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

A new way of thinking about pains

ABSTRACT

The traditional construct of acute pain vs chronic pain is arbitrary and obscures fundamental differences in clinical pain phenomena. A more powerful dichotomy between peripherally generated pain and centrally maintained pains can facilitate advances in both pain research and clinical care. We should abandon the temporally based pain classification scheme because it does not accurately reflect the underlying principles inherent in the phenomena of pain.

Occupational cold exposure is associated with neck pain, low back pain, and lumbar radiculopathy

Ambient cold exposure can pose health risks, and this study was aimed at investigating associations with musculoskeletal disorders. A postal survey was performed on 12,627 men and women, ages 18-70 years, living in northern Sweden. Statistical associations were determined using multiple logistic regression. The study sample consisted of 6,886 women (54.5%), and 5,741 men. Reporting high occupational ambient cold exposure was statistically significantly associated with neck pain (OR 1.36; 95% CI 1.16-1.59), low back pain (OR 1.38; 95% CI 1.17-1.63), and lumbar radiculopathy (OR 1.36; 95% CI 1.07-1.73), after adjusting for age, gender, body mass index, physical work load, daily smoking, and stress. We conclude that ambient cold exposure during work was an independent predictor of neck pain, low back pain, and lumbar radiculopathy. In occupational health care settings, cold exposure should be recognised as a possible risk factor for musculoskeletal disorders. Practitioner summary: This cross-sectional, survey-based study investigated associations between self-reported occupational ambient cold exposure and musculoskeletal disorders. It showed significant associations between high cold exposure and neck pain, low back pain and lumbar radiculopathy. In occupational health care settings, cold exposure should be recognised as a possible risk factor for musculoskeletal disorders.

Features and methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system: a Delphi expert consensus study

ABSTRACT

Classification of musculoskeletal pain based on underlying pain mechanisms (nociceptive, neuropathic, and nociplastic pain) is challenging. In the absence of a gold standard, verification of features that could aid in discrimination between these mechanisms in clinical practice and research depends on expert consensus. This Delphi expert consensus study aimed to: (1) identify features and assessment findings that are unique to a pain mechanism category or shared between no more than 2 categories and (2) develop a ranked list of candidate features that could potentially discriminate between pain mechanisms. A group of international experts were recruited based on their expertise in the field of pain. The Delphi process involved 2 rounds: round 1 assessed expert opinion on features that are unique to a pain mechanism category or shared between 2 (based on a 40% agreement threshold); and round 2 reviewed features that failed to reach consensus, evaluated additional features, and considered wording changes. Forty-nine international experts representing a wide range of disciplines participated. Consensus was reached for 196 of 292 features presented to the panel (clinical examination-134 features, quantitative sensory testing-34, imaging and diagnostic testing-14, and pain-type questionnaires-14). From the 196 features, consensus was reached for 76 features as unique to nociceptive (17), neuropathic (37), or nociplastic (22) pain mechanisms and 120 features as shared between pairs of pain mechanism categories (78 for neuropathic and nociplastic pain). This consensus study generated a list of potential candidate features that are likely to aid in discrimination between types of musculoskeletal pain.

Pain Extent Is Not Associated with Sensory-Associated Symptoms, Cognitive or Psychological Variables in COVID-19 Survivors Suffering from Post-COVID Pain

We aimed to investigate the relationship between pain extent, as a sign of sensitization, and sensory-related, cognitive and psychological variables in hospitalized COVID-19 survivors with post-COVID pain. One hundred and forty-six (67 males, 79 females) previously hospitalized COVID-19 survivors with post-COVID pain completed demographic (age, sex, height, weight), sensory-related (Central Sensitization Inventory, Self-Report Leeds Assessment of Neuropathic Symptoms), cognitive (Pain Catastrophizing Scale, Tampa Scale for Kinesiophobia) and psychological (Hospital Anxiety and Depression Scale, Pittsburgh Sleep Quality Index) variables. Pain extent and frequency maps were calculated from pain drawings using customized software. After conducting a correlation analysis to determine the relationships between variables, a stepwise linear regression model was performed to identify pain extent predictors, if available. Pain extent was significantly and weakly associated with pain intensity (r = -0.201, p = 0.014): the larger the pain extent, the lower the pain intensity. No other significant association was observed between pain extent and sensory-related, cognitive, or psychological variables in individuals with post-COVID pain. Females had higher pain intensity, more sensitization-associated symptoms, higher anxiety, lower sleep quality, and higher kinesiophobia levels than males. Sex differences correlation analyses revealed that pain extent was associated with pain intensity in males, but not in females. Pain extent was not associated with any of the measured variables and was also not related to the presence of sensitization-associated symptoms in our sample of COVID-19 survivors with long-term post-COVID pain.

