Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations. Pain. 2016;157:1851-1871. [PMID: 27152687 DOI: 10.1097/j.pain.0000000000000602]

A Semi-structured Interview Predicts Spinal Cord Stimulator Implantation in Patients with Chronic Pain

Pre-surgical psychological evaluations (PSPE) are required during the spinal cord stimulator (SCS) implantation process, but there is no standard protocol for SCS PSPE. In this study, we assessed the concurrent and predictive validity of the Stanford Integrated Pyschosocial Assessment for Transplantation (SIPAT) compared with patient-reported measures and election for SCS implantation. This study used prospectively collected data at the time of PSPE from N = 222 patients at a Midwestern academic medical center. We collected SIPAT scores and Patient-Reported Outcome Measurement Information Systems (PROMIS) scores, and recorded receipt of permanent SCS implantation as a binary (yes/no) outcome. The SIPAT correlated with patient-reported outcomes of Anxiety, Depression, Fatigue, Sleep, and Pain Interference in the expected direction. The SIPAT was a significant predictor of election for permanent SCS implantation when accounting for age and pain diagnosis, such that individuals with higher SIPAT scores were less likely to elect for surgery. Exploratory analyses showed that the SIPAT Patient Readiness subscale and patient-reported Anxiety and Depression PROMIS scales correlated with election for SCS surgery. Results of this study demonstrated validity of the SIPAT in a novel population, patients with chronic pain referred for SCS implantation.

Beyond pain intensity: Validating single-item pain bothersomeness measures

Chronic pain is a complex and multifaceted health condition, rendering pain intensity alone insufficient for comprehensively understanding the impact of pain. Pain bothersomeness scales have been developed to measure pain's impact on life, however lack adequate validation. Our study examines the validity of two single-item measures (5-point and 11-point response scales) for pain bothersomeness. We collected data from 633 treatment-seeking adults with mixed-etiology chronic pain. Pearson correlations were conducted to examine the relationships between each pain bothersomeness item and 20 general and pain-related functioning measures. ANOVAs examined the ability of pain bothersomeness scores to discriminate between eight groupings based on general and pain-related functioning. Linear regressions analyzed pain bothersomeness as a predictor of 14 measures of general and pain-related functioning three months later. Both pain bothersomeness items correlated significantly with 19 functioning measures and discriminated between eight groupings. Controlling for covariates, both items were consistently predictive of worse pain interference (Total adj r² =.34), pain catastrophizing (Total adj r² =.21-.22), depression (Total adj r² =.25-.26), and satisfaction with social roles (Total adj r² =.13-.16) three months later. Both single-item pain bothersomeness items demonstrated consistent concurrent, discriminant, and predictive validity. These low-burden assessments provide valuable information about patient functioning in clinical settings, suggesting their utility in improving chronic pain care. PERSPECTIVE: Both single-item pain bothersomeness measures demonstrated consistent concurrent and discriminant validity. Both items predicted worse pain interference, pain catastrophizing, depression, and social functioning 3-months later.

Development and preliminary testing of a comprehensive Ecological Momentary Assessment of people with chronic pain

Ecological Momentary Assessment (EMA) is a data collection method to understand people's real-time experience in daily life. To date, no standard instrument exists to measure the pain experience using EMA that provides relevant information for most chronic pain conditions. The goal of this study was to fill this gap by developing a comprehensive EMA pain instrument (cEMAp). Drawing on extant validated retrospective pain measures, the items represented the following pain-relevant constructs: (1) pain intensity, (2) pain fluctuations and patterns, (3) time in pain, (4) pain sensations, (5) pain location, (6) focusing on pain and distraction, (7) pain behavior, (8) other pain sensations, (9) pain impact, (10) pain concerns, (11) causes of pain relief and exacerbations, and (12) pain typicality. Subsequently, interviews with fifty-three adults (mean age=57 years, SD=13.4; female: 74%) with chronic pain were conducted to confirm the relevance and appropriateness of the selected items for real-time pain measurement. We then created an electronic version of the instrument utilizing information from 2-h intervals. We examined its feasibility and acceptability in a 1-week EMA design in a separate sample of twenty adults with chronic pain (mean age=56 years, SD=14.2). Results showed that EMA completion time was reasonable (mean=3.8 min, SD=2.5). Participants reported that the prompts were non-disruptive, the questions overall captured their pain experience, and the frequent pain assessments were useful. We expect this new instrument will allow researchers and clinicians to paint a fine-grained and nuanced picture of people's everyday pain in a comprehensive and standardized way. PERSPECTIVE: This article presents the development of a new pain assessment based on Ecological Momentary Assessment to comprehensively measure chronic pain in daily life. Continued use and examination of the new instrument could facilitate standardization and comparability of momentary pain assessment methods across studies and chronic pain conditions.

The mechanisms of manual therapy: A living review of systematic, narrative, and scoping reviews

INTRODUCTION

Treatment mechanisms are the underlying process or pathway through which a treatment influences the body. This includes molecular, cellular and physiological processes or pathways contributing to treatment effect. Manual therapy (MT) evokes complex mechanistic responses across body systems, interacting with the individual patient and context to promote a treatment response. Challenges arise as mechanistic studies are spread across multiple professions, settings and populations. The purpose of this review is to summarize treatment mechanisms that have been reported to occur with MT application.

METHODS

Four electronic databases were searched (Medline, CINAHL, Cochrane Library, and PEDro) for reviews investigating mechanistic responses which occur during/post application of MT. This review was registered a priori with PROSPERO (CRD42023444839). Methodological quality (AMSTAR-2) and risk of bias (ROBIS) were assessed for systematic and scoping reviews. Data were synthesized by mechanistic domain.

RESULTS

Sixty-two reviews were included. Systematic reviews (n = 35), narrative reviews (n = 24), and scoping reviews (n = 4) of asymptomatic (n = 37), symptomatic (n = 43), non-specified human subjects (n = 7) and animals (n = 7) were included. Reviews of moderate quality supported neurovascular, neurological, and neurotransmitter/neuropeptide changes. Reviews of low quality supported neuroimmunce, neuromuscular, and neuroendocrine changes. Reviews of critically low quality support biomechanical changes.

CONCLUSIONS

Findings support critically low to moderate quality evidence of complex multisystem mechanistic responses occurring with the application of MT. Results support peripheral, segmental spinal, and supraspinal mechanisms occurring with the application of MT, which can be measured directly or indirectly. The clinical value of these findings has not been well established. While MT has proven to be an effective intervention to treat conditions such as pain, the current body of literature leaves uncertainty as to 'why' MT interventions work, and future research should look to better define which mechanisms (or combinations of mechanisms) are mediators of clinical response.

Antidepressants to Manage Osteoarthritic Pain: The Value of Pain Phenotyping

Osteoarthritis (OA) is a chronic condition in which pain significantly affects quality of life, often leading to reduced physical activity and disability. Globally, an estimated 595 million people are affected, with the numbers likely to increase owing to an aging population and rising obesity rates. Effective pain management is crucial, yet current treatments, such as nonsteroidal anti-inflammatory drugs (NSAIDs) and opioids, often provide limited relief and come with risks. One reason for this limited success is the insufficient recognition of the importance of psychosocial factors and heterogeneity of patients with OA (such as anxiety and depression), which can exacerbate pain and its impacts. The variability in patient pain experiences highlights the potential value of pain phenotyping, which involves a comprehensive assessment of pain characteristics to tailor treatments to individual needs. Antidepressants, particularly serotonin-norepinephrine reuptake inhibitors (SNRIs), show promise in alleviating both psychological symptoms and OA-related pain, but their effectiveness varies among individuals. Therefore, further research into standardized pain phenotyping methods and their integration into antidepressant treatment is needed to improve efficacy and minimize side effects through more personalized approaches.

Identifying patient subgroups in the heterogeneous chronic pain population using cluster analysis

Chronic pain is an ill-defined disease with complex biopsychosocial aspects, posing treatment challenges. We hypothesized that treatment failure results, at least partly, from limited understanding of diverse patient subgroups. We aimed to identify subgroups using psychological variables, allowing for more tailored interventions. In a retrospective cohort study, we extracted patient-reported data from two Dutch tertiary multidisciplinary outpatient pain clinics (2018-2023) for unsupervised hierarchical clustering. Clusters were defined by anxiety, depression, pain catastrophizing, and kinesiophobia. Sociodemographics, pain characteristics, diagnosis, lifestyle, health-related quality of life and treatment efficacy were compared among clusters. A prediction model was built utilizing a minimum set of questions to reliably assess cluster allocation. Among 5466 patients with chronic pain, three clusters emerged. Cluster 1 (n=750) was characterized by high psychological burden, low health-related quality of life, lower educational levels and employment rates, and more smoking. Cluster 2 (n=1795) showed low psychological burden, intermediate health-related quality of life, higher educational levels and employment rates, and more alcohol consumption. Cluster 3 (n=2909) showed intermediate features. Pain reduction following treatment was least in cluster 1 (28.6% after capsaicin patch, 18.2% after multidisciplinary treatment), compared to >50% for both treatments in clusters 2 and 3. A model incorporating 15 psychometric questions reliably predicted cluster allocation. In conclusion, our study identified distinct chronic pain patient clusters through 15 psychological questions, revealing one cluster with notably poorer response to conventional treatment. Our prediction model, integrated in a web-based tool, may help clinicians improve treatment by allowing patient-subgroup targeted therapy according to cluster allocation. PERSPECTIVE: Hierarchical clustering of chronic pain patients identified three subgroups with similar pain intensity and diagnoses but distinct psychosocial traits. One group with higher psychological burden showed poorer treatment outcomes. A web-based tool using this model could help clinicians tailor therapies by matching interventions to specific patient subgroups for improved outcomes.

