Relationship between psychological factors and spinal motor behaviour in low back pain: a systematic review and meta-analysis

Associations between pain-related fear and lumbar movement variability during activities of daily living in patients with chronic low back pain and healthy controls

Low back pain (LBP) is a global issue involving biological, psychological, and social factors. Pain-related fear has been shown to influence movement behavior, however, its association with some measures of movement behavior, such as spinal movement variability, remains inconclusive. To further investigate this, spinal kinematics during various activities of daily living (i.e., walking, running, lifting, and stair climbing) of 49 patients with chronic LBP and a group of 51 sex-, age-, and BMI-matched healthy controls were used to calculate lumbar spine movement variability which was quantified using different indices (i.e., coefficient of variation, coupling angle variability in vector coding, deviation phase of the continuous relative phase and an angle-angular velocity variability). General and task-specific pain-related fear was assessed using the Tampa Scale of Kinesiophobia and the Photograph Series of Daily Activities-Short Electronic Version, respectively. Linear regression analyses showed no significant association between movement variability and pain-related fear, however, the sample consisted of younger individuals with moderate disability and with low levels of pain and pain-related fear. In addition, the different variability indices were weakly correlated and varied greatly depending on the method used and the task performed. Therefore, comparisons between studies with different movement variability calculation methods or different activities should be treated with caution.

Pain-related threat and coordination in adults with chronic low back pain during a lifting task: A cross-sectional study

OBJECTIVES

People with low back pain (LBP) exhibit altered coordination, possibly indicating guarded movement. The connection between these changes and pain-related threat remains unclear. We aimed to determine if pain-related threat was related to spinal coordination and variability, during a lifting task, in people with chronic LBP.

METHODS

Participants were adults with chronic LBP (n = 47). Upper lumbar, lower lumbar, and hipkinematics were measured during 10crate lifting/lowering repetitions. Coordination and variability of the Hip-Lower Lumbar, and Lower Lumbar-Upper Lumbar joint pairs were calculated. Pain-related threat was measured using the Tampa Scale for Kinesiophobia, the Pain Catastrophizing Scale, and task-specific fear. Linear regression analyses tested the relationship between pain-related threat and coordination.

RESULTS

Adding catastrophizing to our base model (sex) explained variance in Hip-Lower lumbar coordination (r2 change = 0.125, p = 0.013). General and task specific measures of fear were unrelated to coordination and variability at both joint pairs (r2 change < 0.064, p > 0.05). Exploratory t-tests revealed subgroups aligned with phenotypes of "tight" and "loose" control, where "tight" control was characterized by greater catastrophizing and disability.

CONCLUSION

Pain catastrophizing, but not measures of fear, was related to more in-phase ("tight") Hip-Lower Lumbar coordination during lifting/lowering. Considering this relationship based on subgroups may add clarity.

Task-Specific Perceived Harmfulness Predicts Protective Movement Behaviour in Chronic Low Back Pain

Background/Objectives: There is emerging evidence that task-specific pain-related psychological measures may better predict movement behaviour in chronic low back pain (CLBP) than general pain-related psychological measures. Currently, little is known regarding the prediction of movement duration and movement velocity. Methods: Baseline data from a previously published randomized controlled trial were used (clinicaltrials.gov NCT02773160). Fifty-five patients with CLBP and 54 pain-free persons performed a lifting task while kinematic measurements were obtained to calculate movement velocity of the L1 vertebra, S1 vertebra, and the lumbar spine, as well as the time to complete the lifting task. Scores on the Photograph Daily Activities Series-Short Electronic Version (PHODA-SeV), Tampa Scale for Kinesiophobia (TSK), and its Activity Avoidance and Somatic Focus subscales were used as general pain-related psychological measures. The score on a picture of the PHODA-SeV, showing a person lifting an object with a bent back (PHODA-Lift), was used as task-specific measure of perceived harmfulness. Results: The task-specific measure best predicted movement duration and movement velocity of L1 and the lumbar spine, and explained 35%, 19%, and 25% of the respective movement parameters. Although general perceived harmfulness predicted S1 velocity and movement duration, it only explained 6% and 8% of the respective movement parameters. General measures of pain-related fear were not predictive for any of the movement parameters. It took patients with CLBP significantly longer to complete the lifting task when compared to the pain-free participants (ES = 1.01, p < 0.0001), and patients with CLBP also moved significantly slower at L1 (ES = 0.85, p < 0.0001) and the lumbar spine (ES = 1.01, p < 0.0001). These between-groups differences were larger for CLBP subgroups with higher scores on the PHODA-Lift, and to some extent for subgroups with higher total scores on the PHODA-SeV. Conclusions: Task-specific perceived harmfulness best predicts movement velocity. General pain-related fear measures (i.e., TSK and its subscales) do not predict these movement parameters.

Pain catastrophizing and trunk co-contraction during lifting in people with and without chronic low back pain: A cross sectional study

BACKGROUND

Trunk co-contraction during lifting may reflect a guarded motor response to a threatening task. This work estimated the impact of pain catastrophizing on trunk co-contraction during lifting, in people with and without low back pain.

METHODS

Adults with high pain catastrophizing (back pain: n = 29, healthy: n = 7) and low pain catastrophizing (back pain: n = 20, healthy: n = 11), performed 10 repetitions of a lifting task. Electromyography data of rectus abdominis, erector spinae and external oblique muscles were collected, bilaterally. Co-contraction indices were determined for rectus abdominis/erector spinae and external oblique/erector spinae pairings, bilaterally. Pain catastrophizing was measured using the pain catastrophizing scale and task-specific fear using the Photograph series of daily activities scale. Three-way mixed ANOVAs tested the effects of group (back pain vs. healthy), pain catastrophizing (high vs. low), lifting phase (lifting vs. replacing) and their interactions.

RESULTS

There were no main effects of pain catastrophizing, lifting phase, nor any interactions (p > 0.05). Group effects revealed greater co-contraction for bilateral erector spinae/rectus abdominis pairings (but not erector spinae-external oblique pairings) in people with back pain, compared to healthy participants, independent of pain catastrophizing and lifting phase (p < 0.05). Spearman correlations associated greater task-specific fear and greater erector spinae-left external oblique co-contraction, only in people with back pain (p < 0.05).

CONCLUSIONS

Greater co-contraction in the back pain group occurred independent of pain catastrophizing, as measured with a general questionnaire. A task-specific measure of threat may be more sensitive to detecting relationships between threat and co-contraction.

SIGNIFICANCE STATEMENT

This work contributes evidence that people with back pain commonly exhibit trunk co-contraction when lifting. The lack of a relationship between pain catastrophizing and trunk co-contraction, however, challenges evidence linking psychological factors and guarded motor behaviour in this group. Together, this suggests that other factors may be stronger determinants of co-contraction in people with LBP or that a general construct like pain catastrophizing may not accurately represent this relationship.

Changes in spinal motor behaviour are associated with reduction in disability in chronic low back pain: A longitudinal cohort study with 1-year follow-up

BACKGROUND

The need to improve spinal motor behaviour in chronic low back pain (CLBP) rehabilitation remains unclear. The objective of this study was to test if changes in spinal motor behaviour were associated with changes in disability after an interdisciplinary rehabilitation program (IRP) in patients with CLBP.

METHODS

Seventy-one patients with CLBP participating in an IRP were included. Spinal motor behaviour was assessed with biomechanical (lumbar angular amplitude and velocity, erector spinae muscle activity and duration of the task), cognitive-emotional (task-specific fear [PRF]) and pain-related (movement-evoked pain [MEP]) measures during a lifting task before and after the IRP. Disability was measured before and after the IRP, and at 3-month and 1-year follow-ups.

RESULTS

After adjusting for confounders, changes in disability were significantly associated with MEP changes (β adj. = 0.49, p < 0.001) and PRF changes (β adj. = 0.36, p = 0.008), but not with changes in any of the biomechanical measures. MEP at the end of IRP was also associated with disability at 3 months (β adj. = 0.37, p = 0.001) and 1 year (β adj. = 0.42, p = 0.01). Biomechanical measures at the end of the IRP were not associated with disability, except for the duration of the task that was significantly associated with reduction of disability at 3 months (β non-adj = 0.5, p < 0.001).

CONCLUSIONS

Pain-related and cognitive-emotional measures of spinal motor behaviour were associated with reduction in disability following an IRP. Future research is needed to further investigate causal relationships between spinal motor behaviour and disability.

SIGNIFICANCE STATEMENT

This study supports a multidimensional understanding and analysis of spinal motor behaviour, integrating the cognitive-emotional, pain-related and biomechanical domains. It also supports the consideration of spinal motor behaviour as a potentially important treatment target in chronic low back pain management. Moreover, it suggests that reducing movement-evoked pain and task-specific fear may have more influence on disability than changing lumbar amplitude, lumbar angular velocity or erector muscle activity, which may have important implications for rehabilitation.