The Self-Reported Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) and PainDETECT Questionnaires in COVID-19 Survivors with Post-COVID Pain

This study aimed to analyze correlations between Self-Report Leeds Assessment of Neuropathic Symptoms (S-LANSS) and PainDETECT with proxies of sensitization, pain-related, or psychological/cognitive variables in coronavirus disease, 2019 (COVID-19) survivors exhibiting post-COVID pain. Demographic, clinical, psychological, cognitive, sensitization-associated symptoms, and health-related quality of life were collected in 146 survivors with post-COVID pain. The PainDETECT and S-LANSS questionnaires were used for assessing neuropathic pain-related symptoms. Patients were assessed with a mean of 18.8 (SD 1.8) months after hospitalization. Both questionnaires were positively associated with pain intensity (p < 0.05), anxiety (PainDETECT p < 0.05; S-LANSS p < 0.01), sensitization-associated symptoms (p < 0.01), catastrophism (p < 0.01), and kinesiophobia (p < 0.01) and negatively associated with quality of life (PainDETECT p < 0.05; S-LANSS p < 0.01). Depressive levels were associated with S-LANSS (p < 0.05) but not with PainDETECT. The stepwise regression analyses revealed that 47.2% of S-LANSS was explained by PainDETECT (44.6%), post-COVID pain symptoms duration (1.7%), and weight (1.1%), whereas 51.2% of PainDETECT was explained by S-LANSS (44.6%), sensitization-associated symptoms (5.4%), and anxiety levels (1.2%). A good convergent association between S-LANSS and PainDETECT was found. Additionally, S-LANSS was associated with symptom duration and weight whereas PainDETECT was associated with sensitization-associated symptoms and anxiety levels, suggesting that the two questionnaires evaluate different aspects of the neuropathic pain spectrum in post-COVID pain patients.

Understanding Sensitization, Cognitive and Neuropathic Associated Mechanisms behind Post-COVID Pain: A Network Analysis

This study aimed to describe a network including demographic, sensory-related, psychological/cognitive and other variables in individuals with post-COVID pain after hospitalization. Demographic (i.e., age, height, weight, months with symptoms), sensory-related (Central Sensitization Inventory -CSI-, Self-Report Leeds Assessment of Neuropathic Symptoms -S-LANSS-, PainDETECT), psychological/cognitive (Hospital Anxiety and Depression Scale -HADS-A/HADS-D-, Pain Catastrophizing Scale -PCS-, Tampa Scale for Kinesiophobia -TSK-11-) and other (sleep quality and health-related quality of life -EQ/5D/5L) variables were collected in 146 COVID-19 survivors with post-COVID pain. A network analysis was conducted to quantify the adjusted correlations between the modelled variables, and to assess their centrality indices (i.e., the connectivity with other symptoms in the network and the importance in the system modelled as network). The network revealed associations between sensory-related and psychological/cognitive variables. PainDETECT was associated with S-LANSS (ρ: 0.388) and CSI (ρ: 0.207). Further, CSI was associated with HADS-A (ρ: 0.269), TSK-11 (ρ: 0.165) and female gender (ρ: 0.413). As expected, HADS-A was associated with HADS-D (ρ: 0.598) and TSK-11 with PCS (ρ: 0.405). The only negative association was between sleep quality and EQ-5D-5L (ρ: -0.162). Gender was the node showing the highest strength, closeness, and betweenness centralities. In addition, CSI was the node with the second highest closeness and betweenness centralities, whereas HADS-D was the node with the second highest strength centrality. This is the first study applying a network analysis for phenotyping post-COVID pain. Our findings support a model where sensitization-associated symptoms, neuropathic phenotype, and psychological aspects are connected, reflecting post-COVID pain as a nociplastic pain condition. In addition, post-COVID pain is gender dependent since female sex plays a relevant role. Clinical implications of current findings, e.g., developing treatments targeting these mechanisms, are discussed.

