Chronic primary musculoskeletal pain: a new concept of nonstructural regional pain

Role of physical therapy in adult chronic non-bacterial osteitis: patients' and therapists' perspectives

OBJECTIVES

Chronic nonbacterial osteitis (CNO) is a rare bone disease causing pain and functional impairment. We aimed to explore the application of physical therapy (PT) for adult CNO from the patients' and primary care therapists' perspective.

METHOD

Cross-sectional study among the Dutch adult CNO cohort (1992-present). A survey on PT-use for axial spondylarthritis was adapted for CNO. Patients using PT in the past 2 years (recent PT-users) were asked about modalities, perceived effects, satisfaction, and preferences for provision. Their current physical therapists were invited to complete a self-developed survey covering therapy details and educational preferences.

RESULTS

80/199 invited patients and 14/16 invited therapists completed the survey respectively. 41 (51%) patients used PT for CNO in the preceding 2 years, 14 (18%) used PT >2 years back, and 25 (31%) never used PT. Recent PT-users (n=41) reported diverse treatment modalities, involving massage (61%), joint mobilizations (44%), breathing exercises (49%), muscle strengthening (32%) and counselling through of home-exercises (46%) and pain education (32%). 64% of all patients desired greater emphasis from physicians regarding the role of PT. Most therapists would appreciate referral letters with CNO-specific information (93%), and consultations with specialized therapists (86%).

CONCLUSIONS

In this study, two-third of adult CNO patients had -ever or recently- used PT, which involved variable therapeutic modalities. Most patients were receptive to a larger role of PT in CNO-management and most therapists preferred CNO-specific information to optimize their care. These findings provide a foundation for the development and systematic evaluation of CNO-specific PT.

Integrating mechanistic-based and classification-based concepts into perioperative pain management: an educational guide for acute pain physicians

Chronic pain begins with acute pain. Physicians tend to classify pain by duration (acute vs chronic) and mechanism (nociceptive, neuropathic and nociplastic). Although this taxonomy may facilitate diagnosis and documentation, such categories are to some degree arbitrary constructs, with significant overlap in terms of mechanisms and treatments. In clinical practice, there are myriad different definitions for chronic pain and a substantial portion of chronic pain involves mixed phenotypes. Classification of pain based on acuity and mechanisms informs management at all levels and constitutes a critical part of guidelines and treatment for chronic pain care. Yet specialty care is often siloed, with advances in understanding lagging years behind in some areas in which these developments should be at the forefront of clinical practice. For example, in perioperative pain management, enhanced recovery protocols are not standardized and tend to drive treatment without consideration of mechanisms, which in many cases may be incongruent with personalized medicine and mechanism-based treatment. In this educational document, we discuss mechanisms and classification of pain as it pertains to commonly performed surgical procedures. Our goal is to provide a clinical reference for the acute pain physician to facilitate pain management decision-making (both diagnosis and therapy) in the perioperative period.

Systematic Review of the Psychopathological Symptomatology and Neuropsychological Disorders of Chronic Primary Musculoskeletal Pain

Chronic pain can develop without tissue damage, injury, or underlying illness. There are several intervening biological, psychological, and social factors involved in its appearance that significantly affect the activities of daily life. It is also associated with significant emotional anxiety and/or functional disability. This review systematically analyses works published in the last five years that evaluate the psychopathological symptomatology and neuropsychological disorders of chronic primary musculoskeletal pain (CPMP). A bibliographic search was carried out to identify articles published in English between January 2018 and March 2023 using the Medline, Scopus, PsycInfo, and Pubmed databases. Twenty articles were obtained using the PRISMA selection method. The main results of this study provided evidence of the presence of moderate and severe chronic pain in patients suffering from musculoskeletal pain. This increase in the intensity of pain correlates with greater psychopathological symptomatology, such as depression, anxiety, insomnia, lack of attention, and hyperactivity/impulsiveness, as well as the use of maladaptive coping strategies. Furthermore, there exists dysfunction in the cerebral structures related to attention and the processing of pain in patients with CPMP. This review may help to develop and optimise the multidisciplinary treatments adapted to the deficits caused by this illness.

