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

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

Evaluating sensory profiles in nociplastic chronic low back pain: a cross-sectional validation study.

BACKGROUND: Sensory profiles (SPs) may be useful in classifying patients based on sensory sensitivity and behavioral responses to stimuli to develop personalized treatments for nonspecific chronic low back pain (CLBP). The Adolescent/Adult Sensory Profile (AASP) identifies four sensitivity and behavioral response-related quadrants: Sensory Sensitive, Sensation Avoiding, Low Registration, and Sensation Seeking. It is an appropriate questionnaire for evaluating SPs; however, it has not been validated in CLBP. OBJECTIVES: To assess the internal consistency, test-retest reliability, agreement, and construct validity of the AASP in a CLBP population with nociplastic pain in primary care physiotherapy. DESIGN: Two evaluations were performed at a 2-week interval in this non-experimental cross-sectional study. PARTICIPANTS: Patients with CLBP. METHODS: Questionnaires were used to compare outcomes with the AASP. Reliability was evaluated by assessing internal consistency and test-retest reliability. Construct validity was evaluated in response to the a priori hypothesis. RESULTS: Ninety patients with CLBP were included. Internal consistency was excellent for all SPs (Cronbach's alpha, 0.91-0.92). Test-retest reliability Intraclass Correlation Coefficient (ICC (3,2)) 0.82-0.87, for the SPs (95% CI 0.74-0.91, p< .001). Construct validity correlated positively with Low Registration, Sensory Sensitive, and Sensation Avoiding and negatively with Sensation Seeking. CONCLUSION: The AASP is suitable for evaluating SPs in primary care CLBP patients.

Nociplastic Pain Criteria or Recognition of Central Sensitization? Pain Phenotyping in the Past, Present and Future.

Recently, the International Association for the Study of Pain (IASP) released clinical criteria and a grading system for nociplastic pain affecting the musculoskeletal system. These criteria replaced the 2014 clinical criteria for predominant central sensitization (CS) pain and accounted for clinicians' need to identify (early) and correctly classify patients having chronic pain according to the pain phenotype. Still, clinicians and researchers can become confused by the multitude of terms and the variety of clinical criteria available. Therefore, this paper aims at (1) providing an overview of what preceded the IASP criteria for nociplastic pain ('the past'); (2) explaining the new IASP criteria for nociplastic pain in comparison with the 2014 clinical criteria for predominant CS pain ('the present'); and (3) highlighting key areas for future implementation and research work in this area ('the future'). It is explained that the 2021 IASP clinical criteria for nociplastic pain are in line with the 2014 clinical criteria for predominant CS pain but are more robust, comprehensive, better developed and hold more potential. Therefore, the 2021 IASP clinical criteria for nociplastic pain are important steps towards precision pain medicine, yet studies examining the clinimetric and psychometric properties of the criteria are urgently needed.

Prevalence of Extreme Trait Sensory Profiles and Personality Types in Nonspecific Chronic Low Back Pain with Predominant Central Sensitization: Secondary Analysis of an International Observational Study.

