Investigating the Causal Mechanisms of Symptom Recovery in Chronic Whiplash-associated Disorders Using Bayesian Networks

Unraveling the Mechanisms Behind the Short-Term Effects of Dry Needling: New Insights From a Mediation Analysis With Repeatedly Measured Mediators and Outcomes

OBJECTIVE

To explore the causal pathways underlying the short-term effects of deep dry needling (DDN) in people with chronic neck pain.

DESIGN

Explanatory longitudinal mediation analysis with repeatedly measured mediators and outcomes.

SETTING

Primary care setting.

PARTICIPANTS

Patients (N=128) with chronic neck pain.

INTERVENTIONS

Participants were randomized into 2 groups; DDN of the neck muscles combined with stretching (n=64) and stretching alone (n=64).

MAIN OUTCOME MEASURES

Two outcomes (pain intensity and neck pain-related disability) and 3 candidate mediators (local pressure pain thresholds [PPTs], cervical range of motion [ROM], and neck muscle strength) were included. Pain intensity was also included as a competing mediator in the mediation analysis for disability. Mediators and outcomes were measured at 3 time points: after intervention and at 2- and 4-week follow-up. Age, sex, and the baseline values of the outcome and mediators were included as pretreatment mediator-outcome confounders.

RESULTS

Reductions in pain intensity strongly mediated the short-term effects of DDN on disability, from after intervention to 4-week follow-up. In addition, the attenuation of local hypersensitivity (via increasing PPTs) moderately mediated reductions in pain intensity at each time point. On the other hand, gains in cervical ROM contributed to reducing neck pain-related disability. Changes in muscle strength did not lead to better outcomes.

CONCLUSIONS

This novel study demonstrated that DDN effect on neck pain-related disability is strongly driven by the analgesic effects of this physical therapy modality. Increasing PPTs and cervical ROM seem to be also part of the mechanisms behind DDN's effect.

A functional intervention within a cognitive approach to chronic cervical radiculopathy : Description of the non-surgical treatment arm in a randomised controlled trial evaluating the effectiveness of surgery

BACKGROUND

Most patients with cervical radiculopathy improve within the first months without treatment or with non-surgical treatment. A systematic review concluded that these patients improve, regardless of their intervention. Still, many patients are offered surgery, despite limited evidence regarding the indications for surgical treatments. The aim of this article is to describe the intervention that is going to be followed in the non-surgical treatment arm of a randomised controlled trial (RCT) comparing the effectiveness of surgical and non-surgical treatment for patients with cervical radiculopathy.

METHODS

The non-surgical intervention is a functional intervention within a cognitive approach founded on previous experiences, and current recommendations for best practice care of musculoskeletal pain and cervical radiculopathy. It is based on the biopsychosocial rather than a biomedical perspective, comprises an interdisciplinary approach (physicians, physiotherapy specialists), and includes brief intervention and graded activities. The intervention consists of 6 sessions over 12 weeks. The primary goals are first, to validate the patients´ symptoms and build a therapeutic alliance, second, to explore the understanding and promote alternatives, and third, to explore problems and opportunities based on patients´ symptoms and function. Motivational factors toward self-management are challenging. We will attempt shared decision-making in planning progress for the individual patient and emphasise learning of practical self-help strategies and encouragement to stay active (reinforcing the positive natural course). General physical activities such as walking will be promoted along with simple functional exercises for the neck- and shoulder region. We will also explore social activity, comorbidities, pain location, sleep, and work-related factors. The health providers will set individualised goals together with each patient.

DISCUSSION

The aim of the intervention is to describe a functional intervention within a cognitive approach for patients with chronic cervical radiculopathy. The effectiveness of the present program will be compared to surgery in a randomised controlled trial.