Neuropathic and Nociplastic Pain Profiles are Common in Adult Chronic Nonbacterial Osteitis (CNO)

Chronic nonbacterial osteitis (CNO) is a rare musculoskeletal disease causing chronic bone pain. It is known that chronic musculoskeletal pain may involve other mechanisms than nociceptive pain only. We investigate the prevalence of neuropathic and nociplastic pain in adult CNO and their association with clinical characteristics and treatment outcomes. Survey study among the Dutch adult CNO cohort (n = 84/195 participated), including PAIN-detect for neuropathic pain, and the Central Sensitization Inventory (CSI), Fibromyalgia Rapid Screening Tool (FiRST), and ACTTION-APS Pain Taxonomy (AAPT) for nociplastic pain. Clinical characteristics and CNO-related bone pain scores were compared between patients with exclusive nociceptive pain and those with nociceptive pain plus neuropathic and/or nociplastic pain (mixed pain). 31% (95% CI 21-41) of patients classified as likely having neuropathic pain according to PAIN-detect. 53% (41-64) of patients displayed central sensitization on CSI, 61% (50-72) screened positive for fibromyalgia on FiRST and 14% (7-23) of patients fulfilled the AAPT criteria, all indicative of nociplastic pain. Mixed pain was associated with longer diagnostic delay (mean difference 2.8 years, 95% CI 0.4-5.2, p = 0.023), lower educational level (72% versus 20%, p < 0.001), and opioid use (37% versus 13%, p = 0.036). Despite comparable disease severity and extent, patients with mixed pain reported significantly higher CNO-related bone pain scores. This study demonstrates the high prevalence of mixed pain in adult CNO, in which neuropathic and nociplastic pain exist alongside nociceptive inflammatory bone pain. Disease burden in CNO may extend beyond inflammatory activity, highlighting the need for a multifaceted management approach.

The bidirectional relationship between sleep problems and chronic musculoskeletal pain: a systematic review with meta-analysis

ABSTRACT

Chronic musculoskeletal pain and sleep problems/disorders exhibit a recognized bidirectional relationship; yet, systematic investigations of this claim, particularly in a prospective context, are lacking. This systematic review with meta-analysis aimed to synthesize the literature on the prospective associations between sleep problems/disorders and chronic musculoskeletal pain. A comprehensive search across 6 databases identified prospective longitudinal cohort studies in adults examining the relationship between sleep problems/disorders and chronic musculoskeletal pain. Random-effects meta-analyses, using the Hartung-Knapp adjustment for 95% confidence intervals (CIs), were conducted, and all results were presented as odds ratios (ORs). Certainty of evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluations approach. Including 16 articles from 11 study populations (116,746 participants), meta-analyses indicated that sleep problems at baseline may heighten the risk of chronic musculoskeletal pain in both short term (OR 1.64, 95% CI 1.01-2.65) and long term (OR 1.39, 95% CI 1.21-1.59). The evidence for different sleep problem categories was very uncertain. Chronic musculoskeletal pain at baseline may increase the risk of short-term sleep problems (OR 1.56, 95% CI 1.02-2.38), but long-term evidence was very uncertain. The impact of only local or only widespread pain on short-term sleep problems was very uncertain, whereas widespread pain may elevate the risk of long-term sleep problems (OR 2.0, 95% CI 1.81-2.21). In conclusion, this systematic review with meta-analysis suggests that sleep problems are associated with an increased risk of chronic musculoskeletal pain, but the bidirectional nature of this relationship requires further investigation.