BACKGROUND: Individuals with nonspecific chronic low back pain (NSCLBP) and central sensitization (CS) exhibit sensory hypersensitivity that may be related to pre-existing trait characteristics. Sensory profiles and trait anxiety-related characteristics have sensory sensitivity in common with CS. OBJECTIVES: The objectives of this study were 1) to observe the prevalence of 4 personality types and extreme scores of 4 trait sensory profiles in people with NSCLBP and predominant CS; and 2) to compare these between 2 subgroups based on high and low self-reported CS symptoms. STUDY DESIGN: An international cross-sectional observational study was undertaken. SETTING: Adults (n = 165; mean age = 45 ± 12 standard deviation) were recruited from physiotherapy clinics across 3 countries and 2 continents. METHODS: The inclusion criteria were: NSCLBP, aged 18-64 years, with clinically identified predominant CS pain, without specific pathology. The outcome measures were: Central Sensitization Inventory (CSI), Adolescent/Adult Sensory Profile, State/Trait Anxiety Inventory, and Marlowe Crowne Social Desirability Scale. Descriptive and comparative statistics were used. RESULTS: CSI scores ranged from 19-79 (mean = 50). There was a high prevalence of extreme 1) trait sensory hyper- and, unexpectedly, hyposensitivity profile scores (P < 0.001) and Defensive High Anxious personality type (P < 0.01) in the high-CSI (CSI>= 40; 78%) subgroup, and 2) trait sensory hyposensitivity profile scores (P < 0.01) and Repressor personality type (P < 0.01) in the low-CSI subgroup (CSI < 40; 22%). LIMITATIONS: Self-report measures only were used; limited demographics. CONCLUSIONS: To our knowledge, these results are the first to demonstrate extreme trait sensory profiles and personality types in people with NSCLBP and predominant CS. A subgroup who reports low levels of CS symptoms may have a hyposensitive sensory profile and Repressor personality type. Further study is required to investigate the extent to which these trait characteristics may predict CS symptoms in people with NSCLBP. KEY WORDS: Central sensitization, nonspecific chronic low back pain, prevalence of extreme trait characteristics, sensory profiles, trait anxiety-related personality types.

Trait Sensitivity, Anxiety, and Personality Are Predictive of Central Sensitization Symptoms in Patients with Chronic Low Back Pain.

BACKGROUND: Sensitivity-related trait characteristics involving physical and emotional sensitivities and high trait anxiety personality types have been observed in individuals with nonspecific chronic low back pain (NSCLBP). High trait sensitivity to sensory stimulation combined with interpretation biases based on personality type may contribute to the development of central sensitization (CS) symptoms. To date, there is limited research that has considered both sensitivity levels and personality type in NSCLBP with CS. The purpose of this study was to investigate (1) relationships between trait sensory profiles, trait anxiety, and CS symptoms, and (2) the predictive capacity of sensory profiles, trait anxiety, and personality types on CS symptoms in people with NSCLBP. METHODS: This was a cross-sectional observational study using 4 self-report measures on adults (N = 165, mean age = 45 ± 12 [standard deviation] years) from physiotherapy clinics in England, Ireland, and New Zealand. Inclusion: NSCLBP > 6 months, age 18 to 64 years, predominant CS pain presentation, no other pathology. Parametric and nonparametric correlation statistics and regression analyses were used. RESULTS: Positive correlations were found between central sensitization inventory (CSI) scores and sensory hypersensitivity profiles and trait anxiety. CSI score increases could be predicted by sensory-sensitive, low-registration profiles; trait anxiety scores; and extreme defensive high anxious personality type. CONCLUSIONS: Trait sensory hyper- and/or hyposensitivity and high trait anxiety-related personality type characteristics predict the extent of CS symptoms in people with NSCLBP. Further investigation is required to establish causality between these characteristics and CS symptoms.

Exploring the pre-morbid contexts in which central sensitisation developed in individuals with non-specific chronic low back pain. A qualitative study.

BACKGROUND: Central sensitisation pain is a predominant mechanism in a proportion of individuals with non-specific chronic low back pain and is associated with poor outcomes. It is proposed that the pre-morbid experiences and contexts may be related to the development of central sensitisation. OBJECTIVES: The objective of this study was to explore the pre-morbid experiences and personal characteristics of participants with central sensitisation pain from a non-specific chronic low back pain population. METHODS: This was a qualitative, exploratory study, using a concurrent nested design within a mixed methods protocol. n=9 participants were recruited purposively based on sensory profiles and trait anxiety-related personality types. Data were collected through semi structured interviews, managed using QSR NVivo 10 software and analysed using theoretical thematic analysis. RESULTS: Four themes emerged: developmental learning experiences, personal characteristics, sensitivity and trauma. Reported was lack of confidence, low esteem and a need to please others, physical hyper-sensitivities (smell, light, sound) and emotional sensitivity (anxiety) as well as physical hypo-sensitivity. Participants had also suffered emotional and/or physical trauma. Learning difficulties, sensory sensitivities and trauma are associated with autonomic stress responses, which in turn have been linked to physiological changes seen in central sensitisation pain. CONCLUSION: Central sensitisation pain developed in the context of sensory processing differences related to learning difficulties, sensitivities and trauma, and personal characteristics of low confidence and control, in a group of participants with non-specific chronic low back pain. The role of pre-existing sensory processing differences, as a component of altered central nervous system function, in relation to central sensitisation pain warrants further investigation.

