Do various baseline characteristics of transversus abdominis and lumbar multifidus predict clinical outcomes in nonspecific low back pain? A systematic review

A Critical Review of Trunk and Hip Exercise Prescription: Applying Evidence for a Modern Approach

Exercise targeting the trunk and hip (core) musculature is common practice in rehabilitation and performance training. Historical underpinnings of core exercise focus on providing stability to the spine, thus improving the function of the spine and extremities, while instability has been postulated to result in pathology and impaired performance. Mechanistic studies on the topic are often conflicting and indeterminate, suggesting the theoretical underpinnings of targeted core exercise may be over assumed in common practice. The best modes of intervention also remain undefined, with combined methods having potential to optimize outcomes. This includes moving beyond isolated exercise camps and being inclusive of both targeted exercise and progressive multi-joint movements. The purpose of this clinical commentary is to describe the historical mechanisms of the stability-instability continuum and the role of exercise intervention. A spectrum of ideologies related to core exercise are examined, while appreciating positive outcomes of exercise interventions across healthy and pathological populations. Finally, exercise summaries were compiled to improve critical reasoning within current practice and inspire future investigations.

Level of Evidence

5.

Subgroup Characteristics of Middle-Aged and Older Women with Chronic Low Back Pain by Multiple Factors: A Hierarchical Cluster Analysis

BACKGROUND/OBJECTIVES

Chronic low back pain (CLBP) after middle age is a complex multifactorial condition, and subgrouping is recommended to determine effective treatment strategies. Multidimensional data help create new groupings to increase the effectiveness of interventions in middle-aged and older adults with CLBP. This study aimed to investigate the relationship between the factors associated with CLBP after middle age and to create and characterize a new subgroup based on these factors.

METHODS

A cross-sectional observational study was conducted and included 46 women aged ≥40 years with CLBP who participated in health events. Trunk muscle mass, lumbar movement control ability, autonomic balance, lumbar tenderness threshold, lumbar proprioception, and severity of central sensitization were assessed.

RESULTS

Partial correlation analysis revealed a significant negative correlation between lumbar movement control ability and autonomic balance. A significant positive correlation was observed between trunk muscle mass and the lumbar tenderness threshold. Hierarchical clustering analysis identified three subgroups. The cluster 1 participants had low trunk muscle mass, low tenderness threshold, and low severity of central sensitization. The cluster 2 participants had low trunk muscle mass and tenderness threshold and high severity of central sensitization. The cluster 3 participants had high trunk muscle mass and tenderness threshold and were sympathetically predominant. Trunk muscle mass, pressure pain threshold, severity of central sensitization, and autonomic balance were significantly different between the clusters.

CONCLUSIONS

Three characteristic subgroups were identified. The results contribute to treatment and prevention strategies for middle-aged and older adults with CLBP based on the characteristics of the subgroups rather than a uniform approach.

Modified single-incision MIS-TLIF with expandable tubular assistance for degenerative lumbar spine diseases

Objective

Evaluating the clinical value of the modified single-incision posterior median approach with expandable tubular assistance for lumbar interbody fusion in managing degenerative lumbar spine diseases.

Method

A retrospective analysis was conducted on 121 patients with single-level degenerative lumbar spine disease treated in our spine surgery department from January 2017 to December 2021. Of these, 72 patients underwent a modified single-incision posterior median approach with expandable tubular assistance lumbar interbody fusion (single-incision MIS-TLIF group), while 49 patients received the classic open posterior median incision P-TLIF (open surgery group). We collected basic demographic data including age, gender, BMI, and surgical level. Surgical-related indicators such as operation time, intraoperative blood loss, postoperative drainage, length of hospital stay, hospital costs, and complication rates were compared between the two groups. Laboratory results [whole blood C-reactive protein (CRP), serum creatine kinase (CK)] and clinical outcomes [VAS scores for low back and leg pain, Oswestry Disability Index (ODI), excellent and good rate according to the modified MacNab criteria, and interbody fusion rate according to the Brantigan criteria] were also evaluated.

Result

There were no significant differences in the basic demographics between the two groups. The operation time, postoperative hospital stay, and hospital costs were also similar between the groups. However, significant differences were observed in intraoperative blood loss, postoperative drainage, and complication rates. On postoperative days 1 and 3, whole blood CRP and CK levels showed marked differences between the groups. At 3, 6, and 12 months postoperatively, the single-incision MIS-TLIF group had lower ODI scores and VAS scores for back pain compared to the open surgery group. The excellent and good rate according to the MacNab criteria was higher in the single-incision MIS-TLIF group. There were no significant differences in leg pain VAS scores and interbody fusion rates at 12 months postoperatively between the groups.

Conclusion

The modified single-incision posterior median approach with expandable tubular assistance lumbar interbody fusion is highly effective in treating degenerative lumbar spine diseases. It results in less postoperative pain, faster recovery, and significant improvement in postoperative functional outcomes, making it a valuable treatment option.

Are changes in pain intensity related to changes in balance control in individuals with chronic non-specific low back pain? A systematic review and meta-analysis

PURPOSE

The aim of this study was to summarize the evidence regarding whether pain reduction in individuals with chronic non-specific low back pain (CNSLBP) following conservative interventions is related to corresponding improvements in balance control.

METHODS

Randomized controlled trials were identified from 5 databases (MEDLINE, Cochrane Library, Embase, Web of Science, and PsycINFO). Two reviewers independently screened and identified relevant studies that investigated the effects of non-surgical or non-pharmacological CNSLBP treatments on both pain intensity and balance control. Meta-regression analyses were performed to establish the associations between post-treatment changes in these 2 variables.

RESULTS

Thirty one studies involving 1280 participants with CNSLBP were included. Moderate-quality evidence suggested that pain reduction was associated with and explained 34%-45% of decreases in body sway, as measured by center-of-pressure (CoP) area and CoP velocity with eyes open. However, no significant association was observed between pain reduction and CoP area or velocity in anteroposterior/mediolateral directions. Similarly, there was no significant association between pain reduction and CoP distance or radius. Low-quality evidence indicated that pain relief explained a 15% improvement in one-leg stance with eyes open but not in the eyes-closed condition. Additionally, very low-quality evidence suggested that pain relief explained a 44% decrease in the static anteroposterior stability index with eyes closed but not in the eyes-open, mediolateral, or overall conditions. Furthermore, low-quality evidence indicated that reduced pain was associated with and accounted for 25%-43% of the improved composite and posteromedial scores of the star-excursion balance test, rather than the anterior and posterolateral scores.

CONCLUSION

Depending on the type of balance assessment, pain relief following conservative interventions may slightly to moderately enhance balance control in individuals with CNSLBP. Clinicians should pay close attention to the balance control in patients with CNSLBP, particularly among older adults.

Understanding musculoskeletal disorders in dancers: The role of lumbopelvic muscles and movement competency

OBJECTIVE

To investigate whether transversus abdominis activation (TrA), hip strength, and movement competency are associated with the incidence of musculoskeletal disorder episodes (MDEs) in dancers when controlling for confounding variables. The secondary objectives were to determine if there were differences between professional and preprofessional dancers for the aforementioned factors, as well as to determine if there were differences in TrA activation and hip strength between the dominant and non-dominant sides.

DESIGN

Prospective cohort study.

METHODS

118 dancers were recruited. The independent variables were collected at the beginning of the dance season: 1) TrA activation, 2) hip strength, and 3) movement competency. To assess the development of MDEs, a weekly electronic diary was used over a 38-week period. MDEs were compiled for each dancer's whole body and subdivided into total musculoskeletal disorder episodes (all body parts) and lower quadrant musculoskeletal disorder episodes (lower limb and lower back).

RESULTS

Lower TrA, as well as higher hip abductor and external rotator strength, were associated with a lower incidence of MDEs. TrA activation (β = 0.260, p = 0.023) and hip external rotator strength (β = -0.537, p = 0.002) could significantly explain 25.4% of the variance of total MDEs, as well as 20.9% of the variance of lower quadrant musculoskeletal disorder episodes (β = 0.272, p = 0.016; β = -0.459, p = 0.011). No significant associations were found between movement competency and MDEs.

CONCLUSIONS

Higher hip strength could be a protective factor for MDEs among dancers. Further studies are needed to better understand the involvement of the transversus abdominis in MDEs.