Application of a Clinical Approach to Diagnosing Primary Pain: Prevalence and Correlates of Primary Back and Neck Pain in a Community Physiatry Clinic

Chronic back or neck pain (CBNP) can be primary (nociplastic or neuroplastic; without clear peripheral etiology) or secondary (to nociceptive or neuropathic causes). Expanding on available models of nociplastic pain, we developed a clinic-ready approach to diagnose primary/nociplastic pain: first, a standard physical exam and review of imaging to rule out secondary pain; and second, a detailed history of symptom presentation to rule in primary pain. We trained a physician who evaluated 222 patients (73.9% female, age M = 59.6) with CBNP; patients separately completed pain and psychosocial questionnaires. We estimated the prevalence of primary CBNP and explored biomedical, imaging, and psychological correlates of primary CBNP. Although almost all patients (97.7%) had at least 1 spinal anomaly on imaging, the diagnostic approach estimated that 88.3% of patients had primary pain, 5.0% had secondary pain, and 6.8% had mixed pain. Patients with primary pain were more likely than the other 2 groups of patients (combined as "non-primary pain") to report certain functional conditions, central sensitization, and features such as sensitivity to light touch, spreading pain, and pain worsening with stress; however, no difference was detected in depression, anxiety, and pain catastrophizing between those with primary and nonprimary pain. These findings are consistent with prior estimates that 85 to 90% of CBNP is "nonspecific." Further research is needed to validate and perhaps refine this diagnostic approach, which holds the potential for better outcomes if patients are offered treatments targeted to primary pain, such as pain neuroscience education and several emerging psychological therapies. PERSPECTIVE: We developed an approach to diagnose chronic primary pain, which was applied in a physiatry clinic to 222 patients with CBNP. Most patients (88.3%) had primary pain, despite almost universal anomalies on spinal imaging. This diagnostic approach can guide educational and psychological treatments tailored for primary pain.

Multicenter, Randomized, Placebo-controlled Crossover Trial Evaluating Topical Lidocaine for Mechanical Cervical Pain

BACKGROUND

There are few efficacious treatments for mechanical neck pain, with controlled trials suggesting efficacy for muscle relaxants and topical nonsteroidal anti-inflammatory drugs. Although studies evaluating topical lidocaine for back pain have been disappointing, the more superficial location of the cervical musculature suggests a possible role for topical local anesthetics.

METHODS

This study was a randomized, double-blind, placebo-controlled crossover trial performed at four U.S. military, Veterans Administration, academic, and private practice sites, in which 76 patients were randomized to receive either placebo followed by lidocaine patch for 4-week intervals (group 1) or a lidocaine-then-placebo patch sequence. The primary outcome measure was mean reduction in average neck pain, with a positive categorical outcome designated as a reduction of at least 2 points in average neck pain coupled with at least a 5-point score of 7 points on the Patient Global Impression of Change scale at the 4-week endpoint.

RESULTS

For the primary outcome, the median reduction in average neck pain score was -1.0 (interquartile range, -2.0, 0.0) for the lidocaine phase versus -0.5 (interquartile range, -2.0, 0.0) for placebo treatment (P = 0.17). During lidocaine treatment, 27.7% of patients experienced a positive outcome versus 14.9% during the placebo phase (P = 0.073). There were no significant differences between treatments for secondary outcomes, although a carryover effect on pain pressure threshold was observed for the lidocaine phase (P = 0.015). A total of 27.5% of patients in the lidocaine group and 20.5% in the placebo group experienced minor reactions, the most common of which was pruritis (P = 0.36).

CONCLUSIONS

The differences favoring lidocaine were small and nonsignificant, but the trend toward superiority of lidocaine suggests more aggressive phenotyping and applying formulations with greater penetrance may provide clinically meaningful benefit.