Patients' expectations of physiotherapists before and after an intensive chronic low back pain rehabilitation programme: a qualitative study based on semi-structured interviews and observations

PURPOSE

To investigate the expectations regarding physiotherapists of patients attending an interdisciplinary CLBP rehabilitation programme and the response to these expectations.

MATERIALS AND METHODS

A thematic analysis was conducted, based on interviews of working-age patients with CLBP and without significant comorbidities.

RESULTS

Twenty patients participated (9 male, 11 female, aged 21-58 years; symptoms duration 4.3 ± 3.0 years; pain VAS 53 ± 21 mm). Patients expected to learn pain and activity management. Expected outcomes were a reduction of pain, increased well-being and a return to normality. A collaborative approach involving therapeutic and relational adaptation was expected. Despite divergences concerning emotional aspects, patients expected a large range of applied psychosocial skills.The programme met the expectations of most patients, especially when its goals matched those reported by the individuals. For most participants, the pain relief was below expectations. Active therapies were valued. After the programme, patients felt more ready to take responsibility for their back.

CONCLUSION

The expectation of developing self-management skills was prevalent. Expected treatments were mostly compatible with recommendations. Expectations to resume activities and decrease pain were in line with the rehabilitation goals, although the expected reduction in pain was overestimated. Relational expectations converged towards patient-centred care.

Empowering patients with persistent pain: The potential of cognitive functional therapy in interdisciplinary care: A single-case experimental design

INTRODUCTION AND PURPOSE

Persistent musculoskeletal pain (PMP) is multifactorial and causes both societal and financial burdens. Integration of multifactorial management in patients with PMP remains challenging. A single-case experimental design was performed on three patients suffering from high impact PMP (lumbar spine, shoulder and knee) to i) assess the potential for Cognitive Functional Therapy (CFT) in interdisciplinary care, ii) describe in detail the clinical journey patients experienced during the intervention, and iii) evaluate the changes and associations in relation to the outcome measures of pain, disability, maladaptive movement behavior, subjective overall improvement, health related quality of life and work status. These were monitored over one year, at the end of each of the six intervention modules.

RESULTS

After introducing the intervention systematic changes were seen, with medium to large changes (Non-overlap of All Pairs 0.67-1) for all outcome measures. Associations between changes of the outcome measures were large (r ≥ 0.50) and changes occurred concurrently. Minimally clinically important difference thresholds were exceeded for all outcome measures and two patients achieved relevant improvements related to work reintegration.

DISCUSSION

The positive results of this study are comparable with recent CFT studies. However, the difference regarding the number of sessions and duration of the intervention is evident. The length of the intervention in this study seemed to enable continuous significant improvements up until 12 months post onset and follow-up.

CONCLUSION

CFT in interdisciplinary care was effective for all measures. The detailed descriptions of the clinical processes aim to improve clinical care.

Guarding and flow in the movements of people with chronic pain: A qualitative study of physiotherapists' observations

BACKGROUND

Among the adaptations of movement consistently associated with disability in chronic pain, guarding is common. Based on previous work, we sought to understand better the constituents of guarding; we also used the concept of flow to explore the description of un/naturalness that emerged from physiotherapists' descriptions of movement in chronic pain. The aim was to inform the design of technical systems to support people with chronic pain in everyday activities.

METHODS

Sixteen physiotherapists, experts in chronic pain, were interviewed while repeatedly watching short video clips of people with chronic low back pain doing simple movements; physiotherapists described the movements, particularly in relation to guarding and flow. The transcribed interviews were analysed thematically to elaborate these constructs.

RESULTS

Moderate agreement emerged on the extent of guarding in the videos, with good agreement that guarding conveyed caution about movement, distinct from biomechanical variables of stiffness or slow speed. Physiotherapists' comments on flow showed slightly better agreement, and described the overall movement in terms of restriction (where there was no flow or only some flow), of tempo of the entire movement, and as naturalness (distinguished from normality of movement).

CONCLUSIONS

These qualities of movement may be useful in designing technical systems to support self-management of chronic pain.

SIGNIFICANCE

Drawing on the descriptions of movements of people with chronic low back pain provided by expert physiotherapists to standard stimuli, two key concepts were elaborated. Guarding was distinguished from stiffness (a physical limitation) or slowness as motivated by fear or worry about movement. Flow served to describe harmonious and continuous movement, even when adapted around restrictions of pain. Movement behaviours associated with pain are better understood in terms of their particular function than aggregated without reference to function.

The association between pain-related psychological variables and postural control in low back pain: A systematic review and meta-analysis

BACKGROUND

Alterations in postural control have been found in individuals with low back pain (LBP), particularly during challenging postural tasks. Moreover, higher levels of negative pain-related psychological variables are associated with increased trunk muscle activity, reduced spinal movement, and worse maximal physical performance in individuals with LBP.

RESEARCH QUESTION

Are pain-related psychological variables associated with postural control during static bipedal standing tasks in individuals with LBP?

METHODS

A systematic review and meta-analysis were conducted. Pubmed, Web of Science, and PsycINFO were searched until March 2023. Studies were included if they evaluated postural control during static bipedal standing in individuals with LBP by measuring center of pressure (CoP) variables, and reported at least one pain-related psychological variable. Correlation coefficients between pain-related psychological variables and CoP variables were extracted. Study quality was assessed with the "Quality In Prognosis Studies" tool (QUIPS). Random-effect models were used to calculate pooled correlation coefficients for different postural tasks. Sub-analyses were performed for positional or dynamic CoP variables. Certainty of evidence was assessed with an adjusted "Grading of Recommendations, Assessment, Development, and Evaluations" tool (GRADE). The protocol was registered on PROSPERO (CRD42021241739).

RESULTS

Sixteen studies (n = 723 participants) were included. Pain-related fear (16 studies) and pain catastrophizing (three studies) were the only reported pain-related psychological variables. Both pain-related fear (-0.04 < pooled r < 0.14) and pain catastrophizing (0.28 < pooled r < 0.29) were weakly associated with CoP variables during different postural tasks. For all associations, the certainty of evidence was very low.

SIGNIFICANCE

Pain-related fear and pain catastrophizing are only weakly associated with postural control during static bipedal standing in individuals with LBP, regardless of postural task difficulty. Certainty of evidence is very low thus it is conceivable that future studies accounting for current study limitations might reveal different findings.

The relationships between spinal amplitude of movement, pain and disability in low back pain: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

The role of spinal movement alterations in low back pain (LBP) remains unclear. This systematic review and meta-analyses examined the relationships between spinal amplitude of movement, disability and pain intensity in patients with LBP.

DATABASES AND DATA TREATMENT

We searched PubMed, CINAHL, Embase, Pedro and Web of Science for relevant articles until 14th March 2023. Risk of bias was assessed with the Quality in Prognostic Studies Tool. We analysed the relationships between amplitude of movement, disability and pain intensity with standard correlational meta-analyses and meta-analytic structural equation modelling (MASEM) in cross-sectional and longitudinal data.

RESULTS

A total of 106 studies (9001 participants) were included. In cross-sectional data, larger amplitude of movement was associated with lower disability (pooled coefficient: -0.25, 95% confidence interval: [-0.29 to -0.21]; 69/5899 studies/participants) and pain intensity (-0.13, [-0.17 to -0.09]; 74/5806). An increase in amplitude of movement was associated with a decrease in disability (-0.23, [-0.31 to -0.15]; 33/2437) and pain intensity (-0.25, [-0.33 to -0.17]; 38/2172) in longitudinal data. MASEM revealed similar results and, in addition, showed that amplitude of movement had a very small influence on the pain intensity-disability relationship.

CONCLUSIONS

These results showed a significant but small association between amplitude of movement and disability or pain intensity. Moreover, they demonstrated a direct association between an increase in amplitude of movement and a decrease in pain intensity or disability, supporting interventions aiming to reduce protective spinal movements in patients with LBP.

SIGNIFICANCE

The large meta-analyses performed in this work revealed an association between reductions in spinal amplitude of movement and increased levels of disability and pain intensity in people with LBP. Moreover, it highlighted that LBP recovery is associated with a reduction in protective motor behaviour (increased amplitude of movement), supporting the inclusion of spinal movement in the biopsychosocial understanding and management of LBP.

Trunk resistance to mechanical perturbations, associations with low back pain, pain-related cognitions and movement precision

BACKGROUND

Pain-related cognitions are associated with motor control changes in people with chronic low-back pain (CLBP). The mechanism underlying this association is unclear. We propose that perceived threat increases muscle-spindle-reflex-gains, which reduces the effect of mechanical perturbations, and simultaneously decreases movement precision.

