Movement-Evoked Pain Versus Widespread Pain: A Longitudinal Comparison in Older Adults With Chronic Low Back Pain From the Delaware Spine Studies

It is currently unknown which pain-related factors contribute to long-term disability and poorer perceived health among older adults with chronic low back pain (LBP). This investigation sought to examine the unique influence of movement-evoked pain (MeP) and widespread pain (WP) on longitudinal health outcomes (ie, gait speed, perceived disability, and self-efficacy) in 250 older adults with chronic LBP. MeP was elicited with 3 standardized functional tests, while presence of WP was derived from the McGill Pain Map. Robust regression with HC3 standard errors was used to examine associations between these baseline pain variables and health outcomes at 12-month follow-up. Covariates for these models included age, sex, body mass index, resting and recall LBP intensity, LBP duration, depression, pain catastrophizing, and baseline outcome (eg, baseline gait speed). Greater MeP was independently associated with worse 12-month LBP-related disability (b = .384, t = 2.013, P = .046) and poorer self-efficacy (b = -.562, t = -2.074, P = .039); but not gait speed (P > .05). In contrast, WP and resting and recall LBP intensity were not associated with any prospective health outcome after adjustment (all P > .05). Compared to WP and resting and recall LBP intensity, MeP is most strongly related to longitudinal health outcomes in older adults with chronic LBP.PerspectiveThis article establishes novel independent associations between MeP and worse perceived disability and self-efficacy at 12-months in older adults with chronic LBP. MeP likely has biopsychosocial underpinnings and consequences and may therefore be an important determinant of health outcomes in LBP and other geriatric chronic pain populations.     

Increased Salience Network Connectivity Following Manual Therapy is Associated with Reduced Pain in Chronic Low Back Pain Patients

Chronic low back pain (cLBP) has been associated with changes in brain plasticity. Nonpharmacological therapies such as Manual Therapy (MT) have shown promise for relieving cLBP. However, translational neuroimaging research is needed to understand potential central mechanisms supporting MT. We investigated the effect of MT on resting-state salience network (SLN) connectivity, and whether this was associated with changes in clinical pain. Fifteen cLBP patients, and 16 matched healthy controls (HC) were scanned with resting functional Magnetic Resonance Imaging (fMRI), before and immediately after a MT intervention (cross-over design with two separate visits, pseudorandomized, grades V ‘Manipulation’ and III ‘Mobilization’ of the Maitland Joint Mobilization Grading Scale). Patients rated clinical pain (0–100) pre- and post-therapy. SLN connectivity was assessed using dual regression probabilistic independent component analysis. Both manipulation (Pre: 39.43 ± 16.5, Post: 28.43 ± 16.5) and mobilization (Pre: 38.83 ± 17.7, Post: 31.76 ± 19.4) reduced clinical back pain (P < .05). Manipulation (but not mobilization) significantly increased SLN connectivity to thalamus and primary motor cortex. Additionally, a voxelwise regression indicated that greater MT-induced increase in SLN connectivity to the lateral prefrontal cortex was associated with greater clinical back pain reduction immediately after intervention, for both manipulation (r = -0.8) and mobilization (r = -0.54). Our results suggest that MT is successful in reducing clinical low back pain by both spinal manipulation and spinal mobilization. Furthermore, this reduction post-manipulation occurs via modulation of SLN connectivity to sensorimotor, affective, and cognitive processing regions.PerspectiveMT both reduces clinical low back pain and modulates brain activity important for the processing of pain. This modulation was shown by increased functional brain connectivity between the salience network and brain regions involved in cognitive, affective, and sensorimotor processing of pain.     

Sex and Race Differences in Pain Sensitization among Patients with Chronic Low Back Pain

Growing evidence suggests that chronic low back pain (CLBP) is associated with pain sensitization, and that there are sex and race disparities in CLBP. Given the sex and race differences in pain sensitization, this has been hypothesized as a mechanism contributing to the sex and race disparities in CLBP. This study examined sex and race differences in pain sensitization among patients with CLBP, as well as the role of catastrophizing as a potential mediator of those differences. The study found that compared with men, women required less pressure to produce deep muscle pain and rated mechanical punctate pain as more painful. Compared with non-Hispanic white patients, black patients demonstrated greater pain sensitivity for measures of deep muscle hyperalgesia and mechanical punctate pain. Furthermore, catastrophizing partially mediated the race differences in deep muscle pain such that black participants endorsed greater pain catastrophizing, which partially accounted for their increased sensitivity to, and temporal summation of, deep muscle pain. Taken together, these results support the need to further examine the role of catastrophizing and pain sensitization in the context of sex and race disparities in the experience of CLBP.

