Peru. Pain specialists from 14 Latin American countries attended the consensus meeting. Results: In ICD-11, chronic pain is defined as pain that persists or recurs longer than 3 months and is subdivided into seven categories: chronic primary pain and six types of chronic secondary pain. Chronic primary pain is now considered a disease in itself, and not a mere symptom of an underlying disease. Conclusion: The novel definition and classification of chronic pain in ICD-11 is helpful for better medical care, research and health statistics. ICD-11 will improve chronic pain management in Latin American countries, for both the pain specialist and the primary care physician.

Nociceptive, neuropathic, or nociplastic low back pain? The low back pain phenotyping (BACPAP) consortium's international and multidisciplinary consensus recommendations

The potential to classify low back pain as being characterised by dominant nociceptive, neuropathic, or nociplastic mechanisms is a clinically relevant issue. Preliminary evidence suggests that these low back pain phenotypes might respond differently to treatments; however, more research must be done before making specific recommendations. Accordingly, the low back pain phenotyping (BACPAP) consortium was established as a group of 36 clinicians and researchers from 13 countries (five continents) and 29 institutions, to apply a modified Nominal Group Technique methodology to develop international and multidisciplinary consensus recommendations to provide guidance for identifying the dominant pain phenotype in patients with low back pain, and potentially adapt pain management strategies. The BACPAP consortium's recommendations are also intended to provide direction for future clinical research by building on the established clinical criteria for neuropathic and nociplastic pain. The BACPAP consortium's consensus recommendations are a necessary early step in the process to determine if personalised pain medicine based on pain phenotypes is feasible for low back pain management. Therefore, these recommendations are not ready to be implemented in clinical practice until additional evidence is generated that is specific to these low back pain phenotypes.

Conditioned Pain Modulation and Temporal Summation of Pain in Patients With Traumatic and Non-Specific Neck Pain: A Systematic Review and Meta-Analysis

In patients with neck pain, it is unclear whether pain inhibition and facilitation endogenous pain mechanisms are altered. This systematic review and meta-analysis aimed to improve their understanding by assessing conditioned pain modulation (CPM) and temporal summation of pain (TSP) in patients with neck pain associated with whiplash-associated disorders (WAD) or of a nonspecific neck pain (NSNP) nature compared to pain-free controls. Very low certainty evidence suggests: impaired CPM when assessed remotely in chronic WAD patients (n = 7, 230 patients and 204 controls, standardized mean differences (SMD) = -.47 [-.89 to -.04]; P = .04) but not locally (n = 6, 155 patients and 150 controls; SMD = -.34 [-.68 to .01]; P = .05), impaired CPM in chronic NSNP patients when assessed locally (n = 5, 223 patients and 162 controls; SMD = -.55 [-1.04 to -.06]; P = .04) but not remotely (n = 3, 72 patients and 66 controls; SMD = -.33 [-.92 to .25]; P = .13), TSP not facilitated in either chronic WAD (local TSP: n = 4, 90 patients and 87 controls; SMD = .68 [-.62 to 1.99]) (remote TSP: n = 8, 254 patients and 214 controls; SMD = .18 [-.12 to .48]) or chronic NSNP (local TSP: n = 2, 139 patients and 92 controls; SMD = .21 [-1.00 to 1.41]), (remote TSP: n = 3; 91 patients and 352 controls; SMD = .60 [-1.33 to 2.52]). The evidence is very uncertain whether CPM is impaired and TSP facilitated in patients with WAD and NSNP. PERSPECTIVE: This review and meta-analysis present the current evidence on CPM and TSP in patients with WAD and NSNP. Standardization of measurement methodology is needed to draw clear conclusions. Subsequently, future studies should investigate the clinical relevance of these measurements as prognostic variables or predictors of treatment success.

The Pharmacological Treatment of Neuropathic Pain in Children

The International Association for the Study of Pain (IASP) defines neuropathic pain as pain caused by a lesion or disease of the somatosensory nervous system. It is characterized as a clinical condition in which diagnostic studies reveal an underlying cause of an abnormality in the peripheral or central nervous system. Many common causes of neuropathic pain in adults are rare in children. The purpose of this focused narrative review is, to 1) provide an overview of neuropathic pain in children, 2) highlight unique considerations related to the diagnosis and mechanisms of neuropathic pain in children, and 3) perform a comprehensive analysis of the pharmacological treatments available. We emphasize that data for routine use of pharmacological agents in children with neuropathic pain are largely inferred from adult literature with little research performed on pediatric populations, yet have clear evidence of harms to pediatric patients. Based on these findings, we propose risk mitigation strategies such as utilizing topical treatments whenever possible, assessing pain phenotyping to guide drug class choice, and considering pharmaceuticals in the broader context of the multidisciplinary treatment of pediatric pain. Furthermore, we highlight important directions for future research on pediatric neuropathic pain treatment.

Concurrent validity of dynamic bedside quantitative sensory testing paradigms in breast cancer survivors with persistent pain

BACKGROUND

Studies on the concurrent validity of clinically applicable testing protocols for conditioned pain modulation (CPM) and temporal summation of pain (TSP) in breast cancer survivors (BCS) with persistent pain are lacking.