Trait anxiety and sensory processing profile characteristics in patients with non-specific chronic low back pain and central sensitisation - A pilot observational study.

INTRODUCTION: People with non-specific chronic low back pain (NSCLBP) and central sensitisation (CS) exhibit sensory processing alterations, somatosensory hypersensitivity and differences in the brain's emotional networks. The concept that CS relates to pre-morbid trait sensory processing and anxiety characteristics is unknown. The aims of this pilot observational study were to test concept plausibility in a NSCLBP population with central sensitisation by investigating: 1) the range of Central Sensitisation Inventory scores, to determine the extent of symptoms of central sensitisation, 2) whether there are identifiable patient characteristics of trait anxiety and trait sensory profile differences; and 3) whether potential relationships exist between trait anxiety, trait sensory profiles and the extent of symptoms of central sensitisation. METHODS: People with NSCLBP and CS were recruited from physiotherapy outpatient clinics in New Zealand and the United Kingdom. Outcomes included the Central Sensitisation Inventory (CSI), Adolescent/Adult Sensory Profile and the State/Trait Anxiety Inventory (trait section) with the Marlowe Crowne Sociable Desirability Scale. Descriptive and non-parametric tests for correlation were used to analyse the data, p=<0.05. RESULTS: Of the 21 people recruited, 16 (76.2%) had CSI scores ≥40 in association with 1) an abnormally high prevalence of extreme scores of a) high trait Sensory Sensitive, Sensation Avoiding and Low Registration sensory profiles and b) low trait Sensation Seeking profile, 2) high trait anxiety sub-types and 3) minimal low trait anxiety. Moderate correlations were identified between trait sensory profiles and 1) CS pain (Sensory Sensitive R = 0.57, p < 0.01, CI = 0.07 to 0.88, p < 0.01, Sensation Seeking R = -0.47, p < 0.05, CI = -0.72 to -0.02) and 2) trait anxiety (Sensory sensitive: R = 0.65, p < 0.01, CI = 0.27 to 0.91) and Low Registration (R = 0.49, p < 0.05, CI = 0.03 to 0.84). The CSI scores moderately correlated with trait anxiety (R = 0.63, p < 0.01, CI = 0.22 to 0.86). CONCLUSION: These results provide concept plausibility that the extent of CS pain in people with NSCLBP might be associated with pre-morbid trait anxiety sub-types and abnormal trait sensory processing profiles. A larger study to confirm the findings is warranted.

In the spine or in the brain? Recent advances in pain neuroscience applied in the intervention for low back pain.

Conservative, surgical and pharmacological strategies for chronic low back pain (CLBP) management offer at best modest effect sizes in reducing pain and related disability, indicating a need for improvement. Such improvement may be derived from applying contemporary pain neuroscience to the management of CLBP. Current interventions for people with CLBP are often based entirely on a "biomedical" or "psychological" model without consideration of information concerning underlying pain mechanisms and contemporary pain neuroscience. Here we update readers with our current understanding of pain in people with CLBP, showing that CLBP is not limited to spinal impairments, but is also characterised by brain changes, including functional connectivity reorganisation in several brain regions and increased activation in brain regions of the so-called 'pain matrix' (or 'pain connectome'). Indeed, in a subgroup of the CLBP population brain changes associated with the presence of central sensitisation are seen. Understanding the role of these brain changes in CLBP improves our understanding not only of pain symptoms, but also of prevalent CLBP associated comorbidities such as sleep disturbances and fear avoidance behaviour. Applying contemporary pain neuroscience to improve care for people with CLBP includes identifying relevant pain mechanisms to steer intervention, addressing sleep problems and optimising exercise and activity interventions. This approach includes cognitively preparing patients for exercise therapy using (therapeutic) pain neuroscience education, followed by cognition-targeted functional exercise therapy.