Psychosocial Differences Between High-Risk Acute vs. Chronic Low Back Pain Patients

▪ Abstract:   The present study was designed to evaluate the relative degree and type of emotional distress in high-risk acute low back pain (ALBP) subjects (defined as less than 3 months since initial injury) vs. high-risk chronic low back pain (CLBP) subjects (defined as greater than 3 months since initial injury). It is an extension of earlier findings that demonstrated the significant role that such emotional distress may play in the development of CLBP disability if not appropriately treated in the acute phase. This work stems from a conceptual three-stage model, which characterizes the progression from acute to chronic pain. Several psychosocial measures were administered that included information allowing for the classification of subjects as high-risk based upon an earlier developed screening algorithm. The ancova procedure in SPSS was used to compare groups, controlling for gender, ethnicity, and age. Results revealed that CLBP subjects had higher rates of certain measures of emotional distress and depression relative to ALBP subjects. These findings further support the importance of effectively managing emotional distress factors early, when treating musculoskeletal disorders such as low back pain. ▪     

Reliability and Validity of the Y-balance Test in Young Adults with Chronic Low Back Pain

BackgroundIndividuals with chronic low back pain (CLBP) may demonstrate reduced ability to perform dynamic tasks due to fear of additional pain and injury in response to the movement. The Y-balance test (YBT) is a functional and inexpensive test used with various populations. However, the reliability and validity of the YBT used for assessing dynamic balance in young adults with CLBP have not yet been examined.PurposeTo determine the inter-rater reliability of the YBT and to compare dynamic balance between young adults with CLBP and an asymptomatic group.Study DesignReliability and validity study.MethodsFifteen individuals with CLBP (≥ 12 weeks) and 15 age- and gender-matched asymptomatic adults completed the study. Each group consisted of 6 males and 9 females who were 21-38 years of age (27.47 ± 5.0 years). The YBT was used to measure participant’s dynamic balance in the anterior (ANT), posteromedial (PM) and posterolateral (PL) reach directions. The scores for each participant were independently determined and recorded to the nearest centimeter by two raters. Both the YBT reach distances and composite scores were collected from the dominant leg of asymptomatic individuals and the involved side of participants with CLBP and were used for statistical analysis.ResultsThe YBT demonstrated excellent inter-rater reliability, with intraclass correlation coefficients ranging from 0.99 to 1.0 for the YBT scores of both asymptomatic and CLBP groups. The CLBP group had lower scores than those of the asymptomatic group in the reach distances of the ANT (p = 0.023), PM (p < 0.001), and PL (p = 0.001) directions, and the composite scores (p < 0.001).ConclusionsThe results demonstrated excellent inter-rater reliability and validity of the YBT for assessing dynamic balance in the CLBP population. The YBT may be a useful tool for clinicians to assess dynamic balance deficits in patients with CLBP.Level of Evidence2b.     

Aberrant Lumbopelvic Movements Predict Prospective Functional Decline in Older Adults with Chronic Low Back Pain

ObjectiveTo investigate if clinically observable aberrant lumbopelvic movements are associated with physical function at 12-month follow-up in older adults with chronic low back pain (CLBP), both directly and indirectly through baseline physical function.DesignSecondary analysis of a yearlong prospective cohort study.SettingClinical Research Laboratory.ParticipantsCommunity-dwelling older adults with CLBP (N=250).InterventionsNot applicable.Main Outcome MeasuresData from 239 participants were analyzed. Participants were screened at baseline for aberrant lumbopelvic movements during active trunk flexion; total observable aberrant movements were recorded and summed (range 0-4). Latent constructs of physical function were developed from an array of perception-based and performance-based outcome measures at baseline and 12 months, respectively. Structural Equation Modeling was used to assess the direct effect of baseline aberrant movement score on the latent construct of 12-month physical function, and its indirect effect through baseline physical function.ResultsAberrant movements were present in most participants (64.7%) and had a significant negative total effect on 12-month physical function (γ= -0.278, P<.001). Aberrant movement score's direct effect and indirect effect, through baseline functioning, were significantly negatively associated with physical function at 12-months, after adjusting for covariates (γ=-0.068, P=.038; γ= -0.210, P<.001, respectively).ConclusionsAberrant lumbopelvic movements are associated with decreased physical function at 12-month follow-up in older adults with CLBP, independent of baseline physical function and covariates. Future studies should evaluate if screening for aberrant movements may inform prognostic and interventional efforts in this patient population.     

