The Mediating Role of Pain Cognitions and Pain Sensitivity in the Treatment Effect of Perioperative Pain Neuroscience Education in People Undergoing Surgery for Lumbar Radiculopathy.

Though perioperative pain neuroscience education (PPNE) positively influences patients' surgical outcomes, little is known about the mechanisms behind this treatment's success. Therefore, this study aims to evaluate the potential mediating role of pain cognitions and pain sensitivity in the treatment effect of PPNE on postoperative quality of life in people undergoing surgery for lumbar radiculopathy. This secondary analysis uses data from 120 participants of a randomized controlled trial who were randomized to receive either PPNE or perioperative biomedical education before undergoing surgery for lumbar radiculopathy. Quality of life was assessed 1-year postsurgery using the short form 36-item health survey (SF36) physical and mental component scores. Potential mediators included pain cognitions (ie, kinesiophobia, pain catastrophizing, and hypervigilance) and pain sensitivity (ie, endogenous nociceptive modulation), assessed 6 weeks postsurgery. Mediation models were constructed using structural equation modeling, and 95% confidence intervals (CIs) were calculated using 10,000 bootstrap samples. Analyses show a significant total effect for PPNE (estimate = .464, 95% CI [.105, .825]) and a significant indirect effect via pain catastrophizing on the SF36 physical component (estimate = .124, 95% CI [.001, .293]). No mediating effect was found through the remaining pain cognitions or pain sensitivity measures. Also, no potential mediators were identified for the treatment effect of PPNE on the SF36 mental component. Our findings suggest that pain catastrophizing mediates the treatment effect of PPNE on physical health-related quality of life in people undergoing surgery for lumbar radiculopathy. PERSPECTIVE: This secondary analysis identified pain catastrophizing as a mediator for PPNE in people undergoing surgery for lumbar radiculopathy. More so, its findings indicate that this educational intervention can enhance the postoperative physical health-related quality of life of these patients by addressing their catastrophizing thoughts. TRIAL REGISTRATION: Clinicaltrials.gov (NCT02630732).

Impaired Carbohydrate Metabolism among Women with Chronic Low Back Pain and the Role of Dietary Carbohydrates: A Randomized Controlled Cross-Over Experiment.

Background: Impaired glucose regulation is suggested to be related to chronic low back pain (CLBP), although it is not clear how they interact with each other. Thus, the primary aim of this study was to investigate differences in postprandial glycemic responses (PPGRs) (the first sign of impaired glucose metabolism) to high- (sucrose) and low-glycemic index (GI) (isomaltulose) beverages in normoglycemic women with CLBP and healthy controls (HCs) and explore whether any group that showed greater PPGRs to high-GI beverage intake would benefit when the high-GI beverage was replaced with a low-GI beverage. Secondly, this study aimed to explore the association between PPGR and pain in patients with CLBP. Methods: This study was registered at clinicaltrials.org (NCT04459104) before the start of the study. In this study, 53 CLBP patients and 53 HCs were recruited. After 11-12 h of fasting, each participant randomly received isomaltulose or sucrose. Blood glucose levels were measured during the fasting state and 15, 30, 45, 60, 90, and 120 min after the beverage intake, and each participant underwent experimental pain measures. Results: Compared to the HCs, the CLBP group showed significantly higher PPGRs to sucrose (p < 0.021). Additionally, the CLBP group showed a significantly higher decrease in PPGR (p = 0.045) when comparing PPGR to sucrose with PPGR to isomaltulose. Correlation analysis revealed a positive association between self-reported pain sensitivity and PPGR to sucrose, while there was no association found between any experimental pain measures and glycemic responses. Conclusions: Overall, these findings suggest that normoglycemic CLBP patients might have a higher risk of developing impaired glucose tolerance than the HCs and might benefit more when high-GI foods are replaced with low-GI ones.

Online Exercise Programs for Chronic Nonspecific Neck Pain: A Randomized Controlled Trial Reveals Comparable Effects of Global, Local, and Combined Approaches.