What Are the Predictors of Altered Central Pain Modulation in Chronic Musculoskeletal Pain Populations? A Systematic Review.

BACKGROUND: Altered central pain modulation is the predominant pain mechanism in a proportion of chronic musculoskeletal pain disorders and is associated with poor outcomes. Although existing studies predict poor outcomes such as persistent pain and disability, to date there is little consensus on what factors specifically predict altered central pain modulation. OBJECTIVES: To review the existing literature on the predictive factors specifically for altered central pain modulation in musculoskeletal pain populations. STUDY DESIGN: This is a systematic review in accordance with supplemented PRISMA guidelines. METHODS: A systematic search was performed by 2 mutually blinded reviewers. Relevant articles were screened by title and abstract from Medline, Embase, PubMed, CINAHL, and Web of Science electronic databases. Alternative sources were also sought to locate missed potential articles. Eligibility included studies published in English, adults aged 18 to 65, musculoskeletal pain, baseline measurements taken at the pre-morbid or acute stage, > 3-month follow-up time after pain onset, and primary outcome measures specific to altered central pain modulation. Studies were excluded where there were concurrent diseases or they were non-predictive studies. Risk of bias was assessed using the quality in prognostic studies (QUIPS) tool. Study design, demographics, musculoskeletal region, inclusion/exclusion criteria, measurement timelines, predictor and primary outcome measures, and results were extracted. Data were synthesized qualitatively and strength of evidence was scored using the grading of recommendations, assessment, development, and evaluations (GRADE) scoring system. RESULTS: Nine eligible articles were located, in various musculoskeletal populations (whiplash, n = 2; widespread pain, n = 5; temporomandibular disorder, n = 2). Moderate evidence was found for 2 predictive factors of altered central pain modulation: 1) high sensory sensitivity (using genetic testing or quantitative sensory tests), and 2) psychological factors (somatization and poor self-expectation of recovery), at a pre-morbid or acute stage baseline. LIMITATIONS: At the times of the article publications, the current definitions and clinical guidelines for identifying altered central pain modulation were not yet available. Careful interpretation of the information provided using current knowledge and published guidelines was necessary to extract information specific to altered central pain modulation in some of the studies, avoiding unwarranted assumptions. CONCLUSIONS: Premorbid and acute stage high sensory sensitivity and/or somatization are the strongest predictors of altered central pain modulation in chronic musculoskeletal pain to date. This is the first systematic review specifically targeting altered central pain modulation as the primary outcome in musculoskeletal pain populations. Early identification of people at risk of developing chronic pain with altered central pain modulation may guide clinicians in appropriate management, diminishing the burden of persistent pain on patients and heath care providers alike. Systematic Review Registration no.: PROSPERO 2015:CRD42015032394.Key words: Predictive factors, pre-morbid and acute stage baselines, altered central pain modulation, chronic musculoskeletal pain, sensory processing, somatization.

Patient-centeredness in physiotherapy: What does it entail? A systematic review of qualitative studies.