Effect of neck-specific exercises with and without internet support on cervical range of motion and neck muscle endurance in chronic whiplash-associated disorders: analysis of functional outcomes of a randomized controlled trial

OBJECTIVE

To compare the effects of a neck-specific exercise programme with internet support and 4 physiotherapist sessions (NSEIT) and the same neck-specific exercises supervised by a physiotherapist (NSE) on neck muscle endurance and cervical range of motion.

DESIGN

Randomized controlled trial.

PATIENTS

A total of 140 participants with chronic whiplash-associated disorders grade II or grade III were randomly assigned to the NSEIT or NSE groups.

METHODS

Outcomes were changes in active cervical range of motion, cranio-cervical flexion test, neck muscle endurance, and neck pain, at 3- and 15-month follow-ups.

RESULTS

There were no significant differences between the NSEIT and NSE groups. There was a significant group-by-time inter-action effect in active cervical range of motion flexion/extension where the NSEIT group improved to 3-month follow-up, but the NSE group did not. Both groups were significantly improved over time in all other outcomes (p < 0.001) at 3- and 15-month follow-ups, with effect size between 0.64 and 1.35 in active cervical range of motion, cranio-cervical flexion test, dorsal neck muscle endurance, and neck pain, and effect size between 0.22 and 0.42 in ventral neck muscle endurance.

CONCLUSION

Both NSE and NSEIT led to improved neck function. Depending on the patients' needs, either NSE or NSEIT could be used as treatment for patients with chronic whiplash-associated disorders.

Network analyses reveal the interaction between physical features, fear of movement and neck pain and disability in people with acute and chronic whiplash-associated disorders

BACKGROUND AND OBJECTIVE

A network analysis can be used to quantitatively assess and graphically describe multiple interactions. This study applied network analyses to determine the interaction between physical and pain-related factors and fear of movement in people with whiplash-associated disorders (WAD) during periods of acute and chronic pain.

METHODS

Physical measurements, including pressure pain-thresholds (PPT) over neural structures, cervical range of motion, neck flexor and extensor endurance and the cranio-cervical flexion test (CCFT), in addition to subjective reports including the Tampa Scale of Kinesiophobia (TSK-11), Neck Disability Index (NDI) and neck pain and headache intensity, were assessed at baseline in 47 participants with acute WAD. TSK-11, NDI and pain intensity were assessed for the same participants 6 months later (n = 45). Two network analyses were conducted to estimate the associations between features at baseline and at 6 months and their centrality indices.

RESULTS

Both network analyses revealed that the greatest weight indices were found for NDI and CCFT at baseline and for neck pain and headache intensity and NDI and TSK-11 at both time points. Associations were also found betweeen cervical muscle endurance and neck pain intensity in the acute phase. Cervical muscle endurance assesssed during the acute phase was also associated with NDI after 6 months - whereas PPT measured at baseline was associsated with headache intensity after 6 months.

CONCLUSION

The strongest associations were found for headache and neck pain intensity and neck disability and fear of movement, both during acute pain and when mesured 6 months later. The extent of neck endurance and measures of PPT at baseline may be associated with neck disability and headache, respectively, 6 months after a whiplash injury.

SIGNIFICANCE

Through two network analyses, we evaluated the interaction between pain-related factors, fear of movement, neck disability and physical factors in people who had experienced a whiplash injury. We demonstrated that physical factors may be involved in the maintenance and development of chronic pain after a whiplash injury. Nevertheless, the strongest associations were found for headache and neck pain intensity and neck disability and fear of movement, both during acute and chronic phases.

Temporal Relations Between Pain Catastrophizing and Adverse Health and Mental Health Outcomes After Whiplash Injury

OBJECTIVES

Pain catastrophizing has been shown to be a prognostic indicator for pain severity and the co-occurrence of mental health conditions such as depression and post-traumatic stress disorder after whiplash injury. However, the pattern of available findings is limited in its implications for the possible "antecedent" or "causal" role of pain catastrophizing. The purpose of the present study was to examine the temporal relations between pain catastrophizing, pain severity, depressive symptoms, and post-traumatic stress symptoms (PTSS) in individuals receiving treatment for whiplash injury.