OBJECTIVES

This study investigated the concurrent validity of two bedside protocols for CPM and TSP in comparison to a respective reference protocol. The participants' preferences for bedside CPM and TSP protocols were assessed.

METHODS

Thirty BCS experiencing persistent pain were included in this study. Each participant underwent a reference test along with two bedside alternatives for assessing both TSP and CPM. For CPM, a cold pressor test (CPT) and blood pressure cuff (BPC) were used as conditioning stimulus. The test stimulus was elicited in parallel by pressure pain threshold after 45 and 90 s of conditioning at the lower limb. The CPM reference test consisted of parallel heat stimuli at the forearms using a two-thermode system. TSP was elicited using a von Frey monofilament (256 mN) and an algometer (98 kPa) at the affected site and opposite lower limb. The TSP reference test consisted of heat stimuli at the affected site and opposite lower limb. Participants' testing preference was examined using a purpose-designed questionnaire. Spearman's rank test examined the correlation between protocols.

RESULTS

The two bedside CPM protocols were strongly correlated (r = 0.787-0.939, p < 0.005). A strong correlation was found between the BPC protocol and reference test using the relative effect magnitude (r = 0.541-0.555, p < 0.005). The bedside TSP protocols were moderately correlated with each other only at the lower limb using absolute change scores (r = 0.455, p = 0.012). No significant correlation was found between the bedside and reference TSP protocols.

CONCLUSION

The significantly moderate to very strong correlations between the bedside protocols validate their interchangeability. Researchers and clinicians should be able to choose which bedside protocol they utilize; however, participants favored the use of a BPC and algometer for the evaluation of CPM and TSP, respectively.

COVID-19 and musculoskeletal pain: an overview of the current knowledge

The Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) has provoked billions of infections worldwide. Several meta-analyses have observed that up to 50% of individuals who had survived to a SARS-CoV-2 acute infection suffer from post-COVID symptoms lasting for weeks or months and up to one year after infection. The prevalence of post-COVID pain ranges between 10% to 20% when assessed with other overall post-COVID symptoms and can reach up to 50% to 60% when investigated specifically. The most common musculoskeletal manifestations of post-COVID-19 condition include fatigue, myalgia, arthralgia or back pain. Despite pain of musculoskeletal origin is one of the most prevalent post-COVID pain symptoms, the exact pathophysiological mechanisms of musculoskeletal post-COVID pain are not completely understood. Studies have reported the complexity of post-COVID pain including immune, biological, and psychological factors, and more recently, they have suggested that genetic and epigenetic factors may also play a potential role, highlighting the need for further investigation into these mechanisms. Its management is still controversial, as no specific guideline for treating musculoskeletal post-COVID pain has been proposed with only general consideration about the relevance of multidisciplinary and multimodal treatment approaches. In this paper we will highlight the clinical features, the mechanism, and the management possibilities of musculoskeletal post-COVID pain.

What are Brazilian orthopaedists' views on the diagnosis and treatment of patients with chronic nonspecific low back pain? A qualitative investigation

BACKGROUND

Orthopaedists are often the first point of contact for patients who present with low back pain (LBP) and chronic LBP in Brazil.

AIM

To explore the views of orthopaedists on therapeutic approaches for chronic non-specific low back pain (CNLBP) with a view to gain insights into aspects of clinical practice considered important to them.

METHODS

A qualitative design underpinned by interpretivism was employed. Participants were (n = 13) orthopaedists with experience in treating patients with CNLBP. Following the pilot interviews, semi-structured interviews were conducted, audio-recorded, transcribed and de-identified. Interview data were thematically analysed.

RESULTS

Four themes were identified. (1) Biophysical aspects are important and predominate, but sometimes their relevance can be unclear; (2) Psychosocial aspects and lifestyle factors influence the therapeutic approach; (3) Treatment of CNLBP - including medication, physical activity, surgery and other invasive procedures and other therapeutic modalities; and (4) Nuances of clinical practice - "it goes beyond medicine".

CONCLUSION

Brazilian orthopaedists value identifying the biophysical cause(s) of chronic low back pain. Psychological factors were often discussed secondary to biophysical aspects, whereas social aspects were rarely mentioned. Orthopaedists highlighted their difficulties in navigating patients' emotions and reassuring patients without referrals to imaging tests. Orthopaedists may benefit from training that targets communication and other relational aspects of care in order to work with people who present with CNLBP.