Nociplastic pain concept, a mechanistic basis for pragmatic approach to fibromyalgia

Nociplastic pain (NP), as a mechanistic term, denotes pain arising from altered nociception without clear evidence of tissue or somatosensory damage. Fibromyalgia (FM), a prototypical NP condition, incorporates a broad continuum of phenotypes with a distinct neurobiological signature and shared NP attributes. The nociplastic concept may provide a new opportunity for early diagnosis of FM by identifying the characteristic NP features before a state of pain generalization and symptoms clustering. In this approach, even individual symptoms associated with NP features are worthy of attention to denote FM. It may provide a timely diagnosis of FM before clinical progression to a severe and hard-to-manage condition. Furthermore, collecting all various FM phenotypes under the nociplastic concept and not delimiting FM to the only typical presentation allows investigators to identify FM subgroups reflecting potentially distinct pathophysiologic mechanisms and biomarkers. This viewpoint can be served in future studies to develop individualized management. In this review, we postulate a novel approach to early FM diagnosis and management based on NP conceptualization and phenotype recognition. Key Points • FM as a NP condition represents overlapping clinical phenotypes and incomplete presentations especially in early stage of illness. • The mechanistic approach based on the NP features of FM can be implicated in the timely diagnosis and management of FM. • The NP-based approach to FM provides a broader viewpoint beyond FM delimitation to pain generalization and polysymptomatic complaints.

Integrative Review and Framework of Suggested Mechanisms in Primary Muscle Tension Dysphonia

PURPOSE

Despite the high prevalence of primary muscle tension dysphonia (MTD-1), its underlying mechanisms and their interrelationships have yet to be fully identified. The objectives of this integrative review were (a) to describe and classify the suggested underlying mechanisms for MTD-1, (b) to appraise the empirical evidence supporting each of the proposed mechanisms, and (c) to summarize the information in an integrative model.

METHOD

PubMed, Scopus, and CINAHL were searched for all publications pertaining to muscle tension dysphonia. Papers were retained if they included theoretical or empirical data pertaining to underlying mechanisms of MTD-1. A total of 921 papers initially qualified for screening, of which 100 remained for consideration in this review. Underlying mechanisms of MTD-1 were extracted using a consensus approach.

RESULTS

Seven broad categories of putative mechanisms involved in MTD-1 were identified: psychosocial, autonomic, sensorimotor, respiratory, postural, inflammatory, and neuromuscular. These categories were further divided into 19 subcategories detailed in the body of this review article. Based on the reviewed evidence, our proposed integrative model presents MTD-1 as an idiosyncratic motor adaptation to physiological perturbation or perceived threat. Under this model, physiologically or psychologically aversive stimuli can instigate a series of motor adaptations at multiple levels of the nervous system, ultimately disturbing muscle activation patterns and their biomechanical outcomes. Importantly, these adaptations appear to have the potential to become chronic even after threatening stimuli are withdrawn.

CONCLUSIONS

The proposed model highlights the importance of personalized rehabilitation in MTD-1 treatment. Limitations of the literature are discussed to provide guidance for future research aimed at improving our understanding of MTD-1.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19586065.

Cannabis for Rheumatic Disease Pain: a Review of Current Literature

PURPOSE OF REVIEW

Changing attitudes about marijuana have led to an increase in use of medicinal marijuana, especially for painful chronic conditions. Patients ask rheumatologists for guidance on this topic. This review provides up-to-date information on the safety and efficacy of medicinal cannabis for rheumatic disease pain.

RECENT FINDINGS

The number of publications related to rheumatic disease and cannabis has increased, but recent literature skews heavily toward reviews vs primary research. Data supporting a role for cannabinoids in rheumatic disease continue to grow. Observational and survey studies show increased use of medicinal cannabis, both by people with rheumatic disease and the general population, and suggest that patients find these treatments beneficial. Prospective studies, however, including randomized controlled clinical trials, are rare and sorely needed. As medicinal cannabis use for rheumatic diseases rises, despite lack of evidence, we review the sparse data available and provide tips for conversations about medicinal cannabis for rheumatologists.

A vision for the future of wearable sensors in spine care and its challenges: narrative review

OBJECTIVE

This review aimed to: (I) provide a brief overview of some topical areas of current literature regarding applications of wearable sensors in the management of low back pain (LBP); (II) present a vision for a future comprehensive system that integrates wearable sensors to measure multiple parameters in the real world that contributes data to guide treatment selection (aided by artificial intelligence), uses wearables to aid treatment support, adherence and outcome monitoring, and interrogates the response of the individual patient to the prescribed treatment to guide future decision support for other individuals who present with LBP; and (III) consider the challenges that will need to be overcome to make such a system a reality.

BACKGROUND

Advances in wearable sensor technologies are opening new opportunities for the assessment and management of spinal conditions. Although evidence of improvements in outcomes for individuals with LBP from the use of sensors is limited, there is enormous future potential.

METHODS

Narrative review and literature synthesis.

