Martin Rabey

Somatosensory nociceptive characteristics differentiate subgroups in people with chronic low back pain: a cluster analysis

Abstract The objectives of this study were to explore the existence of subgroups in a cohort with chronic low back pain (n = 294) based on the results of multimodal sensory testing and profile subgroups on demographic, psychological, lifestyle, and general health factors. Bedside (2-point discrimination, brush, vibration and pinprick perception, temporal summation on repeated monofilament stimulation) and laboratory (mechanical detection threshold, pressure, heat and cold pain thresholds, conditioned pain modulation) sensory testing were examined at wrist and lumbar sites. Data were entered into principal component analysis, and 5 component scores were entered into latent class analysis. Three clusters, with different sensory characteristics, were derived. Cluster 1 (31.9%) was characterised by average to high temperature and pressure pain sensitivity. Cluster 2 (52.0%) was characterised by average to high pressure pain sensitivity. Cluster 3 (16.0%) was characterised by low temperature and pressure pain sensitivity. Temporal summation occurred significantly more frequently in cluster 1. Subgroups were profiled on pain intensity, disability, depression, anxiety, stress, life events, fear avoidance, catastrophizing, perception of the low back region, comorbidities, body mass index, multiple pain sites, sleep, and activity levels. Clusters 1 and 2 had a significantly greater proportion of female participants and higher depression and sleep disturbance scores than cluster 3. The proportion of participants undertaking <300 minutes per week of moderate activity was significantly greater in cluster 1 than in clusters 2 and 3. Low back pain, therefore, does not appear to be homogeneous. Pain mechanisms relating to presentations of each subgroup were postulated. Future research may investigate prognoses and interventions tailored towards these subgroups.

Differing Psychologically Derived Clusters in People With Chronic Low Back Pain are Associated With Different Multidimensional Profiles.

Objectives:To explore the existence of subgroups in a cohort with chronic low back pain (n=294) based upon data from multiple psychological questionnaires, and profile subgroups on data from multiple dimensions. Methods:Psychological questionnaires considered as indicator variables entered into latent class analysis included: Depression, Anxiety, Stress scales, Thought Suppression and Behavioural Endurance subscales (Avoidance Endurance questionnaire), Chronic Pain Acceptance Questionnaire (short-form), Pain Catastrophising Scale, Pain Self-Efficacy Questionnaire, and Fear-Avoidance Beliefs Questionnaire. Multidimensional profiling of derived clusters included: demographics, pain characteristics, pain responses to movement, behaviors associated with pain, body perception, pain sensitivity, and health and lifestyle factors. Results:Three clusters were derived. Cluster 1 (23.5%) was characterized by low Cognitive and Affective Questionnaire scores, with the exception of fear-avoidance beliefs. Cluster 2 (58.8%) was characterized by relatively elevated thought suppression, catastrophizing, and fear-avoidance beliefs, but lower pain self-efficacy, depression, anxiety, and stress. Cluster 3 (17.7%) had the highest scores across cognitive and affective questionnaires.Cluster 1 reported significantly lower pain intensity and bothersomeness than other clusters. Disability, stressful life events, and low back region perceptual distortion increased progressively from cluster 1 to cluster 3, whereas mindfulness progressively decreased. Clusters 2 and 3 had more people with an increase in pain following repeated forward and backward spinal bending, and more people with increasing pain following bending, than cluster 1. Cluster 3 had significantly greater lumbar pressure pain sensitivity, more undiagnosed comorbid symptoms, and more widespread pain than other clusters. Discussion:Clinical implications relating to presentations of each cluster are postulated.

Agreement and correlation between the self-report leeds assessment of neuropathic symptoms and signs and Douleur Neuropathique 4 Questions neuropathic pain screening tools in subjects with low back-related leg pain.

OBJECTIVE The self-report Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) and Douleur Neuropathique 4 Questions (DN4) neuropathic pain screening tools have been shown to be reliable, valid, and able to differentiate neuropathic pain from inflammatory or mixed pain syndromes. However, no studies have compared these tools to determine whether their outcomes are similar. This study evaluated agreement and correlation between the S-LANSS and DN4 in the identification of neuropathic pain in subjects with low back-related leg pain. METHODS This observational study compared S-LANSS and DN4 scores in 45 patients with low back-related leg pain. The S-LANSS and DN4 cutoff scores of 12 and 4, respectively, were used to classify subjects as positive or negative for the presence of neuropathic pain for each screening tool. The κ statistic was used to determine whether there was agreement in classification of neuropathic pain between the 2 screening tools. Pearson correlation coefficient was used to determine correlation between scores of the 2 screening tools. RESULTS Neuropathic pain was identified in 15 subjects (33%) using the S-LANSS and in 19 subjects (42%) using the DN4. Agreement on neuropathic pain classification was fair, with a κ value of 0.34. There was moderate to good correlation (r = 0.62; P < .001) between scores obtained from the 2 tools. CONCLUSIONS The finding of fair agreement suggests that despite the moderate to good correlation between scores, the cutoff points for the classification of neuropathic pain of the 2 tools may not be congruent.