Innovations in acute and chronic pain biomarkers: enhancing diagnosis and personalized therapy

Pain affects millions worldwide, posing significant challenges in diagnosis and treatment. Despite advances in understanding pain mechanisms, there remains a critical need for validated biomarkers to enhance diagnosis, prognostication, and personalized therapy. This review synthesizes recent advancements in identifying and validating acute and chronic pain biomarkers, including imaging, molecular, sensory, and neurophysiological approaches. We emphasize the emergence of composite, multimodal strategies that integrate psychosocial factors to improve the precision and applicability of biomarkers in chronic pain management. Neuroimaging techniques like MRI and positron emission tomography provide insights into structural and functional abnormalities related to pain, while electrophysiological methods like electroencepholography and magnetoencepholography assess dysfunctional processing in the pain neuroaxis. Molecular biomarkers, including cytokines, proteomics, and metabolites, offer diagnostic and prognostic potential, though extensive validation is needed. Integrating these biomarkers with psychosocial factors into clinical practice can revolutionize pain management by enabling personalized treatment strategies, improving patient outcomes, and potentially reducing healthcare costs. Future directions include the development of composite biomarker signatures, advances in artificial intelligence, and biomarker signature integration into clinical decision support systems. Rigorous validation and standardization efforts are also necessary to ensure these biomarkers are clinically useful. Large-scale collaborative research will be vital to driving progress in this field and implementing these biomarkers in clinical practice. This comprehensive review highlights the potential of biomarkers to transform acute and chronic pain management, offering hope for improved diagnosis, treatment personalization, and patient outcomes.

Explorative sensory profile evaluation in central neuropathic pain following spinal cord injury

BACKGROUND

Sensory profiling in neuropathic pain using quantitative sensory testing (QST) has not been extended to central neuropathic pain due to spinal cord injury (SCI). This study aims to fill this gap by evaluating sensory profiles in patients with neuropathic SCI pain.

METHOD

We retrospectively analysed consecutive QST data from 62 patients with neuropathic spinal cord injury pain (SCIP), following the German Research Network on Neuropathic Pain protocol. The study included at-level and below-level SCIP due to a spinal cord lesion, and at-level SCIP following a cauda equina lesion. QST parameters were compared between diagnostic groups. QST profiles of below-level SCIP (central neuropathic pain) were manually assigned to sensory phenotypes based on literature and expert opinion.

RESULTS

No statistical difference in QST parameters between pain diagnoses was found. For central neuropathic pain (below-level SCIP), three phenotypes were descriptively observed: loss of function (59%), thermal and mechanical hyperalgesia combination (16%), and mechanical hyperalgesia (19%). The remaining 5% of patients did not fit a common pattern. There was no statistical difference in clinical and psychological variables between phenotypes. In a subgroup analysis, the loss of function phenotype weakly correlated with older age, longer time since injury, and longer pain duration.

CONCLUSIONS

Here, we capture sensory phenotypes of central neuropathic pain following SCI. The limited sample size, high rate of missing values, and the retrospective nature of the study mean that results should be seen as strictly exploratory. Further research should replicate these findings and explore the significance of phenotypes.

SIGNIFICANCE STATEMENT

The evaluation of sensory phenotypes by quantitative sensory testing in central neuropathic pain due to SCI adds a new perspective on sensory phenotypes in comparison to peripheral neuropathic pain. The described thermal and mechanical hyperalgesia combination might represent involvement of the spinothalamic tract. In addition, there was a trend towards older age and longer time since injury in patients with loss of function.

Pediatric erythromelalgia from multidisciplinary perspectives: a scoping review

Erythromelalgia is a rare, chronic pain disorder characterized by the triad of intense burning sensation, warmth, and redness, primarily involving the hands and feet, and usually alleviated by cold and worsened by heat. The objective of this scoping review was to: 1) map the existing literature on erythromelalgia in youth, 2) identify knowledge gaps, and 3) inform directions for future research in pediatric erythromelalgia. One hundred and sixty-seven studies reporting 411 cases of childhood-onset erythromelalgia were identified. Variability was found in reporting of clinical symptoms, the clinical presentations and diagnostic criteria used for classification of erythromelagia, the clinical assessments and investigations performed, and the types of interventions and management plans utilised. While factors to aid early recognition and optimize management have been identified, there are also significant gaps for future research to address. Ongoing efforts to develop a multicenter registry of pediatric erythromelalgia cases, with standardized data collection and reporting, will be beneficial to establish consensus recommendations for the diagnosis and management of pediatric erythromelalgia. IMPACT: This scoping review maps the existing literature on pediatric erythromelalgia. Variability was found in reporting of clinical symptoms, the clinical presentations and diagnostic criteria used for classification of erythromelagia, the clinical assessments and investigations performed, and the types of interventions and management plans utilised. The development of an international registry would immensely benefit multidisciplinary experts involved in the care of pediatric erythromelalgia and those with lived experience.

Development and validation of a home quantitative sensory testing tool-kit to assess changes in sensory and pain processing: a study in healthy young adults

ABSTRACT

Quantitative sensory testing (QST) is a set of methods for quantifying somatosensory functioning. Limitations of laboratory-based QST (LQST) include high cost, complexity in training, lack of portability, and time requirements for testing. Translating QST to a home setting could facilitate future research and clinical care. The objective of this study was to develop a home QST (HQST) tool-kit that is cost-effective, easy to use, and detects changes in sensory and pain processing. Thirty-two young healthy adults underwent sensory testing on their nondominant forearm using standard in-person LQST, followed by "simulated HQST" using video guidance in a separate room from the investigator before and after application of either a lidocaine or capsaicin cream. We observed good agreement between HQST and LQST scores, with significant correlations observed between the pinprick, pressure, cold and heat measures (|ρ| range = 0.36-0.54). The participants rated the HQST protocol as highly acceptable and safe but can be improved in future implementations. Home QST was able to detect hypoesthesia to vibration after lidocaine cream application ( P = 0.024, d = 0.502) and could detect hypoalgesia and hyperalgesia to pressure and heat pain sensitivity tests after application of lidocaine and capsaicin creams, respectively ( P -value range = <0.001-0.036, d -value range = 0.563-0.901). Despite limitations, HQST tool-kits may become a cost-effective, convenient, and scalable approach for improving sensory profiling in clinical care and clinical research.

Pain sensitization in fibromyalgia. Cross-sectional associations between quantitative sensory testing of pain sensitization and fibromyalgia disease burden

BACKGROUND

Whether fibromyalgia burden is related to measures of sensitization, assessed by quantitative sensory testing (QST), is not clear. We examine the associations between sensitization and fibromyalgia disease burden as measured by the polysymptomatic sistress scale (PDS) and the fibromyalgia impact questionnaire (FIQ) (range 0-100).

MATERIALS AND METHODS

Participants were recruited from referrals to a rheumatology outpatient clinic and the fibromyalgia diagnosis was verified by a rheumatologist. They completed the PDS and FIQ and underwent QST of pressure pain threshold (PPT) at five sites, temporal summation (TS), and conditioned pain modulation (CPM) estimated as post-stimuli/pre-stimuli PPT. The associations between QST and disease burden were analysed in linear regression models adjusted for age, sex, and body mass index.

RESULTS

A total of 78 individuals with clinically verified fibromyalgia (90% women, mean age 40.9 years (SD 7.3)) were recruited. Overall mean PPT was associated with the FIQ total score (β-2.1, 95% CI-4.3, -0.0) and the function component (β-2.1, (-4.3, -0.0)). When examining the associations between PPT at individual sites and fibromyalgia disease severity, PPTs at the distal interphalangeal joint and tibialis anterior muscle were associated with both FIQ total score and the FIQ fatigue component. All associations were weak and insignificant after Bonferroni corrections.

CONCLUSION

In this cohort of individuals with fibromyalgia, sensitization was not significantly associated with self-reported disease burden. Our results point to the multifactorial nature of fibromyalgia disease severity.

SIGNIFICANCE

In patients with fibromyalgia, commonly used measures of sensitization do not explain the symptom burden or the functional impact.

Clinical predictors of treatment response to gabapentin in women with unexplained chronic pelvic pain

Introduction

Chronic pelvic pain affects up to 24% of women worldwide and for up to 55% of these there is no associated pathology. Despite this there are no established treatments in this cohort. This is a secondary analysis of a randomised-controlled trial (GaPP2) to explore if there are measures which enable us to predict treatment outcome.

Methods

GaPP2 recruited women with chronic pelvic pain and no identified pathology and compared the response to gabapentin and placebo. This analysis used variables collected at baseline including validated questionnaires. Binary logistic regression was used to create models to explore whether baseline variables predicted treatment response. Treatment response was determined using 30% reduction in average pain intensity, 30% reduction in worst pain intensity and the Patient Global Impression of Change ('marked' or 'very marked' improvement) individually. We also explored whether baseline variables predicted the occurrence of side-effects (dizziness, visual disturbances and drowsiness).

Results

Using the Patient Global Impression of Change questionnaire, we found a significant binary logistic regression (p = 0.029, explaining 31% of the variance), with those with lower worst pain intensity (odds ratio (OR) of 0.393, 95% CI [0.217, 0.712]), lower bladder symptom score (OR = 0.788, CI [0.628, 0.989]), and higher mental component quality of life score (OR = 0.911, CI [0.840, 0.988]), more likely to have 'marked' or 'very marked' improvement when treated with gabapentin. We could not identify predictors of experiencing side-effects to gabapentin. However, we did find predictors of these in the placebo group (binary logistic regression (p = 0.009) and explained 33% of the variance). Worse mental health (OR = 1.247, CI [1.019, 1.525]) and lower baseline pain interference (OR = 0.687, CI [0.483, 0.978]) were associated with having side effects, whilst the use of hormones reduced the risk of experiencing side effects (OR = 0.239, CI [0.084, 0.676]).