Spinal degeneration and lumbar multifidus muscle quality may independently affect clinical outcomes in patients conservatively managed for low back or leg pain

Few non-surgical, longitudinal studies have evaluated the relations between spinal degeneration, lumbar multifidus muscle (LMM) quality, and clinical outcomes. None have assessed the potential mediating role of the LMM between degenerative pathology and 12-month clinical outcomes. This prospective cohort study used baseline and 12-month follow-up data from 569 patients conservatively managed for low back or back-related leg pain to estimate the effects of aggregate degenerative lumbar MRI findings and LMM quality on 12-month low back and leg pain intensity (0-10) and disability (0-23) outcomes, and explored the mediating role of LMM quality between degenerative findings and 12-month clinical outcomes. Adjusted mixed effects generalized linear models separately estimated the effect of aggregate spinal pathology and LMM quality. Mediation models estimated the direct and indirect effects of pathology on leg pain, and pathology and LMM quality on leg pain, respectively. Multivariable analysis identified a leg pain rating change of 0.99 [0.14; 1.84] (unstandardized beta coefficients [95% CI]) in the presence of ≥ 4 pathologies, and a disability rating change of - 0.65 [- 0.14; - 1.16] for each 10% increase in muscle quality, but no effect on back pain intensity. Muscle quality had a non-significant mediating role (13.4%) between pathology and leg pain intensity. The number of different pathologies present demonstrated a small effect on 12-month leg pain intensity outcomes, while higher LMM quality had a direct effect on 12-month disability ratings but no mediating effect between pathology and leg pain. The relations between degenerative pathology, LMM quality, and pain-related outcomes appear complex and may include independent pathways.

Three-dimensional freehand ultrasonography to measure muscle volume of the lumbar multifidus: Reliability of processing technique and validity through comparison to magnetic resonance imaging

There is a growing interest in muscle characteristics of the lumbar multifidus related to low back pain, but findings between studies are inconsistent. One of the issues explaining these conflicting findings might be the use of two-dimensional measures of cross-sectional area and thickness of the lumbar multifidus in most studies, which might be a suboptimal representation of the entire muscle volume. A three-dimensional volumetric assessment, combined with standardized imaging and processing measurement protocols, is highly recommended to quantify spinal muscle morphology. Three-dimensional freehand ultrasonography is a technique with large potential for daily clinical practice. It is achieved by combining conventional two-dimensional ultrasound with a motion-tracking system, recording the position and orientation of the ultrasound transducer during acquisition, resulting in a three-dimensional reconstruction. This study investigates intra- and interprocessor reliability for the quantification of muscle volume of the lumbar multifidus based on three-dimensional freehand ultrasound and its validity, in 31 patients with low back pain and 20 healthy subjects. Two processors manually segmented the lumbar multifidus on three-dimensional freehand ultrasound images using Stradwin software following a well-defined method. We assessed the concurrent validity of the measurement of multifidus muscle volume using three-dimensional freehand ultrasound compared with magnetic resonance imaging in 10 patients with low back pain. Processing reliability and agreement were determined using intraclass correlation coefficients, Bland-Altman plots, and calculation of the standard error of measurement and minimal detectable change, while validity was defined based on correlation analysis. The processing of three-dimensional freehand ultrasound images to measure lumbar multifidus volume was reliable. Good to excellent intraclass correlation coefficients were found for intraprocessor reliability. For interprocessor reliability, the intraclass correlation coefficients were moderate to good, emphasizing the importance of processing guidelines and training. A single processor analysis is preferred in clinical studies or when small differences in muscle volume are expected. The correlation between magnetic resonance imaging and three-dimensional freehand ultrasound measurements of lumbar multifidus volume was moderate to good but with a systematically smaller multifidus volume measured on three-dimensional freehand ultrasound. These results provide opportunities for both researchers and clinicians to reliably assess muscle structure using three-dimensional freehand ultrasound in patients with low back pain and to monitor changes related to pathology or interventions. To allow implementation in both research and clinical settings, guidelines on three-dimensional freehand ultrasound processing and training were provided.

Do Improved Trunk Mobility and Isometric Strength Correlate with Improved Pain and Disability after Multimodal Rehabilitation for Low Back Pain?

Objective  To determine the correlation between posttreatment trunk range of motion (ROM) and isometric strength (TIS) and pain and disability in patients who underwent multimodal rehabilitation for low back pain (LBP). Methods  In this prospective cohort study, 122 patients undergoing multimodal rehabilitation for LBP were analyzed. The pre- and posttreatment numerical pain rating scale (NPRS) and the Oswestry disability index (ODI) scores, as well as trunk ROM and TIS were compared. The Pearson correlation was used to determine correlation between posttreatment clinical outcomes and ROM and TIS. Results  At the end of treatment, the mean NPRS ( p  < 0.0001) and ODI ( p  < 0.0001) scores, mean trunk extension ( p  < 0.0001), and flexion ( p  < 0.0001) ROMs improved significantly. Similarly, posttreatment, the mean extension ( p  < 0.0001) and flexion ( p  < 0.0001) TISs improved significantly. There was a weak correlation between the NPRS score and ROM extension (r = -0.24, p  = 0.006) and flexion strength (r = -0.28, p  = 0.001), as well as between the ODI score and TIS extension (r = -0.30, p  = 0.0007) and flexion (r = -0.28, p  = 0.001). Conclusion  Despite significant improvement in pain, disability, trunk ROM, and TIS with multimodal treatment, there was a weak correlation between posttreatment pain and function and trunk ROM and TIS. Improvement in pain and function with physical rehabilitation treatment for LBP is a complex phenomenon and needs further investigation.

Surface electromyography analysis of core stabilizing muscles during isometric shoulder contractions in athletes with low back pain

BACKGROUND

The study was carried out in the athletes with and without Low Back Pain (LBP) to determine the surface electromyography activity of core stabilizing muscles while performing isometric shoulder and trunk contractions.

STUDY DESIGN

Cross-sectional study.

METHODS

This study enlisted the participation of 40 athletes. Group A included 20 athletes (18 males and 2 females) without LBP, and Group B included 20 athletes (12 males and 8 females) with LBP. Athletes with LBP were assessed using the Modified Oswestry Disability Questionnaire (MODQ) and Visual Analog Scale (VAS) to determine their level of disability and pain severity, respectively. EMG activity of the rectus abdominis, external oblique, longissimus, and multifidus was recorded in both groups as they performed bilateral isometric shoulder and trunk contractions.

RESULTS

In the LBP group, EMG activity of the rectus abdominis and external oblique muscles was significantly lower (P < 0.05). The LBP group had significantly more multifidus activity (P = 0.03) than the NLBP group. Among all the exercises, bilateral isometric shoulder extension contraction activated the rectus abdominis, right external oblique, and longissimus group of muscles significantly more (P < 0.05) in both groups. In both groups, bilateral isometric shoulder flexion contraction resulted in significantly higher multifidus muscle activation (P = 0.002).

CONCLUSION

The activation of core stabilizing muscles was altered in athletes with LBP. When athletes are unable to contract and activate trunk muscles owing to pain, upper extremity exercises can be used to activate these muscles.

Which muscles exhibit increased stiffness in people with chronic neck pain? A systematic review with meta-analysis

Introduction

Chronic neck pain (CNP) substantially impacts quality of life, posing both personal challenges and economic strains. This systematic review sought to discern muscle-specific stiffness differences between CNP patients and individuals without CNP.

Methods

We searched the PubMed, Scopus, and PEDro databases for studies using ultrasound elastography or myotonometry to compare muscle stiffness between CNP patients and asymptomatic controls. Using a meta-analysis with a random-effects model, we derived the pooled effect as standardized mean difference (SMD).

Results

Out of the six studies selected, the adjusted Newcastle-Ottawa rating scale for cross-sectional studies denoted three as moderate-quality and three as high-quality. Our findings indicate that the upper trapezius (UT) stiffness was elevated in CNP patients compared to their counterparts without CNP (SMD = 0.39, 95% CI = 0.05 to 0.74; p = 0.03; small effect size). The data for other muscles remained inconclusive.

Discussion

Given the case-control design of all reviewed studies, a direct causative link between UT stiffness and CNP is yet to be confirmed. As such, recommending a reduction in trapezius muscle stiffness as a primary rehabilitation strategy for CNP patients is still inconclusive and further research is needed.

Does type 2 diabetes affect the efficacy of therapeutic exercises for degenerative lumbar spinal stenosis?

DESIGN

Propensity-matched retrospective study.

OBJECTIVES

To determine whether type 2 diabetes mellitus (T2D) would affect prognosis in patients with degenerative lumbar spinal stenosis (DLSS) who underwent therapeutic exercises.