Precision management of post-COVID pain: An evidence and clinical-based approach

Background Pain after a SARS-CoV-2 acute infection (post-COVID pain) is becoming a new healthcare emergency but remains underestimated and most likely undertreated due to a lack of recognition of the phenomenon and knowledge of the underlying pain mechanisms. Evidence supporting any particular treatment approach for the management of post-COVID pain is lacking. Large variability in the patient response to any standard pain treatments is clinically observed, which has led to calls for a personalized, tailored approach to treating patients with chronic post-COVID pain (i.e. 'precision pain medicine'). Applying the global concerted action towards precision medicine to post-COVID pain could help guide clinical decision-making and aid in more effective treatments. Methods The current position paper discusses factors to be considered by clinicians for managing post-COVID pain ranging from identification of the pain phenotype to genetic consideration. Results The ability of clinicians to phenotype post-COVID pain into nociceptive, neuropathic, nociplastic or mixed type is suggested as the first step to better planification of a treatment programme. Further, the consideration of other factors, such as gender, comorbidities, treatments received at the acute phase of infection for onset-associated COVID-19 symptoms, factors during hospitalization or the presence of emotional disturbances should be implemented into a treatment programme. Conclusions Accordingly, considering these factors, management of post-COVID pain should include multimodal pharmacological and non-pharmacological modalities targeting emotional/cognitive aspects (i.e. psychological and/or coping strategies), central sensitization-associated mechanisms (i.e. pain neuroscience education), exercise programmes as well as lifestyle interventions (e.g. nutritional support and sleep management). SIGNIFICANCE: This position paper presents an evidence-based clinical reasoning approach for precision management of post-COVID pain.

What's the low back pain problem represented to be? An analysis of discourse of the Australian policy directives

PURPOSE

Low back pain (LBP) directives provide information about how LBP should be managed, communicated and navigated in complex health systems, making them an important form of policy. This study aimed to examine how LBP is problematised (represented) in Australian directives.

MATERIALS AND METHODS

We employed an analysis of discourse of LBP directives drawing on Bacchi's "What's the problem represented to be?" policy problematisation approach.

RESULTS

Our analysis suggests that LBP is problematised as a symptom that tends to improve when individuals take responsibility for themselves, but may require care at times. The way in which LBP is represented in the directives excludes important aspects, such as the uncertainties of scientific knowledge, paradigms other than (post)positivist, multimorbidity, social and structural determinants of health.

CONCLUSION

LBP directives may benefit from problematisations of LBP that consider the ongoing nature of LBP and broader contextual factors that impact on both LBP outcomes and care, beyond individual responsibility. Consideration of a wider range of paradigms and expanded evidence base may also be beneficial, as these are likely to enable individuals, clinicians and the Australian healthcare system to address LBP while dealing with its complexities, enabling real-world changes to lessen the LBP burden.IMPLICATIONS FOR REHABILITATIONHealthcare professionals who work with people who experience low back pain (LBP) may benefit from critically reflecting about discourses embedded in policy directives.Healthcare professionals may consider engaging in policy changes processes to expand the discourses on which LBP policy directives rely.Healthcare professionals' ability to enact policy recommendations may be enhanced by consideration of the fluctuating nature of LBP, uncertainties, multimorbidity and determinants of health.

The Association Between the Patient Self-Report Survey for the Assessment of Fibromyalgia with Pain Sensitivity and Psychological Factors in Individuals with Musculoskeletal Pain

Purpose

The Patient Self-Report Survey for the Assessment of Fibromyalgia may potentially be a method for subgrouping patients with musculoskeletal pain who have a nociplastic pain presentation. Limited research has explored the convergent validity of this questionnaire against psychophysical measures of pain sensitivity and psychological factors in individuals with musculoskeletal pain. Therefore, the purpose of this study is to examine the strength of the association between total scores on the Patient Self-Report Survey for the Assessment of Fibromyalgia with clinical, pain sensitivity, and psychological factors.

Patients and Methods

As a secondary analysis of a cross-sectional study, participants with shoulder (n = 20) or low back pain (n = 20) completed Quantitative Sensory Testing (QST), pain-related psychological questionnaires, and the Patient Self-Report Survey for the Assessment of Fibromyalgia. A Spearman correlation determined the association between total scores on the Patient Self Report Survey for the Assessment of Fibromyalgia with psychological factors and pain sensitivity behaviorally assessed with QST.

Results

Negative psychological factors demonstrate moderate to strong positive associations with the Patient Self-Report Survey for the Assessment of Fibromyalgia (rho range = 0.36-0.80), suggesting greater negative psychological factors were observed in patients with higher severity of fibromyalgia symptoms. Pain sensitivity factors demonstrated weak to moderate negative associations with The Patient Self-Report Survey for the Assessment of Fibromyalgia (PPT rho range=-0.36- -0.41), suggesting that elevated pain sensitivity was observed in individuals with higher severity of nociplastic pain symptoms.

Conclusion

Collectively, this supports the convergent validity of the Patient Self-Report Survey for the Assessment of Fibromyalgia with psychological and pain sensitivity factors in patients with musculoskeletal pain.