Discussion

Researchers and clinicians are increasingly aware of the importance of personalised medicine and treatment decisions being driven by knowledge of what treatments work for whom. Our data suggests an important role of the Patient Global Impression of Change in clinical trials as it may better reflect balance between symptoms reduction and side-effects and therefore be more useful in clinician-patients joint decision making.

Conservative Management of Occipital Neuralgia Supported by Physical Therapy: A Review of Available Research and Mechanistic Rationale to Guide Treatment

PURPOSE OF REVIEW

Conservative management is consistently recommended as a first line intervention for occipital neuralgia (ON); however, there is limited clinical research regarding conservative intervention for ON. This lack of research may lead to underutilization or unwarranted variability in conservative treatment. This article provides mechanism-based guidance for conservative management of ON as a component of a multimodal treatment approach, and discusses the role of the physical therapist in the care team. It also highlights opportunities for further research to refine conservative management of this condition.

RECENT FINDINGS

Published research on conservative interventions specific to ON is limited to very low-quality evidence for the use of TENS. The contemporary shift toward precision pain management emphasizing treatment based on a patient's constellation of clinical features-a phenotype-rather than solely a diagnosis provides more personalized and specifically targeted pain treatment. This paradigm can guide treatment in cases where diagnosis-specific research is lacking and can be used to inform conservative treatment in this case. Various conservative interventions have demonstrated efficacy in treating many of the symptoms and accepted etiologies of ON. Conservative interventions provided by a physical therapist including exercise, manual therapy, posture and biomechanical training, TENS, patient education, and desensitization have mechanistic justification to treat symptoms and causes of ON. Physical therapists have adequate time and skill to provide such progressive and iterative interventions and should be included in a multimodal treatment plan for ON. Further research is required to determine appropriate dosing, sequencing, and progression of conservative treatments.

What is the Status Quo of Patient-Centred Physiotherapy Management of People with Headache within a Biopsychosocial Model? - A Narrative Review

PURPOSE OF REVIEW

Patient-centred care (PCC) is deemed essential in the rehabilitation of musculoskeletal pain. Integrating such care within a biopsychosocial framework, enables to address all facets of the individual pain experience, and to manage the individual instead of the condition. This narrative review describes the status quo of PCC physiotherapy management of people with headache within a biopsychosocial model. PubMed, EMBASE, Web of Science, Scopus were searched (update 07.05.2024). The search-query comprised terminology relating to "headache", "patient-centred", "biopsychosocial", "physiotherapy". Additional eligibility criteria were reviews, trials, cohort, case report, case-control studies in English, Dutch, French.

RECENT FINDINGS

Gaps are exposed in patient-centred physiotherapy management of migraine, tension-type headache, and cervicogenic headache. While a biopsychosocial approach is advised to manage migraine and tension-type headache, its use in clinical practice is not reflected by the literature. A biopsychosocial approach is not advised in cervicogenic headache. Psychosocial-lifestyle interventions are mainly delivered by health-care providers other than physiotherapists. Additionally, psychologically-informed practice is barely introduced in physiotherapy headache management. Though, managing the social context within a biopsychosocial framework is advised, the implementation by physiotherapists is unclear. Comparable conclusions apply to PCC. PCC is recommended for the physiotherapy management of primary and secondary headache. Such recommendation remains however theoretical, not reaching clinical implementation. Yet, a shift from the traditional disease-centred model of care towards PCC is ongoing and should be continued in physiotherapy management. With this implementation, clinical and economical studies are needed to evaluate its effectiveness.

Sleep and circadian rhythm disturbances as risk and progression factors for multiple chronic overlapping pain conditions: a protocol for a longitudinal study

Introduction

Chronic overlapping pain conditions (COPCs), such as chronic low back pain (cLBP) and fibromyalgia, frequently cooccur and incur substantial healthcare costs. However, to date, much focus has been placed on individual anatomically based chronic pain conditions, whereas little is known about the mechanisms underlying progression to multiple (more than 1) COPCs. This study aims to address the gap by investigating the role of common and modifiable risk factors, specifically sleep and circadian rhythm disturbances, in the development of multiple COPCs.

Methods

The study will enroll 300 participants with cLBP, including 200 with cLBP only and 100 with cLBP plus other COPCs (ie, fibromyalgia, temporomandibular disorders, irritable bowel syndrome, and chronic headaches) and follow them up for 12 months. Sleep and circadian rhythms will be assessed using wireless sleep electroencephalography, 24-hour evaluation of the rhythm of urinary 6-sulfatoxymelatonin, actigraphy, and sleep diaries. Pain amplification using quantitative sensory testing, psychological distress using validated self-report measures, and the number of pain sites using a pain body map will also be assessed.

Perspectives

This research aims to (1) comprehensively characterize sleep/circadian disturbances in individuals with single and multiple COPCs using multimodal in-home assessments; (2) examine the associations between sleep/circadian disturbances, changes in pain amplification, and psychological distress; and (3) investigate the relationship among these factors and the progression in the number of pain sites, a proxy for multiple COPCs. The findings will provide insights into the mechanisms leading to multiple COPCs, potentially informing treatment and prevention strategies for these complex conditions.

Hallmarks of primary headache: part 1 - migraine

BACKGROUND AND AIM

Migraine is a common disabling conditions which, globally, affects 15.2% of the population. It is the second cause of health loss in terms of years lived with disability, the first among women. Despite being so common, it is poorly recognised and too often undertreated. Specialty centres and neurologists with specific expertise on headache disorders have the knowledge to provide specific care: however, those who do not regularly treat patients with migraine will benefit from a synopsis on the most relevant and updated information about this condition. This paper presents a comprehensive view on the hallmarks of migraine, from genetics and diagnostic markers, up to treatments and societal impact, and reports the elements that identify migraine specific features.

MAIN RESULTS

The most relevant hallmark of migraine is that it has common and individual features together. Besides the known clinical manifestations, migraine presentation is heterogeneous with regard to frequency of attacks, presence of aura, response to therapy, associated comorbidities or other symptoms, which likely reflect migraine heterogeneous genetic and molecular basis. The amount of therapies for acute and for prophylactic treatment is really wide, and one of the difficulties is with finding the best treatment for the single patient. In addition to this, patients carry out different daily life activities, and might show lifestyle habits which are not entirely adequate to manage migraine day by day. Education will be more and more important as a strategy of brain health promotion, because this will enable reducing the amount of subjects needing specialty care, thus leaving it to those who require it in reason of refractory condition or presence of comorbidities.

CONCLUSIONS

Recognizing the hallmarks of migraine and the features of single patients enables prescribing specific pharmacological and non-pharmacological treatments. Medical research on headaches today particularly suffers from the syndrome of single-disease approach, but it is important to have a cross-sectional and joint vision with other close specialties, in order to treat our patients with a comprehensive approach that a heterogeneous condition like migraine requires.

Emotions in search of words: Does alexithymia predict treatment outcome in chronic musculoskeletal pain?

Chronic pain, with its complex and multidimensional nature, poses significant challenges in identifying effective long-term treatments. There is growing scientific interest in how psychopathological and personality dimensions may influence the maintenance and development of chronic pain. This longitudinal study aimed to investigate whether alexithymia can predict the improvement of pain severity following a treatment-as-usual programme for chronic musculoskeletal pain over and above psychological cofactors (emotional distress, catastrophizing, and self-efficacy). A consecutive sample of 129 patients with diagnosed chronic musculoskeletal pain referred to two tertiary care centres was recruited and treated for 16 weeks. Clinical pain, psychological distress, self-efficacy, catastrophizing, and alexithymia were assessed with validated self-report measures at the first medical visit (T0) and at 16-week follow-up (T1). Compared with non-responder patients (n = 72, 55.8%), those who responded (i.e., reduction of >30% in pain severity; n = 57, 44.2%) reported an overall improvement in psychological variables except alexithymia. Alexithymia showed relative stability between baseline and follow-up within the entire sample and remained a significant predictor of treatment outcome even when other predictive cofactors (i.e., pain interference, depressive symptoms, and catastrophizing) were considered simultaneously. Our results suggest that identifying patients with a co-occurrence between alexithymia, depressive symptoms, catastrophizing, and the stressful experience of chronic pain can be clinically relevant in pain prevention and intervention programs.

Recent developments and challenges in positron emission tomography imaging of gliosis in chronic neuropathic pain

ABSTRACT

Understanding the mechanisms that underpin the transition from acute to chronic pain is critical for the development of more effective and targeted treatments. There is growing interest in the contribution of glial cells to this process, with cross-sectional preclinical studies demonstrating specific changes in these cell types capturing targeted timepoints from the acute phase and the chronic phase. In vivo longitudinal assessment of the development and evolution of these changes in experimental animals and humans has presented a significant challenge. Recent technological advances in preclinical and clinical positron emission tomography, including the development of specific radiotracers for gliosis, offer great promise for the field. These advances now permit tracking of glial changes over time and provide the ability to relate these changes to pain-relevant symptomology, comorbid psychiatric conditions, and treatment outcomes at both a group and an individual level. In this article, we summarize evidence for gliosis in the transition from acute to chronic pain and provide an overview of the specific radiotracers available to measure this process, highlighting their potential, particularly when combined with ex vivo / in vitro techniques, to understand the pathophysiology of chronic neuropathic pain. These complementary investigations can be used to bridge the existing gap in the field concerning the contribution of gliosis to neuropathic pain and identify potential targets for interventions.

Quantitative sensory testing and chronic pain syndromes: a cross-sectional study from TwinsUK

OBJECTIVE

The chronic pain syndromes (CPS) include syndromes such as chronic widespread pain (CWP), dry eye disease (DED) and irritable bowel syndrome (IBS). Highly prevalent and lacking pathognomonic biomarkers, the CPS are known to cluster in individuals in part due to their genetic overlap, but patient diagnosis can be difficult. The success of quantitative sensory testing (QST) and inflammatory biomarkers as phenotyping tools in conditions such as painful neuropathies warrant their investigation in CPS. We aimed to examine whether individual QST modalities and candidate inflammatory markers were associated with CWP, DED or IBS in a large, highly phenotyped population sample.