METHODS

This study included consecutive patients with or without T2D who underwent therapeutic exercises for symptomatic DLSS from December 2018 to January 2020. Baseline demographics and clinical and radiological data were collected. The 2 groups of patients were further matched in a 1:1 fashion based on the propensity score, balancing the groups on pre-treatment factors including age, sex, leg and back pain, and low back disability. The primary outcomes included self-reported leg pain intensity (Numerical Rating Scale, NRS) and low back disability (Oswestry Disability Index, ODI) and the secondary outcomes included low back pain intensity and walking capacity (self-paced walking test, SPWT) were compared at baseline, 6 weeks, and 12 weeks.

RESULTS

Forty-one pairs of patients were selected by propensity matching. After 6-week therapeutic exercises, patients with T2D achieved a lower improvement in leg pain at 6 weeks (NRS leg change, 1.21 ± 0.40 vs. 1.78 ± 0.52, P = 0.021) and 12 weeks (NRS leg change, 1.52 ± 0.92 vs. 2.18 ± 0.96, P = 0.007) above minimal clinically important difference (MCID), with a significant Group × Time interactions (F_1,80 = 16.32, p < 0.001, ηp2 = 0.053). However, the two groups showed no difference in the improvement of ODI, although the sample had significant improvements at 6 weeks (ODI change 3.02 [95% CI, 2.08 to 2.77], P < 0.001) and 12 weeks ([ODI change 3.82 [95% CI, 4.03 to 4.90], P < 0.001), 46% of the patients achieved an MCID.

CONCLUSION

Six-week therapeutic exercises have an inferior effect on DLSS patients with T2D. Findings from this study will provide an increased understanding of exercise treatment in patients with DLSS.

Biopsychosocial Factors for Chronicity in Individuals with Non-Specific Low Back Pain: An Umbrella Review

Low back pain (LBP) is a global and disabling problem. A considerable number of systematic reviews published over the past decade have reported a range of factors that increase the risk of chronicity due to LBP. This study summarizes up-to-date and high-level research evidence on the biopsychosocial prognostic factors of outcomes in adults with non-specific low back pain at follow-up. An umbrella review was carried out. PubMed, the Cochrane Database of Systematic Reviews, Web of Science, PsycINFO, CINAHL Plus and PEDro were searched for studies published between 1 January 2008 and 20 March 2020. Two reviewers independently screened abstracts and full texts, extracted data and assessed review quality. Fifteen systematic reviews met the eligibility criteria; all were deemed reliable according to our criteria. There were five prognostic factors with consistent evidence of association with poor acute-subacute LBP outcomes in the long term (high levels of pain intensity and disability, high emotional distress, negative recovery expectations and high physical demands at work), as well as one factor with consistent evidence of no association (low education levels). For mixed-duration LBP, there was one predictor consistently associated with poor outcomes in the long term (high pain catastrophism). We observed insufficient evidence to synthesize social factors as well as to fully assess predictors in the chronic phase of LBP. This study provides consistent evidence of the predictive value of biological and psychological factors for LBP outcomes in the long term. The identified prognostic factors should be considered for inclusion into low back pain explanatory models.

Reliability and agreement of lumbar multifidus volume and fat fraction quantification using magnetic resonance imaging

INTRODUCTION

Magnetic resonance imaging (MRI) is the standard to quantify size and structure of lumbar muscles. Three-dimensional volumetric measures are expected to be more closely related to muscle function than two-dimensional measures such as cross-sectional area. Reliability and agreement of a standardized method should be established to enable the use of MRI to assess lumbar muscle characteristics.

OBJECTIVES

This study investigates the intra- and inter-processor reliability for the quantification of (1) muscle volume and (2) fat fraction based on chemical shift MRI images using axial 3D-volume measurements of the lumbar multifidus in patients with low back pain.

METHODS

Two processors manually segmented the lumbar multifidus on the MRI scans of 18 patients with low back pain using Mevislab software following a well-defined method. Fat fraction of the segmented volume was calculated. Reliability and agreement were determined using intra-class correlation coefficients (ICC), Bland-Altman plots and calculation of the standard error of measurement (SEM) and minimal detectable change (MDC).

RESULTS

Excellent ICCs were found for both intra-processor and inter-processor analysis of lumbar multifidus volume measurement, with slightly better results for the intra-processor reliability. The SEMs for volume were lower than 4.1 cm³. Excellent reliability and agreement were also found for fat fraction measures, with ICCs of 0.985-0.998 and SEMs below 0.946%.

CONCLUSION

The proposed method to quantify muscle volume and fat fraction of the lumbar multifidus on MRI was highly reliable, and can be used in further research on lumbar multifidus structure.

Reliability of lumbar multifidus ultrasound assessment during the active straight leg raise test

BACKGROUND

Previous evidence showed altered lumbar multifidus (LM) activation in populations with chronic nonspecific low back pain (LBP). We aimed to investigate the test-retest and inter-examiner reliability of ultrasound imaging (US) for assessing LM thickness at rest and activation during the active straight leg raise test (ASLR) and the association between thickness changes with clinical outcomes.

METHODS

Fifty-two patients with LBP and two examiners (one experienced and one novice) participated in this study. A total of 18 B-mode images at L4-L5 or L5-S1 level (both sides, 3 at rest and 6 during ASLR) were collected. For assessing test-retest reliability, the experienced examiner repeated the procedure after 7 days. Intraclass correlation coefficients (ICC), standard error of measurements (SEM) and minimal detectable changes (MDC) were calculated.

RESULTS

Inter-examiner agreement was good to excellent (ICC3,2 = 0.71-0.92) and test-retest reliability was excellent (ICC3,1 = 0.91-0.98). Mean average of multiple measurements improved the agreement. Greater LM thickness at rest (p < .05) and greater thickness change after 3 s (p < .01) and 10 s (homolateral side, p < .01; contralateral side, p < .05) were associated with less pain intensity.

CONCLUSIONS

US is a reliable method to assess the LM thickness at rest and contracted during the ASLR in patients with LBP. The measurement at 3 s after maintaining ASLR, as well as the use of the mean of three measurements, has been shown to be the most reliable method for measuring LM muscle thickness during ASLR.

Wrist, but Not Back, Isometric Contraction Induced Widespread Hypoalgesia in Healthy Participants

Objective: Exercise may reduce pain sensitivity. This phenomenon called exercise-induced hypoalgesia is observed in different types of exercises and involves the activation of endogenous pain modulation systems. Although the effect of limb exercise on pain sensitivity has often been tested, few studies explored the impact of back exercises that are often used to treat low back pain. The main objective is to measure the effect of back-muscle exercise on pain sensitivity and compare it to the effect of a limb-muscle exercise.

Methods: Twenty-three participants who were pain-free performed a 4-min wrist flexion isometric contraction followed by a 4-min low back extension, separated by a 20-min break. Pressure pain thresholds were tested at two low back (S1 spinous process, lumbar erector spinae muscle) and two wrist (capitate bone, wrist flexor muscles) sites before and after each exercise. For each exercise, sites were considered as remote or local in relation to the muscles contracted during the exercise. An independent sample of 11 participants was recruited to confirm the influence of low back extension on pain sensitivity.

Results: Wrist exercise induced a larger increase in pain sensitivity than back exercise at the remote site. Only wrist exercise induced a hypoalgesia effect at both the local and the remote sites. Back exercise induced a similar effect in the independent sample.

Conclusions: This study showed that back and wrist exercises induced a distinct effect on pain sensitivity in participants who were pain-free. The wrist exercise induced a systemic reduction in pain sensitivity (locally and remotely), whereas the back exercise did not. This differential effect may be present because wrist exercise induced most fatigue compared with the back exercise.

Are Morphometric and Biomechanical Characteristics of Lumbar Multifidus Related to Pain Intensity or Disability in People With Chronic Low Back Pain After Considering Psychological Factors or Insomnia?

INTRODUCTION

Lumbar multifidus muscle (LMM) dysfunction is thought to be related to pain and/or disability in people with chronic low back pain (CLBP). Although psychosocial factors play a major role in pain/disability, they are seldom considered as confounders in analyzing the association between LMM and CLBP.

OBJECTIVES

This study aimed to determine: (1) differences in psychological factors, insomnia, and LMM characteristics between people with and without CLBP; (2) associations between psychological factors, insomnia, or LMM characteristics and low back pain (LBP) intensity or LBP-related disability in people with CLBP; and (3) whether LMM characteristics are related to LBP symptoms in people with CLBP after considering confounders.

