Intrarater reliability of pain intensity, tissue blood flow, thermal pain threshold, pressure pain threshold and lumbo-pelvic stability tests in subjects with low back pain

Associations between pain intensity, pain sensitivity, demographics, psychological factors, disability, physical activity, pain phenotype and COVID-19 history in low back pain: An observational study

BACKGROUND AND PURPOSE

Knowledge of the factors affecting pain intensity and pain sensitivity can inform treatment targets and strategies aimed at personalizing the intervention, conceivably increasing its positive impact on patients. Therefore, this study aimed to investigate the association between demographic factors (sex and age), body mass index (BMI), psychological factors (anxiety and depression, kinesiophobia and catastrophizing), self-reported physical activity, pain phenotype (symptoms of central sensitization, and nociceptive or neuropathic pain), history of COVID-19 and pain intensity and sensitivity in patients with chronic non-specific low back pain (LBP).

METHODS

This was a cross-sectional secondary analysis with 83 participants with chronic non-specific LBP recruited from the community between August 2021 and April 2022. BMI, pain intensity (Visual Analog Scale), pain sensitivity at the lower back and at a distant point [pressure pain threshold], catastrophizing (Pain Catastrophizing Scale), kinesiophobia (Tampa Scale for Kinesiophobia), anxiety and depression (Hospital Anxiety and Depression Scale), pain phenotype (Central Sensitization Inventory and PainDetect Questionnaire), physical activity (International Physical Activity Questionnaire), and disability (Roland Morris Disability Questionnaire) were assessed. Multiple linear regression analyses with pain intensity and sensitivity as the dependent variables were used.

RESULTS

The model for pain intensity explained 34% of its variance (Adjusted R2 = -0.343, p < 0.001), with depression and anxiety (p = 0.008) and disability (p = 0.035) reaching statistical significance. The model for pain sensitivity at the lower back, also explained 34% of its variance (Adjusted R2 = 0.344, p < 0.001) at the lower back with sex, BMI, and kinesiophobia reaching statistical significance (p < 0.05) and 15% of the variance at a distant body site (Adjusted R2 = 0.148, p = 0.018) with sex and BMI reaching statistical significance (p < 0.05).

DISCUSSION

This study found that different factors are associated with pain intensity and pain sensitivity in individuals with LBP. Increased pain intensity was associated with higher levels of anxiety and depression and disability and increased pain sensitivity was associated with being a female, higher kinesiophobia, and lower BMI.

Concurrent Validity and Reliability of Video-Based Approach to Assess Physical Function in Adults With Knee Osteoarthritis

OBJECTIVES

The aim of this study was to determine the concurrent validity and reliability of the Osteoarthritis Research Society International recommended performance-based tests delivered by video-based in adults with knee osteoarthritis.

METHODS

Thirty-two participants (aged 40-70 years; 15 men) undertook assessments of 4 performance-based tests via both video-based (real-time and recorded) and face-to-face approaches, on the same day. Outcome measures were performance-based test and the number of technical issues encountered. The performance-based tests included the 40-Meter Fast-Paced Walk Test (velocity, m/s), the 30-Second Chair Stand Test (number of repetitions), the Stair Climb Test (time, seconds), and the Timed "Up & Go" Test (time, seconds). The Bland-Altman limit of agreement measures, standard error of measurement (SEM), coefficient of variation (CV), minimal detectable changes, and bias (mean difference) were employed to analyze the concurrent validity between video-based and face-to-face approaches of the performance-based tests. Reliability was measured using intraclass correlation coefficients, CV, and SEM.

RESULTS

A high degree of concurrent validity for the Timed "Up & Go" Test (bias = -0.22), the 30-Second Chair Stand Test (bias = -0.22), the Stair Climb Test (bias = -0.31), and the 40-Meter Fast-Paced Walk Test (bias = -0.06) was found. SEM and CV values were within the acceptable level for concurrent validity. There was a high degree of reliability demonstrated for all tests analyzed. Intraclass correlation coefficient measures ranged from 0.95 to 1.00 for intrarater reliability, and from 0.95 to 0.99 for interrater reliability.

CONCLUSIONS

Video-based assessment of physical performance tests is a valid and reliable tool for measuring physical function among adults with knee osteoarthritis via Microsoft Teams (Microsoft Corp, Redmond, WA, USA).

IMPACT

Video-based assessment is a promising public health tool to measure physical function in adults with knee osteoarthritis.

The Influence of Pain Hypersensitivity and Psychological Factors on Pain and Disability in the Transition From Acute to Chronic Low Back Pain: A Longitudinal Exploratory Investigation and Cluster Analysis

Pain hypersensitivity is present in some people with acute low back pain (LBP) and thought to be involved in the development of chronic LBP. Early evidence suggests that pain hypersensitivity in acute LBP precedes poor long-term outcome. We aimed to examine whether the presence of pain hypersensitivity in acute LBP influenced recovery status at 6 months and differentiated how pain and disability changed over time. Participants with acute nonspecific LBP (<6 weeks after pain onset, N = 118) were included in this longitudinal study. Quantitative sensory testing, including pressure and heat pain thresholds, and conditioned pain modulation and questionnaires were compared at baseline and longitudinally (at 3 and 6 months) between recovered and unrecovered participants. Using k-means clustering, we identified subgroups based on baseline sensory measures alone, and in combination with psychological factors, and compared pain and disability outcomes between subgroups. Sensory measures did not differ at baseline or longitudinally between recovered (N = 50) and unrecovered (N = 68) participants. Subgrouping based on baseline sensory measures alone did not differentiate pain or disability outcomes at any timepoint. Participants with high psychological distress at baseline (N = 19) had greater disability, but not pain, at all timepoints than those with low psychological distress, regardless of the degrees of pain sensitivity. Our findings suggest that pain hypersensitivity in acute LBP does not precede poor recovery at 6 months or differentiate how pain and disability change over time. High psychological distress during acute LBP is associated with unremitting and pronounced disability, while pain severity is unaffected. PERSPECTIVE: Pain hypersensitivity is thought to be involved in the transition to chronic LBP. Contradictory to prevailing hypothesis, our findings suggest pain hypersensitivity alone in acute LBP does not precede poor recovery. High psychological distress in acute LBP has a stronger influence than pain hypersensitivity on long-term disability, but not pain outcomes.

The interrater and test-retest reliability of 3 modalities of quantitative sensory testing in healthy adults and people with chronic low back pain or rheumatoid arthritis

Introduction

Quantitative Sensory Testing (QST) modalities used to assess central pain mechanisms require different protocols in people with different musculoskeletal conditions.

Objectives

We aimed to explore the possible effects of musculoskeletal diagnosis and test site on QST interrater and test-retest reliability.

Methods

The study included participants with rheumatoid arthritis (RA, n = 18; QST conducted on lower leg) and low back pain (LBP, n = 25; QST conducted on forearm), plus 45 healthy control participants (n = 20 QST on lower leg and n = 25 QST on forearm). Test-retest reliability was assessed from QST conducted 1 to 3 weeks apart. Quantitative sensory testing modalities used were pressure pain detection threshold (PPT) at a site distant to tissue pathology, temporal summation (TS), and conditioned pain modulation (CPM). Temporal summation was calculated as difference or ratio of single and repeated punctate stimuli and unconditioned thresholds for CPM used single or mean of multiple PPTs. Intraclass correlation coefficients (ICCs) were compared between different subgroups.

Results

High to very high reliability was found for all assessments of PPT and TS across anatomical sites (lower leg and forearm) and participants (healthy, RA, and LBP) (ICC ≥ 0.77 for PPT and ICC ≥ 0.76 for TS). Reliability was higher when TS was calculated as a difference rather than a ratio. Conditioned pain modulation showed no to moderate reliability (ICC = 0.01-0.64) that was similar between leg or forearm, and between healthy people and those with RA or LBP.