OBJECTIVE: Specific neck exercises are recommended in the rehabilitation of chronic nonspecific neck pain (CNNP). They are unfortunately often accompanied by acute pain flare-ups. Global exercises might be a beneficial addition, as they activate endogenous analgesia without overloading painful structures. However, it is still unclear which type of exercise is most effective. This randomized controlled trial was done to evaluate the effect of an online blended program of global and specific neck exercises, compared to programs including only 1 of both types of exercise. METHODS: Forty-eight patients with CNNP were randomized into 3 groups. Online questionnaires were collected at baseline, at midtreatment, immediately after treatment, and at the 3-month follow-up. Quantitative sensory testing and actigraphy were assessed at baseline and after treatment. Linear mixed-model analyses were performed to evaluate treatment effects within and between groups. Neck pain-related disability after treatment was considered the primary outcome. RESULTS: No time × treatment interaction effects were found. All groups improved in neck pain-related disability, pain intensity, self-reported symptoms of central sensitization, local pain sensitivity, physical activity, and pain medication use. No effects were found on quality of life, sleep quality, depression, anxiety, stress, widespread pain sensitivity, health economics, or actigraphy measurements. A higher global perceived effect was reported after performing the blended program, compared to the other groups. CONCLUSION: A blended exercise program was not superior to the stand-alone programs in reducing disability. Nevertheless, the global perceived effect of this type of exercise was higher. Future research necessitates larger sample sizes to adequately explore the optimal type of exercise for patients with CNNP. IMPACT: Exercise therapy should be an important part of the rehabilitation of patients with CNNP, regardless of the type of exercise.

Towards a Real-Life Understanding of the Altered Functional Behaviour of the Default Mode and Salience Network in Chronic Pain: Are People with Chronic Pain Overthinking the Meaning of Their Pain?

Chronic pain is a source of substantial physical and psychological suffering, yet a clear understanding of the pathogenesis of chronic pain is lacking. Repeated studies have reported an altered behaviour of the salience network (SN) and default mode network (DMN) in people with chronic pain, and a majority of these studies report an altered behaviour of the dorsal ventromedial prefrontal cortex (vmPFC) within the anterior DMN. In this topical review, we therefore focus specifically on the role of the dorsal vmPFC in chronic pain to provide an updated perspective on the cortical mechanisms of chronic pain. We suggest that increased activity in the dorsal vmPFC may reflect maladaptive overthinking about the meaning of pain for oneself and one's actions. We also suggest that such overthinking, if negative, may increase the personal "threat" of a given context, as possibly reflected by increased activity in, and functional connectivity to, the anterior insular cortex within the SN.

Influence of Preoperative Pain, Cognitions, and Quantitative Sensory Testing Measures on the Effects of Perioperative Pain Neuroscience Education for People Receiving Surgery for Lumbar Radiculopathy: Secondary Analysis of a Randomized Controlled Trial.

OBJECTIVE: To explore whether preoperative pain intensity, pain cognitions, and quantitative sensory measures influence the established effectiveness of perioperative pain neuroscience education (PPNE) on health-related quality of life at 1 year after surgery for lumbar radiculopathy. DESIGN: Secondary analysis of a triple-blinded randomized controlled trial. METHODS: Participants (n = 90) were Dutch-speaking adults (18-65 years) who were scheduled for surgery for lumbar radiculopathy in 3 Belgian hospitals. They were randomized (1:1) to receive PPNE (n = 41) or perioperative biomedical education (n = 49). Linear mixed models were built for health-related quality of life (ie, SF-6D utility values, Physical and Mental Component of the 36-item Short Form Health Survey) using the following independent variables: therapy, time, and preoperative scores for back and leg pain intensity, pain catastrophizing, kinesiophobia, hypervigilance, and quantitative sensory measures. RESULTS: The impact of PPNE on SF-6D utility values over time was influenced by kinesiophobia (F = 3.30, P = .02) and leg pain intensity (F = 3.48, P = .02). Regardless of the intervention, back pain intensity negatively influenced SF-6D values over time (F = 3.99, P = .009). The Physical Component scores were negatively impacted by back pain intensity (F = 9.08, P = .003) and were influenced over time by leg pain intensity (F = 2.87, P = .04). The Mental Component scores were negatively impacted by back pain intensity (F = 6.64, P = .01) and pain catastrophizing (F = 5.42, P = .02), as well as hypervigilance (F = 3.16, P = .03) and leg pain intensity (F = 3.12, P = .03) over time. CONCLUSION: PPNE may be more effective than perioperative biomedical education in improving postoperative health utility values in patients who reported higher kinesiophobia and leg pain intensity before surgery for lumbar radiculopathy. J Orthop Sports Phys Ther 2024;54(4):1-10. Epub 8 January 2024. doi:10.2519/jospt.2024.12051.