Psychosocial and personality factors and physical measures in lateral epicondylalgia reveal two groups of “tennis elbow” patients, requiring different management

Graphical abstract Isometric low load pain tolerance test position. Abstract Background and purpose Nirschl’s lateral epicondylalgia (LE) classification appears prognostic but is based upon an outdated model of tendinopathy. Psychosocial factors which may negatively influence treatment outcomes, central nervous system mediated hypersensitivity and motor impairment all occur in epicondylalgia. This study examines psychosocial/personality factors and physical measures in LE correlating them with Nirschl’s sub-groups. Methods Fifty-four subjects with LE and 43 healthy controls, recruited from primary care in Norway were assessed. Measures included: pressure pain threshold (PPT), isometric maximal load pain tolerance (MLT) and isometric low load (sustained hold of 0.5 kg weight) pain tolerance (LLT) of the wrist extensors, all of which were undertaken bilaterally; the Örebro Musculoskeletal Pain Questionnaire (ÖMPSQ), and the Swedish Scales of Personality. Results Patients had significantly lower pain thresholds than controls especially at the common extensor origin, but thresholds did not differentiate Nirschl’s groups. MLT did not differentiate between controls and patients or between pain groups. LLT differentiated pain patients from controls but not between different pain groups. The ÖMPSQ score was significantly different between three out of four of Nirschl’s pain groups and both pain thresholds and MLT in both the painful and non-/less painful arms were significantly but negatively correlated with the ÖMPSQ score. Somatic anxiety was significantly different between healthy controls and Nirschl’s most symptomatic pain group; and also correlated with the OMPSQ score. Conclusions The ÖMPSQ differentiated Nirschl’s sub-groups more effectively than the PPT, MLT or LLT, but the control group did not complete the ÖMPSQ, so a comparison of the subjects with LE to symptom-free subjects was not possible. Elevated somatic anxiety in the most symptomatic patients may indicate possible alexithymia or an inability to understand or cope with somatic symptoms of distress. The subjects in this study with epicondylalgia exhibited widespread, likely central nervous system mediated hypersensitivity, motor impairment and psychosocial factors in keeping with a modern model of LE. This hypersensitivity suggests epicondylalgia should not be considered a localised pathology and management should be tailored towards underlying multidimensional biopsychosocial pain mechanisms. Possible pain mechanisms driving this hypersensitivity are postulated. LLT, a novel impairment test, is significantly reduced in LE and should be examined in this patient group, and possibly rehabilitated specifically. Based upon physical and psychological data from this study, Nirschl’s sub-grouping seems too detailed and our results suggest that the four groups should be reduced to two. Thus, for diagnostic purposes the Nirschl’s groups I and II could be collapsed to one group, and groups III and IV to a second group. Implications Psychosocial and personality factors should be measured in subjects with epicondylalgia as they correlate with physical signs. Management should therefore be tailored to patient presentations, particularly where significant psychosocial factors or specific motor impairments exist.

The RESOLVE Trial for people with chronic low back pain: protocol for a randomised clinical trial