MATERIALS AND METHODS

The sample consisted of 388 individuals enrolled in a multidisciplinary program for whiplash injury. Participants completed self-report measures of pain catastrophizing, pain severity, depressive symptoms, and PTSS at the time of admission, mid-treatment (4 week), and treatment completion (7 week). A cross-lagged panel analysis was used to examine the temporal relations between pain catastrophizing, pain severity, depressive symptoms, and PTSS across all 3 timepoints.

RESULTS

Model fit was acceptable after the inclusion of modification indices. Pain catastrophizing at the time of admission predicted all other variables at 4 weeks. Pain catastrophizing at 4 weeks also predicted all other variables at 7 weeks. In addition, some bidirectional relations were present, particularly for variables assessed at week 4 and week 7.

DISCUSSION

Findings support the view that pain catastrophizing might play a transdiagnostic role in the onset and maintenance of health and mental health conditions. The findings call for greater emphasis on the development of treatment techniques that target pain catastrophizing in intervention programs for whiplash injury.

Effectiveness of psychological interventions delivered by physiotherapists in the management of neck pain: a systematic review with meta-analysis

Physiotherapists are increasingly using psychological treatments for musculoskeletal conditions. We assessed the effects of physiotherapist-delivered psychological interventions on pain, disability, and quality of life in neck pain. We evaluated quality of intervention reporting. We searched databases for randomized controlled trials (RCTs) comprising individuals with acute or chronic whiplash-associated disorder (WAD) or nontraumatic neck pain (NTNP), comparing physiotherapist-delivered psychological interventions to standard care or no treatment. Data were extracted regarding study characteristics and outcomes. Standardised mean difference (SMD) was calculated by random-effects meta-analysis. We evaluated certainty of evidence using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) and intervention reporting using TIDieR. Fourteen RCTs (18 articles-4 detail additional outcome/follow-up data) were included comprising 2028 patients, examining acute WAD (n = 4), subacute/mixed NTNP (n = 3), chronic WAD (n = 2), and chronic NTNP (n = 5). Treatment effects on pain favoured psychological interventions in chronic NTNP at short-term (SMD -0.40 [95% CI -0.73, -0.07]), medium-term (SMD -0.29 [95% CI -0.57, 0.00]), and long-term (SMD -0.32 [95% CI -0.60, -0.05]) follow-up. For disability, effects favoured psychological interventions in acute WAD at short-term follow-up (SMD -0.39 [95% CI -0.72, -0.07]) and chronic NTNP at short-term (SMD -0.53 [95% CI -0.91, -0.15]), medium-term (SMD -0.49 [95% CI -0.77, -0.21]), and long-term (SMD -0.60 [95% CI -0.94, -0.26]) follow-up. GRADE ratings were typically moderate, and intervention reporting often lacked provision of trial materials and procedural descriptions. Psychological interventions delivered by physiotherapists were more effective than standard physiotherapy for chronic NTNP (small-to-medium effects) and, in the short term, acute WAD.

Path Analysis Models Integrating Psychological, Psycho-physical and Clinical Variables in Individuals With Tension-Type Headache