DESIGN

Cross-sectional study.

SETTING

Community-dwelling cohort.

PARTICIPANTS

Twins from the TwinsUK cohort PRIMARY AND SECONDARY OUTCOME MEASURES: We compared 10 QST modalities, measured in participants with and without a CWP diagnosis between 2007 and 2012. We investigated whether inflammatory markers measured by Olink were associated with CWP, including interleukin-6 (IL-6), IL-8, IL-10, monocyte chemoattractant protein-1 and tumour necrosis factor. All analyses were repeated in DED and IBS with correction for multiple testing.

RESULTS

In N=3022 twins (95.8% women), no association was identified between individual QST modalities and CPS diagnoses (CWP, DED and IBS). Analyses of candidate inflammatory marker levels and CPS diagnoses in n=1368 twins also failed to meet statistical significance.

CONCLUSION

Our findings in a large population cohort suggest a lack of true association between singular QST modalities or candidate inflammatory markers and CPS.

Lessons learnt in evidence-based perioperative pain medicine: changing the focus from the medication and procedure to the patient

Over time, the focus of evidence-based acute pain medicine has shifted, from a focus on drugs and interventions (characterized by numbers needed to treat), to an appreciation of procedure-specific factors (characterized by guidelines and meta-analyses), and now anesthesiologists face the challenge to integrate our current approach with the concept of precision medicine. Psychometric and biopsychosocial markers can potentially guide clinicians on who may need more aggressive perioperative pain management, or who would respond particularly well to a given analgesic intervention. The challenge will be to identify an easily assessable set of parameters that will guide perioperative physicians in tailoring the analgesic strategy to procedure and patient.

Oxycodone or Higher Dose of Levodopa for the Treatment of Parkinsonian Central Pain: OXYDOPA Trial

BACKGROUND

Among the different types of pain related to Parkinson's disease (PD), parkinsonian central pain (PCP) is the most disabling.

OBJECTIVES

We investigated the analgesic efficacy of two therapeutic strategies (opioid with oxycodone- prolonged-release (PR) and higher dose of levodopa/benserazide) compared with placebo in patients with PCP.

METHODS

OXYDOPA was a randomized, double-blind, double-dummy, placebo-controlled, multicenter parallel-group trial run at 15 centers within the French NS-Park network. PD patients with PCP (≥30 on the Visual Analogue Scale [VAS]) were randomly assigned to receive oxycodone-PR (up to 40 mg/day), levodopa/benserazide (up to 200 mg/day) or matching placebo three times a day (tid) for 8 weeks at a stable dose, in add-on to their current dopaminergic therapy. The primary endpoint was the change in average pain intensity over the previous week rated on VAS from baseline to week-10 based on modified intention-to-treat analyses.

RESULTS

Between May 2016 and August 2020, 66 patients were randomized to oxycodone-PR (n = 23), levodopa/benserazide (n = 20) or placebo (n = 23). The mean change in pain intensity was -17 ± 18.5 on oxycodone-PR, -8.3 ± 11.1 on levodopa/benserazide, and -14.3 ± 18.9 in the placebo groups. The absolute difference versus placebo was -1.54 (97.5% confidence interval [CI], -17.0 to 13.90; P = 0.8) on oxycodone-PR and +7.79 (97.5% CI, -4.99 to 20.58; P = 0.2) on levodopa/benserazide. Similar proportions of patients in each group experienced all-cause adverse events. Those leading to study discontinuation were most frequently observed with oxycodone-PR (39%) than levodopa/benserazide (5%) or placebo (15%).

CONCLUSIONS

The present trial failed to demonstrate the superiority of oxycodone-PR or a higher dose of levodopa in patients with PCP, while oxycodone-PR was poorly tolerated. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Utilization of Blood Flow Restriction Therapy with a Former Triathlete After Total Knee Arthroplasty: A Case Report

Introduction and Purpose

Knee osteoarthritis (OA) is a common condition that limits function and reduces quality of life. Total knee arthroplasty (TKA) is a surgical procedure that replaces the joint surfaces to address anatomical changes due to knee OA. While TKA improves symptoms and function, postoperative impairments are common, including reduced quadriceps strength. Blood flow restriction (BFR) may be a viable option for patients following TKA, as it can improve strength with a minimal amount of joint loading compared to traditional strength training. The purpose of this case report is to describe the impact of BFR use in an individual after TKA, employing pain measurements, quantitative sensory testing, patient-reported outcome measures, physical performance tests, and muscle strength and power testing to explore potential treatment effects and identify potential predictors of response for future studies.

Case Description

A 49-year-old former female triathlete with a history of knee injury and arthroscopic surgery underwent a right TKA and sought physical therapy (PT) due to pain, limited range of motion (ROM), and knee instability during weight bearing activity. PT interventions included manual therapy, gait training, and a home program. Despite participating in supervised PT, she had persistent pain, ROM deficits, and muscle weakness 16 weeks following TKA. BFR was incorporated into her home program, 16-weeks postoperatively. The Short Form McGill Pain Questionnaire-2 (SF-MPQ-2) and Numeric Pain Rating Scale (NPRS) were used to measure pain. Quantitative sensory testing included pressure pain threshold (PPT) and two-point discrimination (TPD) to measure change in sensory perception. Patient-reported outcome measures to assess perceived physical function were the Knee injury and Osteoarthritis Outcome Score (KOOS) and the KOOS- Joint Replacement (KOOS-JR). Physical performance was measured through the 30-second fast walk test (30SFW), timed stair climb test (SCT), 30-second chair standing test (CST), and the timed up and go (TUG). Knee ROM was assessed through standard goniometry. Knee extensor and flexor muscle strength and power were measured with an instrumented dynamometer for isokinetic and isometric testing, generating a limb symmetry index (LSI).

Outcomes

Pain and quantitative sensory testing achieved clinically meaningful improvement suggesting reduced sensitivity during and after BFR utilization. Perceived physical function and symptoms significantly improved, particularly in sports and recreation activities, and were best captured in the KOOS, not the KOOS-JR. Physical performance reached clinically meaningful improvement in walking speed, chair stand repetitions, and timed stair climb tests after BFR. Isokinetic and isometric strength and power in knee extensors and flexors increased significantly after BFR compared to the uninvolved leg as determined by LSI.

Discussion

In this case, BFR appeared to be a safe and well-tolerated intervention. The results suggest potential benefits in terms of increased function, strength, power, and reduced pain in this specific person after TKA. Comprehensive pain and sensory assessments alongside clinical measures may help identify suitable patients for BFR after TKA. The KOOS-Sport & Recreation subscale may be more responsive to monitor functional recovery compared to the KOOS-JR, possibly due to the subject's athletic background.

Level of Evidence

4.

Phenotypic characteristics of patients with chronic widespread pain and fibromyalgia: a cross-sectional cluster analysis

OBJECTIVE

This study aimed to explore whether phenotypic characteristics of patients with chronic widespread pain (CWP) and fibromyalgia (FM) can be aggregated into definable clusters that may help to tailor treatments.

METHOD

Baseline variables (sex, age, education, marital/employment status, pain duration, prior CWP/FM diagnosis, concomitant rheumatic disease, analgesics, tender point count, and disease variables derived from standardized questionnaires) collected from 1099 patients (93.4% females, mean age 44.6 years) with a confirmed CWP or FM diagnosis were evaluated by hierarchical cluster analysis. The number of clusters was based on coefficients in the agglomeration schedule, supported by dendrograms and silhouette plots. Simple and multiple regression analyses using all variables as independent predictors were used to assess the likelihood of cluster assignment, reported as odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

Only one cluster emerged (Cluster 1: 455 patients). Participants in this cluster were characterized as working (OR 66.67, 95% CI 7.14 to 500.00), with a medium-term/higher education (OR 16.80, 95% CI 1.94 to 145.41), married/cohabiting (OR 14.29, 95% CI 1.26 to 166.67), and using mild analgesics (OR 25.64, 95% CI 0.58 to > 999.99). The odds of being an individual in Cluster 1 were lower when having a worse score on the PDQ (score ≥ 18) (OR < 0.001, 95% CI < 0.001 to 0.02).

CONCLUSION

We identified one cluster, where participants were characterized by a potentially favourable clinical profile. More studies are needed to evaluate whether these characteristics could be used to guide the management of patients with CWP and FM.

Differences in the relationship between pain and anxiety in total knee and hip arthroplasty: a longitudinal cross-lagged analysis mediated by depression and pain catastrophizing

Acute postsurgical pain (APSP) is an important risk factor for pain chronification, with reports of being more intense after total knee arthroplasty (TKA) than after total hip arthroplasty (THA). Psychological variables have been associated with differences in postsurgical pain experience. This study aimed to analyse the longitudinal reciprocal association between pain and anxiety levels in patients undergoing TKA or THA, to investigate the moderator role of the type of surgery and to explore psychological mediators in the anxiety - pain association. Patients undergoing TKA (n = 120) or THA (n = 109) were evaluated before surgery and in the acute postsurgical period (48 h postsurgery). Presurgical assessment comprised sociodemographic, pain-related and psychological variables (anxiety, depression, pain catastrophizing, self-efficacy, optimism and satisfaction with life). Postsurgical assessment focused on pain frequency, pain intensity and anxiety. Longitudinal associations were explored using cross-lagged panel models that included the indirect effect paths through possible mediators (pain catastrophizing and depression). Multigroup analyses compared TKA and THA. In the global sample, higher APSP was predicted by higher presurgical pain and worse presurgical anxiety. Multigroup analyses revealed that worse APSP was predicted by higher presurgical anxiety in patients undergoing TKA and by higher presurgical pain in patients undergoing THA. Furthermore, there was a positive significant indirect effect of pain catastrophizing, but not depressive symptoms, in the relationship between presurgical anxiety and APSP in THA. Anxiety and APSP are differently interrelated in TKA and THA. Psychological characteristics could be managed before surgery to favour better APSP control and potentially prevent pain chronification after total joint arthroplasty.