Analysis of pain research literature through keyword Co-occurrence networks

Pain is a significant public health problem as the number of individuals with a history of pain globally keeps growing. In response, many synergistic research areas have been coming together to address pain-related issues. This work reviews and analyzes a vast body of pain-related literature using the keyword co-occurrence network (KCN) methodology. In this method, a set of KCNs is constructed by treating keywords as nodes and the co-occurrence of keywords as links between the nodes. Since keywords represent the knowledge components of research articles, analysis of KCNs will reveal the knowledge structure and research trends in the literature. This study extracted and analyzed keywords from 264,560 pain-related research articles indexed in IEEE, PubMed, Engineering Village, and Web of Science published between 2002 and 2021. We observed rapid growth in pain literature in the last two decades: the number of articles has grown nearly threefold, and the number of keywords has grown by a factor of 7. We identified emerging and declining research trends in sensors/methods, biomedical, and treatment tracks. We also extracted the most frequently co-occurring keyword pairs and clusters to help researchers recognize the synergies among different pain-related topics.

Validity of the Central Sensitization Inventory to Address Human Assumed Central Sensitization: Newly Proposed Clinically Relevant Values and Associations

Central sensitization cannot be directly demonstrated in humans and thus a gold standard is missing. Therefore, we used human assumed central sensitization (HACS) when associated with humans. The central sensitization inventory (CSI) is a screening questionnaire for addressing symptoms that are associated with HACS. This cross-sectional study compared patients with chronic pain and at least one central sensitivity syndrome with healthy, pain-free controls via ROC analyses. Analyses were performed for all participants together and for each sex separately. Regression analyses were performed on patients with chronic pain with and without central sensitivity syndromes. Based on 1730 patients and 250 healthy controls, cutoff values for the CSI for the total group were established at 30 points: women: 33 points; men: 25 points. Univariate and multivariate regression analyses were used to identify possible predictors for the CSI score in 2890 patients with chronic pain. The CSI score is associated with all independent factors and has a low association with pain severity in women and a low association with pain severity, age, and body mass index in men. The newly established CSI cutoff values are lower than in previous studies and different per sex, which might be of clinical relevance in daily practice and importance in research.

Is there any benefit of adding a central nervous system-focused intervention to a manual therapy and home stretching program for people with frozen shoulder? A randomized controlled trial

BACKGROUND

Frozen shoulder (FS) is a highly disabling pathology of poorly understood etiology, which is characterized by the presence of intense pain and progressive loss of range of motion. The aim of this study was to evaluate the effect of adding a central nervous system (CNS)-focused approach to a manual therapy and home stretching program in people with FS.

METHODS

A total of 34 patients with a diagnosis of primary FS were randomly allocated to receive a 12-week manual therapy and home stretching program or manual therapy and home stretching program plus a CNS-focused approach including graded motor imagery and sensory discrimination training. The Shoulder Pain and Disability Index score, self-perceived shoulder pain (visual analog scale score), shoulder range of motion, and the Patient-Specific Functional Scale score were measured at baseline, after a 2-week washout period just before starting treatment, after treatment, and at 3 months' follow-up.

RESULTS

No significant between-group differences in any outcome were found either after treatment or at 3 months' follow-up.

CONCLUSION

A CNS-focused approach provided no additional benefit to a manual therapy and home stretching program in terms of shoulder pain and function in people with FS.

Urinary TNF-α as a potential biomarker for chronic primary low back pain

Introduction

Over two thirds of individuals with low back pain (LBP) may experience recurrent or persistent symptoms in the long term. Yet, current data do not allow to predict who will develop chronic low back pain and who will recover from an acute episode. Elevated serum levels of the proinflammatory cytokine tumor necrosis factor-α (TNF-α) have been associated with poor recovery and persistent pain following an acute episode of LBP. Inflammatory cytokines may also mediate mechanisms involved in nociplastic pain, and thus, have significant implications in chronic primary low back pain (CPLBP).

Methods

This study aimed to investigate the potential of urinary TNF-α levels for predicting outcomes and characterizing clinical features of CPLBP patients. Twenty-four patients with CPLBP and 24 sex- and age-matched asymptomatic controls were recruited. Urinary TNF-α concentrations were measured at baseline and after 4 weeks, during which CPLBP patients underwent spinal manipulative therapy (SMT).

Results

Concentrations of TNF-α were found to be elevated in baseline urine samples of CPLBP patients compared to asymptomatic controls. Moreover, these values differed among patients depending on their pain trajectory. Patients with persistent pain showed higher levels of TNF-α, when compared to those with episodic CPLBP. Furthermore, baseline TNF-α concentrations and their changes after 4 weeks predicted alterations in pain intensity and disability following SMT in patients with CPLBP.

Discussion

These findings warrant further research on the potential use of urinary TNF-α concentrations as a prognostic biomarker for CPLBP.