AIM

To evaluate effects of CLBP and pain-related cognitions on the impact of mechanical perturbations on trunk movement, and associations between these perturbation effects and movement precision.

METHODS

30 participants with CLBP and 30 healthy controls, performed two consecutive trials of a seated repetitive reaching task. During both trials participants were warned for mechanical perturbations, which were only administered during the second trial. The perturbation effect was characterized by the deviation of the trajectory of the T8 vertebra relative to the sacrum. Trunk movement precision was expressed as tracking error during a trunk movement target tracking task. We assessed pain-related cognitions with the task-specific 'Expected Back Strain'-scale (EBS). We used a two-way-Anova to assess the effect of Group (CLBP vs back-healthy) and dichotomized EBS (higher vs lower) on the perturbation effect, and a Pearson's correlation to assess associations between perturbation effects and movement precision.

FINDINGS

Higher EBS was associated with smaller perturbation effects (p ≤ 0.011). A negative correlation was found between the perturbation effect and the tracking error, in the higher EBS-group (r = -0.5, p = 0.013).

INTERPRETATION

These results demonstrate that pain-related cognitions influence trunk movement control and support the idea that more negative pain-related cognitions lead to an increased resistance against perturbations, at the expense of movement precision.

An exploration of knowledge-organizing technologies to advance transdisciplinary back pain research

Chronic low back pain (LBP) is influenced by a broad spectrum of patient-specific factors as codified in domains of the biopsychosocial model (BSM). Operationalizing the BSM into research and clinical care is challenging because most investigators work in silos that concentrate on only one or two BSM domains. Furthermore, the expanding, multidisciplinary nature of BSM research creates practical limitations as to how individual investigators integrate current data into their processes of generating impactful hypotheses. The rapidly advancing field of artificial intelligence (AI) is providing new tools for organizing knowledge, but the practical aspects for how AI may advance LBP research and clinical are beginning to be explored. The goals of the work presented here are to: (1) explore the current capabilities of knowledge integration technologies (large language models (LLM), similarity graphs (SGs), and knowledge graphs (KGs)) to synthesize biomedical literature and depict multimodal relationships reflected in the BSM, and; (2) highlight limitations, implementation details, and future areas of research to improve performance. We demonstrate preliminary evidence that LLMs, like GPT-3, may be useful in helping scientists analyze and distinguish cLBP publications across multiple BSM domains and determine the degree to which the literature supports or contradicts emergent hypotheses. We show that SG representations and KGs enable exploring LBP's literature in novel ways, possibly providing, trans-disciplinary perspectives or insights that are currently difficult, if not infeasible to achieve. The SG approach is automated, simple, and inexpensive to execute, and thereby may be useful for early-phase literature and narrative explorations beyond one's areas of expertise. Likewise, we show that KGs can be constructed using automated pipelines, queried to provide semantic information, and analyzed to explore trans-domain linkages. The examples presented support the feasibility for LBP-tailored AI protocols to organize knowledge and support developing and refining trans-domain hypotheses.

Associations between Combined Psychological and Lifestyle Factors with Pain Intensity and/or Disability in Patients with Chronic Low Back Pain: A Cross-Sectional Study

Chronic low back pain (CLBP) is common in primary care, causing disability and economic burden globally. We aimed to compare socio-demographic, health, lifestyle, and psychological factors in people with and without CLBP and correlate them with clinical outcomes in people with CLBP. A total of 253 volunteers with and 116 without CLBP provided sociodemographic information, daily habits, medical history, subjective sleep complaints (Penn State Sleep Questionnaire), low back pain intensity, and disability (Quebec Back Pain Disability Scale), as well as the Zung Self-Rating Scale for self-assessment of depression and Self-Rating Anxiety Scale. CLBP diagnosis was linked with female gender and older age, as well as a higher level of sleep complaints such as sleepiness, OSA and insomnia symptoms, and a higher prevalence of moderate to severe depressive symptoms. The combination of moderate to severe depressive symptoms with obstructive sleep apnea or insomnia symptoms was the most important predictive factor for functional disability in CBLP patients (OR 13.686, 95% CI 4.581-40.885; p < 0.001). In conclusion, depressive symptoms and subjective sleep complaints appear to relate to greater CLBP intensity and/or CLBP-related disability in people with CLBP. A holistic approach is crucial for treating chronic CLBP patients, including psychological and sleep issue assessment and management, to improve their quality of life.

Dynamic postural control in women athletes with and without nonspecific low back pain with high and low pain-related anxiety- A case-control study

BACKGROUND

Low back pain is common among athletes and it has been shown that postural control is altered in the general population with nonspecific low back pain (NSLBP). Psychological factors may also predispose individuals to risk of altered postural control. Dynamic postural control is essential to the performance of athletes. This study aimed to compare the dynamic postural control between women athletes with and without NSLBP with high and low pain-related anxiety.

METHODS

Forty-five female athletes (15 NSLBP with high pain-related anxiety, 15 NSLBP with low pain-related anxiety, and 15 healthy (control)) were included. Pain-related anxiety was assessed using the Pain Anxiety Symptom Scale-20 (PASS-20). Based on the cut-off score of 30 for the total score of PASS-20, NSLBP patients were classified into two groups of low and high pain-related anxiety. Participants performed double-leg vertical drop jump (DVJ) and single-leg vertical jump (SVJ) tests on a Kistler force plate (type 9260AA6, Kistler Instruments Inc, Switzerland). The total root mean square (RMS) of the center of pressure (COP), COP displacement in the anteroposterior (AP), and mediolateral (ML) directions, COP mean velocity, and time to stabilization (TTS) in vertical, AP, and total directions were extracted from COP and ground reaction force data using MATLAB software. One-way Analysis of variance (ANOVA) and Welch's ANOVA were employed to compare the groups. In case of significant findings, post hoc tests were performed.

RESULTS

The results showed that during DJV, athletes with high pain-related anxiety had significantly greater TTS in all total, AP, and ML directions than other groups (P < 0.05). Also, the control group showed greater total RMS distance during DJV than either NSLBP group. However, no significant differences in TTS and COP parameters were found between the groups during SVJ (P > 0.05).

CONCLUSIONS

The findings suggest that pain-related anxiety may contribute to athletes' postural control strategies. Therefore, it is important to consider the level of pain-related anxiety during planning postural control exercises for women athletes with NSLBP.

The Role of Back Muscle Dysfunctions in Chronic Low Back Pain: State-of-the-Art and Clinical Implications

Changes in back muscle function and structure are highly prevalent in patients with chronic low back pain (CLBP). Since large heterogeneity in clinical presentation and back muscle dysfunctions exists within this population, the potential role of back muscle dysfunctions in the persistence of low back pain differs between individuals. Consequently, interventions should be tailored to the individual patient and be based on a thorough clinical examination taking into account the multidimensional nature of CLBP. Considering the complexity of this process, we will provide a state-of-the-art update on back muscle dysfunctions in patients with CLBP and their implications for treatment. To this end, we will first give an overview of (1) dysfunctions in back muscle structure and function, (2) the potential of exercise therapy to address these dysfunctions, and (3) the relationship between changes in back muscle dysfunctions and clinical parameters. In a second part, we will describe a framework for an individualised approach for back muscle training in patients with CLBP.

Biomechanical Phenotyping of Chronic Low Back Pain: Protocol for BACPAC

OBJECTIVE

Biomechanics represents the common final output through which all biopsychosocial constructs of back pain must pass, making it a rich target for phenotyping. To exploit this feature, several sites within the NIH Back Pain Consortium (BACPAC) have developed biomechanics measurement and phenotyping tools. The overall aims of this article were to: 1) provide a narrative review of biomechanics as a phenotyping tool; 2) describe the diverse array of tools and outcome measures that exist within BACPAC; and 3) highlight how leveraging these technologies with the other data collected within BACPAC could elucidate the relationship between biomechanics and other metrics used to characterize low back pain (LBP).

METHODS

The narrative review highlights how biomechanical outcomes can discriminate between those with and without LBP, as well as among levels of severity of LBP. It also addresses how biomechanical outcomes track with functional improvements in LBP. Additionally, we present the clinical use case for biomechanical outcome measures that can be met via emerging technologies.

RESULTS

To answer the need for measuring biomechanical performance, our "Results" section describes the spectrum of technologies that have been developed and are being used within BACPAC.

