Pressure in the erector spinae muscle during exercise

The microcapillary infusion method was evaluated in recording intramuscular pressure during isometric and concentric exercise of the erector spinae muscle. Intramuscular pressure at rest was 6.1 (SD = 1.4) mm Hg without infusion and 8.3 with an infusion rate of 1.5 ml/hour. When the subject experienced muscle fatigue during exercise, the muscle relaxation pressure had increased to 14 mm Hg. The erector spinae muscle was found to be heavily loaded during exercise with an average muscle contraction pressure of 175 mm Hg. Recording of intramuscular pressure in the erector spinae muscle during exercise tests can be an additional method in the study of ergonomics and biomechanics of the spine as well as in the diagnosis of chronic compartment syndrome in this muscle.     

Changes in the flexion relaxation response induced by lumbar muscle fatigue

Background  

The flexion relaxation phenomenon (FRP) is an interesting model to study the modulation of lumbar stability. Previous investigations have explored the effect of load, angular velocity and posture on this particular response. However, the influence of muscular fatigue on FRP parameters has not been thoroughly examined. The objective of the study is to identify the effect of erector spinae (ES) muscle fatigue and spine loading on myoelectric silence onset and cessation in healthy individuals during a flexion-extension task.     

Histochemistry and morphology of erector spinae muscle in lumbar disc herniation

The purpose of this study was to detect any changes in the erector spinae muscles in patients undergoing surgery for lumbar disc herniation (LDH) and to analyze which factors (sex, age, the level and site of disc protrusion, and duration of symptoms) would be related to these changes. The percentage of mean area of the type I fibers was significantly larger in males and in the older age group (P less than 0.05), due to the decreasing size of type IIa and IIb fibers. Patients with LDH have: 1) angulated and selective atrophy of type II fibers with a higher type IIb/IIa ratio; 2) with increasing age and duration of symptoms, more marked atrophy of type II fibers; and 3) other unspecific pathologic changes.     

Morphological studies on the erector spinae muscle in sixty consecutive scoliotic patients

Paraspinal muscle biopsy was done on the erector spinae muscles in sixty consecutive scoliotic patients. Together with the clinical and muscle biopsy findings, these sixty patients were classified into thirty-two patients with idiopathic scoliosis, eleven patients with myopathic scoliosis, nine patients with neuropathic scoliosis, and eight patients with miscellaneous scoliosis. Of the thirty-two patients with idiopathic scoliosis, nineteen cases displayed neurogenic changes in the grouping of the Type 1 fibers and target fiber formation more common on the convex side back muscles. The myopathies consisted of central core disease, nemalin myopathy, congenital fiber type disproportion, mitochondrial myopathy, congenital muscular dystrophy, and myositis. Patients with neuropathic scoliosis all showed loss of the normal mosaic pattern and grouping of both Type 1 and 2 fibers in their muscle biopsies. This result indicates that there is a variety of neuromuscular diseases in scoliotic patients. The neurogenic changes observed more commonly on the convex side muscle of idiopathic scoliotic patients deserve further investigation.     

Altered erector spinae activity and trunk motion occurs with moderate and severe unilateral hip OA

People with hip osteoarthritis (OA) demonstrate altered movement patterns in the hip joint, as well as the pelvis and spine. While kinematic changes have been described in the literature, little is known about the associated erector spinae (ES) activity. Increased or prolonged ES activity may contribute to the low back pain often associated with hip OA. Using a cross‐sectional cohort study, 3D trunk motions and ES surface electromyography were recorded on 19 individuals with severe OA (SOA), 20 with moderate hip OA (MOA), and 19 asymptomatic (ASYM) individuals during treadmill walking, using standardized collection and processing procedures. Principal component analysis was used to derive electromyographic amplitude and temporal waveform features. Three‐dimensional thoracic motion in a global system, and thoraco‐lumbar motion was calculated. Various statistical analyses determined between group differences (α = 0.05). In the sagittal plane, thoracic motion was greater in the SOA group (p < 0.001), whereas the ASYM group used less thoraco‐lumbar motion than either OA group (p ≤ 0.002). Greater frontal plane angular excursion during early stance was found in the thoracic region in the SOA group (p ≤ 0.001) . With increasing OA severity, bilateral ES activity increased during the swing phase of gait (p < 0.001), whereas during stance, the SOA ipsilateral ES activity was higher than other groups (p < 0.001). Statement of clinical significance: with moderate and severe OA, sagittal, and frontal trunk motion increases during gait. ES activity during the entire gait cycle is more sustained with increased disease severity, which may aide our understanding of low back pain associated with hip OA. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1826–1832, 2018.