Carpal Tunnel Syndrome: Neuropathic Pain Associated or Not with a Nociplastic Condition

Carpal tunnel syndrome (CTS) has been traditionally classified as primarily a neuropathic condition with or without pain. Precision medicine refers to an evidence-based method of grouping patients based on their susceptibility to biology, prognosis of a particular disease, or in their response to a specific treatment, and tailoring specific treatments accordingly. In 2021, the International Association for the Study of Pain (IASP) proposed a grading system for classifying patients into nociceptive, neuropathic, or nociplastic phenotypes. This position paper presents data supporting the possibility of subgrouping individuals with specific CTS related-pain into nociceptive, neuropathic, nociplastic or mixed-type phenotypes. Carpal tunnel syndrome is a neuropathic condition but can also be comorbid with a nociplastic pain condition. The presence of extra-median symptoms and the development of facilitated pain processing seem to be signs suggesting that specific CTS cases can be classified as the nociplastic pain phenotype. The clinical responses of therapeutic approaches for the management of CTS are inconclusive. Accordingly, the ability to identify the predominant pain phenotype in patients with CTS could likely be problematic for producing efficient treatment outcomes. In fact, the presence of a nociplastic or mixed-type pain phenotype would explain the lack of clinical effect of treatment interventions targeting the carpal tunnel area selectively. We propose a clinical decision tree by using the 2021 IASP classification criteria for identifying the predominant pain phenotype in people with CTS-related pain, albeit CTS being a priori a neuropathic pain condition. The identification of a nociplastic-associated condition requires a more nuanced multimodal treatment approach to achieve better treatment outcomes.

The effect of skilled motor training on corticomotor control of back muscles in different presentations of low back pain

Transcranial magnetic stimulation (TMS) has revealed differences in the motor cortex (M1) between people with and without low back pain (LBP). There is potential to reverse these changes using motor skill training, but it remains unclear whether changes can be induced in people with LBP or whether this differs between LBP presentations. This study (1) compared TMS measures of M1 (single and paired-pulse) and performance of a motor task (lumbopelvic tilting) between individuals with LBP of predominant nociceptive (n = 9) or nociplastic presentation (n = 9) and pain-free individuals (n = 16); (2) compared these measures pre- and post-training; and (3) explored correlations between TMS measures, motor performance, and clinical features. TMS measures did not differ between groups at baseline. The nociplastic group undershot the target in the motor task. Despite improved motor performance for all groups, only MEP amplitudes increased across the recruitment curve and only for the pain-free and nociplastic groups. TMS measures did not correlate with motor performance or clinical features. Some elements of motor task performance and changes in corticomotor excitability differed between LBP groups. Absence of changes in intra-cortical TMS measures suggests regions other than M1 are likely to be involved in skill learning of back muscles.

Myofascial Pain Syndrome: A Nociceptive Condition Comorbid with Neuropathic or Nociplastic Pain

Myofascial pain syndrome is featured by the presence of myofascial trigger points (TrPs). Whether TrPs are primary or secondary phenomena or if they relate to central or peripheral nervous system disorders is controversial. Referred pain, a cardinal sign of TrPs, is a central phenomenon driven by peripheral input. In 2021, the International Association for the Study of Pain (IASP) proposed a clinical criteria and grading system for classifying patients with pain on nociceptive, neuropathic, or nociplastic phenotypes. Myofascial TrP pain has been traditionally categorized as a nociceptive phenotype; however, increasing evidence supports that this condition could be present in patients with predominantly nociplastic pain, particularly when it is associated with an underlying medical condition. The clinical response of some therapeutic approaches for managing TrPs remains unclear. Accordingly, the ability to classify myofascial TrP pain into one of these phenotypes would likely be critical for producing more successful clinical treatment outcomes by a precision medicine approach. This consensus paper presents evidence supporting the possibility of subgrouping individuals with myofascial TrP pain into nociceptive, nociplastic, or mixed-type phenotype. It is concluded that myofascial pain caused by TrPs is primarily a nociceptive pain condition, is unlikely to be classified as neuropathic or nociplastic, but can be present in patients with predominantly neuropathic or nociplastic pain. In the latter cases, management of the predominant central pain problem should be a major treatment goal, but the peripheral drive from TrPs should not be ignored, since TrP treatment has been shown to reduce sensitization-associated symptomatology in nociplastic pain conditions, e.g., fibromyalgia.

Assessment of exercise-induced hypoalgesia in chronic low back pain and potential associations with psychological factors and central sensitization symptoms: A case-control study

INTRODUCTION

Exercise is the most recommended treatment for chronic low back pain (CLBP) and is effective in reducing pain, but the mechanisms underlying its effects remain poorly understood. Exercise-induced hypoalgesia (EIH) may play a role and is thought to be driven by central pain modulation mechanisms. However, EIH appears to be disrupted in many chronic pain conditions and its presence in people with CLBP remains unclear. As people suffering from chronic pain often exhibit psychological factors and central sensitization symptoms influencing pain perception, EIH might be associated with these factors.

OBJECTIVE

The aim of this study is to compare the level of EIH between participants with and without CLBP following back and wrist exercises and to assess the associations between EIH, psychological factors, and symptoms of central sensitization (using the central sensitization inventory - CSI) in CLBP.

METHOD

Twenty-eight participants with CLBP and 23 without pain were recruited. Pressure pain thresholds (PPT) were measured at 4 sites (2 bony sites = capitate, S1|2 muscle sites = wrist flexors, lumbar erector spinae) before and after each of two exercises (wrist flexion and lumbar extension). Exercise-induced hypoalgesia was defined as percent change in PPT from pre- to post-exercise. Participants with CLBP also completed questionnaires to measure psychological factors (e.g., kinesiophobia, catastrophizing, anxiety, and self-efficacy) and symptoms of central sensitization (CSI), and correlations with EIH were calculated.