METHODS

Seventy-eight volunteers with CLBP and 73 without CLBP provided sociodemographic information, filled the 11-point numeric pain rating scale and Roland-Morris disability questionnaire (RMDQ). They completed the Hospital Anxiety and Depression Scale (HADS), Pain Catastrophizing Scale (PCS), Fear Avoidance Belief Questionnaire (FAB), and Insomnia Severity Index Scale (ISI). Resting and contracted thickness of LMM at L4-S1 levels were measured from brightness-mode ultrasound images. Percent thickness changes of LMM at L4-S1 levels during contraction were calculated. Resting LMM stiffness at L4-S1 was measured by shear wave elastography. Associations among LMM, psychosocial or insomnia parameters and clinical outcomes were analyzed by univariate and multivariate analyses.

RESULTS

People with CLBP demonstrated significantly higher LBP-intensity, RMDQ, HADS, FAB, PCS, and ISI scores than asymptomatic controls (p < 0.05). The former also had significantly smaller percent thickness changes of LMM at L4/L5 during contraction. LBP-intensity was positively related to scores of PCS-total, PCS-helplessness, FAB-total, FAB-work, and ISI in people with CLBP (p < 0.05). RMDQ scores were positively associated with the scores of HADS-total, HADS-depression, PCS-total, FAB-total, FAB-physical activity, PCS-helplessness, and ISI in people with CLBP (p < 0.05). FAB-work and ISI scores together explained 24% of LBP-intensity. FAB-total scores alone explained 34% of variance of LBP-related disability in people with CLBP.

CONCLUSION

More fear-avoidance belief or insomnia is related to greater LBP-intensity and/or LBP-related disability in people with CLBP. Although people with CLBP were thought to have aberrant LMM morphometry/function, no LMM characteristics were related to LBP-intensity or LBP-related disability after considering other confounders.

Are Changes in Sleep Quality/Quantity or Baseline Sleep Parameters Related to Changes in Clinical Outcomes in Patients With Nonspecific Chronic Low Back Pain?: A Systematic Review

OBJECTIVES

Sleep disturbance is prevalent among patients with chronic low back pain (CLBP). This systematic review aimed to summarize the evidence regarding the: (1) temporal relations between changes in sleep quality/quantity and the corresponding changes in pain and/or disability; and (2) role of baseline sleep quality/quantity in predicting future pain and/or disability in patients with CLBP.

METHODS

Four databases were searched from their inception to February 2021. Two reviewers independently screened the abstract and full text, extracted data, assessed the methodological quality of the included studies, and evaluated the quality of evidence of the findings using the Grading of Recommendations Assessment Development and Evaluation (GRADE).

RESULTS

Of 1995 identified references, 6 articles involving 1641 participants with CLBP were included. Moderate-quality evidence substantiated that improvements in self-reported sleep quality and total sleep time were significantly correlated with the corresponding LBP reduction. Low-quality evidence showed that self-reported improvements in sleep quality were related to the corresponding improvements in CLBP-related disability. There was conflicting evidence regarding the relation between baseline sleep quality/quantity and future pain/disability in patients with CLBP.

DISCUSSION

This is the first systematic review to accentuate that improved self-reported sleep quality/quantity may be associated with improved pain/disability, although it remains unclear whether baseline sleep quality/quantity is a prognostic factor for CLBP. These findings highlight the importance of understanding the mechanisms underlying the relation between sleep and CLBP, which may inform the necessity of assessing or treating sleep disturbance in people with CLBP.

TREATMENT OF NON-SPECIFIC CHRONIC LOW BACK PAIN: RESISTANCE TRAINING WITH OR WITHOUT USING WEIGHTS?

ABSTRACT Introduction: Dysfunction of the core muscles contributes to the persistence of pain in patients with chronic low back pain. Evidence shows that the active approach is beneficial in the rehabilitation of these patients. However, there is uncertainty as to the most effective methods or form of exercise, as the literature offers little guidance in this regard. Objective: To analyze and compare the impact on quality of life, function, flexibility, abdominal strength and abdominal fat rate in patients with non-specific chronic low back pain after a program of resistance training using two different forms of exercise. Methods: Thirty individuals, aged between 18 and 65 years, participated in the study. Twenty performed physical training program twice a week for eight weeks, and ten did not perform any physical exercises, but received guidance and pain relief. The physically active individuals were randomly divided in two groups and received similar resistance training, focusing on the same muscle groups. Ten performed training with dumbbells and bodybuilding machines (TRCP) and ten did not use this equipment (TRSP). All were assessed before and after the intervention, through questionnaires on quality of life and function, and tests for flexibility, abdominal strength and measurement of the abdominal fat rate. Results: In the intra-group comparison (initial vs eight weeks), there were no significant differences in quality of life in any of the groups. However, regarding function, the three groups showed significant improvement, with TRSP showing the best evolution. For flexibility and abdominal strength gain, TRCP showed the best evolution in both instruments. For decrease in abdominal fat rate, only TRCP showed significant differences. In the intergroup comparison, there were no significant differences for any of the evaluated outcomes. Conclusion: The two exercise programs were effective in improving function, flexibility and abdominal strength in patients with chronic, non-specific low back pain. However, there were no statistically significant differences in any of the outcomes in the comparison between groups. Level evidence II, Comparative prospective study.

The predictive value of preoperative paraspinal muscle morphometry on complications after lumbar surgery: a systematic review

PURPOSE

The effect of paraspinal muscles atrophy and fat infiltration (FI) on the complications of spinal surgery has not been established.

METHODS

A review of the literature was conducted from a search of the PubMed, EMBASE, and Web of Science databases from inception through January 2021. The literature was searched and assessed by independent reviewers based on criteria that included an assessment of preoperative paraspinal muscle morphology in addition to measuring its relationship to surgical complications. All relevant papers were assessed for risk of bias according to the modified Newcastle Ottawa Scale and the Joanna Briggs Institute Critical Appraisal Tools. A narrative synthesis was conducted.

RESULTS

The initial search yielded 5632 studies, of which 16 studies were included in the analysis. All included studies were at a low risk of bias. There existed strong evidence that the atrophy and FI of paraspinal muscles had an association with the development of bone nonunion (two high quality studies), pedicle screw loosening (two high quality studies), adjacent segment degeneration (three high quality studies) and proximal junctional kyphosis (five high quality studies) after lumbar surgery. Besides, there is also limited evidence for association between atrophy and FI of paraspinal extensor muscles and less local and global curve improvement.

CONCLUSIONS

Strong evidence was found for an association between preoperative paraspinal muscle degeneration and multiple postoperative complications after lumbar surgery. However, the findings should be interpreted with caution due to the small quantity of the available literature and high heterogeneity among studies.

Is the pain pressure threshold linked to the transversus abdominis in women with chronic neck pain?: a preliminary report

PURPOSE

The present study aimed to investigate the relationship between the ultrasonography parameters of transversus abdominis and neck pain manifestations in women with chronic neck pain.

MATERIALS AND METHODS

Thirty women (mean age: 38.44 ± 9.56 years, BMI: 25.57 ± 3.32 kg/m²) with chronic neck pain were included in the study. The pain severity, disability scores, and bilateral pain pressure threshold of upper trapezius were assessed. The thickness of transversus abdominis in-rest and abdominal draw-in conditions were evaluated by two-dimensional ultrasonography. Pearson's correlation coefficients and linear regression statistics were determined.

RESULTS

We found a moderate correlation between the thickness of transversus abdominis in abdominal draw-in and the pain pressure threshold of right (r = 0.636, p < 0.001), and left upper trapezius (r = 0.403, p = 0.03). Moreover, there was a moderate correlation between the pain pressure threshold of the right upper trapezius and the thickness of transversus abdominis in-rest (r = 0.498, p = 0.006). No significant correlation was found between pain intensity, disability scores, and ultrasonography parameters of transversus abdominis. There was also a significant total effect of transversus abdominis' thickness on abdominal draw-in manoeuvre on predicting pain pressure threshold of right upper trapezius (B = 0.636, SE = 0.765, p < 0.001) and pain pressure threshold of left upper trapezius (B = 0.403, SE = 0.840, p = 0.03).

CONCLUSIONS

Our results revealed that upper trapezius muscle tenderness may associated with decreased muscle thickness of transversus abdominis. Addressing new exercise methodologies including transversus abdominis training in the management of chronic neck pain may be helpful to improve neck pain symptoms.