Conclusion

PPT and TS are transferable tools to quantify pain sensitivity at different testing sites in different musculoskeletal diagnoses. Low apparent reliability of CPM protocols might indicate minute-to-minute dynamic pain modulation.

Effect of virtual running with exercise on functionality in pre-frail and frail elderly people: randomized clinical trial

BACKGROUND

Virtual mirror therapies could increase the results of exercise, since the mirror neuron system produces an activation of motor execution cortical areas by observing actions performed by others. In this way, pre-frail and frail people could use this system to reach an exercise capacity threshold and obtain health benefits.

AIM

The aim of this study is to evaluate the effects of a virtual running (VR) treatment combined with specific physical gait exercise (PE) compared to placebo VR treatment combined with PE on functionality, pain, and muscular tone in pre-frail and frail older persons.

METHODS

A single blinded, two-arm, randomised controlled trial design was employed. Thirty-eight participants were divided into two intervention arms: Experimental Intervention (EI) group, in which VR and gait-specific physical exercises were administered and Control Intervention (CI) group, in which a placebo virtual gait and the same exercise programme was administered. Functionality, pain, and tone were assessed.

RESULTS

EI group improved in aerobic capacity, functional lower-limb strength, reaction time, and pain, while CI group remained the same. Regarding static balance and muscle tone, no differences were found for either group. Further analysis is needed to asses VR effectiveness for improving gait, stand-up and sit-down performance and velocity.

CONCLUSIONS

Virtual running therapy appears to enhance capacities related with voluntary movements (i.e., aerobic capacity, functional lower-limb strength, and reaction time) and reduce pain.

Within-Session Test-Retest Reliability of Pressure Pain Threshold and Mechanical Temporal Summation in Chronic Low Back Pain

OBJECTIVES

To determine the absolute and relative within-session test-retest reliability of pressure pain threshold (PPT) and temporal summation of pain (TSP) at the low back and the forearm in individuals with chronic low back pain (CLBP) and to test the impact of different sequences of measurements on reliability metrics.

MATERIALS AND METHODS

Twenty-eight adults with CLBP were recruited. Relative (intraclass correlation coefficient [ICC] and coefficient of variation) and absolute reliability (standard error of measurement and minimal detectable changes) were quantified at 4 sites (back: sacrum and lumbar erector spinae; wrist: hand dorsum and wrist flexors) for PPT and 2 sites (hand and low back) for TSP, for various sequences of measurements.

RESULTS

Systematic differences were found between within test and retest for most PPT sequences at the lumbar erector spinae site and 1 TSP sequence (1-2-3) at back and hand sites, precluding reliability analyses for these data. Within-session PPT relative reliability was excellent at low back (ICC = 0.83 to 0.94) and wrist (ICC = 0.88 to 0.97) sites, whereas TSP showed good to excellent reliability at hand (ICC = 0.80 to 0.90) and low back (ICC = 0.73 to 0.89). In general, 2 and 3 measurements optimized absolute and relative reliability for TSP and PPT, respectively.

DISCUSSION

Within-session reliability was generally excellent for PPT and TSP at the low back and hand sites among individuals with CLBP. We recommend using 3 measurements for PPT and 2 for TSP to optimize reliability. Caution is recommended when testing PPT of the painful lower back area since a systematic difference was present between the test and retest.

Soft-Tissue Mobilization and Pain Neuroscience Education for Chronic Nonspecific Low Back Pain with Central Sensitization: A Prospective Randomized Single-Blind Controlled Trial

This study was conducted to demonstrate the therapeutic effect of soft-tissue mobilization (STM) combined with pain neuroscience education (PNE) for patients with chronic nonspecific low back pain with central sensitization. A total of 28 participants were recruited and randomly allocated to either the STM group (SMG) (n = 14) or the STM plus PNE group (BG; blended group) (n = 14). STM was applied twice a week for four weeks, with a total of eight sessions, and PNE was applied within four weeks, for a total of two sessions. The primary outcome was pain intensity, and the secondary outcomes were central sensitization, pressure pain, pain cognition, and disability. Measurements were made at baseline, after the test, and at 2-week and 4-week follow-ups. The BG showed significant improvement in pain intensity (p < 0.001), pressure pain (p < 0.001), disability (p < 0.001), and pain cognition (p < 0.001) compared to the SMG. This study demonstrated that STM plus PNE is more effective for all measured outcomes compared to STM alone. This finding suggests that the combination of PNE and manual therapy has a positive effect on pain, disability index, and psychological factors in the short term.

Human assumed central sensitization in people with acute non-specific low back pain: A cross-sectional study of the association with brain-derived neurotrophic factor, clinical, psychological and demographic factors

BACKGROUND

Early evidence suggests human assumed central sensitization (HACS) is present in some people with acute low back pain (LBP). Factors influencing individual variation in HACS during acute LBP have not been fully explored. We aimed to examine the evidence for HACS in acute LBP and the contribution of brain-derived neurotrophic factor (BDNF), clinical, psychological and demographic factors to HACS.

METHODS

Participants with acute LBP (<6 weeks after pain onset, N = 118) and pain-free controls (N = 57) from a longitudinal trial were included. Quantitative sensory testing including pressure and heat pain thresholds and conditioned pain modulation, BDNF serum concentration and genotype and questionnaires were assessed.

RESULTS

There were no signs of HACS during acute LBP at group level when compared with controls. Sensory measures did not differ when compared between controls and LBP participants with different BDNF genotypes. Two LBP subgroups with distinct sensory profiles were identified. Although one subgroup (N = 60) demonstrated features of HACS including pressure/heat pain hypersensitivity at a remote site and deficient conditioned pain modulation, pain severity and disability did not differ between the two subgroups. Variation in sensory measures (~33%) was partially explained by BDNF genotype, sex, age and psychological factors.

CONCLUSIONS

This study confirms that HACS is present in some people with acute LBP, but this was not associated with pain or disability. Further, no relationship was observed between BDNF and HACS in acute LBP. More research is needed to understand factors contributing to individual variation in sensory measures in LBP.

SIGNIFICANCE

Human assumed central sensitization (HACS) is present in acute low back pain (LBP) but factors contributing to individual variation are not fully explored. This study investigated the relationship between factors such as brain derived neurotrophic factor (BDNF) and HACS in acute LBP. Our findings indicate that HACS was present in specific LBP subgroups but BDNF was unrelated to HACS. Combinations of BDNF genotype, demographic and psychological factors explained a small proportion of the variation in sensory measures during acute LBP.

Pain phenotyping and investigation of outcomes in physical therapy: An exploratory study in patients with low back pain

Phenotypes have been proposed as a method of characterizing subgroups based on biopsychosocial factors to identify responders to analgesic treatments. This study aimed to, first, confirm phenotypes in patients with low back pain receiving physical therapy based on an a priori set of factors used to derive subgroups in other pain populations. Second, an exploratory analysis examined if phenotypes differentiated pain and disability outcomes at four weeks of physical therapy. Fifty-five participants completed psychological questionnaires and pressure pain threshold (PPT). Somatization, anxiety, and depression domains of the Symptom-Checklist-90-Revised, and PPT, were entered into a hierarchical agglomerative cluster analysis with Ward's method to identify phenotypes. Repeated measures ANOVAs assessed pain ratings and disability by phenotype at four weeks. Three clusters emerged: 1) high emotional distress and pain sensitivity (n = 10), 2) low emotional distress (n = 34), 3) low pain sensitivity (n = 11). As an exploratory study, clusters did not differentiate pain ratings or disability after four weeks of physical therapy (p's>0.05). However, trends were observed as magnitude of change for pain varied by phenotype. This supports the characterization of homogenous subgroups based on a protocol conducted in the clinical setting with varying effect sizes noted by phenotype for short-term changes in pain. As an exploratory study, future studies should aim to repeat this trial in a larger sample of patients.