EDITOR’S PERSPECTIVE

Can Myofascial Trigger Points Involve Nociplastic Pain? A Scoping Review on Animal Models

Nociplastic pain is a non-specific, regional pain lasting more than three months, characterised by the onset of hypersensitivity, despite no clear evidence of tissue damage. It is a relatively new classified type of pain. As a result, there has not yet been much work describing its precise modelling. The mechanism of its formation needs to be clearly explained. Authors point out that the occurrence of myofascial trigger points (MTrPs) can lead to this type of pain as one possibility. This paper summarises the available literature on modelling nociplastic pain and MTrPs. It complies with studies describing animal model creation and presents the results of performed experiments. The literature search was conducted in December 2022 and included the following databases: PubMed, Scopus, and Web of Science. In this scoping review, six studies were included. Two described the creation of animal models of nociplastic pain, one adapted old models to nociplastic pain, and three described the modelling of MTrPs. This is the first paper pointing in the possible direction of detecting and studying the correlation between MTrPs and nociplastic pain in animal models. However, there is currently insufficient evidence to describe MTrPs as nociplastic, as few studies with animal models exist.

Relationship between latent trigger points, lower limb asymmetry and muscle fatigue in elite short-track athletes

BACKGROUND

Short-track speed skating movement involves asymmetric overloading of the lower left side of the body. The gluteus maximus fatigue limits the physical and mental athletic capacity to perform set tasks. A possible link between the presence of latent trigger points (LTrPs) and muscle fatigue development/persistence has been posited. The aim of the study was to determine whether elite short-track speed skating can result in the impairment of the musculoskeletal system of the lower limbs.

METHODS

Elite short-track athletes as the experimental group (EXP) = 9, 19.5 ± 1.8 years, and healthy subjects as the control group (CON) = 18, 20.8 ± 1.2 years, were tested for: (i) lower limb loading asymmetry using ground reaction force (GRF) measurements during quiet standing, (ii) gluteus maximus fatigue measured with surface electromyography (sEMG) during the Biering-Sorensen test, and (iii) LTrPs presence in the 14 examined muscles of the pelvic girdle and lower limbs.

RESULTS

There were between-group differences in the number of LTrPs, with the EXP group (left lower limb (LLL) n = 18, right lower limb (RLL) n = 9) showing more LTrPs compared to the CON group (LLL n = 2, RLL n = 1), (p < 0.001), and within-group differences in the EXP group only (p < 0.001). There were also significant differences in muscle fatigue for the left side (p < 0.001) both between the groups and within the EXP group (p ≤ 0.001). The vertical ground reaction force (GRF) measurement showed a loading rate of 2% (p = 0.013) in the athletes' LLL exclusively.

CONCLUSIONS

The study confirmed an increased prevalence of LTrPs, increased muscle fatigue and left-sided limb load asymmetry in elite short-track athletes.

TRIAL REGISTRATION

The study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of the Poznan University of Medical Sciences (Resolution No 110/22 of 10 March 2022).

TRIAL REGISTRATION

20/07/2022, Trial Id: ACTRN12622001016729.

What Do We Know about Nociplastic Pain?

Nociplastic pain is a recently distinguished type of pain, distinct from neuropathic and nociceptive pain, and is well described in the literature. It is often mistaken for central sensitization. Pathophysiology has not been clearly established with regard to alteration of the concentration of spinal fluid elements, the structure of the white and gray matter of the brain, and psychological aspects. Many different diagnostic tools, i.e., the painDETECT and Douleur Neuropathique 4 questionnaires, have been developed to diagnose neuropathic pain, but they can also be applied for nociplastic pain; however, more standardized instruments are still needed in order to assess its occurrence and clinical presentation. Numerous studies have shown that nociplastic pain is present in many different diseases such as fibromyalgia, complex regional pain syndrome type 1, and irritable bowel syndrome. Current pharmacological and nonpharmacological treatments for nociceptive and neuropathic pain are not entirely suitable for treating nociplastic pain. There is an ongoing effort to establish the most efficient way to manage it. The significance of this field has led to several clinical trials being carried out in a short time. The aim of this narrative review was to discuss the currently available evidence on pathophysiology, associated diseases, treatment possibilities, and clinical trials. It is important that physicians widely discuss and acknowledge this relatively new concept in order to provide optimized pain control for patients.