Tension type headache (TTH) is a prevalent but poorly understood pain disease. Current understanding supports the presence of multiple associations underlying its pathogenesis. Our aim was to compare competing multivariate pathway models that explains the complexity of TTH. Headache features (intensity, frequency, or duration - headache diary), headache-related disability (Headache Disability Inventory-HDI), anxiety/depression (Hospital Anxiety and Depression Scale), sleep quality (Pittsburgh Sleep Quality Index), widespread pressure pain thresholds (PPTs) and trigger points (TrPs) were collected in 208 individuals with TTH. Four latent variables were formed from the observed variables - Distress (anxiety, depression), Disability (HDI subscales), Severity (headache features), and Sensitivity (all PPTs). Structural equation modelling (SEM) and Bayesian network (BN) analyses were used to build and compare a theoretical (model_theory) and a data-driven (model_BN) latent variable model. The model_BN (root mean square error of approximation [RMSEA] = 0.035) provided a better statistical fit than model_theory (RMSEA = 0.094). The only path common between model_bn and model_theory was the influence of years with pain on TrPs. The model_BN revealed that the largest coefficient magnitudes were between the latent variables of Distress and Disability (β=1.524, P = .006). Our theoretical model proposes a relationship whereby psycho-physical and psychological factors result in clinical features of headache and ultimately affect disability. Our data-driven model proposes a more complex relationship where poor sleep, psychological factors, and the number of years with pain takes more relevance at influencing disability. Our data-driven model could be leveraged in clinical trials investigating treatment approaches in TTH. PERSPECTIVE: A theoretical model proposes a relationship where psycho-physical and psychological factors result in clinical manifestations of headache and ultimately affect disability. A data-driven model proposes a more complex relationship where poor sleep, psychological factors, and number of years with pain takes more relevance at influencing disability.

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.

Concussion coach for postconcussive symptoms: A randomized, controlled trial of a smartphone application with Afghanistan and Iraq war Veterans

Objective: Investigate the effectiveness of Concussion Coach, an interactive smartphone application, as a treatment for residual neurobehavioral symptoms and distress in Veterans with a history of mild traumatic brain injury (mild TBI). Methods: Veterans with mild TBI were randomized to Concussion Coach (n = 238) or Treatment-as-Usual (TAU) (n = 241) in a 3-month randomized controlled trial. Primary outcome measures included postconcussive symptom (PCS) severity as measured by the Neurobehavioral Symptom Inventory (NSI), and psychological distress as measured by the Brief Symptom Inventory-18 (BSI-18). Measures of self-efficacy, social support, and comfort with technology were administered as potential moderators and mediators. An intention-to-treat (ITT) analysis was performed (N = 461: Concussion Coach = 231 and TAU = 230) using Bayesian Network (BN)modeling. Results: The probability of decreased PCS severity was significantly greater for those assigned to Concussion Coach, .35 [.32,.37], than for TAU, .29 (.27, .32), with an odds ratio (OR) of 1.29. Also, Concussion Coach showed a significantly greater probability of increased self-efficacy (.36 [.32, .39]) than did TAU (.28 [.25, .30], OR = 1.42). In turn, self-efficacy (increased vs. decreased) showed a significantly greater probability of decreased PCS severity (.51 [.47, .54] vs. .27 [.24, .30], OR = 2.71) and decreased psychological distress (.53 [.49, .56] vs. .32 [.29, .35], OR = 2.35), suggesting that self-efficacy may have mediated Concussion Coach effects. Conclusions: Concussion Coach is effective at reducing PCS severity and psychological distress. Increased self-efficacy/perception of self-management of symptoms may be key to successful treatment of residual symptoms in those with history of concussion.

Video-oculographic measures of eye movement control in the smooth pursuit neck torsion test can classify idiopathic neck pain patients from healthy individuals: A datamining based diagnostic accuracy study

BACKGROUND

Idiopathic neck pain patients frequently experience oculomotor disfunctions with deficits in eye movement control between neutral and neck torsion position (SPNT test) being commonly investigated in clinical and research settings.

OBJECTIVES

The aim of the study was to determine accuracy of SPNT test in classifying idiopathic neck pain patients.

DESIGN

a datamining based diagnostic accuracy study.

METHODS

The study was conducted on a referred sample of 38 chronic neck pain patients from orthopaedic outpatient clinic and 40 healthy controls. Video-oculography was used to study gain and SPNT_diff during SPNT test under three target movement velocities and amplitudes and two different angles of neck torsion. A Naïve Bayesian predictive model was used to classify neck pain patients based on gain or SPNT_diff.