CONCLUSIONS

Substantial research is underway by groups internationally to develop and test elements of this system, to design innovative new sensors that enable recording of new data in new ways, and to fuse data from multiple sources to provide rich information about an individual's experience of LBP. Together this system, incorporating data from wearable sensors has potential to personalise care in ways that were hitherto thought impossible. The potential is high but will require concerted effort to develop and ultimately will need to be feasible and more effective than existing management.

Implication of the Nociplastic Features for Clinical Diagnosis of Fibromyalgia: Development of the Preliminary Nociplastic-Based Fibromyalgia Features (NFF) Tool

OBJECTIVE

Nociplastic concept incorporates a broad continuum of pain phenotypes shared with clinical peculiarity. This study aimed to develop and validate a diagnostic tool, the preliminary Nociplastic-based Fibromyalgia Features (NFF), to detect fibromyalgia (FM) in patients with chronic pain.

METHODS

Items requiring yes or no responses and relating to the most relevant clinical nociplastic pain (NP) features of FM were compiled by a group of expert rheumatologists. The provisional list was tested in a prospective study on 185 consecutive patients with chronic pain (126 patients with FM and 59 patients with non-FM non-inflammatory chronic pain) diagnosed based on expert decision. Identification of the most discriminant combinations of items for FM and the calculation of their sensitivity and specificity were based on both univariate and multivariate (stepwise logistic regression) analyses. All participants were investigated through the final NFF, the 2011 American College of Rheumatology (ACR) criteria, and the 2016 ACR criteria. NFF performance was assessed with receiver operating characteristic curve analysis.

RESULTS

Based on multivariate analyses, we retained only seven items in the final version of the NFF. A cut-off score of 4 (corresponding to the number of positive items) gave the highest rate of correct identification of patients (85%), with a sensitivity of 82% and a specificity of 91%. The NFF showed the highest concordance rate with expert diagnosis (85%) and the lowest value (77%) with the ACR 2016 criteria.

CONCLUSION

The preliminary NFF with respect to the various aspects of NP showed good performance for detection of the FM in the clinical setting. This tool may provide a more pragmatic approach to the timely diagnosis of FM.

MATLAB Analysis of SP Test Results—An Unusual Parasympathetic Nervous System Activity in Low Back Leg Pain: A Case Report

The Skorupska Protocol (SP) test is a new validated tool used to confirm nociplastic pain related to muscles based on a pathological autonomic nervous system (ANS) activity due to muscle nociceptive noxious stimulation analyzed automatically. Two types of amplified vasomotor response are defined as possible: vasodilatation and vasoconstriction. Until now, amplified vasodilatation among low back leg pain and/or sciatica subjects in response to the SP test was confirmed. This case report presents an unusual vasomotor response to the SP test within the pain zone of a sciatica-like case. Conducted twice, the SP test confirmed amplified vasoconstriction within the daily complaint due to noxiously stimulated muscle-referred pain for the first time. Additionally, a new type of the SP test analysis using MATLAB was presented. The SP test supported by MATLAB seems to be an interesting solution to confirm nociplastic pain related to muscles based on the pathological autonomic reactivity within the lower leg back pain zone. Further studies using the SP test supported by MATLAB are necessary to compare the SP test results with the clinical state and other types of nociplastic pain examination.

Pain Phenotypes in Adults Living With Cerebral Palsy

Background and Objectives

To identify pain phenotypes among adults living with cerebral palsy (CP) and compare phenotypes of pain intensity, anxiety and depressive symptoms, and self-reported perceived stress.

Methods

Seventy-one adults with CP presented to the University of Michigan (mean age = 39.3 ± 16.2; 43 women, 28 men). The median of 6 on the American College of Rheumatology fibromyalgia survey was used to classify patients for nociplastic pain centralization. The painDETECT Score was used to classify patients for neuropathic pain. These measures were then used to cross-classify each patient into 1 of 4 possible pain categories: neuropathic, nociplastic, mixed neuropathic/noclipastic, or nociceptive pain (-neuropathic/-nociplastic pain).

Results

Twenty-eight adults with CP (39.4%) were classified as nociceptive, 24 (33.8%) as nociplastic, 8 (11.3%) as neuropathic, and 11 (15.5%) as mixed neuropathic/nociplastic. Subgroups differed significantly on average scores on the Brief Pain Inventory pain intensity scale, the Perceived Stress Scale, and on the Patient-Reported Outcomes Measurement Information System measures of anxiety and depression; the nociceptive pain subgroup reported lower pain and emotional distress compared with the other groups.

Discussion

Findings suggest that type of pain is variable among adults with CP and may arise through multiple mechanisms.