Prevalence/Incidence of Low Back Pain and Associated Risk Factors Among Nursing and Medical Students: A Systematic Review and Meta-Analysis

OBJECTIVE

To summarize evidence regarding the prevalence and incidence of low back pain and associated risk factors in nursing and medical students. TYPE: Systematic review and meta-analysis.

LITERATURE SURVEY

The protocol was registered with PROSPERO (CRD42015029729). Its reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Seven databases were searched until August 2020 to identify relevant studies.

METHODOLOGY

Two independent reviewers screened, extracted, and evaluated the risk of bias of the selected studies. Meta-analyses were used to estimate 12-month prevalence/incidence rates of low back pain and associated risk factors in these students. Levels of evidence for risk factors were determined by the updated Guidelines for Systematic Reviews in the Cochrane Collaboration Back Review Group.

SYNTHESIS

Sixteen studies involving 7072 students were included. The pooled 12-month prevalence rates of low back pain for nursing and medical students were 44% (95% confidence interval [95% CI]: 27%-61%) and 53% (95% CI: 44%-62%), respectively. The 12-month incidence of low back pain in nursing students ranged from 29% to 67%. No incidence rate was reported in medical students. Strong/moderate-quality evidence supported that final year of study (pooled odds ratio [OR] from five studies, 1.96, 95% CI: 1.13-3.40), anxiety (OR ranging from 3.12 to 4.61), or high mental pressure or psychological distress (OR ranging from 1.37 to 4.52) was associated with a higher 12-month low back pain prevalence in both student groups. Moderate-quality evidence suggested that prior history of low back pain (pooled OR from two studies: 3.46, 95% CI: 1.88-6.36) was associated with a higher 12-month low back pain incidence in nursing students. Similarly, moderate-quality evidence suggested that female medical students (pooled OR from two studies: 1.77, 95% CI: 1.09-2.86) demonstrated a higher 12-month low back pain prevalence than male counterparts.

CONCLUSIONS

Although it is impossible to alter nonmodifiable risk factors for low back pain, universities may develop and implement proper strategies to mitigate modifiable risk factors in these students.

Methodological tools and sensitivity analysis for assessing quality or risk of bias used in systematic reviews published in the high-impact anesthesiology journals

Background

A crucial element in the systematic review (SR) methodology is the appraisal of included primary studies, using tools for assessment of methodological quality or risk of bias (RoB). SR authors can conduct sensitivity analyses to explore whether their results are sensitive to exclusion of low quality studies or a high RoB. However, it is unknown which tools do SR authors use for assessing quality/RoB, and how they set threshold for quality/RoB in sensitivity analyses. The aim of this study was to assess quality/RoB assessment tools, the types of sensitivity analyses and quality/RoB thresholds for sensitivity analyses used within SRs published in high-impact pain/anesthesiology journals.

Methods

This was a methodological study. We analyzed SRs published from January 2005 to June 2018 in the 25% highest-ranking journals within the Journal Citation Reports (JCR) “Anesthesiology” category. We retrieved the SRs from PubMed. Two authors independently screened records, full texts, and extracted data on quality/RoB tools and sensitivity analyses. We extracted data about quality/RoB tools, types of sensitivity analyses and the thresholds for quality/RoB used in them.

Results

Out of 678 analyzed SRs, 513 (76%) reported the use of quality/RoB assessments. The most commonly reported tools for assessing quality/RoB in the studies were the Cochrane tool for risk of bias assessment (N = 251; 37%) and Jadad scale (N = 99; 15%). Meta-analysis was conducted in 451 (66%) of SRs and sensitivity analysis in 219/451 (49%). Most commonly, sensitivity analysis was conducted to explore the influence of study quality/RoB (90/219; 41%) on the results. Quality/RoB thresholds used for sensitivity analysis for those studies were clearly reported in 47 (52%) articles that used them. The quality/RoB thresholds used for sensitivity analyses were highly heterogeneous and inconsistent, even when the same tool was used.

Conclusions

A quarter of SRs reported using quality/RoB assessments, and some of them cited tools that are not meant for assessing quality/RoB. Authors who use quality/RoB to explore the robustness of their results in meta-analyses use highly heterogeneous quality/RoB thresholds in sensitivity analyses. Better methodological consistency for quality/RoB sensitivity analyses is needed.

The Effects of Stabilization Exercise on the Thickness of Lateral Abdominal Muscles During Standing Tasks in Women With Chronic Low Back Pain: A Randomized Triple-Blinded Clinical Trial Study

CONTEXT

Chronic low back pain (CLBP) often presents with a dysfunction in deep abdominal muscles activity during standing tasks. Although some studies indicated that deep abdominal muscle activity improved during some functional tasks following stabilization exercise (SE), there is no study to evaluate the effect of SE on lateral abdominal muscles thickness during standing postural tasks.

OBJECTIVE

The purpose of this study was (1) to evaluate the lateral abdominal muscles thickness in the participants with CLBP while standing on a balance board and (2) to compare the effects of SE and a general exercise (GE) program on the lateral muscles thickness changes.

METHODS

This was a between-groups, triple-blinded randomized controlled trial design. In total, 40 females with CLBP were randomly assigned into 2 groups:  GE (control group) and supervised progressive SE (experimental group). Diagnostic ultrasound imaging was used before and after the intervention to measure lateral abdominal muscles thickness during standing on 2 different levels of platform in the Biodex Balance System. Visual analog scale and Roland-Morris Disability Questionnaire were used to evaluate changes in pain intensity and disability.

RESULTS

The results indicated significant increases in transverse abdominis muscle thickness during all standing tasks (P = .02) and significant decreases in pain intensity and disability following SE intervention (P < .001). However, the lateral abdominal muscle thicknesses were not changed after GE intervention while standing postural tasks (P > .05). The GE group revealed only significant decreases in pain intensity after intervention (P = .03).

CONCLUSION

Supervised progressive SE improved the activity of deep abdominal muscles in standing postural tasks in the patients with CLBP.

The Evolving Case Supporting Individualised Physiotherapy for Low Back Pain

Low-back pain (LBP) is one of the most burdensome health problems in the world. Guidelines recommend simple treatments such as advice that may result in suboptimal outcomes, particularly when applied to people with complex biopsychosocial barriers to recovery. Individualised physiotherapy has the potential of being more effective for people with LBP; however, there is limited evidence supporting this approach. A series of studies supporting the mechanisms underpinning and effectiveness of the Specific Treatment of Problems of the Spine (STOPS) approach to individualised physiotherapy have been published. The clinical and research implications of these findings are presented and discussed. Treatment based on the STOPS approach should also be considered as an approach to individualised physiotherapy in people with LBP.

Factors Associated With the Ultrasound Characteristics of the Lumbar Multifidus: A Systematic Review

OBJECTIVE

The first aim of this review was to investigate the association between age, sex, height, weight, physical activity level, posture, lumbar level and body side, and structural characteristics (cross-sectional area [CSA], thickness, linear dimensions, and echo intensity) of the lumbar multifidus (LM) measured by ultrasound. Second, differences between healthy individuals and patients with chronic low back pain (CLBP) were investigated. TYPE: Systematic review.

LITERATURE SURVEY

PubMed, Embase and Web of Science were searched until September 2018.

METHODOLOGY

Studies were included if (a) full text was available in English, Dutch, or French; (b) participants were older than 18 years of age and were asymptomatic or had nonspecific CLBP; and (c) the relation between structural characteristics of the LM, measured by ultrasound, and at least one of the above-mentioned factors was described, and/or a comparison between a CLBP and control group was made. Data were extracted independently by two reviewers. Quality of studies was assessed using an adapted version of the Downs and Black checklist.

SYNTHESIS

Twenty-seven studies were included. Thickness and CSA of the LM do not correlate with age. Males have a larger LM size than females. Thickness and CSA of left and right LM are highly correlated in healthy subjects. More significant side-to-side differences are present in subjects with CLBP than in those without. Muscle size increases from proximal to caudal lumbar levels. The presence of CLBP is associated with muscle size and function.

CONCLUSIONS

The association between the factors age, sex, height, weight, physical activity level, posture, lumbar level, body side, and presence of CLBP, and the ultrasound characteristics of the LM is discussed. These factors should be taken into account in future research on structural muscle characteristics, or when correlating with functional behavior or investigating the effect of a targeted intervention.

LEVEL OF EVIDENCE

I.

Analysis of Motor Control in Patients With Low Back Pain: A Key to Personalized Care?