RESULTS

Gain during two target movement profiles at velocities of 30°s^-1 and amplitudes of 30° and 40° under 45° of neck torsion presented with highest area under the curve (0.837), specificity (92%), sensitivity (94%), highest true positive and lowest false negative predicted value. Highest area under the curve (0.760), specificity (50%), sensitivity (71%), highest true positive and lowest false negative values were observed for SPNT_diff at velocities of 30°s^-1 and amplitude of 30° applying 45° of neck torsion.

CONCLUSION

SPNT test provides useful diagnostic tool for classifying neck pain patients when using single or combination of two target movement profiles. Neck torsion of 45° as opposed to 30° should be used during SPNT test when investigating patients with neck pain disorders.

A network analysis reveals the interaction between fear and physical features in people with neck pain

Although neck pain is known to be a complex and multifactorial condition characterised by the interplay between physical and psychological domains, a comprehensive investigation examining the interactions across multiple features is still lacking. In this study, we aimed to unravel the structure of associations between physical measures of neuromuscular function and fear of movement in people with a history of neck pain. One hundred participants (mean age 33.3 ± 9.4) were assessed for this cross-sectional study, and the neuromuscular and kinematic features investigated were the range of motion, velocity of neck movement, smoothness of neck movement, neck proprioception (measured as the joint reposition error), and neck flexion and extension strength. The Tampa Scale for Kinesiophobia was used to assess fear of movement. A network analysis was conducted to estimate the associations across features, as well as the role of each feature in the network. The estimated network revealed that fear of movement and neuromuscular/kinematic features were conditionally dependent. Higher fear of movement was associated with a lower range of motion, velocity, smoothness of neck movement, neck muscle strength, and proprioception (partial correlations between − 0.05 and − 0.12). Strong interactions were also found between kinematics features, with partial correlations of 0.39 and 0.58 between the range of motion and velocity, and between velocity and smoothness, respectively. The velocity of neck movement was the most important feature in the network since it showed the highest strength value. Using a novel approach to analysis, this study revealed that fear of movement can be associated with a spectrum of neuromuscular/kinematic adaptations in people with a history of neck pain.

Negative Psychological Factors' Influence on Delayed Onset Muscle Soreness Intensity, Reduced Cervical Function and Daily Activities in Healthy Participants

We examined the influence of negative psychological factors (catastrophizing, distress and kinesiophobia) on delayed onset muscle soreness (DOMS) intensity, cervical function (strength and range of motion) and on daily activities (ADL), and the suitability of an exercise protocol designed to induce DOMS within the cervical region. Psychological factors and cervical function were assessed in 86 healthy participants at baseline before applying a DOMS provocation protocol in the cervical flexor muscles. After 24hour, cervical function was reassessed. In addition, at 24hour and 48hour, the intensity of DOMS and its impact on ADL were assessed using the visual analog scale (VAS). The protocol was effective given that it generated low-moderate intensity DOMS (VAS≈30 -40mm) and a statistically significant reduction in cervical strength and range of motion. Psychological distress (anxiety and depression), but not kinesiophobia and catastrophism, predicted a loss of cervical strength (explained 43% of the variance) and range of motion (explained 22% of the variance) after induction of DOMS. In addition, participants' anxiety level predicted DOMS intensity at 24hour (explained 19% of the variance). PERSPECTIVE: The present findings highlight the relevance of evaluating psychological distress as a preventive/therapeutic measure, given that high levels of distress could lead to more intense and disabling pain in acute injuries, and all these aspects are considered risk factors for the chronification of symptoms.

Do Short-Term Effects Predict Long-Term Improvements in Women Who Receive Manual Therapy or Surgery for Carpal Tunnel Syndrome? A Bayesian Network Analysis of a Randomized Clinical Trial

OBJECTIVE

The purpose of this study was to develop a data-driven Bayesian network approach to understand the potential multivariate pathways of the effect of manual physical therapy in women with carpal tunnel syndrome (CTS).