Measurement of soft tissue deformation at discomfort and pain threshold in different regions of the head

Understanding of product-soft tissue interface and related discomfort is essential while designing wearable devices. Although pressure thresholds at the perception of discomfort and pain have been measured in the past, associated tissue deformation is yet to be studied. This data can provide a holistic understanding of user discomfort and be a valuable reference for ergonomic product design. Hence, in the current study, tissue deformation at discomfort and pain threshold was measured using an ultrasound indentation device at 18 landmarks for 83 Chinese adults on the head and face. Results show that deformation was higher in the facial region than the scalp and forehead, with maximum deformation in the cheek area and minimum in the forehead region for both thresholds. Also, for most landmarks, the tissue deformation data showed no significant relationship with age and Body Mass Index (BMI). Nearly half of the landmarks exhibited significant gender-based differences. Overall, the measured data showed acceptable within-session and between-session reliability. Practitioner Summary: In this study, tissue deformation was measured in different head regions for discomfort and pain thresholds, and corresponding deformation maps were developed. Measured tissue deformation data showed no significant relationship with BMI and age. This data can be a useful reference in the design, testing, and evaluation of headgears.

The Efficacy of Lumbar Support on Pain, Disability, and Motor Control in Women With Postpartum Pelvic Girdle Pain: Protocol for a Randomized Controlled Trial

Background

Pregnancy-related posterior pelvic girdle pain (PPGP) is one of the most important clinical manifestations of postpartum back pain. Those affected often complain of discomfort during daily activities. It is hypothesized that altered motor control is associated with perceived pain. Pelvic support can regulate possible underlying altered motor control mechanisms and decrease pain. However, the influence of a lumbosacral orthosis, which is broader support that allows for a wider contact area and more skin sensory stimulation to restore proper motor function, has not yet been investigated in women with postpartum PPGP.

Objective

This study investigates the efficacy of broader lumbar support and narrower pelvic support on pain, proprioception, disability, and muscle strength in women with pregnancy-related PPGP.

Methods

This study will be a single-center, 3-armed, participant-blinded, randomized controlled trial. In total, 84 women diagnosed with pregnancy-related PPGP will be recruited and randomly assigned into 3 groups. Intervention groups A and B will receive pelvic and lumbar supports, respectively. Group C (control) will receive only a patient education leaflet containing advice on strengthening exercises, comfortable positions, and other practical information. The study outcomes are pain, effort score during the active straight leg raising test, maximum isometric hip flexion force, maximum isometric hip external rotation force, maximum isometric trunk rotation force, and joint position reproduction of hip abduction. The study outcomes will be measured at 4 time points: baseline (T1), immediately after the intervention (T2), 4 weeks following interventions began (at this time, the intervention period is completed) (T3), and 1 week after discontinuing the interventions (T4) to evaluate the possible lasting effects of wearing supports. Multivariate analysis of variance will be used to test between- and within-group differences.

Results

Recruitment for this study will be started in summer 2022 and is expected to be completed by the end of fall 2022.

Conclusions

This study will examine the efficacy of broader lumbar support as an early rehabilitative treatment for women receiving postpartum posterior pelvic pain support compared to those receiving a narrower pelvic support. We expect the broader lumbar support to impact pain management and disability better than the current narrower pelvic belt. Long-term follow-up studies will help determine whether such lumbosacral orthosis reduces pain and improves daily activities in women with pregnancy-related PPGP.

Trial Registration

Iranian Registry of Clinical Trials IRCT20150210021034N11; https://www.irct.ir/trial/54808

International Registered Report Identifier (IRRID)

PRR1-10.2196/40553

A cross-sectional analysis of persistent low back pain, using correlations between lumbar stiffness, pressure pain threshold, and heat pain threshold

Introduction

Little is known about the underlying biomechanical cause of low back pain (LBP). Recently, technological advances have made it possible to quantify biomechanical and neurophysiological measurements, potentially relevant factors in understanding LBP etiology. However, few studies have explored the relation between these factors. This study aims to quantify the correlation between biomechanical and neurophysiological outcomes in non-specific LBP and examine whether these correlations differ when considered regionally vs. segmentally.

Methods

This is a secondary cross-sectional analysis of 132 participants with persistent non-specific LBP. Biomechanical data included spinal stiffness (global stiffness) measured by a rolling indenter. Neurophysiological data included pain sensitivity (pressure pain threshold and heat pain threshold) measured by a pressure algometer and a thermode. Correlations were tested using Pearson’s product-moment correlation or Spearman’s rank correlation as appropriate. The association between these outcomes and the segmental level was tested using ANOVA with post-hoc Tukey corrected comparisons.

Results

A moderate positive correlation was found between spinal stiffness and pressure pain threshold, i.e., high degrees of stiffness were associated with high pressure pain thresholds. The correlation between spinal stiffness and heat pain threshold was poor and not statistically significant. Aside from a statistically significant minor association between the lower and the upper lumbar segments and stiffness, no other segmental relation was shown.

Conclusions

The moderate correlation between spinal stiffness and mechanical pain sensitivity was the opposite of expected, meaning higher degrees of stiffness was associated with higher pressure pain thresholds. No clinically relevant segmental association existed.

Reliability of pressure pain threshold to discriminate individuals with neck and low back pain

BACKGROUND

Pressure pain threshold (PPT) is decreased in several musculoskeletal disorders, giving indirect evidence regarding pain status. Despite the fact that PPT has been already proven to be reliable in patients with acute conditions, there is great variability of methods and results observed within studies, and only a few evidences confirming its reliability in chronic conditions.

OBJECTIVE

The objective of this study was to determine the test-retest reliability of PPT in the neck and low back regions to discriminate individuals with neck or low back pain from healthy individuals. Additionally, one secondary aim was to establish the minimum detectable change (MDC) and the standard error of measurement for future clinical studies and interventions.

METHODS

In this reliability study, 74 individuals (15 individuals from the neck pain and 17 from the neck control group; 21 individuals from the low back pain and 21 from the low back control group). PPT was measured in the neck region (suboccipital, trapezius and supraspinal muscles) and in the lower back region (paraspinal muscles in the levels of L1, L3 and L5). Intrarater reliability was assessed using intraclass correlation coeficient and Bland-Altman.

RESULTS

Excellent intra-rater reliability was observed for both (ICC of 0.874 for the neck pain versus ICC of 0.895 in neck control group; ICC of 0.932 for the low back pain group versus ICC of 0.839 for the control group). A small bias was observed for all groups (-0.08 for the neck pain group versus 0.10 in the control group; and 0.32 in low back pain group versus 0.44 in the control group). Minimum detectable change of 0.63 kgf of neck pain and 1.21 kgf of low back pain was calculated. It was found difference in PPT between pain and control groups (p< 0.05).

CONCLUSION

It may be suggested that the protocol with PPT is reliable and able to discriminate individuals with and without neck and low back pain with a minor measurement error. Therefore, this method may be used to detect possible progress after interventions in patients with neck or low back pain.

Spinal manipulation and modulation of pain sensitivity in persistent low back pain: a secondary cluster analysis of a randomized trial

BACKGROUND

Pain hypersensitivity can be assessed using Quantitative Sensory Testing (QST) and is associated with persistent low back pain. Spinal manipulation appears to modify pain hypersensitivity, and this could function as one mechanism leading to clinical improvements. In the current study, we applied a comprehensive QST battery to assess pain sensitivity in a cohort of low back pain patients before and after spinal manipulation to improve our understanding of the association between QST and clinical improvements. This study addresses two questions: Are clinical improvements following spinal manipulation in low back pain patients contingent on pain hypersensitivity, and does pain sensitivity change following spinal manipulation?