Gray Matter Adaptations to Chronic Pain in People with Whiplash-Associated Disorders are Partially Reversed After Treatment: A Voxel-based Morphometry Study.

Gray matter (GM) changes are often observed in people with chronic spinal pain, including those with chronic whiplash-associated disorders (CWAD). These GM adaptations may be reversed with treatment, at least partially. Pain neuroscience education combined with exercise (PNE+Exercise) is an effective treatment, but its neural underlying mechanisms still remain unexplored in CWAD. Here, we performed both cross-sectional and longitudinal voxel-based morphometry to 1) identify potential GM alterations in people with CWAD (n = 63) compared to age- and sex-matched pain-free controls (n = 32), and 2) determine whether these GM alterations might be reversed following PNE+Exercise (compared to conventional physiotherapy). The cross-sectional whole-brain analysis revealed that individuals with CWAD had less GM volume in the right and left dorsolateral prefrontal cortex and left inferior temporal gyrus which was, in turn, associated with higher pain vigilance. Fifty individuals with CWAD and 29 pain-free controls were retained in the longitudinal analysis. GM in the right dorsolateral prefrontal cortex increased after treatment in people with CWAD. Moreover, the longitudinal whole-brain analysis revealed that individuals with CWAD had decreases in GM volumes of the left and right central operculum and supramarginal after treatment. These changes were not specific to treatment modality and some were not observed in pain-free controls over time. Herewith, we provide the first evidence on how GM adaptations to CWAD respond to treatment. PERSPECTIVE: This article presents which gray matter adaptations are present in people with chronic pain after whiplash injuries. Then, we examine the treatment effect on these alterations as well as whether other neuroplastic effects on GM following treatment occur.

Exercise-Induced Hypoalgesia in Patients with Chronic Whiplash-Associated Disorders: Differences between Subgroups Based on the Central Sensitization Inventory.

BACKGROUND: Physical exercise is an important element in the rehabilitation of chronic whiplash-associated disorders, with the physiological process underlying pain reduction called exercise-induced hypoalgesia. In chronic whiplash-associated disorders, exercise-induced hypoalgesia appears impaired, and the research suggests a relationship with symptoms of dysfunctional nociceptive processing, such as central sensitization. This study improves our understanding of exercise-induced hypoalgesia in chronic whiplash-associated disorders by examining the differences between the extent of exercise-induced hypoalgesia in subgroups based on scores on the central sensitization inventory (CSI). METHODS: Data were collected from 135 participants with chronic whiplash-associated disorders who completed a set of questionnaires. Pain pressure thresholds and temporal summations were assessed before and after a submaximal aerobic bicycle exercise test. RESULTS: We observed no interaction effect between exercise-induced hypoalgesia and the CSI scores for both pain pressure threshold and temporal summation. No overall statistical effect was measured in the analysis of the effect of time. The pain pressure threshold significantly related to the CSI. The temporal summation showed no correlation. CONCLUSIONS: During this study, we did not find evidence for a difference in the presence of exercise-induced hypoalgesia when the subgroups were created based on the central sensitization cluster calculator. Limited evidence was found for the influence of CSI scores on the delta pain pressure threshold.

Exploring Interactions Between Sex, Pain Characteristics, Disability, and Quality of Life in People With Chronic Spinal Pain: A Structural Equation Model.