METHODS

Data from a randomized clinical trial (n = 104) were analyzed comparing manual therapy including desensitization maneuvers of the central nervous system versus surgery in women with CTS. All variables included in the original trial were included in a Bayesian network to explore its multivariate relationship. The model was used to quantify the direct and indirect pathways of the effect of physical therapy and surgery on short-term, mid-term, and long-term changes in the clinical variables of pain, related function, and symptom severity.

RESULTS

Manual physical therapy improved function in women with CTS (between-groups difference: 0.09; 95% CI = 0.07 to 0.11). The Bayesian network showed that early improvements (at 1 month) in function and symptom severity led to long-term (at 12 months) changes in related disability both directly and via complex pathways involving baseline pain intensity and depression levels. Additionally, women with moderate CTS had 0.14-point (95% CI = 0.11 to 0.17 point) poorer function at 12 months than those with mild CTS and 0.12-point (95% CI = 0.09 to 0.15 point) poorer function at 12 months than those with severe CTS.

CONCLUSION

Current findings suggest that short-term benefits in function and symptom severity observed after manual therapy/surgery were associated with long-term improvements in function, but mechanisms driving these effects interact with depression levels and severity as assessed using electromyography. Nevertheless, it should be noted that between-group differences depending on severity determined using electromyography were small, and the clinical relevance is elusive. Further data-driven analyses involving a broad range of biopsychosocial variables are recommended to fully understand the pathways underpinning CTS treatment effects.

IMPACT

Short-term effects of physical manual therapy seem to be clinically relevant for obtaining long-term effects in women with CTS.

Effects of dry needling of the obliquus capitis inferior on sensorimotor control and cervical mobility in people with neck pain: A double-blind, randomized sham-controlled trial

BACKGROUND

Impairments of sensorimotor control relating to head and eye movement control and postural stability are often present in people with neck pain. The upper cervical spine and particularly the obliquus capitis inferior (OCI) play an important proprioceptive role; and its impairment may alter cervical sensorimotor control. Dry needling (DN) is a valid technique to target the OCI.

OBJECTIVES

To investigate if a single DN session of the OCI muscle improves head and eye movement control-related outcomes, postural stability, and cervical mobility in people with neck pain.

METHODS

Forty people with neck pain were randomly assigned to receive a single session of DN or sham needling of the OCI. Cervical joint position error (JPE), cervical movement sense, standing balance and oculomotor control were examined at baseline, immediately post-intervention, and at one-week follow-up. Active cervical rotation range of motion and the flexion rotation test were used to examine the global and upper cervical rotation mobility, respectively.

RESULTS

Linear mixed-models revealed that the DN group showed a decrease of JPE immediately post-intervention compared to the sham group (mean difference [MD]= -0.93°; 95% confidence interval [CI]: -1.85, -0.02) which was maintained at one-week follow-up (MD= -1.64°; 95%CI: -2.85, -0.43). No effects on standing balance or cervical movement sense were observed in both groups. Upper cervical mobility showed an increase immediately after DN compared to the sham group (MD= 5.14°; 95%CI: 0.77, 9.75) which remained stable at one-week follow-up (MD= 6.98°; 95%CI: 1.31, 12.40). Both group showed an immediate increase in global cervical mobility (MD= -0.14°; 95%CI: -5.29, 4.89).

CONCLUSION

The results from the current study suggest that a single session of DN of the OCI reduces JPE deficits and increases upper cervical mobility in patients with neck pain. Future trials should examine if the addition of this technique to sensorimotor control training add further benefits in the management of neck pain.

Understanding racial disparities in severe maternal morbidity using Bayesian network analysis

Previous studies have evaluated the marginal effect of various factors on the risk of severe maternal morbidity (SMM) using regression approaches. We add to this literature by utilizing a Bayesian network (BN) approach to understand the joint effects of clinical, demographic, and area-level factors. We conducted a retrospective observational study using linked birth certificate and insurance claims data from the Arkansas All-Payer Claims Database (APCD), for the years 2013 through 2017. We used various learning algorithms and measures of arc strength to choose the most robust network structure. We then performed various conditional probabilistic queries using Monte Carlo simulation to understand disparities in SMM. We found that anemia and hypertensive disorder of pregnancy may be important clinical comorbidities to target in order to reduce SMM overall as well as racial disparities in SMM.