CONCLUSION AND FUTURE DIRECTIONS

The outcome measures collected by these technologies will be an integral part of longitudinal and cross-sectional studies conducted in BACPAC. Linking these measures with other biopsychosocial data collected within BACPAC increases our potential to use biomechanics as a tool for understanding the mechanisms of LBP, phenotyping unique LBP subgroups, and matching these individuals with an appropriate treatment paradigm.

Tampa Scale of Kinesiophobia may underestimate task-specific fear of movement in people with and without low back pain

Introduction

The Tampa Scale of Kinesiophobia (TSK) is commonly used to assess fear of movement (FoM) in people with low back pain (LBP). However, the TSK does not provide a task-specific measure of FoM, whereas image-based or video-based methods may do so.

Objectives

To compare the magnitude of FoM when assessed using 3 methods (TSK-11, image of lifting, video of lifting) in 3 groups of people: current LBP (LBP), recovered LBP (rLBP), and asymptomatic controls (control).

Methods

Fifty-one participants completed the TSK-11 and rated their FoM when viewing images and videos depicting people lifting objects. Low back pain and rLBP participants also completed the Oswestry Disability Index (ODI). Linear mixed models were used to estimate the effects of methods (TSK-11, image, video) and group (control, LBP, rLBP). Linear regression models were used to assess associations between the methods on ODI after adjusting for group. Finally, a linear mixed model was used to understand the effects of method (image, video) and load (light, heavy) on fear.

Results

In all groups, viewing images (P = 0.009) and videos (P = 0.038) elicited greater FoM than that captured by the TSK-11. Only the TSK-11 was significantly associated with the ODI (P < 0.001). Finally, there was a significant main effect of load on fear (P < 0.001).

Conclusion

Fear of specific movements (eg, lifting) may be better measured using task-specific measures, such as images and videos, than by task-generic questionnaires, such as the TSK-11. Being more strongly associated with the ODI, the TSK-11 still plays an important role in understanding the impact of FoM on disability.

Neuromuscular adaptations to experimentally induced pain in the lumbar region: systematic review and meta-analysis

ABSTRACT

Experimental pain models are frequently used to understand the influence of pain on the control of human movement. In this systematic review, we assessed the effects of experimentally induced pain in the lumbar region of healthy individuals on trunk muscle activity and spine kinematics. Databases were searched from inception up to January 31, 2022. In total, 26 studies using either hypertonic saline injection (n = 19), heat thermal stimulation (n = 3), nociceptive electrical stimulation (n = 3), or capsaicin (n = 1) were included. The identified adaptations were task dependent, and their heterogeneity was partially explained by the experimental pain model adopted. Meta-analyses revealed an increase of erector spinae activity (standardized mean difference = 0.71, 95% confidence interval [CI] = 0.22-1.19) during full trunk flexion and delayed onset of transversus abdominis to postural perturbation tasks (mean difference = 25.2 ms, 95% CI = 4.09-46.30) in the presence of pain. Low quality of evidence supported an increase in the activity of the superficial lumbar muscles during locomotion and during voluntary trunk movements during painful conditions. By contrast, activity of erector spinae, deep multifidus, and transversus abdominis was reduced during postural perturbation tasks. Reduced range of motion of the lumbar spine in the presence of pain was supported by low quality of evidence. Given the agreement between our findings and the adaptations observed in clinical populations, the use of experimental pain models may help to better understand the mechanisms underlying motor adaptations to low back pain.

The effect of chronic low back pain on postural control during quiet standing: A meta-analysis

Low back pain (LBP) has been associated with altered body sway during quiet standing, but the pattern of results is inconsistent. The purpose of this meta-analysis is to examine the effects of vision (eyes open, eyes closed) and changing the support surface (foam surface, firm surface) on postural sway during quiet standing in individuals with chronic LBP (cLBP). Five electronic databases were searched on March 27th, 2022. Of 2,856, 16 studies (n = 663) were included. Across all conditions, we found a positive and medium effect size (g = 0.77 [0.50, 1.04]) that represented greater body sway in individuals with cLBP. Subgroup analyses revealed medium effects during eyes open conditions (firm surface: g = 0.60 [0.33, 0.87]; foam surface: g = 0.68 [0.38, 0.97]), and large effects during eyes closed conditions (firm surface: g = 0.97 [0.60, 1.35]; foam surface: g = 0.89 [0.28, 1.51]). We quantified effects of self-reported pain and found a moderate effect during eyes closed plus firm surface conditions (Q = 3.28; p = 0.070). We conclude that cLBP is associated with increased postural sway, with largest effect sizes evident when vision is removed and when self-reported pain intensity is higher.

Associations between gait performance and pain intensity, psychosocial factors, executive functions as well as prefrontal cortex activity in chronic low back pain patients: A cross-sectional fNIRS study

Introduction

Activities of daily living, such as walking, are impaired in chronic low back pain (CLBP) patients compared to healthy individuals. Thereby, pain intensity, psychosocial factors, cognitive functioning and prefrontal cortex (PFC) activity during walking might be related to gait performance during single and dual task walking (STW, DTW). However, to the best of our knowledge, these associations have not yet been explored in a large sample of CLBP patients.

Method

Gait kinematics (inertial measurement units) and PFC activity (functional near-infrared spectroscopy) during STW and DTW were measured in 108 CLBP patients (79 females, 29 males). Additionally, pain intensity, kinesiophobia, pain coping strategies, depression and executive functioning were quantified and correlation coefficients were calculated to determine the associations between parameters.

Results

The gait parameters showed small correlations with acute pain intensity, pain coping strategies and depression. Stride length and velocity during STW and DTW were (slightly to moderately) positively correlated with executive function test performance. Specific small to moderate correlations were found between the gait parameters and dorsolateral PFC activity during STW and DTW.

Conclusion

Patients with higher acute pain intensity and better coping skills demonstrated slower and less variable gait, which might reflect a pain minimization strategy. Psychosocial factors seem to play no or only a minor role, while good executive functions might be a prerequisite for a better gait performance in CLBP patients. The specific associations between gait parameters and PFC activity during walking indicate that the availability and utilization of brain resources are crucial for a good gait performance.

Understanding Discrepancies in a Person's Fear of Movement and Avoidance Behavior: A Guide for Musculoskeletal Rehabilitation Clinicians Who Support People With Chronic Musculoskeletal Pain

BACKGROUND: Generic self-report measures do not reflect the complexity of a person's pain-related behavior. Since variations in a person's fear of movement and avoidance behavior may arise from contextual and motivational factors, a person-centered evaluation is required-addressing the cognitions, emotions, motivation, and actual behavior of the person. CLINICAL QUESTION: Most musculoskeletal rehabilitation clinicians will recognize that different people with chronic pain have very different patterns of fear and avoidance behavior. However, an important remaining question for clinicians is "How can I identify and reconcile discrepancies in fear of movement and avoidance behavior observed in the same person, and adapt my management accordingly?" KEY RESULTS: We frame a clinical case of a patient with persistent low back pain to illustrate the key pieces of information that clinicians may consider in a person-centered evaluation (ie, patient interview, self-report measures, and behavioral assessment) when working with patients to manage fear of movement and avoidance behavior. CLINICAL APPLICATION: Understanding the discrepancies in a person's fear of movement and avoidance behavior is essential for musculoskeletal rehabilitation clinicians, as they work in partnership with patients to guide tailored approaches to changing behaviors. J Orthop Sports Phys Ther 2023;53(5):1-10. Epub: 9 March 2023. doi:10.2519/jospt.2023.11420.

The development and measurement properties of the Dutch version of the fear-avoidance components scale (FACS-D) in persons with chronic musculoskeletal pain

OBJECTIVES

The Fear-Avoidance Components Scale (FACS) is a recently developed patient-reported instrument assessing different constructs related to the fear-avoidance model of pain. The aim was to translate the original English FACS into Dutch (FACS-D) and assess its measurement properties in persons with chronic musculoskeletal pain.

METHODS

The original English FACS (20 item-scale, range: 0-100) was translated in Dutch through standard forward-backward translation methodology. The FACS-D's measurement properties were evaluated in 224 persons with chronic musculoskeletal pain. Internal consistency, test-retest reliability and measurement error were assessed with the Cronbach's alpha coefficient (α), intraclass correlation coefficient (ICC), and standard error of measurement (SEM). Construct validity was assessed through inter-item correlation analyses, exploratory factor analysis, association with other fear-avoidance-related constructs, and hypothesis testing.

RESULTS

Internal consistency, test-retest reliability and hypotheses testing were good (α=0.92; ICC=0.92, CI 0.80-0.96; 7/8 hypotheses confirmed). Similar to the original FACS and other translated versions, a two-factor model best fit the data. However, the item distribution differed from other versions. One factor represented "pain-related cognitions and emotions" and a second factor represented "avoidance behaviour." In contrast to the original FACS, low inter-item correlations for item 12 were found. The FACS-D was more strongly associated with fear-avoidance-related constructs of pain severity, perceived disability, feelings of injustice, and depressive/anxiety symptoms than the other fear-avoidance-related scales studied here.