In people with nonspecific chronic spinal pain (nCSP), disability and quality of life are associated with clinical, cognitive, psychophysical, and demographic variables. However, evidence regarding the interactions between these variables is only limited to this population. Therefore, this study aims to explore path models explaining the multivariate contributions of such variables to disability and quality of life in people with nCSP. This secondary analysis uses baseline data from a randomized controlled trial including 120 participants with nCSP. Structural equation modeling was used to explore path models for the Pain Disability Index (PDI), the Short Form 36-item physical (SF-36 PC), and mental (SF-36 MC) component scores. All models included sex, pain catastrophizing, kinesiophobia, hypervigilance, and pain intensity. Additionally, the PDI and SF-36 PC models included pressure pain thresholds (PPTs) at the dominant pain site (ie, neck or low back). Significant associations were found between sex, pain cognitions, pain intensity, and PPTs. Only pain catastrophizing significantly directly influenced the PDI (P ≤ .001) and SF-36 MC (P = .014), while the direct effects on the SF-36 PC from kinesiophobia (P = .008) and pain intensity (P = .006) were also significant. However, only the combined effect of all pain cognitions on the SF-36 PC was mediated by pain intensity (P = .019). Our findings indicate that patients' pain-related cognitions have an adverse effect on their physical health-related quality of life via a negative influence on their pain intensity in people with nCSP. PERSPECTIVE: This secondary analysis details a network analysis confirming significant interactions between sex, pain cognitions, pain intensity, and PPTs in relation to disability and health-related quality of life in people with chronic spinal pain. Moreover, its findings establish the importance of pain cognitions and pain intensity for these outcomes. TRIALS REGISTRATION: Clinicaltrials.gov (NCT02098005).

Proinflammatory Dietary Intake Relates to Pain Sensitivity in Chronic Nonspecific Low Back Pain: A Case-Control Study.

Nonspecific chronic low back pain (nCLBP) has been associated with nutrition. Yet, it is not clear how nutritional factors and nCLBP relate to one another. Therefore, the aim of the present study was to investigate differences in diet quality and dietary intake levels between nCLBP patients and healthy controls (HCs) and explore the association between nutritional factors and pain sensitivity in nCLBP. In this case-control study, 106 participants (ie, n = 53 nCLBP and n = 53 HCs) were recruited and completed a 3-day food diary to assess their dietary intake, which allowed to generate individual diet quality scores (ie, the Healthy Eating Index-2015 and Dietary Inflammatory Index). Additionally, each participant underwent an experimental pain assessment (quantitative sensory testing) and filled out self-reported pain questionnaires. Compared to HCs, the nCLBP group showed significantly lower diet quality, higher inflammatory scores, and a lower intake of total protein, total fat, dietary fiber, omega-3 fatty acids, vitamin B6, vitamin A, beta-carotene, vitamin E, and magnesium. Pain sensitivity mainly showed a negative correlation with nutritional intakes known for anti-inflammatory properties (ie, vitamins E, D, A, B6, B12, and zinc). Interestingly, total fat, cholesterol, saturated, and monounsaturated fat intakes were found to be inversely associated with pain sensitivity. Overall, patients with nCLBP have a lower diet quality, eat more proinflammatory, have less intake of nutrients known for their anti-inflammatory and antioxidative properties, and drink less water compared to HCs. Accordingly, pain sensitivity was mainly found to be positively associated with proinflammatory dietary intake. PERSPECTIVE: This study emphasizes the association between a proinflammatory diet and nCLBP. Among nCLBP patients, positive association between increased pain sensitivity and the proinflammatory potential of a diet, highlighting the potential for individualized pain management strategies and leading to the development of novel therapeutic methods.

Unravelling Impaired Hypoalgesia at Rest and in Response to Exercise in Patients with Chronic Whiplash-Associated Disorders: Effects of a Single Administration of Selective Serotonin Reuptake Inhibitor versus Selective Norepinephrine Reuptake Inhibitor.