INTRODUCTION Low back pain is the leading worldwide cause of disability, and results in significant personal hardship. Most available treatments, when tested in high-quality randomised, controlled trials, achieve only modest improvements in pain, at best. Recently, treatments that target central nervous system function have been developed and tested in small studies. Combining treatments that target central nervous system function with traditional treatments directed towards functioning of the back is a promising approach that has yet to be tested in adequately powered, prospectively registered, clinical trials. The RESOLVE trial will be the first high-quality assessment of two treatment programs that combine central nervous system-directed and traditional interventions in order to improve chronic low back pain. AIM To compare the effectiveness of two treatment programs that combine central nervous system-directed and traditional interventions at reducing pain intensity at 18 weeks post randomisation in a randomised clinical trial of people with chronic low back pain. DESIGN Two-group, randomised, clinical trial with blinding of participants and assessors. PARTICIPANTS AND SETTING Two hundred and seventy-five participants with chronic low back pain that has persisted longer than 3 months and no specific spinal pathology will be recruited from the community and primary care in Sydney, Australia. INTERVENTIONS Both of the interventions contain treatments that target central nervous system function combined with treatments directed towards functioning of the back. Adherence to the intervention will be monitored using an individual treatment diary and adverse events recorded through passive capture. Participants are informed prior to providing informed consent that some of the treatments are not active. Blinding is maintained by not disclosing any further information. Complete disclosure of the contents of the intervention has been made with the UNSW HREC (HC15357) and an embargoed project registration has been made on the Open Science Framework to meet the Declaration of Helsinki requirement for transparent reporting of trial methods a priori. INTERVENTION A Participants randomised to Intervention A will receive a 12-session treatment program delivered as 60-minute sessions, scheduled approximately weekly, over a period of 12 to 18 weeks. All treatment sessions are one-on-one. The program includes a home treatment component of 30minutes, five times per week. The intervention comprises discussion of the participants low back pain experience, graded sensory training, graded motor imagery training and graded, precision-focused and feedback-enriched, functional movement training. Treatment progression is determined by participant proficiency, with mandatory advancement at set time points with respect to a standard protocol. INTERVENTION B Participants randomised to Intervention B will receive a 12-session treatment program of the same duration and structure as Intervention A. The intervention comprises discussion of the participants low back pain experience, transcranial direct current stimulation to the motor and pre-frontal cortices, cranial electrical stimulation, and low-intensity laser therapy and pulsed electromagnetic energy to the area of greatest pain. Treatment is delivered according to published recommendations and progressed with respect to a standard protocol. MEASUREMENTS The primary outcome is pain intensity at 18 weeks post randomisation. Secondary outcomes will include disability, depression, pain catastrophising, kinesiophobia, beliefs about back pain, pain self-efficacy, quality of life, healthcare resource use, and treatment credibility. Assessment will occur at baseline and at 18, 26 and 52 weeks after randomisation. Treatment credibility will be assessed at baseline and 2 weeks after randomisation only. ANALYSIS A statistician blinded to group status will analyse the data by intention-to-treat using linear mixed models with random intercepts. Linear contrasts will be constructed to compare the adjusted mean change (continuous variables) in outcome from baseline to each time point between intervention A and intervention B. This will provide effect estimates and 95% confidence intervals for any difference between the interventions. SIGNIFICANCE Preliminary data suggest that combining treatments that target central nervous system function with traditional interventions is a promising approach to chronic low back pain treatment. In the context of modest effects on pain intensity from most available treatments, this approach may lead to improved clinical outcomes for people with chronic low back pain. The trial will determine which, if either, of two treatment programs that combine central nervous system-directed and traditional interventions is more effective at reducing pain intensity in a chronic low back pain cohort. Central nervous system-directed interventions constitute a completely new treatment paradigm for chronic low back pain management. The results have the potential to be far reaching and change current physiotherapy management of chronic low back pain in Australia and internationally.

Process of Change in Pain-Related Fear: Clinical Insights From a Single Case Report of Persistent Back Pain Managed With Cognitive Functional Therapy

Study Design Single case report with repeated measures over 18 months. Background Management of persistent low back pain (PLBP) associated with high pain-related fear is complex. This case report aims to provide clinicians with insight into the process of change in a person with PLBP and high bending-related fear, who was managed with an individualized behavioral approach of cognitive functional therapy. Case Description A retired manual worker with PLBP believed that his spine was degenerating, that bending would hurt him, and that avoidance was the only form of pain control. At baseline, he presented high levels of pain-related fear on the Tampa Scale of Kinesiophobia (score, 47/68) and a high-risk profile on the Örebro Musculoskeletal Pain Questionnaire (score, 61/100). Unhelpful beliefs and behaviors led to a vicious cycle of fear and disengagement from valued life activities. Guided behavioral experiments were used to challenge his thoughts and protective responses, indicating that his behavior was modifiable and the pain controllable. Using a multidimensional clinical-reasoning framework, cognitive functional therapy management was tailored to target key drivers of PLBP and delivered over 6 sessions in a 3-month period. Outcomes Over an 18-month clinical journey, he demonstrated improvements in bending-related fear, pain expectancy, and pain experience, and substantial changes in pain-related fear (Tampa Scale of Kinesiophobia: 33/68; change, -14 points) and risk profile (Örebro Musculoskeletal Pain Questionnaire: 36/100; change, -25 points). Clinical interviews at 6 and 18 months revealed positive changes in mindset, understanding of pain, perceived pain control, and behavioral responses to pain. Discussion This case report provides clinicians with an insight to using a multidimensional clinical-reasoning framework to identify and target the key drivers of the disorder, and to using cognitive functional therapy to address unhelpful psychological and behavioral responses to pain in a person with PLBP and high pain-related fear. Level of Evidence Therapy, level 5. J Orthop Sports Phys Ther 2017;47(9):637-651. Epub 13 Jul 2017. doi:10.2519/jospt.2017.7371.