METHODS

We performed a secondary analysis of data from a randomized clinical trial. One hundred and thirty-two participants with persistent LBP were treated with spinal manipulation four times over two weeks. Patient-reported outcomes and QST were assessed at baseline, after the fourth spinal manipulation session, and 14-days later. The clinical outcomes were changes in low back pain intensity and disability. Using latent profile analysis, we categorized the participants into clusters depending on their baseline QST scores. We used linear mixed models to examine the association between clusters and changes in patient-reported outcomes and QST.

RESULTS

Two clusters emerged: a Sensitized and a Not sensitized. The former had significantly lower regional pressure and thermal pain thresholds, remote pressure pain tolerance, and lower inhibitory conditioned pain modulation than the Not sensitized group. However, we only found between-cluster differences for regional pressure pain threshold following spinal manipulation. Thus, the clusters were not associated with patient-reported pain and disability changes or the remaining QST outcomes.

CONCLUSIONS

We report that the baseline QST profile was not associated with clinical improvements following spinal manipulation. We did observe a substantial change for regional pressure pain threshold, which suggests that any effect of spinal manipulation on pain sensitivity is most likely to be observed as changes in regional, mechanical pain threshold. However, the mechanism that invokes clinical improvement and pain sensitivity changes appear distinct. Due to methodological caveats, we advise caution when interpreting the results.

TRIAL REGISTRATION

Clinical.Trial.gov identifier: NCT04086667 , registered 11 September 2019 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04086667.

Changes in pain sensitivity and spinal stiffness in relation to responder status following spinal manipulative therapy in chronic low Back pain: a secondary explorative analysis of a randomized trial

Background

In a prior randomized trial, we demonstrated that participants receiving spinal manipulative therapy at a pain-sensitive segment instead of a stiff segment experienced increased mechanical pressure pain thresholds. We hypothesized that the targeted segment mediated this increase through a segment-dependent neurophysiological reflective pathway. Presently, it is not known if this decrease in pain sensitivity is associated with clinical improvement. Therefore, we performed an explorative analysis to examine if changes in experimental pain sensitivity (mechanical and thermal) and lumbar stiffness were further dependent on clinical improvement in disability and patient-reported low back pain.

Methods

This study is a secondary explorative analysis of data from the randomized trial that compared 132 participants with chronic low back pain who received lumbar spinal manipulative therapy applied at either i) the stiffest segment or ii) the segment having the lowest pain threshold (i.e., the most pain-sensitive segment). We collected data at baseline, after the fourth session of spinal manipulation, and at 14-days follow-up. Participants were dichotomized into responders/non-responders using different clinical variables (disability and patient-reported low back pain) with varying threshold values (0, 30, and 50% improvement). Mixed models were used to assess changes in experimental outcomes (stiffness and pain sensitivity). The fixed interaction terms were time, segment allocation, and responder status.

Results

We observed a significant increase in mechanical pressure pain thresholds for the group, which received spinal manipulative therapy at the most pain-sensitive segment independent of whether they improved clinically or not. Those who received spinal manipulation at the stiffest segment also demonstrated increased mechanical pain sensitivity, but only in the subgroup with clinical improvement. We did not observe any changes in lumbar stiffness.

Conclusion

Our results suggest the existence of two different mechanistic pathways associated with the spinal manipulation target. i) A decrease of mechanical pain sensitivity independent of clinical outcome (neurophysiological) and ii) a decrease as a reflection of the clinical outcome. Together, these observations may provide a novel framework that improves our understanding of why some respond to spinal manipulative therapy while others do not.

Trial registration

ClinicalTrials.gov identifier: NCT04086667 registered retrospectively September 11th 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-020-03873-3.

The effect on clinical outcomes when targeting spinal manipulation at stiffness or pain sensitivity: a randomized trial

The mechanisms underlying pain relief following spinal manipulative therapy (SMT) are not understood fully although biomechanical and neurophysiological processes have been proposed. As such, we designed this randomized trial to elucidate the contributions of biomechanical and neurophysiological processes. A total of 132 participants with low back pain were randomly assigned to receive SMT at either the lumbar segment measured as the stiffest or the segment measured as having the lowest pain threshold. The primary outcome was patient reported low back pain intensity following treatment. Secondary outcomes were biomechanical stiffness and neurophysiological pressure pain threshold. All outcomes were measured at baseline, after the fourth and final session and at 2-weeks follow-up. Data were analyzed using linear mixed models, and demonstrated that the SMT application site did not influence patient reported low back pain intensity or stiffness. However, a large and significant difference in pressure pain threshold was observed between groups. This study provides support that SMT impacts neurophysiological parameters through a segment-dependent neurological reflex pathway, although this do not seem to be a proxy for improvement. This study was limited by the assumption that the applied treatment was sufficient to impact the primary outcome.

Lumbar interspinous pressure pain threshold values for healthy young men and women and the effect of prolonged fully flexed lumbar sitting posture: An observational study

BACKGROUND

Low back pain (LBP) is a common condition with large burden worldwide. Exposure to prolonged sitting with a flexed lumbar posture has been suggested in the literature to be a potential risk factor for self-reported LBP. No study has previously investigated whether exposure to prolonged flexed sitting posture provokes discomfort/pain and decreased interspinous pressure pain thresholds for healthy young men and women without back pain, despite this being a suggested risk factor for LBP.

AIM

To investigate whether sitting in a prolonged flexed lumbar posture provokes discomfort and lowers interspinous pressure pain thresholds in the lumbar spine for healthy young men and women without previous LBP.

METHODS

This is a an observational before and after study of 26 participants (13 men, 13 women) between 20-35 years old. Algometry was used to examine the pain threshold for pressure applied between spinous processes of the lumbar spine L1-L5. Pressure algometer measures were performed in prone before and after participants were instructed to sit in a fully flexed posture for a maximum of 15 min or until discomfort was experienced in the low back (Borg CR10 = 7/10). Wilcoxon signed-rank test was used for analyze values from the before and after test conditions. Mann-Whitney U test was used to investigate potential gender difference.

RESULTS

Fully flexed lumbar spine sitting posture up to 15 min provoked temporary discomfort but the proportion of participants experiencing discomfort 7/10 in the low back was 62%. For all pain pressure threshold locations tested, there was a significant difference for the study population with moderate-large decreased (r = -0.56) pressure pain threshold after exposure to prolonged flexed sitting posture (P < 0.01). Comparisons between gender did not show any significant difference.

CONCLUSION

The result showed that exposure to fully flexed lumbar sitting posture for up to 15 min produced temporary discomfort in the low back in young healthy adults with no previous history of LBP and significantly reduced lumbar interspinous pressure pain thresholds. No gender-based differences were observed.

Physical and psychosocial work environmental risk factors of low-back pain: protocol for a 1 year prospective cohort study

Background

Musculoskeletal disorders, and in particular low-back pain (LBP), are common among blue collar workers. In the work environment, both physical- and psychosocial risk factors exist. Working in warehouses in Denmark involve large quantities of occupational lifting, high work pace and a low degree of influence at work. This study investigates both acute and long-term associations between physical- and psychosocial work environmental factors and risk of LBP in warehouse workers. The specific study aims are to investigate 1) exposure-response associations between quantity of occupational lifting and short-term (day-to-day) changes in LBP, 2) the influence of accumulated workdays and rest days during a working week on LBP, 3) long-term association between occupational lifting exposure and LBP when assessed over 1 year, and 4) the role of psychological and social factors on the above associations.