(1) Background: Noradrenaline and serotonin have modulatory roles in pain signaling and in exercise-induced hypoalgesia. Patients with chronic whiplash-associated disorders often show impaired exercise-induced hypoalgesia. Therefore, this study aimed to examine the isolated effect of activating serotonergic or noradrenergic descending pathways on hypoalgesia at rest and in response to exercise in patients with chronic WAD by using respectively a single dose of a selective serotonin reuptake inhibitor (SSRI) and a selective norepinephrine reuptake inhibitor (NRI). (2) Methods: Twenty-five people with chronic WAD participated in this double-blind randomized controlled crossover experiment. Serotonin and noradrenaline concentrations were modulated by the oral ingestion of a single dose of citalopram (i.e., SSRI) or atomoxetine (i.e., SNRI). Quantitative sensory testing (including pressure pain thresholds and conditioned pain modulation) was measured before and after exercise in combination with no medication (1), atomoxetine (2), or citalopram (3) at three different test days. (3) Results: Random-intercept linear mixed models analysis was used to analyze pain outcomes (i.e., pain at rest and exercise-induced hypoalgesia) before and after exercise over the three conditions in patients with chronic WAD. No differences in pain at rest were found between the three conditions before exercise. The effect of exercise on pain outcome measures was not influenced by medication intake. The occupational status of the participants had a significant influence on the effect of exercise and medication on pain outcomes (p < 0.05). Patients working full-time had some positive effect of atomoxetine on pain facilitation (p < 0.05). Unemployed patients had some negative effect of citalopram on pain tolerance and experienced exercise-induced hypoalgesia (p < 0.05). (4) Conclusions: A single dose of citalopram or atomoxetine did not result in changes in hypoalgesia at rest and in response to exercise. These results do not support the use of SSRI or selective NRI to overcome impaired hypoalgesia at rest or in response to exercise in people with chronic WAD. Effect of exercise and medication on pain in patients with chronic WAD is influenced by the occupational status.

The Role of Serotonergic and Noradrenergic Descending Pathways on Performance-Based Cognitive Functioning at Rest and in Response to Exercise in People with Chronic Whiplash-Associated Disorders: A Randomized Controlled Crossover Study.

(1) Background: Dysregulation in serotonergic and noradrenergic systems may be implicated in the neurobiophysiological mechanisms underlying pain-related cognitive impairment in chronic whiplash-associated disorders (CWAD). This study aimed to unravel the role of serotonergic and noradrenergic descending pathways in cognitive functioning at rest and in response to exercise in people with CWAD. (2) Methods: 25 people with CWAD were included in this double-blind, randomized, controlled crossover study. Endogenous descending serotonergic and noradrenergic inhibitory mechanisms were modulated by using a single dose of a selective serotonin reuptake inhibitor (Citalopram) or a selective norepinephrine reuptake inhibitor (Atomoxetine). Cognitive performance was studied at rest and in response to exercise (1) without medication intake; (2) after intake of Citalopram; and (3) after intake of Atomoxetine. (3) Results: After Atomoxetine intake, selective attention improved compared with the no medication day (p < 0.05). In contrast, a single dose of Citalopram had no significant effect on cognitive functioning at rest. When performing pairwise comparisons, improvements in selective attention were found after exercise for the no medication condition (p < 0.05). In contrast, after intake of Citalopram or Atomoxetine, selective and sustained attention worsened after exercise. (4) Conclusions: A single dose of Atomoxetine improved selective attention only in one Stroop condition, and a single dose of Citalopram had no effect on cognitive functioning at rest in people with CWAD. Only without medication intake did selective attention improve in response to exercise, whereas both centrally acting medications worsened cognitive performance in response to a submaximal aerobic exercise bout in people with CWAD.

Effect of perioperative pain neuroscience education in people undergoing surgery for lumbar radiculopathy: a multicentre randomised controlled trial.

BACKGROUND: Perioperative education should be improved to decrease unfavourable outcomes after lumbar surgery. This trial aimed to compare effectiveness in terms of pain, quality of life, pain cognition, surgical experience, healthcare use, work resumption, and cost-effectiveness of perioperative pain neuroscience education (PPNE) vs traditional biomedical education (perioperative biomedical education [PBE]) in people undergoing surgery for lumbar radiculopathy. METHODS: In this multicentre RCT (ClinicalTrials.gov: NCT02630732), patients undergoing surgery for lumbar radiculopathy in three Belgian hospitals were randomised to receive PPNE or PBE. Both groups received one preoperative and one postoperative one-to-one education session and a booklet (balanced interventions), with an essentially different content (PPNE: biopsychosocial; PBE: biomedical). Pain was the primary outcome (Visual Analogue Scales+quantitative sensory testing). Assessments were at 3 days, 6 weeks, and 6 and 12 months after surgery. RESULTS: Between March 2016 and April 2020, participants were randomly assigned to PPNE (n=58) or PBE (n=62). At 12 months, PPNE did not lead to significantly better pain outcomes, but it did result in more favourable 36-item Short Form Health Survey physical component (additional increase: 46.94; 95% confidence interval [CI]: 14.16-79.73; medium effect), Tampa Scale of Kinesiophobia (additional decrease: 3.15; 95% CI: 0.25-6.04; small effect), and Pain Catastrophising Scale (additional decrease: 6.18; 95% CI: 1.97-10.39; medium effect) scores. Females of the PPNE group showed higher probability for work resumption (95% vs 60% in the PBE group). PPNE was cost-effective compared with PBE (incremental costs: €-2732; incremental quality-adjusted life years: 0.012). CONCLUSIONS: Perioperative pain neuroscience education showed superior clinical and cost-effectiveness than perioperative biomedical education in people undergoing surgery for lumbar radiculopathy. CLINICAL TRIAL REGISTRATION: NCT02630732.