Multidimensional Prognostic Modelling in People With Chronic Axial Low Back Pain

Objectives: To derive prognostic models for people with chronic low back pain (CLBP) (n=294) based upon an extensive array of potentially prognostic multidimensional factors. Materials and Methods: This study entered multidimensional data (demographics, pain characteristics, pain responses to movement, behaviors associated with pain, pain sensitivity, psychological, social, health, lifestyle) at baseline, and interventions undertaken, into prognostic models for pain intensity, disability, global rating of change and bothersomeness at 1-year. Results: The prognostic model for higher pain intensity (explaining 23.2% of the variance) included higher baseline pain intensity and punishing spousal interactions, and lower years in education, while participating in exercise was prognostic of lower pain intensity. The model for higher disability (33.6% of the variance) included higher baseline disability, longer forward bending time, psychological principal component scores representing negative pain-related cognitions and punishing spousal interactions; while exercising was prognostic of lower disability. The odds of reporting global rating of change much/very much improved were increased by participating in exercise, having leg pain as well as CLBP and having greater chronic pain acceptance. The receiver operating characteristic area under the curve was 0.72 indicating acceptable discrimination. The odds of reporting very/extremely bothersome CLBP were increased by having higher baseline pain intensity, longer forward bending time and receiving injection(s); while higher age, more years in education and having leg pain decreased the odds (receiver operating characteristic area under the curve, 0.80; acceptable discrimination). Discussion: The variance explained by prognostic models was similar to previous reports, despite an extensive array of multidimensional baseline variables. This highlights the inherent multidimensional complexity of CLBP.

Pain provocation following sagittal plane repeated movements in people with chronic low back pain: Associations with pain sensitivity and psychological profiles

Abstract Background and aims Provocative pain responses following standardised protocols of repeated sagittal plane spinal bending have not been reported in people with chronic low back pain (CLBP). Potential differing pain responses to movement likely reflect complex sensorimotor interactions influenced by physical, psychological and neurophysiological factors. To date, it is unknown whether provocative pain responses following repeated bending are associated with different pain sensitivity and psychological profiles. Therefore the first aim of this study was to determine whether data-driven subgroups with different, clinically-important pain responses following repeated movement exist in a large CLBP cohort, specifically using a standardised protocol of repeated sagittal plane spinal bending. The second aim was to determine if the resultant pain responses following repeated movement were associated with pain and disability, pain sensitivity and psychological factors. Methods Clinically-important (≥2-points, 11-point numeric rating scale) changes in pain intensity following repeated forward/backward bending were examined. Participants with different provocative pain responses to forward and backward bending were profiled on age, sex, pain sensitivity, psychological variables, pain characteristics and disability. Results Three groups with differing provocative pain responses following repeated movements were derived: (i) no clinically-important increased pain in either direction (n = 144, 49.0%), (ii) increased pain with repeated bending in one direction only (unidirectional, n = 112, 38.1%), (iii) increased pain with repeated bending in both directions (bidirectional, n = 38, 12.9%). After adjusting for psychological profile, age and sex, for the group with bidirectional pain provocation responses following repeated spinal bending, higher pressure and thermal pain sensitivity were demonstrated, while for the group with no increase in pain, better cognitive and affective psychological questionnaire scores were evident. However, these associations between provocative pain responses following movement and pain sensitivity and psychological profiles were weak. Conclusions Provocative pain responses following repeated movements in people with CLBP appear heterogeneous, and are weakly associated with pain sensitivity and psychological profiles. Implications To date, suboptimal outcomes in studies examining exercise interventions targeting directional, movement-based subgroups in people with CLBP may reflect limited consideration of broader multidimensional clinical profiles associated with LBP. This article describes heterogeneous provocative pain responses following repeated spinal bending, and their associated pain sensitivity and psychological profiles, in people with CLBP. These findings may help facilitate targeted management. For people with no increase in pain, the lack of pain provocation following repeated spinal bending, in combination with a favourable psychological profile, suggests this subgroup may have fewer barriers to functional rehabilitation. In contrast, those with pain provoked by both forward and backward bending may require specific interventions targeting increased pain sensitivity and negative psychological cognitions and affect, as these may be may be important barriers to functional rehabilitation.

Response to: "Letter to the Editor entitled: Unjustified extrapolation" [by authors: Supp G., Rosedale R., Werneke M.]

The aim of our paper was not a critique or review of movement ased classification systems, as it appears to have been perceived y Supp et al. Rather, the rationale for undertaking this study was ased upon the fact that all contemporary movement based clasification systems for low back pain (as described by O’Sullivan, ahrmann, McKenzie, etc.) involve a degree of clinical judgement, .e. they involve and/or were developed based upon clinical opinion r theoretical models. We would like to re-iterate that data-driven i.e. non-judgemental) subgrouping involves statistical subgroup erivation, without any reliance upon clinical opinion or underlyng theoretical models. The data is allowed to “speak for itself” [1]. s we were not aware of any purely data driven movement based lassification systems for people with low back pain, we wanted to xamine this possibility. Hence, participants were instructed what pecific task to perform, but not given specific instructions on how o perform the movements and they were asked to rate their pain sing a numeric pain rating scale.