How does individualised physiotherapy work for people with low back pain? A Bayesian Network analysis using randomised controlled trial data

PURPOSE

Individualised physiotherapy is an effective treatment for low back pain. We sought to determine how this treatment works by using randomised controlled trial data to develop a Bayesian Network model.

METHODS

300 randomised controlled trial participants (153 male, 147 female, mean age 44.1) with low back pain (of duration 6-26 weeks) received either individualised physiotherapy or advice. Variables with potential to explain how individualised physiotherapy works were included in a multivariate Bayesian Network model. Modelling incorporated the intervention period (0-10 weeks after study commencement-"early" changes) and the follow-up period (10-52 weeks after study commencement-"late" changes). Sequences of variables in the Bayesian Network showed the most common direct and indirect recovery pathways followed by participants with low back pain receiving individualised physiotherapy versus advice.

RESULTS

Individualised physiotherapy directly reduced early disability in people with low back pain. Individualised physiotherapy exerted indirect effects on pain intensity, recovery expectations, sleep, fear, anxiety, and depression via its ability to facilitate early improvement in disability. Early improvement in disability, led to an early reduction in depression both directly and via more complex pathways involving fear, recovery expectations, anxiety, and pain intensity. Individualised physiotherapy had its greatest influence on early change variables (during the intervention period).

CONCLUSION

Individualised physiotherapy for low back pain appears to work predominately by facilitating an early reduction in disability, which in turn leads to improvements in other biopsychosocial outcomes. The current study cannot rule out that unmeasured mechanisms (such as tissue healing or reduced inflammation) may mediate the relationship between individualised physiotherapy treatment and improvement in disability. Further data-driven analyses involving a broad range of plausible biopsychosocial variables are recommended to fully understand how treatments work for people with low back pain.

TRIALS REGISTRATION

ACTRN12609000834257.

Neck-related function and its connection with disability in chronic whiplash-associated disorders: secondary analysis of a randomized controlled study

BACKGROUND

More than 40% of individuals with whiplash injury experience persistent neck pain and disability years later, called whiplash-associated disorders (WAD). A randomized controlled trial evaluated three exercise interventions in WAD and found that neck-specific exercise (NSE) and NSE with a behavioral approach (NSEB) significantly improve disability compared to prescribed physical activity (PPA). However, the relationship between neck-related function and disability is inconclusive and needs to be further investigated.

AIM

The present study compares the effect of NSE, NSEB, and PPA on neck muscle endurance (NME), active cervical range of motion (AROM), grip strength, and pain intensity immediately before and after the physical tests, and neck disability in individuals who are below or above the cut-off for normative reference values regarding NME, AROM, and grip strength.

DESIGN

Follow-up to a multicenter randomized clinical trial.

SETTING

Primary healthcare centers and hospital outpatient services.

POPULATION

The selected population of this study included 216 patients with persistent WAD grades II and III.

METHODS

This is a secondary analysis including 12 months' follow-up. NME, AROM, grip strength, pain, and self-reported disability were recorded at baseline, 3, 6, and 12 months. Linear mixed models were used, and sub-group analyses evaluated by non-parametric tests.

RESULTS

NSE and NSEB resulted in greater improvements compared to PPA (P<0.01) in ventral (only males) and dorsal NME, AROM, and pain intensity during testing. We found no significant between-group differences in grip strength and no significant differences between the NSE and NSEB groups. Improvement in disability was seen at the 12-month follow-up of NSE and/or NSEB for individuals both below and above the cut-off reference values for NME and AROM. Individuals in the PPA group below the reference values for NME and AROM reported increasing disability at 12 months compared to baseline.