慢性腰痛的表面肌电研究进展

表面肌电可以在运动过程中记录神经电信号,反映肌肉活动,被应用于观察慢性腰痛患者躯干和下肢肌肉活动。通过对比腰痛患者与正常人在不同活动下的不同肌电信号特征,可以为慢性腰痛的发病机制、诊疗研究提供新思路。     

Pain and Pain-Related Disability Associated With Proprioceptive Impairment in Chronic Low Back Pain Patients: A Systematic Review

ObjectiveThe purpose of this study was to systematically review the evidence on the correlation between lumbar proprioception and clinical low back pain (LBP) characteristics.MethodsThe literature was investigated through a systematic review. Six electronic databases (EMBASE, Scopus, Elsevier, PubMed, ProQuest, and Google Scholar) and reference lists of the relevant articles were searched from inception until December 2017. Studies that investigated the correlation between lumbar proprioception and pain and disability in patients with chronic nonspecific LBP were included in the analytical review.ResultsFive studies (204 patients) were included. Lumbar proprioception was measured via active or passive joint repositioning error or threshold to detection of passive motion. Four of the studies were rated as medium and only 1 as high quality. Four studies had investigated the correlation between proprioception and functional disability scores, all of which found them to be weakly correlated. Although no significant correlation was reported between pain and joint repositioning error (measured in all included studies), one had reported a fair to moderate correlation between pain and threshold to detection of passive motion.ConclusionCurrent literature shows that although LBP pain-related disability is poorly to moderately correlated with proprioceptive functioning, the relationship between pain intensity and proprioception seems to be more complex.     

Self-Efficacy and Fear Avoidance Beliefs in Chronic Low Back Pain Patients: Coexistence and Associated Factors

A cross sectional study was conducted with the objective to assess the coexistence of self-efficacy and fear avoidance beliefs and establish the associated factors. Data collection was performed (215 individuals with lower back pain at three health services and two industries). The following instruments were used: Tampa Scale for Kinesiophobia, Beck's Depression Inventory, Piper's Fatigue Scale, Oswestry Disability Index, and the Chronic Pain Self-Efficacy Scale. Wilks' lambda test was performed, followed by MANOVA model to assess the effect of self-efficacy beliefs and fear avoidance on independent variables. Most subjects were women (65.1%), 45 years of age or younger (50.7%), with a family income between $450 and $1,350 per month (49.3%). Depression was present in 21.4%, fatigue in 29.3%, and disability in 68%. The average (standard deviation) of self-efficacy was 180.8 (60.4), and fear avoidance was 42.0 (11.5). A significant negative correlation was observed between the total score of both beliefs. The Wilks' lambda test showed that gender, income, depression, disability, and fatigue were significant and were included in the model. In the Manova analysis, low self-efficacy was associated with lower income, fatigue, depression, and level of disability (p < .001). High fear avoidance was associated to the male gender, lower income, depression, and level of disability (p < .001). The analysis of the confidence areas showed that a reduced self-efficacy and increased fear avoidance are related to an increased level of disability (p < .001). Specific intervention strategies must be implemented change these beliefs.     

瑜伽练习对慢性腰背痛患者的治疗效果

目的探讨瑜伽练习对慢性腰背痛患者的治疗效果。方法便利抽样选择2012年3月至2013年5月,重庆市3所医疗机构收治的的慢性腰背痛患者148例,按人院先后将148例患者分为观察组76例和对照组72例。对照组接受常规康复治疗（物理和药物治疗）,观察组除康复治疗外,还接受12周的瑜伽练习。调查并比较两组患者干预前后的疼痛程度、功能障碍及生活质量评分。结果干预前两组患者的疼痛、功能障碍及生活质量的评分差异均无统计学意义（均P〉O．05）;干预后,观察组患者的最重疼痛、平均疼痛及功能障碍的评分均低于对照组（均P〈O．05）,躯体疼痛、社会功能、情感职能及精神健康的评分均高于对照组（均P〈O．05）,其他方面评分的差异均无统计学意义（均P〉O．05）。结论瑜伽练习能减轻慢性腰背痛患者的疼痛程度,改善其功能障碍,提高患者的生活质量。     

Long-Term Medicare Costs Associated With Opioid Analgesic Therapy vs Spinal Manipulative Therapy for Chronic Low Back Pain in a Cohort of Older Adults