From Muscle to the Myofascial Unit: Current Evidence and Future Perspectives

The "motor unit" or the "muscle" has long been considered the quantal element in the control of movement. However, in recent years new research has proved the strong interaction between muscle fibers and intramuscular connective tissue, and between muscles and fasciae, suggesting that the muscles can no longer be considered the only elements that organize movement. In addition, innervation and vascularization of muscle is strongly connected with intramuscular connective tissue. This awareness induced Luigi Stecco, in 2002, to create a new term, the "myofascial unit", to describe the bilateral dependent relationship, both anatomical and functional, that occurs between fascia, muscle and accessory elements. The aim of this narrative review is to understand the scientific support for this new term, and whether it is actually correct to consider the myofascial unit the physiological basic element for peripheral motor control.

Back Pain without Disease or Substantial Injury in Children and Adolescents: A Twin Family Study Investigating Genetic Influence and Associations

This twin family study first aimed to investigate the evidence for genetic factors predicting the risk of lifetime prevalence of non-specific low back pain of at least three months duration (LBP (life)) and one-month current prevalence of thoracolumbar back pain (TLBP (current)) using a study of children, adolescents, and their first-degree relatives. Secondly, the study aimed to identify associations between pain in the back with pain in other regions and also with other conditions of interest. Randomly selected families (n = 2479) with child or adolescent twin pairs and their biological parents and first siblings were approached by Twins Research Australia. There were 651 complete twin pairs aged 6-20 years (response 26%). Casewise concordance, correlation, and odds ratios were compared for monozygous (MZ) and dizygous (DZ) pairs to enable inference about the potential existence of genetic vulnerability. Multivariable random effects logistic regression was used to estimate associations between LBP (life) or TLBP (current) as an outcome with the potentially relevant condition as predictors. The MZ pairs were more similar than the DZ pairs for each of the back pain conditions (all p values < 0.02). Both back pain conditions were associated with pain in multiple sites and with primary pain and other conditions using the combined twin and sibling sample (n = 1382). Data were consistent with the existence of genetic influences on the pain measures under the equal environments assumption of the classic twin model and associations with both categories of back pain were consistent with primary pain conditions and syndromes of childhood and adolescence which has research and clinical implications.

Central Sensitization and Psychological State Distinguishing Complex Regional Pain Syndrome from Other Chronic Limb Pain Conditions: A Cluster Analysis Model

Complex regional pain syndrome (CRPS) taxonomy has been updated with reported subtypes and is defined as primary pain alongside other chronic limb pain (CLP) conditions. We aimed at identifying CRPS clinical phenotypes that distinguish CRPS from other CLP conditions. Cluster analysis was carried out to classify 61 chronic CRPS and 31 CLP patients based on evoked pain (intensity of hyperalgesia and dynamic allodynia, allodynia area, and after-sensation) and psychological (depression, kinesiophobia, mental distress, and depersonalization) measures. Pro-inflammatory cytokine IL-6 and TNF-α serum levels were measured. Three cluster groups were created: ‘CRPS’ (78.7% CRPS; 6.5% CLP); ‘CLP’ (64.5% CLP; 4.9% CRPS), and ‘Mixed’ (16.4% CRPS; 29% CLP). The groups differed in all measures, predominantly in allodynia and hyperalgesia (p < 0.001, η² > 0.58). ‘CRPS’ demonstrated higher psychological and evoked pain measures vs. ‘CLP’. ‘Mixed’ exhibited similarities to ‘CRPS’ in psychological profile and to ‘CLP’ in evoked pain measures. The serum level of TNF-αwas higher in the ‘CRPS’ vs. ‘CLP’ (p < 0.001) groups. In conclusion, pain hypersensitivity reflecting nociplastic pain mechanisms and psychological state measures created different clinical phenotypes of CRPS and possible CRPS subtypes, which distinguishes them from other CLP conditions, with the pro-inflammatory TNF-α cytokine as an additional potential biomarker.