The interplay between symptoms of insomnia and pain in people with osteoarthritis: A narrative review of the current evidence.

Osteoarthritis (OA) is a leading cause of disability worldwide and clinical pain is the major symptom of OA. This clinical OA-related pain is firmly associated with symptoms of insomnia, which are reported in up to 81% of people with OA. Since understanding the association between both symptoms is critical for their appropriate management, this narrative review synthesizes the existing evidence in people with OA on i) the mechanisms underlying the association between insomnia symptoms and clinical OA-related pain, and ii) the effectiveness of conservative non-pharmacological treatments on insomnia symptoms and clinical OA-related pain. The evidence available identifies depressive symptoms, pain catastrophizing and pain self-efficacy as mechanisms partially explaining the cross-sectional association between insomnia symptoms and pain in people with OA. Furthermore, in comparison to treatments without a specific insomnia intervention, the ones including an insomnia intervention appear more effective for improving insomnia symptoms, but not for reducing clinical OA-related pain. However, at a within-person level, treatment-related positive effects on insomnia symptoms are associated with a long-term pain reduction. Future longitudinal prospective studies offering fundamental insights into neurobiological and psychosocial mechanisms explaining the association between insomnia symptoms and clinical OA-related pain will enable the development of effective treatments targeting both symptoms.

Exploration of Somatosensory Function of Patients With Acute Nonspecific Neck Pain, Through Quantitative Sensory Testing and Self-reported Symptoms.

OBJECTIVES: Adaptations in somatosensory function characterize several chronic pain conditions, including nonspecific neck pain (NNP). Early signs of central sensitization (CS) contribute to pain chronification and poor treatment responses after conditions such as whiplash injury and low back pain. Despite this well-established association, the prevalence of CS in patients with acute NNP, and accordingly, the potential impact of this association, is still unclear. Therefore, this study aimed to investigate whether changes in somatosensory function occur during the acute phase of NNP. METHODS: This cross-sectional study compared 35 patients with acute NNP with 27 pain-free individuals. All participants completed standardized questionnaires and an extensive multimodal Quantitative Sensory Testing protocol. A secondary comparison was made with 60 patients, with chronic whiplash-associated disorders, a population wherein CS is well-established. RESULTS: Compared with pain-free individuals, pressure pain thresholds (PPTs) in remote areas and thermal detection and pain thresholds were unaltered. However, patients with acute NNP showed lower cervical PPTs and conditioned pain modulation, higher temporal summation, Central Sensitization Index scores, and pain intensity. Compared with the group with chronic whiplash-associated disorders, PPTs did not differ at any location, yet the Central Sensitization Index scores were lower. DISCUSSION: Changes in somatosensory function occur already in acute NNP. Local mechanical hyperalgesia demonstrated peripheral sensitization, while enhanced pain facilitation, impaired conditioned pain modulation, and self-reported symptoms of CS suggest adaptations in pain processing already early in the stage of NNP.

Neural processing of pain-related distress to neck-specific movements in people with chronic whiplash-associated disorders.