CONCLUSIONS

The results suggest that neck-specific exercises (i.e., NSE, NSEB) improve clinical function and decrease disability in chronic WAD compared to PPA, but PPA can increase disability for patients with low neck-related function.

CLINICAL REHABILITATION IMPACT

Higher neck-related function seems to be important for reduced disability in persistent WAD grades II and III. Neck-specific exercises could lead to higher neck-related function.

Mechanisms of recovery after neck-specific or general exercises in patients with cervical radiculopathy

BACKGROUND

The mechanisms of action that facilitate improved outcomes after conservative rehabilitation are unclear in individuals with cervical radiculopathy (CR). This study aims to determine the pathways of recovery of disability with different exercise programs in individuals with CR.

METHODS

We analysed a dataset of 144 individuals with CR undergoing conservative rehabilitation. Eleven variables collected at baseline, 3, 6 and 12 months follow-up were used to build a Bayesian Network (BN) model: treatment group (neck-specific vs. general exercises), age, sex, self-efficacy, catastrophizing, kinesiophobia, anxiety, neck-arm pain intensity, headache pain intensity and disability. The model was used to quantify the contribution of different mediating pathways on the outcome of disability at 12th months.

RESULTS

All modelled variables were conditionally independent from treatment groups. A one-point increase in anxiety at 3rd month was associated with a 2.45-point increase in 12th month disability (p <.001). A one-point increase in head pain at 3rd month was associated with a 0.08-point increase in 12th month disability (p <.001). Approximately 83% of the effect of anxiety on disability was attributable to self-efficacy. Approximately 88% of the effect of head pain on disability was attributable to neck-arm pain.

CONCLUSIONS

No psychological or pain-related variables mediated the different treatment programs with respect to the outcome of disability. Thus, the specific characteristics investigated in this study did not explain the differences in mechanisms of effect between neck-specific training and prescribed physical activity. The present study provides candidate modifiable mediators that could be the target of future intervention trials.

SIGNIFICANCE

Psychological and pain characteristics did not differentially explain the mechanism of effect that two exercise regimes had on disability in individuals with cervical radiculopathy. In addition, we found that improvements in self-efficacy was approximately five times more important than that of neck-arm pain intensity in mediating the anxiety-disability relationship. A mechanistic understanding of recovery provides candidate modifiable mediators that could be the target of future intervention trials.

TRIALS REGISTRATION

ClinicalTrials.gov identifier: NCT01547611.

Self-efficacy beliefs mediate the association between pain intensity and pain interference in acute/subacute whiplash-associated disorders

PURPOSE

To evaluate whether a set of pre-accident demographic, accident-related, post-accident treatment and psychosocial factors assessed in people with acute/subacute whiplash-associated disorders (WAD) mediate the association between pain intensity and: (1) pain interference and (2) expectations of recovery, using Bayesian networks (BNs) analyses. This study also explored the potential mediating pathways (if any) between different psychosocial factors.

METHODS

This was a cross-sectional study conducted on a sample of 173 participants with acute/subacute WAD. Pain intensity, pain interference, pessimism, expectations of recovery, pain catastrophizing, and self-efficacy beliefs were assessed. BN analyses were conducted to analyse the mediating effects of psychological factors on the association between pain intensity and pain-related outcomes.

RESULTS

The results revealed that self-efficacy beliefs partially mediated the association between pain intensity and pain interference. Kinesiophobia partially mediated the association between self-efficacy and pain catastrophizing. Psychological factors did not mediate the association between pain intensity and expectations of recovery.

CONCLUSION

These results indicate that individuals with acute/subacute WAD may present with lesser pain interference associated with a determined pain intensity value when they show greater self-efficacy beliefs. As the cross-sectional nature of this study limits firm conclusions on the causal impact, researchers are encouraged to investigate the role that patient's self-efficacy beliefs play in the transition to chronic WAD via longitudinal study designs.