Methods

The present study is designed as a 1-year prospective cohort study that will examine full-time warehouse workers from up to five retail chains in Denmark. Study aims 1 and 2 will be addressed using objective data based on company records with information on weight of all the goods handled by each warehouse worker during every single workday for 3 weeks. During this period, each worker will reply to text messages received before and after every workday (also on days off work) in which study participants will score their pain in the low back, bodily fatigue and perceived mental stress (scale 0–10). Long-term pain development is assessed using questionnaire surveys before and after 1 year. Further, pressure pain threshold (PPT) will be measured for selected trunk extensor muscles in approximately 50 workers using algometry along with measurements of maximal trunk extensor strength. Associations are modelled using linear mixed models with repeated measures between variables and LBP controlled for relevant confounders.

Discussion

This study provides knowledge about the acute and long-term associations between physical- and psychosocial work environmental factors and LBP. The obtained data will have the potential to provide recommendations on improved design of the working week to minimize the risk of LBP among warehouse workers, and may potentially enable to identify a reasonable maximum lifting threshold per day (ton lifted/day).

Concurrent validity and reliability of telerehabilitation-based physiotherapy assessment of cervical spine in adults with non-specific neck pain

INTRODUCTION

The aim of this study was to determine the concurrent validity and reliability of telerehabilitation (TR)-based evaluation of the cervical spine among adults with non-specific neck pain (NS-NP).

METHODS

A total of 11 participants with NS-NP were recruited. Pain intensity, active range of motion (AROM), posture, deep neck flexor (DNF) endurance, combined neck movements and disability were measured using face-to-face and TR methods, with a one-hour break in between. TelePTsys, an image-based TR system, was used for TR assessment.

RESULTS

A high degree of concurrent validity for pain (bias = 0.90), posture (bias = 0.96°), endurance (bias = -2.3 seconds), disability (bias = 0.10), AROM (extension bias = -0.60 cm, flexion bias = 1.2 cm, side flexion bias = -1.00, rotation bias = -0.30 cm) was found. Standard error of measurement and coefficient of variation (CV) values were within the acceptable level for concurrent validity, except the CV for cervical flexion and endurance. There was a high degree of reliability demonstrated for pain, posture, AROM, endurance and disability measurements. The average-measure interclass correlation coefficient (ICC_(3,1)) ranged from 0.96 to 0.99 for inter-rater, and 0.93 to 0.99 for intra-rater reliabilities. There was moderate agreement for combination movement for validity (78.5%, p < 0.05), inter- (78.5%, p < 0.05) and intra-rater (76.4%, p < 0.05) reliabilities.

DISCUSSION

TR-based physiotherapy assessment of cervical spine is a valid and reliable tool for measuring pain intensity, AROM, DNF muscle endurance, sagittal neck posture and disability among adults with NS-NP via telePTsys.

A randomized clinical trial comparing non-thrust manipulation with segmental and distal dry needling on pain, disability, and rate of recovery for patients with non-specific low back pain

Objective: The purpose of this study was to examine the within and between-group effects of segmental and distal dry needling (DN) without needle manipulation to a semi-standardized non-thrust manipulation (NTM) targeting the symptomatic spinal level for patients with non-specific low back pain (NSLBP). Methods: Sixty-five patients with NSLBP were randomized to receive either DN (n = 30) or NTM (n = 35) for six sessions over 3 weeks. Outcomes collected included the oswestry disability index (ODI), patient specific functional scale (PSFS), numeric pain rating scale (NPRS), and pain pressure thresholds (PPT). At discharge, patients perceived recovery was assessed. Results: A two-way mixed model ANOVA demonstrated that there was no group*time interaction for PSFS (p = 0.26), ODI (p = 0.57), NPRS (p = 0.69), and PPT (p = 0.51). There was significant within group effects for PSFS (3.1 [2.4, 3.8], p = 0.018), ODI (14.5% [10.0%, 19.0%], p = 0.015), NPRS (2.2 [1.5, 2.8], p = 0.009), but not for PPT (3.3 [0.5, 6.0], p = 0.20). Discussion: The between-group effects were neither clinically nor statistically significant. The within group effects were both significant and exceeded the reported minimum clinically important differences for the outcomes tools except the PPT. DN and NTM produced comparable outcomes in this sample of patients with NSLBP. Level of evidence: 1b.

Effects of Massage as a Combination Therapy with Lumbopelvic Stability Exercises as Compared to Standard Massage Therapy in Low Back Pain: a Randomized Cross-Over Study

BACKGROUND

Little is known about the effects of providing massage as a combination therapy (CT) with lumbopelvic stability training (LPST) in management of chronic nonspecific low back pain (CLBP) among elite female weight lifters. It is unclear whether massage therapy (MT) together with LPST has any additional clinical benefits for individuals with CLBP.

PURPOSE

The current study compares the therapeutic effects of CT against MT as a stand-alone intervention on pain intensity (PI), pain pressure threshold (PPT), tissue blood flow (TBF), and lumbopelvic stability (LPS) among elite weight lifters with CLBP.

SETTING

The study was conducted at the campus for National Olympic weight lifting training camp.

PARTICIPANTS

A total of 16 professional female elite weight lifting athletes who were training for Olympic weight lifting competition participated in the study.

RESEARCH DESIGN

A within-subject, repeated measures, crossover, single-blinded, randomized allocation study.

INTERVENTION

The athletes were randomized into three sessions of CT and MT with a time interval of 24 hrs within sessions and a wash out period of four weeks between the sessions.

MAIN OUTCOME MEASURES

The PI, PPT, TBF, and LPS were measured before and after each session repeatedly in both groups of intervention. The changes in the PI, PPT, TBF, and LPS were analyzed using repeated measures analysis of variance (ANOVA).

RESULTS

The results showed that the CT significantly demonstrated greater effects in reducing pain perception (45%-51%), improving pain pressure threshold (15% up to 25%), and increasing tissue blood flow (131%-152%) than MT (p < .001).

CONCLUSION

The combination therapy of massage therapy and LPST is likely to provide more clinical benefits in terms of PI, PPT, and TBF when compared to massage as a stand-alone therapy among individuals with chronic nonspecific low back pain.

Relationship between ultrasound detected tendon abnormalities, and sensory and clinical characteristics in people with chronic lateral epicondylalgia

Objective

To investigate the relationship between tendon structural changes determined by static ultrasound images (US) and sensory changes using quantitative sensory testing (QST), and clinical measures in lateral epicondylalgia.

Materials and methods

Both elbows of 66 adult participants with a clinical diagnosis of lateral epicondylalgia were investigated. Using a standardised ultrasound image rating scale, common extensor hypoechogenicity, heterogenicity, neovascularity, and bony abnormalities at the enthesis were scored, and tendon thickness (longitudinal and transverse plane) was measured by a trained assessor. Sensory measures of pressure, heat and cold pain thresholds and vibration detection threshold were recorded. Pain and function were assessed using the patient-rated tennis elbow (PRTEE), pain-free grip strength, pain visual analog scale (PVAS) and quality of life (EuroQoL EQ -5D). Univariate and multivariate linear regression analyses were used to explore the association between tendon structural, sensory and clinical variables which were adjusted for age, gender and duration of symptoms.

Results

A negative correlation was identified between the presence of neovascularity and cold pain threshold (P = 0.015). Multiple regression analyses revealed that a combination of female gender (P = 0.044) and transverse tendon thickness (P = 0.010) were significantly associated with vibration detection threshold in affected elbows, while gender (P = 0.012) and total ultrasound scale score (P = 0.024) were significantly associated with heat pain threshold and vibration detection threshold in unaffected elbows. Heat pain threshold and gender were significantly associated with pain and disability (PRTEE; P < 0.001), and pain-free grip strength (P < 0.001) respectively, in the affected elbows.