CONCLUSIONS

The FACS-D demonstrated good reliability and construct validity, suggesting that it may be a useful measure for Dutch-speaking healthcare providers. Two clinically relevant factors, with a different item distribution than the original FACS, were identified: one covering items on pain-related cognitions and emotions, and one covering items on avoidance behaviour. The stronger association between FACS-D and fear-avoidance related constructs suggests that the FACS-D may be more effective in evaluating the cognitive, emotional and behavioural constructs of pain-related fear-avoidance than other similar measures.

Clinical phenotypes and prognostic factors in persons with hip osteoarthritis undergoing total hip arthroplasty: protocol for a longitudinal prospective cohort study (HIPPROCLIPS)

BACKGROUND

Large heterogeneity exists in the clinical manifestation of hip osteoarthritis (OA). It is therefore not surprising that pain and disability in individuals with hip OA and after total hip arthroplasty (THA) cannot be explained by biomedical variables alone. Indeed, also maladaptive pain-related cognitions and emotions can contribute to pain and disability, and can lead to poor treatment outcomes. Traumatic experiences, mental disorders, self-efficacy and social support can influence stress appraisal and strategies to cope with pain, but their influence on pain and disability has not yet been established in individuals with hip OA undergoing THA. This study aims (1) to determine the influence of traumatic experiences and mental disorders on pain processing before and shortly after THA (2) to identify preoperative clinical phenotypes in individuals with hip OA eligible for THA, (3) to identify pre- and early postoperative prognostic factors for outcomes in pain and disability after THA, and (4) to identify postoperative clinical phenotypes in individuals after THA.

METHODS

This prospective longitudinal cohort study will investigate 200 individuals undergoing THA for hip OA. Phenotyping variables and candidate prognostic factors include pain-related fear-avoidance behaviour, perceived injustice, mental disorders, traumatic experiences, self-efficacy, and social support. Peripheral and central pain mechanisms will be assessed with thermal quantitative sensory testing. The primary outcome measure is the hip disability and osteoarthritis outcome score. Other outcome measures include performance-based measures, hip muscle strength, the patient-specific functional scale, pain intensity, global perceived effect, and outcome satisfaction. All these measurements will be performed before surgery, as well as 6 weeks, 3 months, and 12 months after surgery. Pain-related cognitions and emotions will additionally be assessed in the early postoperative phase, on the first, third, fifth, and seventh day after THA. Main statistical methods that will be used to answer the respective research questions include: LASSO regression, decision tree learning, gradient boosting algorithms, and recurrent neural networks.

DISCUSSION

The identification of clinical phenotypes and prognostic factors for outcomes in pain and disability will be a first step towards pre- and postoperative precision medicine for individuals with hip OA undergoing THA.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05265858. Registered on 04/03/2022.

Reduction in pain-related fear is not associated with improvement in spinal biomechanics but with decrease in movement-evoked pain in patients with chronic low back pain

BACKGROUND AND AIMS

While a causal relationship between pain-related fear and spinal movement avoidance in patients with chronic low back pain (CLBP) has frequently been postulated, evidence supporting this relationship is limited. This study aimed to test if decreases in pain-related fear or catastrophizing were associated with improvements in spinal biomechanics, accounting for possible changes in movement-evoked pain.

METHODS

Sixty-two patients with CLBP were assessed before and after an interdisciplinary rehabilitation program (IRP). Pain-related fear was assessed with general and task-specific measures. Lower and upper lumbar angular amplitude and velocity as well as paraspinal muscle activity were recorded during five daily-life tasks to evaluate spinal biomechanics. Relationships were tested with multivariable linear regression analyses.

RESULTS

The large decreases in pain-related fear and catastrophizing following the IRP were scarcely and inconsistently associated with changes in spinal biomechanics (< 3% of the models reported a statistically significant association). Results remained comparable for activities inducing more or less fear, for specific or general measures of pain-related fear, and for analyses performed on the entire population or limited to subgroups of patients with higher levels of task-specific fear. In contrast, reductions in task-specific pain-related fear were significantly associated with decreases in movement-evoked pain in all tasks (r = 0.26-0.62, p ≤ 0.02).

CONCLUSION

This study does not support an association between pain-related fear and spinal movement avoidance. However, it provides evidence supporting a direct relationship between decreased pain-related fear and decreased movement-evoked pain, possibly explaining some mechanisms of the rehabilitation programs.

Data-driven network analysis identified subgroup-specific low back pain pathways: a cross-sectional GLA:D Back study

OBJECTIVES

To understand the physical, activity, pain, and psychological pathways contributing to low back pain (LBP) -related disability, and if these differ between subgroups.

METHODS

Data came from the baseline observations (n = 3849) of the "GLA:D Back" intervention program for long-lasting nonspecific LBP. 15 variables comprising demographic, pain, psychological, physical, activity, and disability characteristics were measured. Clustering was used for subgrouping, Bayesian networks (BN) were used for structural learning, and structural equation model (SEM) was used for statistical inference.

RESULTS

Two clinical subgroups were identified with those in subgroup 1 having worse symptoms than those in subgroup 2. Psychological factors were directly associated with disability in both subgroups. For subgroup 1, psychological factors were most strongly associated with disability (β = 0.363). Physical factors were directly associated with disability (β = -0.077), and indirectly via psychological factors. For subgroup 2, pain was most strongly associated with disability (β = 0.408). Psychological factors were common predictors of physical factors (β = 0.078), pain (β = 0.518), activity (β = -0.101), and disability (β = 0.382).

CONCLUSIONS

The importance of psychological factors in both subgroups suggests their importance for treatment. Differences in the interaction between physical, pain, and psychological factors and their contribution to disability in different subgroups may open the doors toward more optimal LBP treatments.

Effect of postural threat on motor control in people with and without low back pain

INTRODUCTION

Negative pain-related cognitions are associated with persistence of low-back pain (LBP), but the mechanism underlying this association is not well understood. We propose that negative pain-related cognitions determine how threatening a motor task will be perceived, which in turn will affect how lumbar movements are performed, possibly with negative long-term effects on pain.

OBJECTIVE

To assess the effect of postural threat on lumbar movement patterns in people with and without LBP, and to investigate whether this effect is associated with task-specific pain-related cognitions.

METHODS

30 back-healthy participants and 30 participants with LBP performed consecutive two trials of a seated repetitive reaching movement (45 times). During the first trial participants were threatened with mechanical perturbations, during the second trial participants were informed that the trial would be unperturbed. Movement patterns were characterized by temporal variability (CyclSD), local dynamic stability (LDE) and spatial variability (meanSD) of the relative lumbar Euler angles. Pain-related cognition was assessed with the task-specific 'Expected Back Strain'-scale (EBS). A three-way mixed Manova was used to assess the effect of Threat, Group (LBP vs control) and EBS (above vs below median) on lumbar movement patterns.

RESULTS

We found a main effect of threat on lumbar movement patterns. In the threat-condition, participants showed increased variability (MeanSDflexion-extension, p<0.000, η2 = 0.26; CyclSD, p = 0.003, η2 = 0.14) and decreased stability (LDE, p = 0.004, η2 = 0.14), indicating large effects of postural threat.

CONCLUSION

Postural threat increased variability and decreased stability of lumbar movements, regardless of group or EBS. These results suggest that perceived postural threat may underlie changes in motor behavior in patients with LBP. Since LBP is likely to impose such a threat, this could be a driver of changes in motor behavior in patients with LBP, as also supported by the higher spatial variability in the group with LBP and higher EBS in the reference condition.

Distinction of non-specific low back pain patients with proprioceptive disorders from healthy individuals by linear discriminant analysis

The central nervous system (CNS) dynamically employs a sophisticated weighting strategy of sensory input, including vision, vestibular and proprioception signals, towards attaining optimal postural control during different conditions. Non-specific low back pain (NSLBP) patients frequently demonstrate postural control deficiencies which are generally attributed to challenges in proprioceptive reweighting, where they often rely on an ankle strategy regardless of postural conditions. Such impairment could lead to potential loss of balance, increased risk of falling, and Low back pain recurrence. In this study, linear and non-linear indicators were extracted from center-of-pressure (COP) and trunk sagittal angle data based on 4 conditions of vibration positioning (vibration on the back, ankle, none or both), 2 surface conditions (foam or rigid), and 2 different groups (healthy and non-specific low back pain patients). Linear discriminant analysis (LDA) was performed on linear and non-linear indicators to identify the best sensory condition towards accurate distinction of non-specific low back pain patients from healthy controls. Two indicators: Phase Plane Portrait ML and Entropy ML with foam surface condition and both ankle and back vibration on, were able to completely differentiate the non-specific low back pain groups. The proposed methodology can help clinicians quantitatively assess the sensory status of non-specific low back pain patients at the initial phase of diagnosis and throughout treatment. Although the results demonstrated the potential effectiveness of our approach in Low back pain patient distinction, a larger and more diverse population is required for comprehensive validation.