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.

Identifying Weekly Trajectories of Pain Severity Using Daily Data From an mHealth Study: Cluster Analysis

BACKGROUND

People with chronic pain experience variability in their trajectories of pain severity. Previous studies have explored pain trajectories by clustering sparse data; however, to understand daily pain variability, there is a need to identify clusters of weekly trajectories using daily pain data. Between-week variability can be explored by quantifying the week-to-week movement between these clusters. We propose that future work can use clusters of pain severity in a forecasting model for short-term (eg, daily fluctuations) and longer-term (eg, weekly patterns) variability. Specifically, future work can use clusters of weekly trajectories to predict between-cluster movement and within-cluster variability in pain severity.

OBJECTIVE

This study aims to understand clusters of common weekly patterns as a first stage in developing a pain-forecasting model.

METHODS

Data from a population-based mobile health study were used to compile weekly pain trajectories (n=21,919) that were then clustered using a k-medoids algorithm. Sensitivity analyses tested the impact of assumptions related to the ordinal and longitudinal structure of the data. The characteristics of people within clusters were examined, and a transition analysis was conducted to understand the movement of people between consecutive weekly clusters.

RESULTS

Four clusters were identified representing trajectories of no or low pain (1714/21,919, 7.82%), mild pain (8246/21,919, 37.62%), moderate pain (8376/21,919, 38.21%), and severe pain (3583/21,919, 16.35%). Sensitivity analyses confirmed the 4-cluster solution, and the resulting clusters were similar to those in the main analysis, with at least 85% of the trajectories belonging to the same cluster as in the main analysis. Male participants spent longer (participant mean 7.9, 95% bootstrap CI 6%-9.9%) in the no or low pain cluster than female participants (participant mean 6.5, 95% bootstrap CI 5.7%-7.3%). Younger people (aged 17-24 y) spent longer (participant mean 28.3, 95% bootstrap CI 19.3%-38.5%) in the severe pain cluster than older people (aged 65-86 y; participant mean 9.8, 95% bootstrap CI 7.7%-12.3%). People with fibromyalgia (participant mean 31.5, 95% bootstrap CI 28.5%-34.4%) and neuropathic pain (participant mean 31.1, 95% bootstrap CI 27.3%-34.9%) spent longer in the severe pain cluster than those with other conditions, and people with rheumatoid arthritis spent longer (participant mean 7.8, 95% bootstrap CI 6.1%-9.6%) in the no or low pain cluster than those with other conditions. There were 12,267 pairs of consecutive weeks that contributed to the transition analysis. The empirical percentage remaining in the same cluster across consecutive weeks was 65.96% (8091/12,267). When movement between clusters occurred, the highest percentage of movement was to an adjacent cluster.

CONCLUSIONS

The clusters of pain severity identified in this study provide a parsimonious description of the weekly experiences of people with chronic pain. These clusters could be used for future study of between-cluster movement and within-cluster variability to develop accurate and stakeholder-informed pain-forecasting tools.

General and Pain-Associated Psychological Distress Phenotypes Among Patients With Low Back Pain in the Military Health System

OBJECTIVE

The primary objective was to describe rates of general and pain-related psychological distress for individuals with low back pain (LBP) in the Military Health System (MHS). We identified common phenotypes defined by rates of general and pain-related psychological distress and compared phenotypes on their level of pain interference, physical function, anxiety, and depression.

METHODS

We created a cohort from two completed trials assessing nonpharmacological treatment for LBP in the MHS (n = 510 total). The Optimal Screening for Prediction of Referral and Outcome Yellow Flag assessment tool identified the presence of 11 different yellow flags. Latent class analysis (LCA) used yellow flag indicators to identify common psychological phenotypes. We then compared Patient-Reported Outcomes Measurement Information Systems measures of pain interference, physical function, sleep disturbance, depression, and anxiety across phenotypes.

RESULTS

LCA identified five phenotypes (percentage of the sample): low distress (32%), high distress (27%), poor pain coping and low self-efficacy (18%), low self-efficacy and acceptance (14%), and poor pain coping (10%). Highly distressed phenotypes reported higher levels of pain interference, sleep disturbance, depression, and anxiety than those with other phenotypes, whereas the low distress phenotype had significantly lower pain interference and higher physical function scores than those characterized by all other phenotypes.

CONCLUSION

These phenotypes provide opportunities for clinicians and researchers to develop novel LBP treatment pathways tailored to patients with different profiles of psychological distress. Future work is needed to validate their predictive capabilities for clinical outcomes.

CPM-Related Mechanisms Could Play a Key Role in the Effects on Pain Sensitivity Induced by Manual Therapy: Three Crossover Trials Investigating the Effects of Manual Pressure

Objective: The aim of this study is to assess whether pain-inducing manual pressure (PIMP) leads to effects on pressure pain threshold (PPT) mediated by conditioned pain modulation (CPM) and whether these effects are influenced by the intensity and repetition of the stimulus. Additionally, the influence of psychological factors and physical activity on the response to PIMP was explored. Methods: A total of 72 pain-free students were randomly assigned to three crossover trials. Trial 1 compared the effects of PIMP with the cold pressor task and pain-inducing electrostimulation. Trial 2 compared the effects of manual pressure that elicited moderate pain, mild pain, and no pain. Trial 3 compared a single PIMP stimulation with four stimuli applied at the same site or at different sites. Results: PIMP produced a lower increase in PPT than cold pressor task and no difference with electrostimulation. Manual pressure that caused moderate pain led to a greater increase in PPT compared to mild pain and pain-free application. Repetition of PIMP stimulus, whether at the same or different sites, did not significantly increase PPT compared to a single stimulation. No association with psychological factors or physical activity was found. Conclusions: PIMP produces an increase in PPT, suggesting the involvement of CPM-related mechanisms.

Longitudinal multisite study of the chronobiological control of chronic pain: the CircaHealth CircaPain study protocol

INTRODUCTION

One in five Canadians lives with chronic pain. Evidence shows that some individuals experience pain that fluctuates in intensity following a circadian (24-hour) rhythm. Endogenous molecular rhythms regulate the function of physiological processes that govern pain mechanisms. Addressing chronic pain rhythmicity on a molecular and biopsychosocial level can advance understanding of the disease and identify new treatment/management strategies. Our CircaHealth CircaPain study uses an online survey combined with ecological momentary assessments and biosample collection to investigate the circadian control of chronic pain and identify potential biomarkers. Our primary objective is to understand interindividual variability in pain rhythmicity, by collecting biopsychosocial measures. The secondary objective accounts for seasonal variability and the effect of latitude on rhythmicity.

METHODS AND ANALYSIS

Following completion of a baseline questionnaire, participants complete a series of electronic symptom-tracking diaries to rate their pain intensity, negative affect, fatigue and stress on a 0-10 scale at 8:00, 14:00 and 20:00 daily over 10 days. These measures are repeated at 6 and 12 months postenrolment to account for potential seasonal changes. We aim to recruit ≥2500 adults with chronic pain within Canada. Infrastructure is being developed to facilitate the collection of blood samples from subgroups of participants (~800) two times per day over 24-48 hours to identify rhythmic expression of circulating genes and/or proteins.

ETHICS AND DISSEMINATION

Ethical approval for this study was obtained by the Queen's University Health Sciences and Affiliated Teaching Hospitals Research Ethics Board (File No. 6038114). Participants provide informed consent to participate, and their data will not be identifiable in any publication or report. Findings will be published in a relevant scientific journal and disseminated at scientific meetings and online webinars. We maintain a website to post updated resources and engage with the community. We employ knowledge mobilisation in the form of direct data sharing with participants.

Quantitative sensory testing for assessment of somatosensory function in children and adolescents: a scoping review

Quantitative sensory testing (QST) refers to a group of noninvasive psychophysical tests that examine responses to a range of calibrated mechanical and thermal stimuli. Quantitative sensory testing has been used extensively in adult pain research and has more recently been applied to pediatric pain research. The aims of this scoping review were to map the current state of the field, to identify gaps in the literature, and to inform directions for future research. Comprehensive searches were run in 5 databases. Titles, abstracts, and full texts were screened by 2 reviewers. Data related to the study aims were extracted and analyzed descriptively. A total of 16,894 unique studies were identified, of which 505 were screened for eligibility. After a full-text review, 301 studies were retained for analysis. Date of publication ranged from 1966 to 2023. However, the majority of studies (61%) were published within the last decade. Studies included participants across the developmental trajectory (ie, early childhood to adolescence) and most often included a combination of school-age children and adolescents (49%). Approximately 23% of studies were conducted in healthy samples. Most studies (71%) used only one QST modality. Only 14% of studies reported using a standardized QST protocol. Quantitative sensory testing in pediatric populations is an emerging and rapidly growing area of pain research. Future work is needed using comprehensive, standardized QST protocols to harness the full potential that this procedure can offer to our understanding of pediatric pain.

Pressure pain mapping of equine distal joints: feasibility and reliability

Background

Osteoarthritis is a prevalent degenerative joint disease initiating chronic pain and lameness in horses. While several objective gait analysis systems have been developed and validated to quantify lameness severity in horses, methods to evaluate whether peripheral sensitization contributes to the pain experienced are missing.

Objectives

To evaluate whether periarticular pressure pain mapping could be proposed as an auxiliary assessment tool in horses. Specific aims were to evaluate the feasibility and intra- and inter-rater reliability of pressure pain thresholds (PPT) determination at sites overlying the distal thoracic limb joints of clinically healthy horses.

Study design

Prospective, randomized validation study.