ABSTRACT: Pain-related distress contributes to long-term disability in chronic whiplash-associated disorders. Recently, neuroimaging studies have revealed altered neural responses to viewing pictures of movements associated with back pain in key regions for threat and affective processing. In this study, we examined neural correlates of imagining neck-specific movements designed to elicit pain-related distress in individuals with whiplash-associated disorders (n = 63) when compared with that in sex-matched pain-free controls (n = 32). In the scanner, participants were presented with neck-specific movement-related pictures divided into 3 categories (high fear, moderate-fear, and neutral control pictures) and asked to imagine how they would feel if they were performing the movement. Whole-brain analyses revealed greater differential activation (high-fear vs neutral) in individuals with whiplash-associated disorders when compared with that in pain-free controls in 6 clusters including right and left postcentral gyri, left parietal operculum, dorsal precuneus, left superior frontal gyrus/anterior cingulate cortex, and posterior cingulate cortex/ventral precuneus. For the contrast moderate-fear vs neutral, patients showed greater differential activation than controls in the right and left posterolateral cerebellum. Activation patterns in the precuneus and posterior cingulate cortex were negatively associated with pain-related fear, but no other correlations were observed. Together, the findings suggest that when conceptualizing neck-specific movements associated with pain, people with chronic whiplash-associated disorders may predict-and potentially amplify-their sensory and affective consequences and therewith trigger dysfunctional affective and/or behavioral responses. Herewith, we provide new insights into the neural mechanisms underlying chronic pain in people with whiplash-associated disorders, pointing towards a complex interplay between cognitive/affective and sensorimotor circuitry.

Exploring Associations between Healthcare Use and Demographics, Pain and Pain Cognitions in People Scheduled for Surgery for Lumbar Radiculopathy: A Cross-Sectional Study.

This cross-sectional study explored associations between demographics, pain intensity and cognitions on the one hand and healthcare use (HCU) on the other hand in people undergoing surgery for lumbar radiculopathy. HCU during the 2 months preceding surgery was evaluated using a retrospective questionnaire. Demographics included sex, age and level of education and equivalent income. Back and leg pain intensity were evaluated using a visual analogue scale. Pain cognitions were assessed with the Tampa scale of kinesiophobia, the pain catastrophizing scale and the pain vigilance and awareness questionnaire. The sample comprised 120 participants (52% males; 49 years (Quartile (Q)1-Q3: 37.3-57.43)). The number of visits to the general practitioner was associated with sex (incidence rate ratio (IRR) for males = 0.811; p = 0.050), pain catastrophizing (IRR = 1.010; p = 0.041), pain magnification (IRR = 1.058; p = 0.004) and leg pain intensity (IRR = 1.004; p = 0.038). The number of neurosurgeon visits was associated with level of education (IRR moderate education = 1.518; p = 0.016 (reference: low education)). Receiving zero physiotherapy visits was associated with higher back pain intensity (Beta = 0.018; p = 0.028). Highest level of analgesics used was associated with sex (IRR for males = 0.502; p = 0.047) and leg pain (IRR = 1.014; p = 0.034). Only the association between general practitioner visits and pain magnification remained significant in multivariable analyses (IRR = 1.061; p = 0.033). The results suggest a rather indirect relationship between HCU and demographics, pain intensity and cognitions, involving a potential interplay between several patient- and healthcare system-related factors.

Experimental Pain Measurements Do Not Relate to Pain Intensity and Pain Cognitions in People Scheduled for Surgery for Lumbar Radiculopathy.

OBJECTIVE: The present cross-sectional study aims to unravel associations of pain intensity and cognitions with quantitative sensory testing in people scheduled for surgery for lumbar radiculopathy. Additionally, insight will be provided into the presence of dysfunctional nociceptive processing and maladaptive pain cognitions in this population. DESIGN: Cross-sectional study. SETTING: Data from three hospitals in Belgium. SUBJECTS: The final sample comprised 120 participants with lumbar radiculopathy scheduled for surgery, included between March 2016 and April 2019. METHODS: Self-reported pain intensity was assessed on a visual analog scale, and pain cognitions were assessed with self-reported questionnaires (Pain Catastrophizing Scale, Tampa Scale for Kinesiophobia, and Pain Vigilance and Awareness Questionnaire). Quantitative sensory testing (detection thresholds, pain thresholds, temporal summation, and conditioned pain modulation) was evaluated, as well. RESULTS: Evidence was found for the presence of an impaired inhibitory response to nociceptive stimuli and maladaptive pain cognitions in this population. Kinesiophobia was found to be present to a maladaptive degree in the majority of the patients (n = 106 [88%]). Significant, but weak, associations between electrical pain thresholds at the sural nerves and leg pain intensity (sural nerve symptomatic side: r = -0.23; P = 0.01; non-symptomatic side: r = -0.22; P = 0.02) and kinesiophobia levels (sural nerve non-symptomatic side: r = -0.26; P = 0.006) were identified. CONCLUSIONS: Electrical detection thresholds and correlates for endogenous nociceptive facilitation and inhibition were not found to be related to any of the pain cognitions or to pain intensity in people scheduled to undergo surgery for lumbar radiculopathy.