The Relationship Between Pain-Related Psychological Factors and Maximal Physical Performance in Low Back Pain: A Systematic Review and Meta-Analysis

Theoretical frameworks explain how pain-related psychological factors may influence the physical performance. In this systematic review and meta-analysis, we evaluated the evidence regarding the relationship between the pain-related psychological factors and the maximal physical performance in patients with low back pain (LBP). Pubmed, Embase, CINAHL and Web of Science databases were searched from inception to May 2022. Cross-sectional or longitudinal studies reporting cross-sectional measures of association between at least one pain-related psychological factor and a quantitatively measured outcome of maximal physical performance in patients with LBP were eligible for inclusion. Thirty-eight studies (n = 2,490; 27 cross-sectional studies, n = 1,647 (66%); 11 longitudinal studies, n = 843 (34%)) were included, with 92% of participants (n = 2,284) having chronic LBP. Results showed that pain-related fear, pain catastrophizing, and anticipated pain were consistently and negatively associated with the maximal physical performance in chronic LBP, whereas pain-self efficacy showed positive correlations. Overall, magnitudes of absolute pooled r-values were small (r ≤ 0.25), except for anticipated pain, which was moderately associated with maximal physical performance (r = -0.34 to -0.37). Subanalyses and sensitivity analyses yielded similar pooled correlation coefficients. Certainty of evidence using the GRADE recommendations was very low to moderate for pain-related fear, and very low to low for the other pain-related psychological factors. Prospero registration: CRD42021227486. PERSPECTIVE: Overall, small pooled correlation coefficients were shown between pain-related psychological factors and maximal physical performance in chronic LBP. Certainty of evidence was very low to low for all pain-related psychological factors other than pain-related fear. Future studies taking into account limitations of the current literature may therefore change these conclusions.

The association of fear of movement and postural sway in people with low back pain

BACKGROUND

Fear of movement is thought to interfere with the recovery from low back pain (LBP). To date, the relationship between fear of movement and postural balance has not been adequately elucidated. Recent findings suggest that more specific fears need to be assessed and put in relation to a specific movement task. We propose that the fear to bend the trunk in a certain direction is distinctly related to the amount of postural sway in different directions. Therefore, our aim was to investigate whether fear of movement in general and fear of bending the trunk in a certain plane is related to postural sway.

METHODS

Data was collected from participants with LBP during two assessments ~3 weeks apart. Postural sway was measured with a force-platform during quiet standing with the eyes closed. Fear of movement was assessed with an abbreviated version of the Tampa Scale of Kinesiophobia (TSK-11) and custom items referring to fear of bending the trunk in the sagittal and the frontal plane.

RESULTS

Based on data from 25 participants, fear of bending the trunk in the frontal plane was positively related to displacement in the sagittal and frontal plane and to velocity in the frontal plane (χ 2 = 4.35, p = 0.04; χ 2 = 8.15, p = 0.004; χ 2 = 9.79, p = 0.002). Fear of bending the trunk in the sagittal plane was not associated with any direction specific measure of sway. A positive relation of the TSK-11 with velocity of the frontal plane (χ 2 = 7.14, p = 0.008) was found, but no association with undirected measures of sway.

DISCUSSION

Fear of bending the trunk in the frontal plane may be especially relevant to postural sway under the investigated stance conditions. It is possible that fear of bending the trunk in the frontal plane could interfere with balance control at the hip, shifting the weight from side to side to control balance.

CONCLUSION

For the first time the directional relationship of fear of movement and postural sway was studied. Fear of bending the trunk in the frontal plane was positively associated with several measures of postural sway.

A Systematic Review and Meta-Analysis Protocol on How Best to Use Non-Pharmacologic Therapies to Manage Chronic Low Back Pain and Associated Depression

PURPOSE

To evaluate the efficacy of different non-pharmacologic therapies (NPTs) on relieving depressive symptoms and pain intensity in individuals living with chronic low back pain (LBP) and associated depression.

METHODS

A comprehensive search of seven English databases and two Chinese databases from inception to the search date will be undertaken. The reference lists of previously published relevant reviews and included trials will also be searched. Only peer-reviewed and published moderate-to-high quality randomized controlled trials (RCTs) for chronic LBP and associated depression treated with NPTs will be considered. Two independent reviewers will identify studies, extract data, assess risk of bias, and evaluate the strength of evidence using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Meta-analysis will be conducted to estimate the treatment effect of various NPTs. Heterogeneity will be assessed using Cochrane's Q and the I-squared statistics. Subgroup and sensitivity analyses will be performed to assess the robustness of findings. A funnel plot will be developed to evaluate reporting bias, and Begg's and Egger's tests will be used to assess funnel plot symmetries.

RESULTS

This protocol outlines the planned scope and methodology for an upcoming systematic review and meta-analysis, which will provide up-to-date evidence on 1) which NPTs are associated with improvements in depressive symptoms and pain intensity and 2) whether the effects of NPTs on chronic LBP and associated depression vary according to clinical condition, participant, and treatment characteristics.

CONCLUSION

Our meta-analyses of moderate-to-high quality RCTs will help to develop specific recommendations on prescribing NPTs in patients with chronic LBP and associated depression.

STUDY REGISTRATION

This protocol is registered on the International Platform of Registered Systematic Review and Meta-analysis (INPLASY) protocols platform as record No. INPLASY202260055.

From protection to non-protection: A mixed methods study investigating movement, posture and recovery from disabling low back pain

BACKGROUND

Movement and posture are commonly believed to relate to low back pain (LBP). Yet, we know little about how people make sense of the relationship between their LBP, movement and posture, particularly after recovery. We aimed to qualitatively explore this understanding, how it changes and how it relates to quantitative changes.

METHODS

A mixed method study in the context of an existing single-case design involving 12 people with disabling non-specific LBP. Interviews were conducted before and after a 12-week physiotherapy-led Cognitive Functional Therapy intervention, and qualitative findings from these were integrated with individualized, quantitative measures of movement, posture, psychological factors, pain and activity limitation.

RESULTS

Strong beliefs about movement and posture were identified during the baseline interviews. Lived experiences of tension and stiffness characterized the embodiment of 'nonconscious protection', while healthcare and societal messages prompted pain-related fear and 'conscious protection'. Through varied journeys, most participants reported improvements over time with less protective movement and postural strategies. For some, being less protective required focused attention ('conscious non-protection'), but most returned to automatic, normal and fearless patterns ('nonconscious non-protection'), forgetting about their LBP. One participant reported no meaningful shift, remaining protective. Greater spinal range, faster movement, more relaxed postures and less back muscle EMG accompanied positive changes in self-report factors.

CONCLUSION

The findings offer a framework for understanding how people make sense of movement and posture during the process of recovery from persistent, disabling non-specific LBP. This involved a re-conceptualisation of movement and posture, from threatening, to therapeutic.

SIGNIFICANCE

Findings from qualitative interviews before and after a Cognitive Functional Therapy intervention in 12 people with disabling low back pain highlighted an individualized recovery journey from conscious and nonconscious protection to conscious non-protection for some, and nonconscious non-protection for many. Pre and post-quantitative measures of movement, posture, psychological factors, pain and activity limitation integrated well with the qualitative findings. The findings suggest movement and posture may form part of a multidimensional pain schema.

Task-specific fear rather than general kinesiophobia assessment is associated with kinematic differences in chronic low back pain during lumbar flexion: a preliminary investigation

Introduction

Kinematic data obtained during a movement task by individuals with chronic low back pain seem to be related to pain-related fear. General kinesiophobia assessments, such as Tampa Scale for Kinesiophobia, are often used to assess pain-related fear. However, these questionnaires could suffer from a lack of sensitivity and do not measure the fear of specific movements.

Objectives

The purpose of this study was to investigate whether the task-specific assessment of pain-related fear exhibits a closer association with trunk kinematics during lumbar flexion compared with the general kinesiophobia in individuals with chronic low back pain.