RESULTS

After wrist exercise, EIH measured at the muscle sites was lower in the CLBP group compared with the pain-free group (p = 0.047) but no differences were found at bony sites (p = 0.49). No significant differences for EIH were observed following back exercise at muscle sites (p = 0.14) or at bony sites (p = 0.65). Exercise-induced hypoalgesia was not correlated with any psychological factors or with the CSI score.

CONCLUSION

The lower EIH following wrist exercises may represent an alteration in pain modulation control in CLBP. However, psychological factors and central sensitization symptoms may not explain the differences observed.

Efficacy and safety of colchicine for the treatment of osteoarthritis: a systematic review and meta-analysis of intervention trials

OBJECTIVE

Colchicine, an approved treatment for gout, has been trialed in many diseases including osteoarthritis (OA) due to its anti-inflammatory effects. However, its efficacy and safety remain unclear in OA. This systematic review and meta-analysis evaluated the efficacy and safety of colchicine for the treatment of OA.

METHODS

PubMed, Web of Science, Scopus, and Cochrane Central were searched from inception through September 2022. Two reviewers independently screened for randomized controlled trials (RCTs) comparing colchicine with placebo or other active comparators for the treatment of OA (knee, hand, or hip OA), extracted data, and performed Cochrane risk of bias assessments.

RESULT

Nine RCTs for the knee OA and one for the hand OA were identified, consisting of 847 patients (429 in colchicine arms, 409 in control arms). The studies were conducted between 2002 and 2021 with follow-up periods ranging from 2 to 12 months, in India, Iran, Turkey, Australia, Singapore, and Iraq. Moderate-quality evidence showed no clinically important pain reduction with colchicine compared to control (standardized mean difference [SMD], 0.17; 95% confidence interval [CI], - 0.55, 0.22). Moderate-quality evidence showed no improvement in function with colchicine compared to control in knee OA patients (SMD, - 0.37; 95% CI, - 0.87, 0.13). Colchicine showed an acceptable safety profile with AEs/SAEs comparable to control.

CONCLUSION

Current evidence does not suggest a benefit of colchicine in reducing pain and improving physical function in the overall cohort of hand/knee OA patients. Future trials should focus on the subgroups of OA patients with local or systemic inflammation and/or mineralization who might benefit from colchicine.

Mechanisms of chiropractic spinal manipulative therapy for patients with chronic primary low back pain: protocol for a mechanistic randomised placebo-controlled trial

INTRODUCTION

Chronic low back pain (CLBP) is a highly prevalent and disabling condition. Identifying subgroups of patients afflicted with CLBP is a current research priority, for which a classification system based on pain mechanisms was proposed. Spinal manipulative therapy (SMT) is recommended for the management of CLBP. Yet, little data are available regarding its mechanisms of action, making it difficult to match this intervention to the patients who may benefit the most. It was suggested that SMT may influence mechanisms associated with central sensitisation. Therefore, classifying patients with CLBP according to central sensitisation mechanisms may help predict their response to SMT.

METHODS AND ANALYSIS

This protocol describes a randomised placebo-controlled trial aiming to examine which variables linked to central sensitisation may help predict the clinical response to SMT in a cohort of patients with CLBP. One hundred patients with chronic primary low back pain will be randomised to receive 12 sessions of SMT or placebo SMT over a 4-week period. Pain intensity and disability will be assessed as primary outcomes after completing the 4-week treatment (primary endpoint), and at 4-week and 12-week follow-ups. Baseline values of two pain questionnaires, lumbar pressure pain thresholds, concentrations of an inflammatory cytokine and expectations of pain relief will be entered as predictors of the response to SMT in a multiple regression model. Changes in these variables after treatment will be used in a second multiple regression model. The reference values of these predictors will be measured from 50 age and sex-matched healthy controls to allow interpretation of values in patients. Mixed analyses of variance will also be conducted to compare the primary outcomes and the predictors between groups (SMT vs placebo) over time (baseline vs post-treatment).

ETHICS AND DISSEMINATION

Ethical approval was granted by the Fundación Jiménez Díaz Clinical Research Ethics Committee.

TRIAL REGISTRATION NUMBER

NCT05162924.

Sensitization symptoms are associated with psychological and cognitive variables in COVID-19 survivors exhibiting post-COVID pain

OBJECTIVE

To investigate the association between demographic, clinical, psychological, cognitive, and health-related variables and the Central Sensitization Inventory (CSI) in previously hospitalized COVID-19 survivors exhibiting "de novo" post-COVID pain.

METHODS

Seventy-seven (n = 77) COVID-19 survivors with "de novo" post-COVID pain completed demographic (age, height, and weight), clinical (duration and intensity of the pain), psychological (depressive/anxiety levels and sleep quality), cognitive (catastrophizing and kinesiophobia levels), and health-related quality of life variables as well as the CSI. A multivariable correlation analysis was conducted to determine the association between variables, and a stepwise multiple linear regression model was performed to identify CSI predictors.