Conclusion

Generally, structural and sensory measures were weakly correlated. However, neovascularity and transverse tendon thickness may be related to sensory system changes in LE.

Topographic mapping of pain sensitivity of the lower back – a comparison of healthy controls and patients with chronic non-specific low back pain

Background and aims

The choice of testing site for quantitative sensory testing (QST) of pain sensitivity is important and previous studies have demonstrated patterns in pain sensitivity within discrete areas in different body regions. Some areas are characterized by a relatively high degree of spatial pain discrimination and recognizable patterns of pain referral, whilst others are not. The lumbar region is likely to have relatively low pain acuity and overlapping of pain referral. The current study was conducted to determine whether patterns of pain sensitivity (detection thresholds) could be identified in the lower back, whether differences in such patterns exist between different groups and whether such patterns could help identify a clinical source of pain and localized increased pain sensitivity.

Methods

Twenty-one patients with non-specific chronic low back pain and 21 healthy controls were tested for pressure and heat pain thresholds on 30 pre-defined locations over the mid and lower back. Topographical maps of mean pain thresholds and variability were produced, inspected visually and analyzed statistically. Between group differences in pain threshold were analyzed statistically as an indicator of widespread increased pain sensitivity. Evidence of segmental increased pain sensitivity was examined by group statistical comparison of mid-line lower range.

Results

A clear pattern of higher pain thresholds in the mid-line was evident in both groups and for both pain modalities. No discernible patterns were evident for variability within groups, but marked differences were seen between groups: variability for pressure pain thresholds appeared similar between groups, however for heat pain threshold, variability was uniformly low in the control group and uniformly high in the patient group. A highly significant (p<0.0001) difference in pain thresholds for pressure and heat was found with patients exhibiting lower thresholds than controls. No between group difference was found for mid-line lower range for either modality (p>0.05).

Conclusions

The current study supports previous findings of widespread, increased pain sensitivity in chronic non-specific low-back pain patients. It also indicates that there are discernible and similar topographical patterns of pain sensitivity in the dorsal area in both groups, but that this pattern is related to the lateral position of the test site and not the segmental level. Specific segments with increased pain sensitivity could not be identified in the patient group, which casts doubt on the utility of pressure and heat pain thresholds as indicators of the clinical source of spinal pain – at least in a population of chronic non-specific low-back pain.

Implications

In a cohort of chronic non-specific low-back pain patients and with the chosen methodology, topographical QST mapping in the lumbar region does not appear useful for identifying the spinal segment responsible for clinical pain, but it does demonstrate widespread group differences in pain sensitivity.

Effect of physical exercise on musculoskeletal pain in multiple body regions among healthcare workers: Secondary analysis of a cluster randomized controlled trial

BACKGROUND

While physical exercise is beneficial for back and neck-shoulder pain, only few intervention studies have evaluated effects on pain in multiple body regions. Furthermore, direct measurement of pain threshold can provide additional information to self-reported pain intensity.

OBJECTIVES

To evaluate the effect of workplace versus home-based physical exercise on pressure pain threshold (PPT) and musculoskeletal pain intensity in multiple body regions.

STUDY DESIGN

Secondary analysis of an examiner-blinded, cluster randomized controlled trial with allocation concealment.

METHOD

Two-hundred female healthcare workers from 18 departments at three hospitals were cluster-randomized to 10 weeks of: 1) home-based physical exercise (HOME) performed alone during leisure time for 5 × 10 min per week or 2) workplace physical exercise (WORK) performed in groups during working hours for 5 × 10 min per week and up to 5 motivational coaching sessions. PPT (neck, lower back, lower leg) and perceived pain intensity in multiple body regions (feet, knee, hips, lower and upper back, elbow, hand, shoulder, neck, and head) were measured at baseline and 10-week follow-up.

RESULTS

In some of the body regions, PPT and pain intensity improved more following WORK than HOME. Between-group differences at follow-up (WORK vs. HOME) were 41 kPA [95% CI 13-70, effect size (ES): 0.22] for PPT in the lower back, and -0.7 [95% CI -1.0-0.3, ES: 0.26] and -0.6 points [95% CI -0.9--0.2, ES: 0.23] for pain intensity in the lower back and feet, respectively. HOME did not improve more than WORK for any of the measurements.

CONCLUSION

Physical exercise recommendations for healthcare workers should consider the setting, i.e. performing supervised group-based exercise at work and motivational coaching sessions is more effective than exercising alone at home.

Respiratory characteristics of individuals with non-specific low back pain: A cross-sectional study

Non-specific low back pain (NS-LBP) is known to cause respiratory dysfunction. In this study, we investigated alterations in breathing, respiratory strength and endurance, core stability, diaphragm mobility, and chest expansion among patients with NS-LBP and healthy individuals. The specific aim of the study was to correlate between respiratory function and other variables among NS-LBP patients. Thirty four patients with NS-LBP were matched with 34 healthy participants before undergoing total faulty breathing scale, spirometer, respiratory pressure meter, chest expansion, ultrasound, and pressure biofeedback measurements. There were signs of faulty breathing in the NS-LBP patients when compared to the healthy participants. Diaphragmatic mobility and respiratory muscle endurance were lower in the NS-LBP group. Chest expansion exhibited a significant decrease at the level of the fourth intercostal space in the NS-LBP group, but respiratory muscle strength and core stability were not significant between the two groups. Positive correlations were found to be fairly significant regarding respiratory muscle strength. The findings of this study indicated altered respiratory characteristics in the NS-LBP patients, and suggested that they would improve through respiratory exercises.

The Biomechanics of Standing Start and Initial Acceleration: Reliability of the Key Determining Kinematics

The reliability of the key determining kinematic variables associated with short sprint performance provide insight into how and why movement may vary between individual trials. Currently, literature surrounding these determinants is scarce when investigating the first three strides of a sprint. The purpose of this study was to investigate the reliability of sprint acceleration and the key kinematic determinants involved during the first three steps of the movement. The aim was to use a practical method of kinematic analysis to help explain why changes may occur in sprint performance via the use of correlative statistics and to provide reference values for intervention research to make conclusions about their change scores. Ten male volunteers from various team sports attended two separate testing sessions, a minimum of 48 hours apart. They performed three maximal sprint trials over a 10m distance from a standing start, where researchers captured 5m and 10m sprint times alongside high speed camera footage, from which the key kinematic variables were measured. Results demonstrated that although 5m and 10m sprint times depicted moderate to large levels of similarity between sessions, neither of these variables met the criteria to be classified as adequately, or highly reliable. Kinematic measures typically produced ICC values > 0.70 and CV% < 10%, demonstrating all relevant statistical traits to be categorised as reliable measures. Step frequency and flight time during the third step showed the largest correlation with performance, exhibiting 'r' values of -0.386 and 0.396, respectively. These findings demonstrate that kinematic variables may not have an influential role with sprint times; therefore suggesting kinetic concepts may in fact be the key determinants of speed. Future research is required investigating the interaction of kinetic and kinematic variables associated with sprinting and how the variability in these concepts effects the reliability of performance.

Lumbopelvic Core Stabilization Exercise and Pain Modulation Among Individuals with Chronic Nonspecific Low Back Pain

BACKGROUND

Lumbopelvic stabilization training (LPST) may provide therapeutic benefits on pain modulation in chronic nonspecific low back pain conditions. This study aimed to examine the effects of LPST on pain threshold and pain intensity in comparison with the passive automated cycling intervention and control intervention among patients with chronic nonspecific low back pain.

METHODS

A within-subject, repeated-measures, crossover randomized controlled design was conducted among 25 participants (7 males and 18 females) with chronic nonspecific low back pain. All the participants received 3 different types of experimental interventions, which included LPST, the passive automated cycling intervention, and the control intervention randomly, with 48 hours between the sessions. The pressure pain threshold (PPT), hot-cold pain threshold, and pain intensity were estimated before and after the interventions.