Methods

We assessed pain-related factors, task-specific fear, and Tampa Scale for Kinesiophobia-11 scores of 51 company employees. The lumbar angle during a lumbar flexion task was recorded by 2 wireless Axivity Ax3 accelerometers attached to the subject's spinous process (L3) and sacral spine (S2). Only task-specific fear was evaluated after the lumbar flexion task. We calculated the maximum lumbar flexion angle (°) and the peak angular velocity of lumbar flexion/return from flexion (°/s2). We conducted a hierarchical multiple linear regression analysis to determine variance explained in lumbar flexion task performance by task-specific fear after controlling for demographic, pain, and general kinesiophobia.

Results

The results showed that task-specific fear was associated with the peak angular velocity of lumbar return from flexion (R 2 adj. = 0.36, P < 0.01) and lumbar flexion (R 2 adj. = 0.3, P = 0.01).

Discussion

Our results suggest that clinicians should consider the potential added value of task-specific fear assessment over the sole use of conventional kinesiophobia assessment.

The sensorimotor theory of pathological pain revisited

Harris (1999) proposed that pain can arise in the absence of tissue damage because changes in the cortical representation of the painful body part lead to incongruences between motor intention and sensory feedback. This idea, subsequently termed the sensorimotor theory of pain, has formed the basis for novel treatments for pathological pain. Here we review the evidence that people with pathological pain have changes to processes contributing to sensorimotor function: motor function, sensory feedback, cognitive representations of the body and its surrounding space, multisensory processing, and sensorimotor integration. Changes to sensorimotor processing are most evident in the form of motor deficits, sensory changes, and body representations distortions, and for Complex Regional Pain Syndrome (CRPS), fibromyalgia, and low back pain. Many sensorimotor changes are related to cortical processing, pain, and other clinical characteristics. However, there is very limited evidence that changes in sensorimotor processing actually lead to pain. We therefore propose that the theory is more appropriate for understanding why pain persists rather than how it arises.

Influence of kinesiophobia on pain intensity, disability, muscle endurance, and position sense in patients with chronic low back pain-a case-control study

Background

Patients with chronic low back pain (CLBP) frequently present with kinesiophobia. Though large body of evidence reported the impact of kinesiophobia in patients with CLBP, there are paucity of studies in associating kinesiophobia to muscle endurance and position sense in patients with CLBP. The primary aim of the study is to compare the impact of kinesiophobia on lumbar extensor endurance, position sense in patient with CLBP, and asymptomatic individuals. Secondarily, we aim to examine the association between kinesiophobia and lumbar extensor endurance, position sense, pain intensity, and functional ability in patients with CLBP. Thirdly, we aim to assess the degree of association of various factors on CLBP, lumbar endurance, and position sense.

Material and methods

This case-control study will have 200 patients with CLBP and 400 controls. Kinesiophobia, lumbar endurance, and lumbar position sense will be assessed with Tampa Scale, Soren’s lumbar extensor test, and lumbar repositioning test respectively. Secondarily, the pain intensity will be assessed with visual analog scale and functional ability with Patient-specific Functional Scale in patients with CLBP. Lumbar endurance and joint position sense will be compared between subjects with and without kinesiophobia. Kinesiophobia scores will be compared with lumbar extensor endurance and proprioception joint position errors, pain intensity, and functional ability. Simple and multiple binary logistic regression will be used to determine crude and adjusted odd’s ratio for kinesiophobia, lumbar position sense and kinesiophobia, and lumbar endurance.

Discussion

The finding from this study can be generalized as this study has adequate sample size and subgroup analysis by adjusting the variables to draw a valid conclusion. The finding of this study will help the working physician to include assessment of kinesiophobia as part of musculoskeletal evaluation for patient with CLBP in a prospective diagnostic intervention.

Trial registration

ClinicalTrials.gov NCT05079893. Registered on 14 October 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06406-6.

Between/within-session reliability of spinal kinematic and lumbar muscle activity measures in patients with chronic low back pain and asymptomatic individuals

BACKGROUND

Longitudinal research is required to better understand the role of spinal movement alterations in chronic low back pain (CLBP). To this end, it is critical to assess the between-session reliability of spinal movement measures.

RESEARCH QUESTION

What is the within/between-session reliability of spinal movement measures in patients with CLBP and asymptomatic controls?

METHODS

Spinal movement was recorded prospectively during two sessions, a week apart, for 20 patients with CLBP (60% male; 40.0 ± 12.3 years old) and 20 asymptomatic individuals (55% male; 38.2 ± 10.9 years old). Sagittal-plane angular amplitude and angular velocity at the lower lumbar, upper lumbar, lower thoracic and upper thoracic joints, as well as maximal erector spinae activity were measured during five daily-activity tasks. In addition, task-independent measures were obtained by averaging the measures across tasks. The Intraclass Correlation Coefficient (ICC 2,1) and the minimal detectable change (MDC) were calculated. Pearson correlation was used to compare task-independent and task-specific measures.

RESULTS

Between-session ICCs in patients with CLBP were mostly moderate to good for maximal angular amplitude and erector spinae activity measures. Lower ICCs were observed for range of angular motion and angular velocity measures (42% of ICCs < 0.5). Median MDCs were 9.6°, 18.3°/s and 1.0% for angular amplitude, angular velocity and erector spinae activity measures, respectively. The reliability of task-independent and task-specific measures was strongly correlated (r = 0.91, p < 0.001).

SIGNIFICANCE

Sagittal-plane maximal angular amplitude and erector spinae activity measures during various daily-activity tasks demonstrated mostly moderate to good between-session ICCs. However, relatively large MDCs suggested that important changes are needed to be detectable. Task-independent measures reported similarly acceptable ICCs than task-specific measures, supporting their use to describe spinal movement.

Abnormal Anatomical and Functional Connectivity of the Thalamo-sensorimotor Circuit in Chronic Low Back Pain: Resting-state Functional Magnetic Resonance Imaging and Diffusion Tensor Imaging Study

Thalamocortical dysfunction is thought to underlie the pathophysiology of chronic pain revealed by electroencephalographic studies. The thalamus serves as a primary relay center to transmit sensory information and motor impulses via dense connections with the somatosensory and motor cortex. In this study, diffusion tensor imaging (DTI) (probabilistic tractography) and resting-state functional magnetic resonance imaging (functional connectivity) were used to characterize the anatomical and functional integrity of the thalamo-sensorimotor pathway in chronic low back pain (cLBP). Fifty-four patients with cLBP and 54 healthy controls were included. The results suggested significantly increased anatomical connectivity of the left thalamo-motor pathway characterized by probabilistic tractography in patients with cLBP. Moreover, there was significantly altered resting-state functional connectivity (rsFC) of bilateral thalamo-motor/somatosensory pathways in patients with cLBP as compared to healthy controls. We also detected a significant correlation between pain intensity during the MRI scan and rsFC of the right thalamo-somatosensory pathway in cLBP. Our findings highlight the involvement of the thalamo-sensorimotor circuit in the pathophysiology of cLBP.

Identifying Motor Control Strategies and Their Role in Low Back Pain: A Cross-Disciplinary Approach Bridging Neurosciences With Movement Biomechanics

Persistent low back pain (LBP) is a major health issue, and its treatment remains challenging due to a lack of pathophysiological understanding. A better understanding of LBP pathophysiology has been recognized as a research priority, however research on contributing mechanisms to LBP is often limited by siloed research within different disciplines. Novel cross-disciplinary approaches are necessary to fill important knowledge gaps in LBP research. This becomes particularly apparent when considering new theories about a potential role of changes in movement behavior (motor control) in the development and persistence of LBP. First evidence points toward the existence of different motor control strategy phenotypes, which are suggested to have pain-provoking effects in some individuals driven by interactions between neuroplastic, psychological and biomechanical factors. Yet, these phenotypes and their role in LBP need further validation, which can be systematically tested using an appropriate cross-disciplinary approach. Therefore, we propose a novel approach, connecting methods from neuroscience and biomechanics research including state-of-the-art optical motion capture, musculoskeletal modeling, functional magnetic resonance imaging and assessments of psychological factors. Ultimately, this cross-disciplinary approach might lead to the identification of different motor control strategy phenotypes with the potential to translate into clinical research for better treatment options.

The Relationship Between Pain-Related Threat and Motor Behavior in Nonspecific Low Back Pain: A Systematic Review and Meta-Analysis

OBJECTIVE

Although pain-related fear and catastrophizing are predictors of disability in low back pain (LBP), their relationship with guarded motor behavior is unclear. The aim of this meta-analysis was to determine the relationship between pain-related threat (via pain-related fear and catastrophizing) and motor behavior during functional tasks in adults with LBP.