SYNOPSIS

Motor control exercise has been shown to be effective in the management of low back pain (LBP). However, the effect sizes for motor control exercise are modest, possibly because studies have used a one-size-fits-all approach, while the literature suggests that patients may differ in presence or type of motor control issues. In this commentary, we address the question of whether consideration of such variation in motor control issues might contribute to more personalized motor control exercise for patients with LBP. Such an approach is plausible, because motor control changes may play a role in persistence of pain through effects on tissue loading that may cause nociceptive afference, particularly in the case of peripheral sensitization. Subgrouping systems used in clinical practice, which comprise motor control aspects, allow reliable classification that is, in part, aligned with findings in studies on motor control in patients with LBP. Motor control issues may have heuristic value for treatment allocation, as the different presentations observed suggest different targets for motor control exercise, but this remains to be proven. Finally, clinical assessment of patients with LBP should take into account more aspects than motor control alone, including pain mechanisms, musculoskeletal health, and psychosocial factors, and may need to be embedded in a stratification approach based on prognosis to avoid undue diagnostic procedures. J Orthop Sports Phys Ther 2019;49(6):380-388. Epub 12 Jun 2018. doi:10.2519/jospt.2019.7916.

Neuromuscular morphometric characteristics in low back pain with unilateral radiculopathy caused by disc herniation: An ultrasound imaging evaluation

BACKGROUND

Little is known about the neuromuscular morphometric characteristics in patients with sciatica.

OBJECTIVE

To evaluate the possible changes of nerve and muscle structures in patients with low back pain with unilateral radiculopathy due to lumbar disc herniation by ultrasound imaging.

DESIGN

A case-control observational study.

METHODS

Forty individuals were divided into case (n = 20; low back pain with unilateral radiculopathy due to disc herniation), and healthy control groups (n = 20). The thickness of lumbar multifidus at L5 level, and of lower limb muscles (i.e., biceps femoris, medial gastrocnemius, and soleus) was measured during both rest and full contraction to calculate the rest/contraction ratio of these muscles. Additionally, the sciatic nerve cross-sectional area and the echogenicity of the nerve and muscles were measured based on ultrasound imaging. The association between severity of low back pain radiculopathy (i.e., pain and patients' perceived disability) and rest/contraction ratio was assessed.

RESULTS

Patients with sciatica showed sciatic nerve enlargement, and different contraction ratios for multifidus (at L5)/ankle plantar flexors compared to the controls. The rest/contraction ratio for biceps femoris was similar between the two groups.

CONCLUSION

According to these findings, ultrasound imaging can be considered a useful tool to detect changes in the sciatic nerve and muscles due to disc herniation. Furthermore, regarding the observation of significant changes in muscle rest/contraction ratio in the multifidus and gastrosoleus, one might attribute these changes to the nerve root compression.

Association Between Clinical Tests Related to Motor Control Dysfunction and Changes in Pain and Disability After Lumbar Stabilization Exercises in Individuals With Chronic Low Back Pain

OBJECTIVE

To investigate whether clinical tests used to detect motor control dysfunction can predict improvements in pain and disability in patients with chronic nonspecific low back pain (LBP) who have undergone an 8-week lumbar stabilization exercise program.

STUDY DESIGN

A prospective cohort study.

SETTING

Outpatient physical therapy university clinic.

PARTICIPANTS

Seventy people with chronic nonspecific LBP were recruited, and 64 completed the exercise program (N=64).

INTERVENTIONS

The lumbar stabilization program was provided twice a week for 8 weeks.

MAIN OUTCOME MEASURES

Pain intensity (11-point numerical rating scale) and disability (Roland Morris Disability Questionnaire) and clinical tests, such as the Deep Muscle Contraction (DMC) scale, Clinical Test of Thoracolumbar Dissociation (CTTD), and Passive Lumbar Extension (PLE) test. Univariate and multivariate linear regression models were used in the prediction analysis.

RESULTS

Mean changes in pain intensity and disability following the 8-week stabilization program were -3.8 (95% confidence interval [CI], -3.2 to -4.4) and -7.4 (95% CI, -6.3 to -8.5), respectively. Clinical test scores taken at baseline did not predict changes in pain and disability at 8-week follow-up.

CONCLUSION

Our findings revealed that the DMC scale, CTTD, PLE test, clinical tests used to assess motor control dysfunction, do not predict improvements in pain and disability in patients with chronic nonspecific LBP following an 8-week lumbar stabilization exercise program.

Difference between subjects in early chronic phase of low back pain with and without neuropathic component: observational cross-sectional study

BACKGROUND

Neuropathic pain in early chronic low back pain is insufficiently recognized and treated.

AIM

The aim of this study was to establish if there is a difference among chronic low back pain subjects with and without neuropathic pain and healthy subjects, in clinical characteristic and the level of trunk muscle activation.

DESIGN

Cross sectional observational study.

SETTING

Rehabilitation clinic, inpatient and outpatient.

POPULATION

Thirty-three subjects in early chronic phase of low back pain and 26 healthy subjects were included in this research.

METHODS

Clinical characteristics and relative thickness change of lumbar multifidus and transversal abdominal muscle, measured by ultrasound, in neuropathic, non-neuropathic chronic low back pain and healthy subjects were analyzed.

RESULTS

Chronic low back pain subjects with neuropathic pain reported higher level of pain on Visual Analog Scale (VAS) (back pain P=0.016, leg pain P=0.006), had higher Oswestry Disability Score (P=0.029), had lower motor (P=0.001) and sensory leg scores (P=0.000), and decreased level of activation of transversal abdominal muscle (P=0.000) comparing to chronic low back pain group without neuropathic pain. Low back pain subjects with leg pain ≥5 on VAS were 11.2 times more prone to develop neuropathic pain. Motor leg score ≤47 increases this chance 35 times. Sensory leg score ≤25 increases this chance 14 times. Reduced activation of transversal abdominal muscle for 40-50% increases this chance 7-24 times.

CONCLUSIONS

Chronic low back pain subjects with neuropathic pain were more painful and disabled, had lower motor and sensory scores, and lower relative thickness change of transversal abdominal muscle comparing to the low back pain group without neuropathic pain. Self -reported leg pain intensity of 5 or more on VAS, motor score of 47 and less, sensory scores of 25 and less and diminished activation of transversal abdominal muscle significantly increase the chance that chronic low back pain subject has neuropathic component of pain.

CLINICAL REHABILITATION IMPACT

Neuropathic pain in early chronic low back pain subjects might be more readily recognized if patients with radiculopathy and diminished activation of transversal abdominal muscle were regularly screened for neuropathic pain.

Relationships between paraspinal muscle morphology and neurocompressive conditions of the lumbar spine: a systematic review with meta-analysis

Background

Individual study results have demonstrated unclear relationships between neurocompressive disorders and paraspinal muscle morphology. This systematic review aimed to synthesize current evidence regarding the relationship lumbar neurocompressive disorders may have with lumbar paraspinal muscle morphology.

Methods

Searches were conducted in seven databases from inception through October 2017. Observational studies with control or comparison groups comparing herniations, facet degeneration, or canal stenosis to changes in imaging or biopsy-identified lumbar paraspinal muscle morphology were included. Data extraction and risk of bias assessment were performed by review author pairs independent of one another. Morphological differences between individuals with and without neurocompressive disorders were compared qualitatively, and where possible, standardised mean differences were obtained.

Results

Twenty-eight studies were included. Lumbar multifidus fiber diameter was smaller on the side of and below herniation for type I [SMD: −0.40 (95% CI = −0.70, −0.09) and type II fibers [SMD: −0.38 (95% CI = −0.69, −0.06)] compared to the unaffected side. The distribution of type I fibers was greater on the herniation side [SMD: 0.43 (95% CI = 0.03, 0.82)]. Qualitatively, two studies assessing small angular fiber frequency and fiber type groupings demonstrated increases in these parameters below the herniation level. For diagnostic imaging meta-analyses, there were no consistent differences across the various assessment types for any paraspinal muscle groups when patients with herniation served as their own control. However, qualitative synthesis of between-group comparisons reported greater multifidus and erector spinae muscle atrophy or fat infiltration among patients with disc herniation and radiculopathy in four of six studies, and increased fatty infiltration in paraspinal muscles with higher grades of facet joint degeneration in four of five studies. Conflicting outcomes and variations in study methodology precluded a clear conclusion for canal stenosis.