RESULTS

Patients were assessed a mean of 6.0 (SD 0.8) months after hospital discharge. Twenty-six (33.7%) individuals showed indications of sensitization-associated symptoms (CSI score ≥40 points). The CSI score was positively associated with pain intensity (r: 0.371), anxiety (r: 0.784), depressive (r: 0.709), catastrophizing (r: 0.620), and kinesiophobia (r: 0.359) levels (all, p < 0.001). The stepwise regression analysis revealed that 60.2% of CSI was explained by anxiety levels and pain intensity.

CONCLUSION

This study found that psychological and cognitive variables were associated with the CSI score in previously hospitalized COVID-19 survivors with "de novo" post-COVID pain. Anxiety levels and the intensity of pain symptoms were independently associated with CSI score suggesting a significant overlap with psychological construct. The "de novo" post-COVID pain association with CSI may indicate changes in the pain processing important for managing the pain.

Characteristics and Outcomes of Patients Receiving Physical Therapy for Low Back Pain with a Nociplastic Pain Presentation: A Secondary Analysis

Introduction

Individuals with low back pain (LBP) may be classified based on mechanistic descriptors, such as a nociplastic pain presentation (NPP). The purpose of this secondary analysis was to examine the frequency and characteristics of patients with a NPP referred to physical therapy with LBP. Additionally, we characterized patients with LBP meeting the criteria for NPP by demographic, clinical, psychological, and pain sensitivity variables. Finally, we examined short- and long-term clinical outcomes in patients with a NPP compared to those without a NPP.

Materials and Methods

Patients referred to physical therapy for LBP completed the Patient Self-report Survey for the Assessment of Fibromyalgia. Participants were categorized as "LBP with NPP" or "LBP without NPP" based on the threshold established in this measure. A rank sum test examined for differences in pain-related psychological factors and pressure-pain threshold between groups. Next, a Friedman test examined if LBP intensity and disability trajectories differed by groups at one and six months after initiation of physical therapy.

Results

22.2% of patients referred to physical therapy for LBP met the criteria for a NPP. Patients with a NPP reported significantly greater disability, pain catastrophizing, depression, anxiety, and somatization compared to individuals without a NPP (p < 0.05). Pressure-pain threshold did not differ between groups (p > 0.05). Individuals with LBP with a NPP demonstrated nonsignificant, small to medium reductions in pain and disability at one and six months. Individuals experiencing LBP without a NPP demonstrated significant reductions in pain and disability in the short- and long term.

Conclusion

Patients with LBP with a NPP displayed greater negative pain-related psychological factors but similar pain sensitivity compared to LBP without NPP.

Association between nociplastic pain and premature endocrine therapy discontinuation in breast cancer patients

PURPOSE

At least 5 years of adjuvant endocrine therapy (ET) is recommended for patients with hormone receptor-positive invasive breast cancer to reduce cancer recurrence risk. Up to half of patients prematurely discontinue ET, often due to musculoskeletal pain. Nociplastic pain is abnormal central nervous system pain processing without evidence of tissue or neuronal damage. This study aimed to evaluate the relationship between baseline nociplastic pain and ET discontinuation.

METHODS

This was a retrospective, single center, cohort study. Included patients were female, had stage 0-III invasive breast cancer, did not receive neoadjuvant therapy, and completed quality of life questionnaires prior to breast surgery, including Fibromyalgia Survey for nociplastic pain. Clinical data including duration of ET were abstracted from the medical record. Patient characteristics were analyzed with t-tests and Chi-squared tests, as appropriate. Univariate and multivariable regressions were performed with Cox proportional hazard models.

RESULTS

Six hundred eighty-one patients diagnosed between 2012 and 2019 met inclusion criteria; 480 initiated ET and were included in the analysis. Of these 480 patients, 203 (42.3%) prematurely discontinued initial ET therapy. On univariate analysis, tamoxifen use (hazard ratio [HR] 0.70, p = 0.021) and premenopausal status (HR 0.73, p = 0.04) were inversely associated with ET discontinuation, while Fibromyalgia Score was positively associated (HR 1.04, p = 0.043). On multivariable analysis, baseline Fibromyalgia Score remained associated with ET discontinuation.

CONCLUSION

Nociplastic pain present prior to surgery was associated with premature ET discontinuation. Fibromyalgia Score screening may be useful for evaluating ET discontinuation risk. Treatments targeting nociplastic pain may be more effective for treating ET-emergent pain.