Methods

For feasibility assessment, PPT were measured with a hand-held digital algometer at six periarticular landmarks (2 sites per joint, 3 joints) bilaterally on the distal thoracic limb of 40 healthy horses (20 warmblood and 20 Freiberger). The joints tested were the metacarpophalangeal, on the latero-palmar and dorsal aspects (L-MCP and D-MCP), the proximal interphalangeal, on the dorsal and palmar aspect (D-PIP and P-PIP) and the distal interphalangeal, on the dorsal and lateral aspect (D-DIP and L-DIP). A feasibility score, ranging from 0 to 5, was attributed to each testing session. For intra- and inter-rater reliability assessment, L-MCP and D-MCP were selected to be tested again at 2 weeks intervals in 20 out of the 40 horses. Data were analyzed using a mixed-effect linear model to test differences in threshold per site and limb. Intra- and inter-rater correlation was calculated. Bland-Altman plots were performed to evaluate the variability of the measures.

Results

The procedure was considered feasible (score <2) in 95% of horses (95% CI 88%-100%). Overall, median [interquartile range (IQR)] PPT was 9.4 (7.5-11.3) N. No significant side differences were found. P-PIP and D-DIP recorded significantly lower PPT (p < 0.001 and p = 0.002, respectively) than L-MCP. Median (IQR) were 9.9 (7.3-12.4) N, 8.4 (6.1-10.5) N and 9.0 (7.4-10.6) N for L-MCP, P-PIP and D-DIP, respectively. The intra-rater agreement was 0.68 (95% CI 0.35-0.86) for L-MCP, and 0.50 (95% CI 0.08-0.76) for D-MCP. Inter-rater agreement was 0.85 (95% CI 0.66-0.94) for L-MCP and 0.81 (0.57, 0.92) for D-MCP.

Main limitations

Evaluation of feasibility was performed only for distal thoracic limbs joints; no data are provided for hind limbs or proximal joints. Only warmblood and Freiberger horses were included. Intra- and inter-rater reliability assessments were performed exclusively on data collected at the MCP joint.

Conclusion

Pressure pain mapping of distal thoracic limb joints was feasible in horses. Local sensitivity differed among sites and no side differences were noticed. Data collected from the MCP joint suggest highly variable, subject dependent intra-rater reliability, ranging from poor to good, and good to excellent inter-rater reliability. Further studies evaluating pathologic vs. healthy joints are needed before recommendations can be made about clinical usability and diagnostic validity.

Cognitive flexibility training for chronic pain: a randomized clinical study

Introduction

Previous studies suggest an association between cognitive flexibility and development of chronic pain after surgery. It is not known whether cognitive flexibility can be improved in patients with chronic pain.

Objectives

This study tested whether a neurocognitive training program results in improved cognitive flexibility and pain in patients with chronic pain.

Methods

We conducted a single-center, prospective, randomized study investigating 5-week daily neurocognitive training in patients with chronic pain. Participants (n = 145) were randomized into neurocognitive training or care as usual, and they completed assessments at baseline, posttreatment, and 3 months. The treatment group was asked to spend 35 minutes daily completing a program with tasks on cognitive flexibility, memory, attention, and speed. The primary outcome was performance on the neurocognitive performance test (NCPT). Secondary outcomes included levels of pain interference and severity.

Results

At 5 weeks, the treatment group showed greater improvements on NCPT compared with the control group (d = 0.37); effect size was smaller at 3 months (d = 0.18). The treatment group reported lower pain severity at 5 weeks (d = 0.16) and 3 months (d = 0.39) than the control group, but pain interference was only lower at 3 months (d = 0.20).

Conclusions

Outcomes suggest that using neurocognitive training to modify cognitive flexibility in patients with chronic pain may improve pain severity. This study provided effect size estimates to inform sample size calculations for randomized controlled trials to test the effectiveness of neurocognitive interventions for the prevention and treatment of chronic pain.

Profiling migraine patients according to clinical and psychophysical characteristics: clinical validity of distinct migraine clusters

AIMS

Investigate if different clinical and psychophysical bedside tools can differentiate between district migraine phenotypes in ictal/perictal (cohort 1) and interictal (cohort 2) phases.

METHOD

This observational study included two independent samples in which patients were subgrouped into distinct clusters using standardized bedside assessment tools (headache frequency, disability, cervical active range of motion, pressure pain threshold in different areas): (A) cohort 1-ictal/perictal migraine patients were subgrouped, based on previous studies, into two clusters, i.e., Cluster-1.1 No Psychophysical Impairments (NPI) and Cluster-1.2 Increased Pain Sensitivity and Cervical Musculoskeletal Dysfunction (IPS-CMD); (B) cohort 2-interictal migraine patients were subgrouped into three clusters, i.e., Cluster-2.1 NPI, Cluster-2.2 IPS, and Cluster-2.3 IPS-CMD. Clinical characteristics (multiple questionnaires), somatosensory function (comprehensive quantitative sensory testing (QST)), and cervical musculoskeletal impairments (cervical musculoskeletal assessment) were assessed and compared across headache clusters and a group of 56 healthy controls matched for sex and age.

RESULTS

Cohort 1: A total of 156 subjects were included. Cluster-1.2 (IPS-CMD) had higher headache intensity (p = 0.048), worse headache-related (p = 0.003) and neck-related disability (p = 0.005), worse quality of life (p = 0.003), and higher symptoms related to sensitization (p = 0.001) and psychological burden (p = 0.005) vs. Cluster-1.1(NPI). Furthermore, Cluster-1.2 (IPS-CMD) had (1) reduced cervical active and passive range of motion (p < 0.023), reduced functionality of deep cervical flexors (p < 0.001), and reduced values in all QST(p < 0.001) vs. controls, and (2) reduced active mobility in flexion, left/right lateral flexion (p < 0.045), and reduced values in QST (p < 0.001) vs. Cluster-1.1 (NPI). Cohort 2: A total of 154 subjects were included. Cluster-2.3 (IPS-CMD) had (1) longer disease duration (p = 0.006), higher headache frequency (p = 0.006), disability (p < 0.001), and psychological burden (p = 0.027) vs. Cluster-2.2 (IPS) and (2) higher headache-related disability (p = 0.010), neck-related disability (p = 0.009), and higher symptoms of sensitization (p = 0.018) vs. Cluster-2.1 (NPI). Cluster-2.3(IPS-CMD) had reduced cervical active and passive range of motion (p < 0.034), and reduced functionality of deep cervical flexors (p < 0.001), vs. controls, Custer-2.1 (NPI), and Cluster-2.2 (IPS). Cluster-2.2 (IPS) and 2.3 (IPS-CMD) had reduced QST values vs. controls (p < 0.001) and Cluster-2.1 (p < 0.039).

CONCLUSION

A battery of patient-related outcome measures (PROMs) and quantitative bedside tools can separate migraine clusters with different clinical characteristics, somatosensory functions, and cervical musculoskeletal impairments. This confirms the existence of distinct migraine phenotypes and emphasizes the importance of migraine phases of which the characteristics are assessed. This may have implications for responders and non-responders to anti-migraine medications.

The Difficulties of Managing Pain in People Living with Frailty: The Potential for Digital Phenotyping

Pain and frailty are closely linked. Chronic pain is a risk factor for frailty, and frailty is a risk factor for pain. People living with frailty also commonly have cognitive impairment, which can make assessment of pain and monitoring of pain management even more difficult. Pain may be sub-optimally treated in people living with frailty, people living with cognitive impairment and those with both these factors. Reasons for sub-optimal treatment in these groups are pharmacological (increased drug side effects, drug-drug interactions, polypharmacy), non-pharmacological (erroneous beliefs about pain, ageism, bidirectional communication challenges), logistical (difficulty in accessing primary care practitioners and unaffordable cost of drugs), and, particularly in cognitive impairment, related to communication difficulties. Thorough assessment and characterisation of pain, related sensations, and their functional, emotional, and behavioural consequences ("phenotyping") may help to enhance the assessment of pain, particularly in people with frailty and cognitive impairment, as this may help to identify who is most likely to respond to certain types of treatment. This paper discusses the potential role of "digital phenotyping" in the assessment and management of pain in people with frailty. Digital phenotyping is concerned with observable characteristics in digital form, such as those obtained from sensing-capable devices, and may provide novel and more informative data than existing clinical approaches regarding how pain manifests and how treatment strategies affect it. The processing of extensive digital and usual data may require powerful algorithms, but processing these data could lead to a better understanding of who is most likely to benefit from specific and targeted treatments.

Association between chronic pain classes and cognitive function in older adults: A cross-sectional study based on latent class analysis

The purpose of this study was to identify latent classes of chronic pain in older adults based on perceptual, cognitive, behavioral, emotional and social factors, and to explore the associations between each class of chronic pain and different cognitive domains. A total of 629 participants were included. Three classes of chronic pain were identified: "episodic recurrent mild pain with good psychosocial state" (class 1), "episodic recurrent moderate pain with general psychosocial state" (class 2) and "continuous multilocational severe pain with attacks accompanied by poor psychosocial state and avoidance of activity" (class 3). After adjusting for relevant confounders, chronic pain presenting as class 1 was associated with worse memory; class 2 was associated with worse global cognitive function, memory, information processing speed, and executive function; and class 3 was additionally associated with worse attention compared to class 2. The findings contribute to the development of targeted programs for treating pain and improving cognitive functioning.

Pain-phenotyping in osteoarthritis: Current concepts, evidence, and considerations towards a comprehensive framework for assessment and treatment

Objectives

Pain as central symptom of osteoarthritis (OA) needs to be addressed as part of successful treatment. The assessment of pain as feature of disease or outcome in clinical practice and drug development remains a challenge due to its multidimensionality and the plethora of confounders. This article aims at providing insights into our understanding of OA pain-phenotypes and suggests a framework for systematic and comprehensive assessments.