PURPOSE: The literature review is aimed at examining and summarizing themes related to patient-centeredness identified in qualitative research from the perspectives of patients and physiotherapists. Following the review, a secondary aim was to synthesize the themes to construct a proposed conceptual framework for utilization within physiotherapy. METHODS: A systematic search of qualitative studies was conducted including all articles up to 2015 September. Methodological quality was examined with a checklist. The studies were examined for themes suggestive of the practice of patient centeredness from perspective of the therapists and/or the patients. Data were extracted using a data extraction form and analyzed following "thematic synthesis." RESULTS: Fourteen articles were included. Methodological quality was high in five studies. Eight major descriptive themes and four subthemes (ST) were identified. The descriptive themes were: individuality (ST "Getting to know the patient" and ST "Individualized treatment"), education, communication (ST "Non-verbal communication"), goal setting, support (ST "Empowerment"), social characteristics of a patient-centered physiotherapist, a confident physiotherapist, and knowledge and skills of a patient-centered physiotherapist. CONCLUSIONS: Patient-centeredness in physiotherapy entails the characteristics of offering an individualized treatment, continuous communication (verbal and non-verbal), education during all aspects of treatment, working with patient-defined goals in a treatment in which the patient is supported and empowered with a physiotherapist having social skills, being confident and showing specific knowledge.

Low back pain: guidelines for the clinical classification of predominant neuropathic, nociceptive, or central sensitization pain.

BACKGROUND: Low back pain (LBP) is a heterogeneous disorder including patients with dominant nociceptive (e.g., myofascial low back pain), neuropathic (e.g., lumbar radiculopathy), and central sensitization pain. In order to select an effective and preferably also efficient treatment in daily clinical practice, LBP patients should be classified clinically as either predominantly nociceptive, neuropathic, or central sensitization pain. OBJECTIVE: To explain how clinicians can differentiate between nociceptive, neuropathic, and central sensitization pain in patients with LBP. STUDY DESIGN: Narrative review and expert opinion SETTING: Universities, university hospitals and private practices METHODS: Recently, a clinical method for the classification of central sensitization pain versus neuropathic and nociceptive pain was developed. It is based on a body of evidence of original research papers and expert opinion of 18 pain experts from 7 different countries. Here we apply this classification algorithm to the LBP population. RESULTS: The first step implies examining the presence of neuropathic low back pain. Next, the differential diagnosis between predominant nociceptive and central sensitization pain is done using a clinical algorithm. LIMITATIONS: The classification criteria are substantiated by several original research findings including a Delphi survey, a study of a large group of LBP patients, and validation studies of the Central Sensitization Inventory. Nevertheless, these criteria require validation in clinical settings. CONCLUSION: The pain classification system for LBP should be an addition to available classification systems and diagnostic procedures for LBP, as it is focussed on pain mechanisms solely.

Applying modern pain neuroscience in clinical practice: criteria for the classification of central sensitization pain.

BACKGROUND: The awareness is growing that central sensitization is of prime importance for the assessment and management of chronic pain, but its classification is challenging clinically since no gold standard method of assessment exists. OBJECTIVES: Designing the first set of classification criteria for the classification of central sensitization pain. METHODS: A body of evidence from original research papers was used by 18 pain experts from 7 different countries to design the first classification criteria for central sensitization pain. RESULTS: It is proposed that the classification of central sensitization pain entails 2 major steps: the exclusion of neuropathic pain and the differential classification of nociceptive versus central sensitization pain. For the former, the International Association for the Study of Pain diagnostic criteria are available for diagnosing or excluding neuropathic pain. For the latter, clinicians are advised to screen their patients for 3 major classification criteria, and use them to complete the classification algorithm for each individual patient with chronic pain. The first and obligatory criterion entails disproportionate pain, implying that the severity of pain and related reported or perceived disability are disproportionate to the nature and extent of injury or pathology (i.e., tissue damage or structural impairments). The 2 remaining criteria are 1) the presence of diffuse pain distribution, allodynia, and hyperalgesia; and 2) hypersensitivity of senses unrelated to the musculoskeletal system (defined as a score of at least 40 on the Central Sensitization Inventory). LIMITATIONS: Although based on direct and indirect research findings, the classification algorithm requires experimental testing in future studies. CONCLUSION: Clinicians can use the proposed classification algorithm for differentiating neuropathic, nociceptive, and central sensitization pain.