Effectiveness and Safety of Acupuncture-Related Therapies for Chronic Musculoskeletal Pain: A Protocol for Systematic Review and Network Meta-Analysis

Introduction

Chronic pain is one of the major health problems worldwide in recent years, and acupuncture-related therapies have been reported to have definite analgesic effects. However, it is still unclear which treatment is the most effective. Our systematic review and network meta-analysis protocol aims to summarize the evidence and determine the most effective method to treat the chronic musculoskeletal pain.

Methods and Analysis

Our literature search will be performed in five electronic databases-the Cochrane Library, EMBASE, and PubMed, AMED, CINAHL, until May 20, 2022. All randomized controlled trials of acupuncture-related therapies for chronic musculoskeletal pain will be included. The primary outcomes will be common pain-related scales, and the secondary outcomes will include quality of life and incidence of adverse events. Excel 2019 will be used for data extraction, RoB2 will be used for bias risk assessment. R 3.6.2 and WinBUGS V.1.4.3 software will be used for network data synthesis and to produce related plots. During the study, literature selection, data extraction, quality assessment and bias risk assessment will be independently completed by two reviewers, and differences will be judged by the third reviewer. Finally, the risk of bias and sources of heterogeneity in the study will be analyzed and explained in order to obtain reliable results.

Results

Our study will evaluate the effectiveness and safety of acupuncture-related therapies for the treatment of chronic musculoskeletal pain, and we will rank all methods to recommend the best appropriate treatment option.

Conclusion

This study will provide a good foundation for complementary and alternative medicine to treat chronic musculoskeletal pain. It will be also helpful to promote the clinical practice by providing evidence-based medical evidence.

Comparison of polynucleotide, sodium hyaluronate, and crosslinked sodium hyaluronate for the management of painful knee osteoarthritis: a multi-center, randomized, double-blind, parallel-group study

OBJECTIVE

To compare the clinical effectiveness of sodium polynucleotide, classic hyaluronic acid, and crosslinked hyaluronic acid for the management of painful knee osteoarthritis.

DESIGN

Randomized, double-blind, parallel-group clinical trial.

SETTING

Multicenter study.

SUBJECTS

Patients with chronic painful knee osteoarthritis.

METHODS

Ninety patients were selected and randomized into polynucleotide, classic hyaluronic acid, and crosslinked hyaluronic acid groups (30 per group). Intra-articular injections of the viscosupplement for each group were administered to the patients three times at one-week intervals. The primary outcome was differences in changes of weight-bearing pain scores at 16 weeks between the groups. The secondary outcomes were changes in the intensity of knee pain during weight-bearing, walking, and rest, and functional disability, quality of life, and adverse events during the 16-week follow-up period.

RESULTS

At 16 weeks, the polynucleotide group showed a higher reduction in pain score using a Visual Analog Scale score (0-100) than the classic hyaluronic acid (-17.6 [95% CI = -35.1 to -0.1]; P = 0.048) and crosslinked hyaluronic acid (-22.4 [95% CI = -41.5 to -3.3]; P = 0.016) groups. The polynucleotide and crosslinked hyaluronic acid groups showed an early-onset reduction in knee pain during weight-bearing, walking, and rest. All three groups showed reductions in functional disability and improved quality of life at 16 weeks without inter-group differences. No severe adverse events were reported throughout the study period.

CONCLUSION

Polynucleotide significantly relieves pain more and relieves pain faster in patients with knee osteoarthritis than classic and crosslinked hyaluronic acid, with improved health-related quality of life.

CLINICAL TRIAL NUMBER AND REGISTRY URL

Clinical Research Information Service (https://cris.nih.go.kr/cris/index.jsp; Identifier: KCT0005308).