METHODS

This review followed PRISMA guidelines. MEDLINE, Embase, PsychINFO, and CINAHL databases were searched to April 2021. Included studies measured the association between pain-related fear or pain catastrophizing and motor behavior (spinal range of motion, trunk coordination and variability, muscle activity) during movement in adults with nonspecific LBP. Studies were excluded if participants were postsurgery or diagnosed with specific LBP. Two independent reviewers extracted all data. The Newcastle-Ottawa Scale was used to assess for risk of bias. Correlation coefficients were pooled using the random-effects model.

RESULTS

Reduced spinal range of motion during flexion tasks was weakly related to pain-related fear (15 studies, r = -0.21, 95% CI = -0.31 to -0.11) and pain catastrophizing (7 studies, r = -0.24, 95% CI = -0.38 to -0.087). Pain-related fear was unrelated to spinal extension (3 studies, r = -0.16, 95% CI = -0.33 to 0.026). Greater trunk extensor muscle activity during bending was moderately related to pain-related fear (2 studies, r = -0.40, 95% CI = -0.55 to -0.23). Pain catastrophizing, but not fear, was related to higher trunk activity during gait (2 studies, r = 0.25, 95% CI = 0.063 to 0.42). Methodological differences and missing data limited robust syntheses of studies examining muscle activity, so these findings should be interpreted carefully.

CONCLUSION

This study found a weak to moderate relationship between pain-related threat and guarded motor behavior during flexion-based tasks, but not consistently during other movements.

IMPACT

These findings provide a jumping-off point for future clinical research to explore the advantages of integrated treatment strategies that target both psychological and motor behavior processes compared with traditional approaches.

Associations of low-back pain and pain-related cognitions with lumbar movement patterns during repetitive seated reaching

BACKGROUND

Development of more effective interventions for nonspecific chronic low back pain (LBP), requires a robust theoretical framework regarding mechanisms underlying the persistence of LBP. Altered movement patterns, possibly driven by pain-related cognitions, are assumed to drive pain persistence, but cogent evidence is missing.

AIM

To assess variability and stability of lumbar movement patterns, during repetitive seated reaching, in people with and without LBP, and to investigate whether these movement characteristics are associated with pain-related cognitions.

METHODS

60 participants were recruited, matched by age and sex (30 back-healthy and 30 with LBP). Mean age was 32.1 years (SD13.4). Mean Oswestry Disability Index-score in LBP-group was 15.7 (SD12.7). Pain-related cognitions were assessed by the 'Pain Catastrophizing Scale' (PCS), 'Pain Anxiety Symptoms Scale' (PASS) and the task-specific 'Expected Back Strain' scale(EBS). Participants performed a seated repetitive reaching movement (45 times), at self-selected speed. Lumbar movement patterns were assessed by an optical motion capture system recording positions of cluster markers, located on the spinous processes of S1 and T8. Movement patterns were characterized by the spatial variability (meanSD) of the lumbar Euler angles: flexion-extension, lateral-bending, axial-rotation, temporal variability (CyclSD) and local dynamic stability (LDE). Differences in movement patterns, between people with and without LBP and with high and low levels of pain-related cognitions, were assessed with factorial MANOVA.

RESULTS

We found no main effect of LBP on variability and stability, but there was a significant interaction effect of group and EBS. In the LBP-group, participants with high levels of EBS, showed increased MeanSD_{lateral-bending} (p = 0.004, η² = 0.14), indicating a large effect. MeanSD_{axial-rotation} approached significance (p = 0.06).

SIGNIFICANCE

In people with LBP, spatial variability was predicted by the task-specific EBS, but not by the general measures of pain-related cognitions. These results suggest that a high level of EBS is a driver of increased spatial variability, in participants with LBP.

Patients With Chronic Low Back Pain Have an Individual Movement Signature: A Comparison of Angular Amplitude, Angular Velocity and Muscle Activity Across Multiple Functional Tasks

Despite a large body of evidence demonstrating spinal movement alterations in individuals with chronic low back pain (CLBP), there is still a lack of understanding of the role of spinal movement behavior on LBP symptoms development or recovery. One reason for this may be that spinal movement has been studied during various functional tasks without knowing if the tasks are interchangeable, limiting data consolidation steps. The first objective of this cross-sectional study was to analyze the influence of the functional tasks on the information carried by spinal movement measures. To this end, we first analyzed the relationships in spinal movement between various functional tasks in patients with CLBP using Pearson correlations. Second, we compared the performance of spinal movement measures to differentiate patients with CLBP from asymptomatic controls among tasks. The second objective of the study was to develop task-independent measures of spinal movement and determine the construct validity of the approach. Five functional tasks primarily involving sagittal-plane movement were recorded for 52 patients with CLBP and 20 asymptomatic controls. Twelve measures were used to describe the sagittal-plane angular amplitude and velocity at the lower and upper lumbar spine as well as the activity of the erector spinae. Correlations between tasks were statistically significant in 91 out of 99 cases (0.31 ≤ r ≤ 0.96, all p < 0.05). The area under the curve (AUC) to differentiate groups did not differ substantially between tasks in most of the comparisons (82% had a difference in AUC of ≤0.1). The task-independent measures of spinal movement demonstrated equivalent or higher performance to differentiate groups than functional tasks alone. In conclusion, these findings support the existence of an individual spinal movement signature in patients with CLBP, and a limited influence of the tasks on the information carried by the movement measures, at least for the twelve common sagittal-plane measures analysed in this study. Therefore, this work brought critical insight for the interpretation of data in literature reporting differing tasks and for the design of future studies. The results also supported the construct validity of task-independent measures of spinal movement and encouraged its consideration in the future.

Physiotherapists' attitudes and beliefs about low back pain influence their clinical decisions and advice

BACKGROUND

Physiotherapists' biomedical orientation influences the implementation of evidenced-based care for low back pain (LBP) management. However, information on physiotherapists' own beliefs about their back and LBP and the influence of these on clinical decisions and advice is lacking.

OBJECTIVES

To identify attitudes and beliefs about LBP among physiotherapists and to analyse the association of these beliefs with physiotherapists' individual characteristics and clinical decisions and advice.

DESIGN

Cross-sectional survey.

METHOD

Attitudes and beliefs about LBP were measured with the Back-Pain Attitudes Questionnaire (Back-PAQ) among French-speaking Swiss physiotherapists. Physiotherapists' clinical decisions and advice were assessed with a clinical vignette to determine their association with the Back-PAQ score.

RESULTS

The study included 288 physiotherapists. The mean Back-PAQ score (82.7; SD 17.2) indicated the presence of helpful beliefs in general, but unhelpful beliefs in relation to back protection and the special nature of LBP (nature of pain, impact, complexity) were frequently identified. Individual characteristics explained 17% of the Back-PAQ score. Unhelpful beliefs were associated with clinical decisions toward back protection and movement avoidance (r = - 0.47, p < 0.001).

CONCLUSIONS

While helpful beliefs and guidelines consistent decisions were generally identified, unhelpful beliefs about back protection and the special nature of LBP were frequently present among physiotherapists. These unhelpful beliefs were associated with less optimal clinical decisions. Educational approaches should challenge unhelpful beliefs and empower physiotherapists to provide explanations and management that increases patients' confidence in the back. Future research should investigate the effect of educational strategies on implementation of best practice for LBP management.

Changes in physiotherapy students' beliefs and attitudes about low back pain through pre-registration training

BACKGROUND

Implementation of best-practice care for patients with low back pain (LBP) is an important issue. Physiotherapists' who hold unhelpful beliefs are less likely to adhere to guidelines and may negatively influence their patients' beliefs. Pre-registration education is critical in moving towards a biopsychosocial model of care. This study aimed to investigate the changes in 2nd year physiotherapy students' beliefs about LBP after a module on spinal pain management and determine whether these changes were maintained at the end of academic training.

METHODS

During three consecutive calendar years, this longitudinal cohort study assessed physiotherapy students' beliefs with the Back Pain Attitudes Questionnaires (Back-PAQ) in their 1st year, before and after their 2nd year spinal management learning module, and at the end of academic training (3rd year). Unpaired t-tests were conducted to explore changes in Back-PAQ score.

RESULTS

The mean response rate after the spinal management module was 90% (128/143 students). The mean (± SD) Back-PAQ score was 87.73 (± 14.21) before and 60.79 (± 11.44) after the module, representing a mean difference of - 26.95 (95%CI - 30.09 to - 23.80, p < 0.001). Beliefs were further improved at the end of 3rd year (- 7.16, 95%CI - 10.50 to - 3.81, p < 0.001).

CONCLUSIONS

A spinal management learning module considerably improved physiotherapy students' beliefs about back pain. Specifically, unhelpful beliefs about the back being vulnerable and in need of protection were substantially decreased after the module. Improvements were maintained at the end of academic training one-year later. Future research should investigate whether modifying students' beliefs leads to improved clinical practice in their first years of practice.