Methods

This narrative review is based on a search of current literature for various combinations of the search terms "pain-phenotype" and "knee OA" and summarizes current knowledge on OA pain-phenotypes, putting OA pain and its assessment into perspective of current research efforts.

Results

Pain is a complex phenomenon, not necessarily associated with tissue damage. Various pain-phenotypes have been described in knee OA. Among those, a phenotype with high pain levels not necessarily matching structural changes and a phenotype with low pain levels and impact are relatively consistent. Further subgroups can be differentiated based on patient reported outcome measures, assessments of comorbidities, anxiety and depression, sleep, activity and objective measures such as quantitative sensory testing.

Conclusions

The complexity of both OA as disease and pain in OA prompt the definition of a set of variables that facilitate assessments comparable across studies to maximize our understanding of pain, as central concern for the patient.

Prediction of duloxetine efficacy in addition to self-management in painful temporomandibular disorders: A randomised, placebo-controlled clinical trial

BACKGROUND

Conditioned pain modulation (CPM) is a potential predictor of treatment response that has not been studied in temporomandibular disorders (TMD).

OBJECTIVES

We conducted a randomised, double-blind, placebo-controlled trial (RCT) of duloxetine in addition to self-management (SM) strategies to investigate its efficacy to reduce pain intensity in painful TMD patients. Moreover, we investigated whether baseline CPM would predict the duloxetine efficacy to reduce TMD pain intensity.

METHODS

Eighty participants were randomised to duloxetine 60 mg or placebo for 12 weeks. The primary outcomes were the change in the pain intensity from baseline to week-12 and CPM-sequential paradigm at baseline. Safety, physical and emotional functioning outcomes were also evaluated.

RESULTS

Of 80 participants randomised, 78 were included in intention-to-treat analysis. Pain intensity decreased for SM-duloxetine and SM-placebo but did not differ between groups (p = .82). A more efficient CPM was associated with a greater pain intensity reduction regardless of the treatment group (p = .035). Physical and emotional functioning did not differ between groups, but adverse events (p = .014), sleep impairment (p = .003) and catastrophizing symptoms (p = .001) were more prevalent in SM-duloxetine group.

CONCLUSION

This study failed to provide evidence of a beneficial effect of adding duloxetine to SM strategies for treatment of painful TMD. Nonetheless, this RCT has shown the feasibility of applying pain modulation assessment to predict short-term treatment response in painful TMD patients, which confirms previous finds that CPM evaluation may serve a step forward in individualising pain treatment.

Rotation-traction manipulation induced intradiskal pressure changes in cervical spine-an in vitro study

Objective: Evaluate the effect of rotation-traction manipulation on intradiskal pressure in human cervical spine specimen with different force and duration parameters, and compare the intradiskal pressure changes between rotation-traction manipulation and traction. Methods: Seven human cervical spine specimens were included in this study. The intradiskal pressure was measured by miniature pressure sensor implanting in the nucleus pulposus. rotation-traction manipulation and cervical spine traction were simulated using the MTS biomechanical machine. Varied thrust forces (50N, 150N, and 250N) and durations (0.05 s, 0.1 s, and 0.15 s) were applied during rotation-traction manipulation with Intradiscal pressure recorded in the neutral position, rotation-anteflexion position, preloading, and thrusting phases. Futuremore, we documented changes in intradiscal pressure during cervical spine traction with different loading forces (50N, 150N, and 250N). And a comparative analysis was performed to discern the impact on intradiscal pressure between manipulation and traction. Results: Manipulation application induced a significant reduction in intradiscal pressure during preloading and thrusting phases for each cervical intervertebral disc (p < 0.05). When adjusting thrust parameters, a discernible decrease in intradiscal pressure was observed with increasing thrust force, and the variations between different thrust forces were statistically significant (p < 0.05). Conversely, changes in duration did not yield a significant impact on intradiscal pressure (p > 0.05). Additionally, after traction with varying loading forces (50N, 150N, 250N), a noteworthy decrease in intradiscal pressure was observed (p < 0.05). And a comparative analysis revealed that rotation-traction manipulation more markedly reduced intradiscal pressure compared to traction alone (p < 0.05). Conclusion: Both rotation-traction manipulation and cervical spine traction can reduce intradiscal pressure, exhibiting a positive correlation with force. Notably, manipulation elicits more pronounced and immediate decompression effect, contributing a potential biomechanical rationale for its therapeutic efficacy.

An international consensus on gaps in mechanisms of forced-based manipulation research: findings from a nominal group technique

Force-Based Manipulation (FBM) including light touch, pressure, massage, mobilization, thrust manipulation, and needling techniques are utilized across several disciplines to provide clinical analgesia. These commonly used techniques demonstrate the ability to improve pain-related outcomes; however, mechanisms behind why analgesia occurs with these hands-on interventions has been understudied. Neurological, neuroimmune, biomechanical, neurovascular, neurotransmitter, and contextual factor interactions have been proposed to influence response; however, the specific relationships to clinical pain outcomes has not been well established. The purpose of this study was to identify gaps present within mechanism-based research as it relates to FBM. An international multidisciplinary nominal group technique (NGT) was performed and identified 37 proposed gaps across eight domains. Twenty-three of these gaps met consensus across domains supporting the complex multisystem mechanistic response to FBM. The strength of support for gaps within the biomechanical domain had less overall support than the others. Gaps assessing the influence of contextual factors had strong support as did those associating mechanisms with clinical outcomes (translational studies). The importance of literature investigating how FBM differs with individuals of different pain phenotypes (pain mechanism phenotypes and clinical phenotypes) was also presented aligning with other analgesic techniques trending toward patient-specific pain management (precision medicine) through the use of pain phenotyping.

Self-regulation training for people with knee osteoarthritis: a protocol for a feasibility randomised control trial (MiNT trial)

Introduction

Knee osteoarthritis (OA) is a chronic secondary musculoskeletal pain condition resulting in disability, reduced quality of life, and high societal costs. Pain associated with knee OA is linked to increased sensitivity in sensory, cognitive, and emotional areas of the brain. Self-regulation training targeting brain functioning related to pain experience could reduce pain and its associated disability. Self-regulatory treatments such as mindfulness meditation (MM) and electroencephalography neurofeedback (EEG-NF) training improve clinical outcomes in people with knee OA. A feasibility clinical trial can address factors that could inform the design of the full trial investigating the effectiveness of self-regulation training programmes in people with knee OA. This clinical trial will evaluate the feasibility, safety, acceptability, experience and perceptions of the self-regulatory training programmes.

Methods

The proposed feasibility trial is based on a double-blind (outcome assessor and investigators), three-arm (MM usual care, EEG-NF + usual care and usual care control group) randomised controlled parallel clinical trial. Participants with knee OA will be recruited from the community and healthcare practices. A research assistant (RA) will administer both interventions (20-min sessions, four sessions each week, and 12 sessions over three successive weeks). Feasibility measures (participant recruitment rate, adherence to interventions, retention rate), safety, and acceptability of interventions will be recorded. An RA blinded to the group allocation will record secondary outcomes at baseline, immediately post-intervention (4th week), and 3 months post-intervention. The quantitative outcome measures will be descriptively summarised. The qualitative interviews will evaluate the participants' experiences and perceptions regarding various aspects of the trial, which includes identifying the barriers and facilitators in participating in the trial, evaluating their opinions on the research procedures, such as their preferences for the study site, and determining the level of acceptability of the interventions as potential clinical treatments for managing knee OA. Māori participant perceptions of how assessment and training practices could be acceptable to a Māori worldview will be explored. The interviews will be audio-recorded and analysed thematically.

Discussion

This trial will provide evidence on the feasibility, safety, and acceptability of the MM and EEG-NF training in people with knee OA, thus informing the design of a full randomised clinical control trial.

A Randomized Controlled Neuroimaging Trial of Cognitive Behavioral Therapy for Fibromyalgia Pain

OBJECTIVE

Fibromyalgia (FM) is characterized by pervasive pain-related symptomatology and high levels of negative affect. Mind-body treatments such as cognitive behavioral therapy (CBT) appear to foster improvement in FM via reductions in pain-related catastrophizing, a set of negative, pain-amplifying cognitive and emotional processes. However, the neural underpinnings of CBT's catastrophizing-reducing effects remain uncertain. This randomized controlled mechanistic trial was designed to assess CBT's effects on pain catastrophizing and its underlying brain circuitry.

METHODS

Of 114 enrolled participants, 98 underwent a baseline neuroimaging assessment and were randomized to 8 weeks of individual CBT or a matched FM education control (EDU) condition.

RESULTS

Compared with EDU, CBT produced larger decreases in pain catastrophizing post treatment (P < 0.05) and larger reductions in pain interference and symptom impact. Decreases in pain catastrophizing played a significant role in mediating those functional improvements in the CBT group. At baseline, brain functional connectivity between the ventral posterior cingulate cortex (vPCC), a key node of the default mode network (DMN), and somatomotor and salience network regions was increased during catastrophizing thoughts. Following CBT, vPCC connectivity to somatomotor and salience network areas was reduced.

CONCLUSION

Our results suggest clinically important and CBT-specific associations between somatosensory/motor- and salience-processing brain regions and the DMN in chronic pain. These patterns of connectivity may contribute to individual differences (and treatment-related changes) in somatic self-awareness. CBT appears to provide clinical benefits at least partially by reducing pain-related catastrophizing and producing adaptive alterations in DMN functional connectivity.