ObjectivesThe purpose of this study was to compare Medicare healthcare expenditures for patients who received long-term treatment of chronic low back pain (cLBP) with either opioid analgesic therapy (OAT) or spinal manipulative therapy (SMT).MethodsWe conducted a retrospective observational study using a cohort design for analysis of Medicare claims data. The study population included Medicare beneficiaries enrolled under Medicare Parts A, B, and D from 2012 through 2016. We assembled cohorts of patients who received long-term management of cLBP with OAT or SMT (such as delivered by chiropractic or osteopathic practitioners) and evaluated the comparative effect of OAT vs SMT upon expenditures, using multivariable regression to control for beneficiary characteristics and measures of health status, and propensity score weighting and binning to account for selection bias.ResultsThe study sample totaled 28,160 participants, of whom 77% initiated long-term care of cLBP with OAT, and 23% initiated care with SMT. For care of low back pain specifically, average long-term costs for patients who initiated care with OAT were 58% lower than those who initiated care with SMT. However, overall long-term healthcare expenditures under Medicare were 1.87 times higher for patients who initiated care via OAT compared with those initiated care with SMT (95% CI 1.65-2.11; P < .0001).ConclusionsAdults aged 65 to 84 who initiated long-term treatment for cLBP via OAT incurred lower long-term costs for low back pain but higher long-term total healthcare costs under Medicare compared with patients who initiated long-term treatment with SMT.     

Pain Self‐Efficacy and Fear of Movement are Similarly Associated with Pain Intensity and Disability in Italian Patients with Chronic Low Back Pain

The purpose of this study was to investigate cross‐sectional associations of pain self‐efficacy and fear of movement with pain intensity and disability in Italian patients with chronic low back pain (CLBP). One hundred and three adult outpatients with nonspecific CLBP were included in the study. Socio‐demographic and clinical characteristics were assessed, together with Italian versions of self‐reported questionnaires to measure the four constructs of interest. Multiple linear regression models were built with psychosocial constructs as main determinants, and pain intensity and disability as outcomes. Potential confounding of socio‐demographic and clinical characteristics was assessed. Pain self‐efficacy and fear of movement displayed moderate correlations with pain intensity (r = ?0.41 and 0.42, respectively) and disability (?0.55 and 0.54). Association models adjusted for pain intensity showed that both pain self‐efficacy (β = ?0.35, 95% CI = ?0.5; ?0.2, R² = 41%) and fear of movement (β = 0.65, 95% CI = 0.36; 0.93, R² = 40%) are significantly and strongly associated with disability. Pain self‐efficacy was no longer significantly associated with pain intensity when disability was added as a confounder to the model, whereas fear of movement retained its significant association (β = 0.06, 95% CI = 0.00;0.11, R² = 30%). No other variables acted as confounders in these associations. Pain self‐efficacy and fear of movement are very similarly associated with main outcomes in this sample of Italian patients with CLBP. The results of this study suggest that both psychosocial constructs should be considered in clinical management. Future studies should investigate whether these findings can be replicated in other samples, in longitudinal designs and if other variables not measured in this study confound the associations.     

Corticomotor Depression is Associated With Higher Pain Severity in the Transition to Sustained Pain: A Longitudinal Exploratory Study of Individual Differences

Aberrant motor cortex plasticity is hypothesized to contribute to chronic musculoskeletal pain, but evidence is limited. Critically, studies have not considered individual differences in motor plasticity or how this relates to pain susceptibility. Here we examined the relationship between corticomotor excitability and an individual's susceptibility to pain as pain developed, was sustained and resolved over 21 days. Nerve growth factor was injected into the right extensor carpi radialis brevis muscle of 20 healthy individuals on day 0, 2, and 4. Corticomotor excitability, pressure pain thresholds and performance on a cognitive conflict task were examined longitudinally (day 0, 2, 4, 6, and 14). Pain and disability were assessed on each alternate day (1,3…21). Two patterns of motor plasticity were observed in response to pain––corticomotor depression or corticomotor facilitation (P = .009). Individuals who displayed corticomotor depression experienced greater pain (P = .027), and had worse cognitive task performance (P = .038), than those who displayed facilitation. Pressure pain thresholds were reduced to a similar magnitude in both groups. Corticomotor depression in the early stage of pain could indicate a higher susceptibility to pain. Further work is required to determine whether corticomotor depression is a marker of pain susceptibility in musculoskeletal conditions.PerspectiveThis article explores individual differences in motor plasticity in the transition to sustained pain. Individuals who developed corticomotor depression experienced higher pain and worse cognitive task performance than those who developed corticomotor facilitation. Corticomotor depression in the early stage of pain could indicate a higher susceptibility to pain.