Conclusions

Based on mixed levels of risk of bias data, in patients with chronic radiculopathy, disc herniation and severe facet degeneration were associated with altered paraspinal muscle morphology at or below the pathology level. As the variability of study quality and heterogeneous approaches utilized to assess muscle morphology challenged comparison across studies, we provide recommendations to promote uniform measurement techniques for future studies.

Trial registration

PROSPERO 2015: CRD42015012985

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2266-5) contains supplementary material, which is available to authorized users.

Comparison of lumbar multifidus thickness and perceived exertion during graded superman exercises with or without an abdominal drawing-in maneuver in young adults

The present study aimed to investigate lumbar multifidus (LM) thickness and perceived exertion during graded superman exercises (GSE) or GSE with an abdominal drawing-in maneuver (GSE-AD) in young adults. Twelve young adult males and females, who were informed of the purpose and procedures of this study and then gave their voluntary consent to participate, were included in this study. All subjects randomly performed three GSE and GSE-AD over 3 days. Ultrasonography was used to measure the LM thickness to the left and right of the L5 region. Additionally, the issue of whole-body fatigue felt by the subject while performing the GSE or GSE-AD was measured using the Borg scale. The intrarater reliability of the LM measurement was found to be intraclass correlation coefficient (ICC[3,1])=0.97 (0.87-0.99) at resting and ICC(3,1)=0.94 (0.78-0.99) at contraction. Both the left and right LM showed significantly higher contraction during the grade 3 GSE (P< 0.05). The whole-body fatigue was significantly greater following GSE 2 and 3 than following GSE-AD 2 and 3 (P<0.05). In particular, GSE-AD had a significantly lower Borg score compared to GSE (P<0.05) and did not show any significant difference in muscle thickness (P>0.05). It is recommended that the abdominal drawing-in maneuver be applied with grade 3 GSE to enhance stability and reduce spinal fatigue.

Development of a Multivariate Prognostic Model for Pain and Activity Limitation in People With Low Back Disorders Receiving Physiotherapy

OBJECTIVE

To identify predictors for back pain, leg pain, and activity limitation in patients with early persistent low back disorders (LBDs).

DESIGN

Prospective inception cohort study.

SETTING

Primary care private physiotherapy clinics in Melbourne, Australia.

PARTICIPANTS

Individuals (N=300) aged 18-65 years with low back and/or referred leg pain of ≥6 weeks and ≤6 months duration.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Numeric rating scales for back pain and leg pain as well as the Oswestry Disability Scale.

RESULTS

Prognostic factors included sociodemographics, treatment related factors, subjective/physical examination, subgrouping factors, and standardized questionnaires. Univariate analysis followed by generalized estimating equations were used to develop a multivariate prognostic model for back pain, leg pain, and activity limitation. Fifty-eight prognostic factors progressed to the multivariate stage where 15 showed significant (P<.05) associations with at least 1 of the 3 outcomes. There were 5 indicators of positive outcome (2 types of LBD subgroups, paresthesia below waist, walking as an easing factor, and low transversus abdominis tone) and 10 indicators of negative outcome (both parents born overseas, deep leg symptoms, longer sick leave duration, high multifidus tone, clinically determined inflammation, higher back and leg pain severity, lower lifting capacity, lower work capacity, and higher pain drawing percentage coverage). The preliminary model identifying predictors of LBDs explained up to 37% of the variance in outcome.

CONCLUSIONS

This study evaluated a comprehensive range of prognostic factors reflective of both the biomedical and psychosocial domains of LBDs. The preliminary multivariate model requires further validation before being considered for clinical use.

Effects of McGill stabilization exercises and conventional physiotherapy on pain, functional disability and active back range of motion in patients with chronic non-specific low back pain

[Purpose] The aim of this study was to compare the effects of “McGill stabilization exercises” and “conventional physiotherapy” on pain, functional disability and active back flexion and extension range of motion in patients with chronic non-specific low back pain. [Subjects and Methods] Thirty four patients with chronic non-specific low back pain were randomly assigned to McGill stabilization exercises group (n=17) and conventional physiotherapy group (n=17). In both groups, patients performed the corresponding exercises for six weeks. The visual analog scale (VAS), Quebec Low Back Pain Disability Scale Questionnaire and inclinometer were used to measure pain, functional disability, and active back flexion and extension range of motion, respectively. [Results] Statistically significant improvements were observed in pain, functional disability, and active back extension range of motion in McGill stabilization exercises group. However, active back flexion range of motion was the only clinical symptom that statistically increased in patients who performed conventional physiotherapy. There was no significant difference between the clinical characteristics while compared these two groups of patients. [Conclusion] The results of this study indicated that McGill stabilization exercises and conventional physiotherapy provided approximately similar improvement in pain, functional disability, and active back range of motion in patients with chronic non-specific low back pain. However, it appears that McGill stabilization exercises provide an additional benefit to patients with chronic non-specific low back, especially in pain and functional disability improvement.

Chronic low back pain and back muscle activity during functional tasks

There is evidence that patients with low back pain favor their trunk muscles when moving. However, it is unknown whether this maladaptive behavior is generalized across different functional tasks. This study analyzed the back muscle activity of patients with chronic low back pain compared to asymptomatic controls during five functional tasks. The secondary aim of this study was to test whether the electromyographic activity of patients' back muscles was correlated with either the TAMPA scale score or the Örebro Questionnaire. Forty patients with chronic, non-specific low back pain and 40 asymptomatic participants were assessed on the electromyographic activity of the lumbar longissimus, ilio-costal and multifidus while picking up and placing an object on the ground, sitting down and standing up, and climbing stairs. There was statistical evidence of two-way interactions involving group by task (F_4,308 = 7.921, p < 0.001, η² = 0.049) and task by muscle (F_18,1386 = 2.912, p < 0.001, η² = 0.004), but not group by muscle (F_7,539 = 1.104, p = 0.359, η² = 0.004). Patients with chronic low back pain showed an increase in back muscle activity regardless of the type of functional task, except the left side of multifidus muscle during the picking up of a ball on the ground task. There was no correlation between the measure of kinesiophobia or the Örebro questionnaire score and the level of electromyographic activity.

Muscle Control and Non-specific Chronic Low Back Pain

Objectives

Chronic low back pain (CLBP) is the most prevalent of the painful musculoskeletal conditions. CLBP is a heterogeneous condition with many causes and diagnoses, but there are few established therapies with strong evidence of effectiveness (or cost effectiveness). CLBP for which it is not possible to identify any specific cause is often referred to as non‐specific chronic LBP (NSCLBP). One type of NSCLBP is continuing and recurrent primarily nociceptive CLBP due to vertebral joint overload subsequent to functional instability of the lumbar spine. This condition may occur due to disruption of the motor control system to the key stabilizing muscles in the lumbar spine, particularly the lumbar multifidus muscle (MF).

Methods

This review presents the evidence for MF involvement in CLBP, mechanisms of action of disruption of control of the MF, and options for restoring control of the MF as a treatment for NSCLBP.

Results

Imaging assessment of motor control dysfunction of the MF in individual patients is fraught with difficulty. MRI or ultrasound imaging techniques, while reliable, have limited diagnostic or predictive utility. For some patients, restoration of motor control to the MF with specific exercises can be effective, but population results are not persuasive since most patients are unable to voluntarily contract the MF and may be inhibited from doing so due to arthrogenic muscle inhibition.

Conclusions

Targeting MF control with restorative neurostimulation promises a new treatment option.

A Machine Learning-based Surface Electromyography Topography Evaluation for Prognostic Prediction of Functional Restoration Rehabilitation in Chronic Low Back Pain

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim of this study was to investigate the feasibility and applicability of support vector machine (SVM) algorithm in classifying patients with LBP who would obtain satisfactory or unsatisfactory progress after the functional restoration rehabilitation program.

SUMMARY OF BACKGROUND DATA

Dynamic surface electromyography (SEMG) topography has demonstrated the potential use in predicting the prognosis of functional restoration rehabilitation for patients with low back pain (LBP). However, processing from raw SEMG topography to make prediction is not easy to clinicians.

METHODS

A total of 30 patients with nonspecific LBP were recruited and divided into "responding" and "non-responding" group according to the change of Visual analog pain rating scale and Oswestry Disability Index. Each patient received a 12-week functional restoration rehabilitation program. A normal database was calculated from a control group from 48 healthy participants. Root-mean-square difference (RMSD) was extracted from the recorded dynamic SEMG topography during symmetrical and asymmetrical trunk-movement. SVM and cross-validation were applied to the prediction based on the optimized features selected by the sequential floating forward selection (SFFS) algorithm.