Adaptive changes in sensorimotor processing in patients with acute low back pain.

In low back pain (LBP), primary care and secondary prevention of recurrent and persistent LBP are not always successful. Enhanced understanding of neural mechanisms of sensorimotor processing and pain modulation in patients with acute LBP is mandatory. This explorative fMRI study investigated sensorimotor processing due to mechanosensory stimulation of the lumbar spine. We studied 19 adult patients with acute LBP (< 4 weeks of an acute episode) and 23 healthy controls. On a numeric rating scale, patients reported moderate mean pain intensity of 4.5 out of 10, while LBP-associated disability indicated mild mean disability. The event-related fMRI analysis yielded no between-group differences. However, the computation of functional connectivity resulted in adaptive changes in networks involved in sensorimotor processing in the patient group: Connectivity strength was decreased in the salience and cerebellar networks but increased in the limbic and parahippocampal networks. Timewise, these results indicate that early connectivity changes might reflect adaptive physiological processes in an episode of acute LBP. These findings raise intriguing questions regarding their role in pain persistence and recurrences of LBP, particularly concerning the multiple consequences of acute LBP pain. Advanced understanding of neural mechanisms of processing non-painful mechanosensations in LBP may also improve therapeutic approaches.

The Predictive Value of Fear Avoidance Beliefs for Outcomes Following Surgery for Lumbar Degenerative Disease: A Systematic Review and Best Evidence Synthesis.

BACKGROUND: Currently, evidence regarding fear avoidance beliefs as potential predictors for lumbar surgery outcomes seems insufficient and strong conclusions are not yet available. OBJECTIVE: This systematic review aimed to evaluate the predictive value of preoperative fear avoidance beliefs for postoperative pain intensity, functional status, and health-related quality of life following surgery for lumbar degenerative disease. STUDY DESIGN: Systematic review and best evidence synthesis. METHODS: An extensive search was performed in PubMed/Medline, EMBASE, PsycINFO, CINAHL and the Cochrane library for articles published up until October 2021. Two independent reviewers performed the screening, data extraction, and quality assessment, with a third independent reviewer consulting to resolve any disagreement. Observational studies that included patients undergoing surgery for lumbar degenerative disease, as well as evaluated fear avoidance beliefs (i.e., pain-related fear, pain catastrophizing, pain anxiety) in relation to a surgical outcome measure (i.e., pain intensity, functional status and health-related quality of life) were included in the review. The CHARMS- and QUIPS-tools were used for data extraction and quality assessment, respectively. A best evidence synthesis was performed resulting in conclusions regarding strong, moderate, conflicting, and limited levels of evidence. RESULTS: A total of 24 studies (n = 17,881) were included in this review. Following best evidence synthesis, 3 included studies reported no significant predictive value of preoperative pain-related fear for postoperative pain intensity resulting in moderate evidence for this relationship. Moderate evidence was also found indicating no significant predictive value of preoperative pain-related fear for postoperative functional status, as 6 out of 8 relevant studies reported this result. Only one study reported on the predictive value of preoperative pain catastrophizing for postoperative health-related quality of life, resulting in limited evidence for the absence of this predictive relationship. All other relationships were found to have conflicting evidence. LIMITATIONS: To evaluate surgical outcome, only patient-reported outcome measures as used by spine registries were included. Thus, our findings cannot be extrapolated to all surgery outcomes following lumbar degenerative disease and should only be interpreted in relation to postoperative pain intensity, functional status, or health-related quality of life. CONCLUSION: Best evidence synthesis showed moderate evidence indicating that preoperative pain-related fear is not a significant predictor for postoperative pain and function following surgery for lumbar degenerative disease. Additionally, limited evidence was found for a lack of predictive value of preoperative pain catastrophizing for postoperative health-related quality of life. As current evidence regarding the predictive value of preoperative fear avoidance beliefs following such a surgery is mixed, further research is required before more definitive conclusions can be made.