RESULTS

Repeated-measures analysis of variance showed that LPST provided therapeutic effects as it improved the PPT beyond the placebo and control interventions (P < 0.01). The pain intensity under the LPST condition was significantly better than that under the passive automated cycling intervention and controlled intervention (P < 0.001). Heat pain threshold under the LPST condition also showed a significant trend of improvement beyond the control (P < 0.05), but no significant effects on cold pain threshold were evident.

CONCLUSIONS

Lumbopelvic stabilization training may provide therapeutic effects by inducing pain modulation through an improvement in the pain threshold and reduction in pain intensity. LPST may be considered as part of the management programs for treatment of chronic low back pain.

Learning Curves Observed in Establishing Targeted Rate of Force Application in Pressure Pain Algometry

Purpose: To determine whether learning curves can be observed with deliberate practice when the goal is to apply a consistent rate of force at 5 N/second during pressure pain threshold (PPT) testing in healthy volunteers. Methods: In this prospective study, 17 clinician participants completed PPT targeted rate-of-application testing with healthy volunteers using three different feedback paradigms. The resultant performances of ramp rate during 36 trials were plotted on a graph and examined to determine whether learning curves were observed. Results: Clinicians were not consistent in the rate of force applied. None demonstrated a learning curve over the course of 36 trials and three testing paradigms. Conclusion: The results of this study indicate that applying a consistent 5 N/second of force is difficult for practising clinicians. The lack of learning curves observed suggests that educational strategies for clinicians using PPT may need to change.

Effects of shock-absorbing insoles during transition from natural grass to artificial turf in young soccer players: a randomized controlled trial

BACKGROUND

Playing soccer on artificial turf can provoke pain in young players. Using shock-absorbing insoles (SAIs) can result in decreased pain perception. We sought to investigate the pain and comfort intensity experienced during the switch from natural grass to third-generation artificial turf and with the use of SAIs on artificial turf during training in young soccer players.

METHODS

In a prospective randomized controlled study, 75 players were included from the youth teams of U15, U17, and U19. Pain intensity and comfort were assessed after training on only grass turf for 3 months. Randomization stratified by team level and age was performed; the intervention group received SAIs, and the control group used their own insoles. Assessments were repeated after 3 weeks on artificial turf (baseline) and 3 more weeks (follow-up) on artificial turf with SAIs/usual insoles.

RESULTS

Pain intensity increased and comfort decreased significantly after 3 weeks of training on artificial grass compared with natural grass (P < .05). The addition of SAIs resulted in significantly reduced pain intensity compared with the usual insoles (P < .05).

CONCLUSIONS

The switch to artificial turf is associated with less comfort and more pain during training in young soccer players. The use of SAIs led to lower pain intensity, highlighting a protective role of the insoles after 6 weeks of training on artificial turf.

Spinal manipulation does not affect pressure pain thresholds in the absence of neuromodulators: a randomized controlled trial

BACKGROUND

Measurement of pressure pain threshold (PPT) is a way to determine one of the many potential treatment effects of spinal manipulative therapy.

OBJECTIVE

To determine how multiple spinal manipulations administered in a single-session affected PPTs at local and distal sites in asymptomatic individuals.

METHODS

Participants were randomly assigned into one of three groups: Group one (n = 18) received a lumbar manipulation followed by a cervical manipulation. Group two (n = 17) received a cervical manipulation followed by a lumbar manipulation. The control group (n = 19) received two bouts of five minutes of rest. At baseline and after each intervention or rest period, each participant's PPTs were obtained using a handheld algometer. The PPTs were tested bilaterally over the lateral epicondyles of the humerus and over the mid-bellies of the upper trapezius, lumbar paraspinal, and the tibialis anterior muscles. This study was registered with ClinicalTrials.gov, and its Identifier is NCT02828501.

RESULTS

Repeated-measures ANOVAs and Kruskal-Wallis tests showed no significant within- or between-group differences in PPT. Within-group effect sizes in the changes of PPT ranged from -.48 at the left paraspinal muscles to .24 at the left lateral humeral epicondyle. Statistical power to detect significant differences at α of 0.05 was calculated to be 0.94.

CONCLUSIONS

This study suggests that in young adults who do not have current or recent symptoms of spinal pain, multiple within-session treatments of cervical and lumbar spinal manipulation fail to influence PPTs. Changes in PPT that are observed in symptomatic individuals are likely to be primarily influenced by pain-related neuromodulators rather than by an isolated, mechanical effect of spinal manipulation.

Intra-session absolute and relative reliability of pressure pain thresholds in the low back region of vine-workers: ffect of the number of trials

BACKGROUND

Pressure pain thresholds (PPT) are commonly used to quantify mechanical pain sensitivity of deep structures. Excellent PPT reliability has been previously reported among the low back of healthy subjects. However, there is a lack of studies assessing PPT over the low back of workers exposed to biomechanical risk factors of low back pain. Thus, the purpose of this study was threefold: (1) to evaluate the intra-session absolute and relative reliability as well as minimal detectable change (MDC) values of PPT within 14 locations covering the low back region of vine-workers and (2) to determine the number of trial required to ensure reliable PPT assessments and (3) to assess the effect of modifier factors such as gender, age, body mass index (BMI) and pain intensity on PPT reliability.

METHODS

Twenty-nine vine-workers voluntarily participated in this study. Twenty-two reported low intensity of low-back pain while seven were pain-free. PPTs were assessed among 14 anatomical locations in the lower back region. Three trials were performed on each location with an interval time of at least one minute. Reliability was assessed computing intraclass correlation coefficients (ICC), standard error of measurement (SEM) for all possible combinations between trials. Bland-Altman plots were also generated to assess potential bias in the dataset. Finally, a repeated measure analysis of variance (RM-ANOVA) with the number of trials used as within subject factor was performed on (1) PPT, (2) ICC and (3) SEM values.

RESULTS

ICC ranged from 0.86 to 0.99 for all anatomical locations and for all possible combinations between trials. SEM for comparison between trial 1-2, 2-3, 1-3 and, 1-2-3 ranged from respectively, 36.7-77.5, 27.8-77.7, 50-95.2 and, 39.3-80.8 kPa. ICC and SEM remained similar to the ones obtained for the entire population when taking modifier factors in consideration. The visual analysis of Bland-Altman plots suggested small measurement errors for all anatomical locations and for all possible combinations between trials.

CONCLUSIONS

The assessment of PPTs of the lower back among vine-workers was found to have excellent relative and absolute reliability. Moreover, reliable measurements can be equally achieved when using the mean of three PPT measurement or with the first one.

Is One Trial Sufficient to Obtain Excellent Pressure Pain Threshold Reliability in the Low Back of Asymptomatic Individuals? A Test-Retest Study

The assessment of pressure pain threshold (PPT) provides a quantitative value related to the mechanical sensitivity to pain of deep structures. Although excellent reliability of PPT has been reported in numerous anatomical locations, its absolute and relative reliability in the lower back region remains to be determined. Because of the high prevalence of low back pain in the general population and because low back pain is one of the leading causes of disability in industrialized countries, assessing pressure pain thresholds over the low back is particularly of interest. The purpose of this study study was (1) to evaluate the intra- and inter- absolute and relative reliability of PPT within 14 locations covering the low back region of asymptomatic individuals and (2) to determine the number of trial required to ensure reliable PPT measurements. Fifteen asymptomatic subjects were included in this study. PPTs were assessed among 14 anatomical locations in the low back region over two sessions separated by one hour interval. For the two sessions, three PPT assessments were performed on each location. Reliability was assessed computing intraclass correlation coefficients (ICC), standard error of measurement (SEM) and minimum detectable change (MDC) for all possible combinations between trials and sessions. Bland-Altman plots were also generated to assess potential bias in the dataset. Relative reliability for both intra- and inter- session was almost perfect with ICC ranged from 0.85 to 0.99. With respect to the intra-session, no statistical difference was reported for ICCs and SEM regardless of the conducted comparisons between trials. Conversely, for inter-session, ICCs and SEM values were significantly larger when two consecutive PPT measurements were used for data analysis. No significant difference was observed for the comparison between two consecutive measurements and three measurements. Excellent relative and absolute reliabilities were reported for both intra- and inter-session. Reliable measurements can be equally achieved when using the mean of two or three consecutive PPT measurements, as usually proposed in the literature, or with only the first one. Although reliability was almost perfect regardless of the conducted comparison between PPT assessments, our results suggest using two consecutive measurements to obtain higher short term absolute reliability.