RESULTS

RMSD feature parameters following rehabilitation in the "responding" group showed a significant difference (P < 0.05) with the one in the "nonresponding" group. The SVM classifier with Quadratic kernel based on SFFS-selected features showed the best prediction performance (accuracy: 96.67%, sensitivity: 100%, specificity: 93.75%, average area under curve [AUC]: 0.8925) comparing with linear kernel (accuracy: 80.00%, sensitivity: 85.71%, specificity: 75.00%, average AUC: 0.7825), polynomial kernel (accuracy: 93.33%, sensitivity: 92.86%, specificity: 93.75%, average AUC: 0.9675), and radial basis function (RBF) kernel (accuracy: 86.67%, sensitivity: 85.71%, specificity: 87.50%, average AUC: 0.7900).

CONCLUSION

The use of SVM-based classifier of SEMG topography can be applied to identify the patient responding to functional restoration rehabilitation, which will help the healthcare worker to improve the efficiency of LBP rehabilitation.

LEVEL OF EVIDENCE

3.

The prevalence of musculoskeletal symptoms in the construction industry: a systematic review and meta-analysis

PURPOSE

Although individual studies have reported high prevalence of musculoskeletal symptoms (MSS) among construction workers, no systematic review has summarized their prevalence rates. Accordingly, this systematic review/meta-analysis aimed to synthesize MSS prevalence in different construction trades, gender and age groups, which may help develop specific ergonomic interventions.

METHODS

Nine databases were searched for articles related to the research objective. Two reviewers independently screened citations, extracted information and conducted quality assessment of the included studies. Meta-analyses were conducted on clinical and statistical homogenous data.

RESULTS

Thirty-five out of 1130 potential citations were included reporting diverse types of period prevalence and case definitions. Only the 1-year prevalence rates of MSS (defined as at least one episode of pain/MSS in the last year) at nine anatomical regions had sufficient homogeneous data for meta-analysis. Specifically, the 1-year prevalence of MSS was 51.1% for lower back, 37.2% for knee, 32.4% for shoulder, 30.4% for wrist, 24.4% for neck, 24.0% for ankle/foot, 20.3% for elbow, 19.8% for upper back, and 15.1% for hip/thigh. Female workers demonstrated a higher prevalence of MSS while there was insufficient information on the prevalence of trade-specific or age-related MSS. The quality assessments revealed that many included studies estimated prevalence solely based on self-reported data, and did not report non-respondents' characteristics.

CONCLUSIONS

Lumbar, knee, shoulder, and wrist MSS are the most common symptoms among construction workers. Future studies should standardize the reporting of period prevalence of MSS in different construction trades to allow meta-analyses and to develop relevant MSS prevention program.

Asymmetrical abdominal muscle morphometry is present in injury free adolescent cricket pace bowlers: A prospective observational study

OBJECTIVES

This study aimed to determine if abdominal muscle thickness, activation and symmetry are associated with prospective in-season injury among adolescent cricket pace bowlers.

DESIGN

A quantitative, prospective, observational study design was used.

SETTING

Data was collected at an indoor venue at a secondary school.

PARTICIPANTS

28 injury-free, male, adolescent pace bowlers between the ages of 13 and 18 participated.

MAIN OUTCOME MEASURES

Muscle thickness of the transversus abdominis (TA), internal oblique (IO) and external oblique (EO) muscles were measured at rest and during an abdominal drawing-in maneuver (ADIM) i.e. activation, using ultrasound imaging. Incidence of injury was monitored monthly during the cricket season.

RESULTS

Thickness of the non-dominant IO at rest was greater than the dominant side for pace bowlers who remained injury free during the cricket season (p = 0.01, effect size (ES) = 0.65). This was, however not the case for bowlers who sustained injuries (p = 0.47; ES = 0.24). TA percentage change during ADIM (activation) on the dominant side was less in bowlers who sustained non-contact injuries compared to those who remained injury free (p = 0.03; ES = 1.17).

CONCLUSIONS

Asymmetry in IO thickness may play a protective role against injury, whilst poor TA activation on the dominant side may pose a risk to injury.

Do Muscle Characteristics on Lumbar Spine Magnetic Resonance Imaging or Computed Tomography Predict Future Low Back Pain, Physical Function, or Performance? A Systematic Review

OBJECTIVE

To determine whether lumbar muscle characteristics on magnetic resonance imaging (MRI) or computed tomography (CT) can inform clinicians as to the course of future low back pain (LBP), functional limitations, or physical performance, in adults with or without LBP. TYPE: Systematic review.

LITERATURE REVIEW

We searched PubMed, Embase, and CINAHL through October 2014 for articles published in English in which authors assessed lumbar muscle characteristics on conventional MRI/CT as predictors of future LBP, functional limitations, or physical performance in adults. Studies with only postsurgical subjects were excluded. Our search identified 3554 articles, of which 6 observational cohort studies were included in the final review.

METHODOLOGY

We used the Newcastle Ottawa Scale to evaluate potential bias. Data were extracted on study design, study population, sample size, participant characteristics, details of MRI/CT assessments, interventions, study outcomes, analysis methods, and study results. Because of heterogeneity between studies, we conducted a qualitative evidence synthesis.

SYNTHESIS

Among high-quality studies, there was limited evidence that, for individuals with or without LBP, greater MRI-detected multifidus cross-sectional area at L5-S1 predicted greater LBP intensity at 1-year follow-up, lesser erector spinae fat infiltration (FI) at L5-S1 predicted greater LBP intensity at 15-year follow-up, and greater erector spinae side-to-side FI asymmetry at L3-L4 predicted lower LBP frequency at 15-year follow-up; however, there was also limited evidence that all other MRI-detected paraspinal muscle characteristics examined were not predictive of LBP incidence, prevalence, frequency, or intensity at follow-up durations ranging from 1 to 15 years. There was limited evidence that greater CT-detected trunk muscle FI predicted worse physical performance in older adults at 3-year follow-up, but that trunk muscle cross-sectional area did not.

CONCLUSION

Few lumbar muscle characteristics have limited evidence for an association with future LBP and physical performance outcomes, and the vast majority have limited evidence for having no association with such outcomes.

Reliability of diagnostic ultrasound in measuring the multifidus muscle

BACKGROUND

Ultrasound is frequently used to measure activity in the lumbar multifidus muscle (LMM). However previous reliability studies on diagnostic ultrasound and LMM have included a limited number of subjects and few have used Bland-Altman's Limits of Agreement (LOA). Further one does not know if activity affects the subjects' ability to contract the LMM.

METHODS

From January 2012 to December 2012 an inter- and intra-examiner reliability study was carried out in a clinical setting. It consisted of a total of four experiments with 30 subjects in each study. Two experienced examiners performed all measurements. Ultrasound measurements were made of: 1. the LMM in the resting state, 2. during a contracted state, 3. on subsequent days, and, before and after walking. Reliability and agreement was tested for 1. resting LMM, 2. contracted LMM, and 3. thickness change in the LMM. Mean values of three measurements were used for statistical analysis for each spinal level. The intra-class correlation coefficient (ICC) 3.1 and 3.2 was used to test for reliability, and Bland-Altman's LOA method to test for agreement.

RESULTS

All of the studies indicate high levels of reliability, but as the LMM thickness increased (increasing contraction) the agreement between examiners was poorer than for low levels of contraction.

CONCLUSIONS

The use of diagnostic ultrasound to measure the LMM seems to be reliable in subjects who have little or no change in thickness of the LMM with contraction.

Core strength training for patients with chronic low back pain

[Purpose] Through core strength training, patients with chronic low back pain can strengthen their deep trunk muscles. However, independent training remains challenging, despite the existence of numerous core strength training strategies. Currently, no standardized system has been established analyzing and comparing the results of core strength training and typical resistance training. Therefore, we conducted a systematic review of the results of previous studies to explore the effectiveness of various core strength training strategies for patients with chronic low back pain. [Methods] We searched for relevant studies using electronic databases. Subsequently, we evaluated their quality by analyzing the reported data. [Results] We compared four methods of evaluating core strength training: trunk balance, stabilization, segmental stabilization, and motor control exercises. According to the results of various scales and evaluation instruments, core strength training is more effective than typical resistance training for alleviating chronic low back pain. [Conclusion] All of the core strength training strategies examined in this study assist in the alleviation of chronic low back pain; however, we recommend focusing on training the deep trunk muscles to alleviate chronic low back pain.