Preliminary outcomes of the COVID-19 pandemic: a new chronic pain profile

In summing up the preliminary results of the COVID-19 pandemic that has not yet ended, modern research pays much attention to the so-called post-COVID syndrome, which includes the long-term consequences of the disease. In English, symptoms are reported as long COVID, post-acute COVID, or chronic post-COVID syndrome and are described as symptoms of fatigue, respiratory disorders, memory, and sleep problems. Symptoms such as muscle pain and decreased endurance when performing habitual physical exertion are mentioned much less often. Meanwhile, among the complaints of those who have been ill, this symptom is present quite often, reducing the quality of life and tolerability of normal physical exertion. This review aimed to provide an in-depth study of a new type of the chronic myofascial pain syndrome after COVID-19, i.e., the frequency of occurrence, causes of the development, and pathophysiology of chronic pain syndrome associated with COVID-19 and manifested as fibromyalgia of various localizations. To answer the questions posed, the authors searched for information in four electronic databases. The key search terms used were COVID-19, long COVID, and signs and symptoms of pain syndrome. A review of current literature data has shown that close study and dynamic monitoring of patients who had COVID-19 can contribute to further deciphering the pathophysiological mechanisms of the development of its long-term consequences and provide answers to questions on the prevention and treatment of chronic pain syndrome in this patient cohort.

Predictors of pain reduction following a program of manual therapies for patients with temporomandibular disorders: A prospective observational study

BACKGROUND

Clinical guidelines recommend conservative treatment for the management of temporomandibular disorders (TMD), and manual therapy (MT) is commonly applied to reduce pain and improve function.

OBJECTIVES

To identify predictors of pain reduction and functional improvement following a program of manual therapies (MTP) in patients with TMD and develop a first screening tool that could be used in clinical practice to facilitate decision-making.

DESIGN

A cohort of 102 adults with a diagnosis of TMD were treated with four weekly sessions within a MTP applied to craniomandibular structures. Candidate predictors were demographic variables, general health variables, psychosocial features, TMD characteristics and related clinical tests. A reduction of pain intensity by at least 30% after the MTP was considered a good outcome. Logistic regression was adopted to develop the predictive model and its performance was assessed considering the explained variance, calibration, and discrimination. Internal validation of the prediction models was further evaluated in 500 bootstrapped samples.

RESULTS

Patients experiencing pain intensity greater than 2/10 during mouth opening, positive expectations of outcome following a MTP, pain localized in the craniocervical region, and a low Central Sensitization Inventory score obtained a good outcome following the MTP. Predictive performance of the identified physical and psychological variables was characterized by high explained variance (R2 = 58%) and discrimination (AUC = 89%) after internal validation. A preliminary screening clinical tool was developed and presented as a nomogram.

CONCLUSIONS

The high discrimination of the prediction model revealed promising findings, although these need to be externally validated in future research.

TRIAL REGISTRATION NUMBER

NCT03990662.

Phenotyping Post-COVID Pain as a Nociceptive, Neuropathic, or Nociplastic Pain Condition

Pain after an acute Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) condition (post-COVID pain) is becoming a new healthcare emergency. Precision medicine refers to an evidence-based method of grouping patients based on their diagnostic/symptom presentation and then tailoring specific treatments accordingly. Evidence suggests that post-COVID pain can be categorized as nociceptive (i.e., pain attributable to the activation of the peripheral receptive terminals of primary afferent neurons in response to noxious chemical, mechanical, or thermal stimuli), neuropathic (i.e., pain associated with a lesion or disease of the somatosensory nervous system and limited to a "neuroanatomically plausible" distribution of the system), nociplastic (i.e., pain arising from altered nociception despite no clear evidence of actual or threatened tissue damage causing the activation of peripheral nociceptors or evidence for disease or lesion of the somatosensory system causing the pain), or mixed type (when two pain phenotypes co-exist). Each of these pain phenotypes may require a different treatment approach to maximize treatment effectiveness. Accordingly, the ability to classify post-COVID pain patients into one of these phenotypes would likely be critical for producing successful treatment outcomes. The 2021 International Association for the Study of Pain (IASP) clinical criteria and grading system provide a framework for classifying pain within a precision pain medicine approach. Here we present data supporting the possibility of grouping patients with post-COVID pain into pain phenotypes, using the 2021 IASP classification criteria, with a specific focus on nociplastic pain, which is probably the primary mechanism involved in post-COVID pain. Nociplastic pain, which is usually associated with comorbid symptomology (e.g., poor sleep quality, fatigue, cognitive-emotional disturbances, etc.) and is considered to be more difficult to treat than other pain types, may require a more nuanced multimodal treatment approach to achieve better treatment outcomes.

Effect of biological DMARDs and JAK inhibitors in pain of chronic inflammatory arthritis

INTRODUCTION

The advent of biological disease-modifying anti-rheumatic drugs (bDMARDs) and, more recently, of Janus kinase inhibitors (JAKi) has had a major impact on the long-term outcomes of chronic inflammatory arthritis (IA). However, the persistence of pain, even in patients with a complete pharmacological control of peripheral inflammation, represents an important clinical challenge in the treatment of IA.

AREAS COVERED

In this review, we provide an overview of possible mechanisms underlying pain in IA and its assessment, as well as the effects of bDMARDs and JAKi on pain management.

EXPERT OPINION

The overall data showed a good effect of bDMARDs and JAKi on pain, more pronounced for JAKi. However, it is challenging to distinguish the effect on the different types of pain (nociceptive, neuropathic, and nociplastic).