Pressure algometry and enzyme-linked immunosorbent assay of natural antibodies in the evaluation of pain syndrome

The dynamics of possible markers of pain syndrome: pain pressure thresholds of intolerance (PTI) and natural antibodies to mediators of pain processing (nAbs) in blood serum at dorsalgia was studied. We have shown that most men and women had reduced PTIs. Night PTIs were lower than daytime PTIs regardless of the gender. The study of the content of nAbs to opioids and biogenic amines by ELISA have shown a prolonged maintenance of their elevated and high levels that could evoke long-term effect in pain chronization. Thus, the pressure algometry and ELISA of nAbs to pain processing mediators make it possible to assess the individual pain status objectively and, on this bases, to propose personal schemes of treatment.

Improvements in tissue blood flow and lumbopelvic stability after lumbopelvic core stabilization training in patients with chronic non-specific low back pain

[Purpose] This study investigated the effects of lumbopelvic stabilization training on tissue blood flow changes in the lumbopelvic region and lumbopelvic stability compared to placebo treatment and controlled intervention among patients with chronic non-specific low back pain. [Subjects and Methods] A total of 25 participants (7 males, 18 females; mean age, 33.3 ± 14.4 years) participated in this within-subject, repeated-measures, double-blind, placebo-controlled comparison trial. The participants randomly underwent three types of interventions that included lumbopelvic stabilization training, placebo treatment, and controlled intervention with 48 hours between sessions. Lumbopelvic stability and tissue blood flow were measured using a pressure biofeedback device and a laser Doppler flow meter before and after the interventions. [Results] The repeated-measures analysis of variance results demonstrated a significant increase in tissue blood flow over the lumbopelvic region tissues for post- versus pre-lumbopelvic stabilization training and compared to placebo and control interventions. A significant increase in lumbopelvic stability before and after lumbopelvic stabilization training was noted, as well as upon comparison to placebo and control interventions. [Conclusion] The current study supports an increase in tissue blood flow in the lumbopelvic region and improved lumbopelvic stability after core training among patients with chronic non-specific low back pain.

Effect of Therapeutic Sequence of Hot Pack and Ultrasound on Physiological Response Over Trigger Point of Upper Trapezius

Background:

Musculoskeletal pain is a common problem among athletes. Apart from sport injuries, the myofascial pain syndrome is another important problem that affects performance of the athlete.

Objectives:

The aim of this study was to evaluate the effects of therapeutic sequences of the hot pack in combination with ultrasound on the physiological responses over the latent myofascial trigger point (LMTrP) of upper trapezius muscle.

Materials and Methods:

Thirty subjects with a latent myofascial trigger point (LMTrP) in both sides of the upper trapezius muscle participated in the study (age 27.33 ± 4.34 years, weight 58.11 ± 7.47 kg, height 161.50 ± 5.82 cm, pressure pain threshold 2.28 ± 0.24 kg/cm², pain intensity 7.17 ± 2.25 VAS). All subjects received both treatments (hot pack followed by ultrasound: HP + US; and ultrasound followed by hot pack: US + HP) by randomization with a 24 to 48-hour interval between sessions. Outcome measures, including the tissue blood flow (TBF), pressure pain threshold (PPT), supra-thermal threshold (STT) and visual analog scale (VAS) were evaluated at baseline, immediately, after 30 minutes and after 60 minutes.

Results:

The TBF and PPT significantly increased from baseline in both treatment conditions (i.e. HP + US and US + HP), while the HP + US condition showed a trend toward significant difference in VAS and STT in 45°C.

Conclusions:

The application of HP and US treatment induces physiological responses (especially, TBF and PPT) on the LMTrP. This finding provides the direction toward the management of MTrPs condition.

Reliability and responsiveness of algometry for measuring pressure pain threshold in patients with knee osteoarthritis

[Purpose] This study aimed to establish the intrarater reliability and responsiveness of a clinically available algometer in patients with knee osteoarthritis as well as to determine the minimum-detectable-change and standard error of measurement of testing to facilitate clinical interpretation of temporal changes. [Subjects] Seventy-three patients with knee osteoarthritis were included. [Methods] Pressure pain threshold measured by algometry was evaluated 3 times at 2-min intervals over 2 clinically relevant sites—mediolateral to the medial femoral tubercle (distal) and lateral to the medial malleolus (local)—on the same day. Intrarater reliability was estimated by intraclass correlation coefficients. The minimum-detectable-change and standard error of measurement were calculated. As a measure of responsiveness, the effect size was calculated for the results at baseline and after treatment. [Results] The intrarater reliability was almost perfect (intraclass correlation coefficient = 0.93–0.97). The standard error of measurement and minimum-detectable-change were 0.70–0.66 and 1.62–1.53, respectively. The pressure pain threshold over the distal site was inadequately responsive in knee osteoarthritis, but the local site was responsive. The effect size was 0.70. [Conclusion] Algometry is reliable and responsive to assess measures of pressure pain threshold for evaluating pain patients with knee osteoarthritis.

Changes in pain perception after pelvis manipulation in women with primary dysmenorrhea: a randomized controlled trial

OBJECTIVE

This study aims to evaluate the immediate effect of a global pelvic manipulation (GPM) technique, bilaterally applied, on low back pelvic pain in women with primary dysmenorrhea (PD).

DESIGN

A prospective, randomized, double-blind, controlled trial.

SETTING

Faculty of Nursing, Physiotherapy and Podiatry. University of Sevilla, Spain.

METHODS

The sample group included 40 women (30 ± 6.10 years) that were divided into an experimental group (EG) (N = 20) who underwent a bilateral GPM technique and a control group (CG) (N = 20) who underwent a sham (placebo) intervention. Evaluations were made of self-reported low back pelvic pain (visual analog scale), pressure pain threshold (PPT) in sacroiliac joints (SIJs), and the endogenous response of the organism to pain following catecholamines and serotonin release in blood levels.

RESULTS

The intragroup comparison showed a significant improvement in the EG in the self-perceived low back pelvic pain (P = 0.003) and in the mechanosensitivity in both SIJs (P = 0.001). In the between-group comparison, there was a decrease in pain perception (P = 0.004; F(1,38) = 9.62; R(2) = 0.20) and an increase in the PPT of both SIJs, in the right side (P = 0.001; F(1,38) = 21.29; R(2) = 0.35) and in the left side (P = 0.001; F(1,38) = 20.63; R(2) = 0.35). There were no intergroup differences for catecholamines plasma levels (adrenaline P = 0.123; noradrenaline P = 0.281; dopamine P = 0.173), but there were for serotonin levels (P = 0.045; F(1,38) = 4.296; R(2) = 0.10).

CONCLUSION

The bilateral GPM technique improves in a short term the self-perceived low back pelvic pain, the PPT in both SIJs, and the serotonin levels in women with PD. It shows no significant differences with a sham intervention in catecholamines plasma levels.