Conditioned Pain Modulation Does Not Differ Between People With Lower-Limb Tendinopathy and Nontendinopathy Controls: A Systematic Review With Individual Participant Data Meta-analysis

OBJECTIVE: To explore whether people with lower-limb tendinopathy have reduced relative conditioned pain modulation (CPM) when compared to nontendinopathy controls. DESIGN: Systematic review with individual participant data (IPD) meta-analysis. LITERATURE SEARCH: Eight databases were searched until August 29, 2022. STUDY SELECTION CRITERIA: Cross-sectional studies comparing the magnitude of the CPM effect in people with lower-limb tendinopathy to nontendinopathy controls in a case-control design. DATA SYNTHESIS: Included studies provided IPD, which was reported using descriptive statistics. Generalized estimating equations (GEEs) determined between-group differences in the relative CPM effect, when adjusting for co-variables. Study quality was assessed using a Joanna Briggs Institute checklist, and certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluations. RESULTS: Five records were included, IPD were provided for 4 studies (n = 219 with tendinopathy, n = 226 controls). The principal GEE (model 1) found no significant relative CPM effects for tendinopathy versus controls (B = -1.73, P = .481). Sex (B = 4.11, P = .160), age (B = -0.20, P = .109), and body mass index (B = 0.28, P = .442) did not influence relative CPM effect. The Achilles region had a reduced CPM effect (B = -22.01, P = .009). In model 2 (adjusting for temperature), temperature (B = -2.86, P = .035) and female sex (B = 21.01, P = .047) were associated with the size of the relative CPM effect. All studies were low-quality, and the certainty of the evidence was moderate. CONCLUSION: There were no between-group differences in the magnitude of the CPM effect, suggesting clinicians should manage lower-limb tendinopathy using interventions appropriate for peripherally dominant pain (eg, tendon loading exercises such as heavy slow resistance). Based on the "moderate"-certainty evidence, future studies are unlikely to substantially change these findings. J Orthop Sports Phys Ther 2023;54(1):1-10. Epub 19 October 2023. doi:10.2519/jospt.2023.11940.

Reproducible and fully automated testing of nocifensive behavior in mice

Pain in rodents is often inferred from their withdrawal from noxious stimulation. Threshold stimulus intensity or response latency is used to quantify pain sensitivity. This usually involves applying stimuli by hand and measuring responses by eye, which limits reproducibility and throughput. We describe a device that standardizes and automates pain testing by providing computer-controlled aiming, stimulation, and response measurement. Optogenetic and thermal stimuli are applied using blue and infrared light, respectively. Precise mechanical stimulation is also demonstrated. Reflectance of red light is used to measure paw withdrawal with millisecond precision. We show that consistent stimulus delivery is crucial for resolving stimulus-dependent variations in withdrawal and for testing with sustained stimuli. Moreover, substage video reveals "spontaneous" behaviors for consideration alongside withdrawal metrics to better assess the pain experience. The entire process was automated using machine learning. RAMalgo (reproducible automated multimodal algometry) improves the standardization, comprehensiveness, and throughput of preclinical pain testing.

Sensory phenotypes in complex regional pain syndrome and chronic low back pain-indication of common underlying pathomechanisms

Introduction

First-line pain treatment is unsatisfactory in more than 50% of chronic pain patients, likely because of the heterogeneity of mechanisms underlying pain chronification.

Objectives

This cross-sectional study aimed to better understand pathomechanisms across different chronic pain cohorts, regardless of their diagnoses, by identifying distinct sensory phenotypes through a cluster analysis.

Methods

We recruited 81 chronic pain patients and 63 age-matched and sex-matched healthy controls (HC). Two distinct chronic pain cohorts were recruited, ie, complex regional pain syndrome (N = 20) and low back pain (N = 61). Quantitative sensory testing (QST) was performed in the most painful body area to investigate somatosensory changes related to clinical pain. Furthermore, QST was conducted in a pain-free area to identify remote sensory alterations, indicating more widespread changes in somatosensory processing.

Results

Two clusters were identified based on the QST measures in the painful area, which did not represent the 2 distinct pain diagnoses but contained patients from both cohorts. Cluster 1 showed increased pain sensitivities in the painful and control area, indicating central sensitization as a potential pathomechanism. Cluster 2 showed a similar sensory profile as HC in both tested areas. Hence, either QST was not sensitive enough and more objective measures are needed to detect sensitization within the nociceptive neuraxis or cluster 2 may not have pain primarily because of sensitization, but other factors such as psychosocial ones are involved.

Conclusion

These findings support the notion of shared pathomechanisms irrespective of the pain diagnosis. Conversely, different mechanisms might contribute to the pain of patients with the same diagnosis.

The Natural History of Knee Osteoarthritis Pain Experience and Risk Profiles

The study aimed to characterize the natural history of the pain experience, concurrently considering intermittent and constant pain over 4 years, and determine baseline factors associated with unfavorable trajectories in individuals with chronic knee pain. The Osteoarthritis Initiative (OAI) is a prospective, observational study of people with or at higher risk for knee osteoarthritis. The Intermittent and Constant Osteoarthritis Pain (ICOAP) was assessed annually at 48-to-96-month OAI visits. Twenty-eight baseline sociodemographic, knee-specific, and health-related characteristics were assessed. Group-based dual-trajectory modeling identified pain experience patterns indicated by ICOAP intermittent and constant pain scores over 4 years. Multivariable multinomial logistic regression models determined baseline factors associated with membership in each dual-trajectory group. Four longitudinal pain experience patterns were identified (n = 3,584, mean age = 64.8 [standard deviation 9.0] years, BMI = 28.6 [5.0] kg/m2; 57.9% women). Group 1 (37.7%) had minimal intermittent and no constant pain; Group 2 (35.1%) had mild intermittent and no constant pain; Group 3 (18.5%) had mild intermittent and low-grade constant pain; and Group 4 (8.7%) had moderate intermittent and constant pain. Baseline widespread pain, knee stiffness, back pain, hip pain, ankle pain, obesity, depressive symptoms, more advanced radiographic disease, and analgesic use were each associated with an increased risk of membership in less favorable Groups 2, 3, and 4. These distinct courses of pain experience may be driven by different underlying pain mechanisms. The benchmarked ICOAP scores could be used to stratify patients and tailor management. Addressing and preventing the development of modifiable risks (eg, widespread pain and knee joint stiffness) may reduce the chance of belonging to unfavorable dual-trajectory groups. PERSPECTIVE: Concurrently tracking intermittent versus constant pain experience, group-based dual-trajectory modeling identified 4 distinct pain experience patterns over 4 years. The benchmarked ICOAP scores in these dual trajectories could aid in stratifying patients for tailored management strategies and intensity of care.

Comparison of Joint Mobilization and Movement Pattern Training for Patients With Hip-Related Groin Pain: A Pilot Randomized Clinical Trial

OBJECTIVE

The objective of this study was to assess the feasibility of completing a randomized clinical trial (RCT) and examine the preliminary effects of 2 interventions for hip-related groin pain (HRGP).

METHODS

In this pilot RCT, patients with HRGP, who were 18 to 40 years old, were randomized (1:1 ratio) to a joint mobilization (JtMob) group or a movement pattern training (MoveTrain) group. Both treatments included 10 supervised sessions and a home exercise program. The goal of JtMob was to reduce pain and improve mobility through peripherally and centrally mediated pain mechanisms. The key element was physical therapist-provided JtMob. The goal of MoveTrain was to reduce hip joint stresses by optimizing the biomechanics of patient-specific tasks. The key element was task-specific instruction to correct abnormal movement patterns displayed during tasks. Primary outcomes were related to future trial feasibility. The primary effectiveness outcome was the Hip Disability and Osteoarthritis Outcome Score. Examiners were blinded to group; patients and treatment providers were not. Data collected at baseline and immediately after treatment were analyzed with analysis of covariance using a generalized linear model in which change was the dependent variable and baseline was the covariate. The study was modified due to the coronavirus disease 2019 (COVID-19) pandemic.

RESULTS

The COVID-19 pandemic affected participation; 127 patients were screened, 33 were randomized (18 to the JtMob group and 15 to the MoveTrain group), and 29 (88%) provided posttreatment data. Treatment session adherence was 85%, and home exercise program component adherence ranged from 71 to 86%. Both groups demonstrated significant mean within-group improvements of ≥5 points on Hip Disability and Osteoarthritis Outcome Score scales. There were no between-group differences in effectiveness outcomes.

CONCLUSIONS

A large RCT to assess the effects of JtMob and MoveTrain for patients with HRGP may be feasible. Preliminary findings suggested that JtMob or MoveTrain may result in improvements in patient-reported pain and activity limitations.

IMPACT

The COVID-19 pandemic interfered with participation, but a randomized controlled trial may be feasible. Modification may be needed if the trial is completed during future pandemics.

Identifying chronic low back pain phenotypic domains and characteristics accounting for individual variation: a systematic review

ABSTRACT

Interpatient variability is frequently observed among individuals with chronic low back pain (cLBP). This review aimed at identifying phenotypic domains and characteristics that account for interpatient variability in cLBP. We searched MEDLINE ALL (through Ovid), Embase Classic and EMBASE (through Ovid), Scopus, and CINAHL Complete (through EBSCOhost) databases. Studies that aimed to identify or predict cLBP different phenotypes were included. We excluded studies that focused on specific treatments. The methodological quality was assessed using an adaptation of the Downs and Black tool. Forty-three studies were included. Although the patient and pain-related characteristics used to identify phenotypes varied considerably across studies, the following were among the most identified phenotypic domains and characteristics that account for interpatient variability in cLBP: pain-related characteristics (including location, severity, qualities, and duration) and pain impact (including disability, sleep, and fatigue), psychological domains (including anxiety and depression), behavioral domains (including coping, somatization, fear avoidance, and catastrophizing), social domains (including employment and social support), and sensory profiling (including pain sensitivity and sensitization). Despite these findings, our review showed that the evidence on pain phenotyping still requires further investigation. The assessment of the methodological quality revealed several limitations. We recommend adopting a standard methodology to enhance the generalizability of the results and the implementation of a comprehensive and feasible assessment framework to facilitate personalized treatments in clinical settings.