Prevalence of Neuropathic Component in Post-COVID Pain Symptoms in Previously Hospitalized COVID-19 Survivors

OBJECTIVES

To investigate the prevalence of neuropathic pain symptoms and to analyze the correlation between neuropathic symptoms with pain-related, psychological, and cognitive variables in COVID-19 survivors exhibiting "de novo" post-COVID pain.

METHODS

Seventy-seven (n = 77) previously hospitalized COVID-19 survivors presenting with post-COVID pain completed demographic (such as age, height, and weight), pain-related (the duration and intensity of pain), psychological (depressive/anxiety levels), and cognitive (catastrophizing and kinesiophobia) variables. The Self-Report Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) questionnaire was also assessed. After conducting multivariable correlation analyses, a stepwise multiple linear regression model was performed to identify S-LANSS predictors.

RESULTS

Participants were assessed a mean of 6.0 (SD 0.8) months after hospital discharge. Nineteen (24.6%) exhibited neuropathic pain symptoms (S-LANSS score≥12 points). The S-LANSS score was positively associated with the duration of post-COVID pain (r: 0.262), anxiety levels (r: 0.275), and kinesiophobia level (r: 0.291) (all, P < 0.05). The stepwise regression analysis revealed that 12.8% of the S-LANSS variance was just explained by kinesiophobia.

CONCLUSION

This study found that almost 25% of previously hospitalized COVID-19 survivors with "de novo" post-COVID pain reported a neuropathic pain component. The presence of neuropathic pain symptomatology was associated with more anxiety and kinesiophobia, but only kinesiophobia level was significantly associated explaining 12.8% of the variance of the S-LANSS score.

The Spatial Extent of Pain Is Associated with Pain Intensity, Catastrophizing and Some Measures of Central Sensitization in People with Frozen Shoulder

The aim of this cross-sectional study was to explore the spatial extent of pain and its association with clinical symptoms, psychological features, and pain sensitization in people with frozen shoulder (FS). Forty-eight individuals with FS completed pain drawings (PDs) and reported their clinical symptoms including pain intensity (Visual Analogue Scale) and shoulder disability (Shoulder Pain and Disability Index). Moreover, pain sensitization measurements (pressure pain thresholds, temporal summation, conditioned pain modulation, and Central Sensitization Inventory (CSI)) were assessed. Psychological features were assessed by Pain Catastrophizing Scale (PCS) and Pain Vigilance and Awareness Questionnaire. Pain frequency maps were generated, Margolis rating scale was used for pain location, and Spearman correlation coefficients were computed. The mean (SD) pain extent was 12.5% (6.7%) and the most common painful area was the anterolateral shoulder region (100%). Women presented a more widespread pain distribution compared with men. Significant positive associations were obtained between pain extent and current pain intensity (rs = 0.421, p < 0.01), PCS (rs = 0.307, p < 0.05) and CSI (rs = 0.358, p < 0.05). The anterolateral region of the shoulder was the most common painful area in people with FS. Women with FS presented more extended areas of pain; and a more widespread distribution of pain was correlated with higher levels of pain, pain catastrophizing and pain sensitization.

The Effect of Noninvasive Brain Stimulation to Reduce Nonspecific Low Back Pain: A Systematic Review and Meta-analysis

OBJECTIVE

We conducted a systematic review/meta-analysis to evaluate noninvasive brain stimulation (NIBS) efficacy to alleviate pain and improve disability in low back pain (LBP).

MATERIALS AND METHODS

A systematic literature search was performed by a librarian in MEDLINE, Embase, EBM Reviews, CINAHL, and Web of Science databases (last search: January 14, 2021). Data were pooled by the number of sessions and follow-up periods. Independent reviewers performed screening, data extraction, and risk of bias. Pain reduction and disability were used as outcomes.

RESULTS

Twelve articles were included in the qualitative synthesis and 8 in the meta-analysis. A single session of NIBS reduced pain compared with sham (standardized mean difference: -0.47; P<0.001; very low-quality evidence). Repeated sessions of NIBS did not impact pain at short-term (mean difference [MD]: -0.31; P=0.23) or midterm (MD: -0.56; P=0.33; moderate quality evidence). Combining NIBS with cointerventions did not influence pain (MD: -0.31; P=0.30; moderate quality evidence). NIBS did not have a statistically significant impact on disability.

DISCUSSION

There is very low-quality evidence suggesting that a single NIBS session reduces LBP intensity. In contrast, there is moderate quality evidence that repeated NIBS sessions or combination with cointervention did not improve pain or disability. Thus, current results do not support NIBS use to treat chronic LBP. Considering that tDCS was tested in 8 of 12 studies with little success, studies focusing on different NIBS techniques or innovative parameters are required to determine their potential to improve pain and disability in chronic LBP.