     

Different parts of erector spinae muscle fatigability in subjects with and without low back pain

Background contextThere is conflicting evidence regarding erector spinae muscle fatigability because previous studies have not considered the thoracic and lumbar components separately. These muscles have very different mechanical responses and, therefore, would be recruited differentially for the chosen task.PurposeThe present study was conducted to compare whether fatigability differences exist in the thoracic and lumbar parts of the erector spinae muscles in subjects with and without low back pain (LBP).Study designThis cross-sectional study was conducted in the Motion Analysis Lab at Cleveland State University.Patient sampleThe study sample included 40 subjects with LBP and 40 subjects without LBP.Outcome measuresThe fatigability of the erector spinae muscles was compared based on median frequency of electromyography (EMG) versus time. The level of pain of each subject was also compared using the Oswestry Disability Index.MethodsFatigue measurements were evaluated between groups based on the assessed sides as well as the thoracic and lumbar parts of the erector spinae muscles using surface EMG. A modified version of the isometric fatigue test as introduced by Sorensen was used to test the endurance of the erector spinae muscles.ResultsThere were significant median EMG frequency (F_{(1, 78)}=28.82, p=.001) differences in the thoracic and lumbar parts of the erector spinae muscles between subjects with and without LBP. The thoracic part had a significantly lower median EMG frequency than the lumbar part in subjects with LBP. The thoracic and lumbar parts of the erector spinae muscles had interactions with group (F_{(1, 78)}=47.88, p=.01] and age (F_{(1, 78)}=16.51, p=.01).ConclusionsThe results of this study suggested that subjects with LBP demonstrated higher fatigability of the erector spinae muscles at the thoracic part than at the lumbar part. The increased fatigability of the thoracic part needs to be emphasized in rehabilitation strategies for subjects with LBP. In addition, as age increased, the median frequency of the lumbar part of the erector spinae muscles significantly decreased. Understanding the anatomical and biomechanical characteristics of the erector spinae muscle may enhance clinical outcomes and rehabilitation strategies for subjects with LBP.     

Correlation of chronic low-back pain behavior and muscle function examination of the flexion-relaxation response

The relationship between videotape ratings of pain behavior and the flexion-relaxation phenomenon was evaluated in a sample of 39 chronic low-back pain patients. The results showed that guarded movement explained approximately 27% of the variability in the flexion-relaxation phenomenon, adjusting for pain intensity rating. There were no significant differences in sex observed. It is recommended that clinicians pay close attention to qualitative aspects of patient behavior to improve the sensitivity of the physical examination in detecting bona fide impairment.     

Age-related sex differences in erector spinae muscle endurance using surface electromyographic power spectral analysis in healthy humans

Background contextPrevious studies reported that the erector spinae muscle is more resistant to fatigue in healthy adult women than in men. However, no study has reported changes in back muscle fatigue with aging in healthy men and women.PurposeThe aim of this study was to evaluate age-related changes in muscle fatigue of erector spinae muscle in men and women.Study design/settingThis cross-sectional study was conducted in a laboratory.Patient sampleFifty-three healthy subjects (11 elderly men, 11 elderly women, 17 young men, and 14 young women) without low back pain history.Outcome measuresThe median frequency (MF) and mean power frequency (MPF) during trunk holding test were derived from the raw electromyographic (EMG) signal using Fast Fourier Transform spectrum analysis program. The rates of changes in MF and MPF were calculated.MethodsSubjects performed the unsupported trunk holding test until exhaustion. The results of power spectral analysis of the EMG activity of the left erector spinae muscle were compared in both age groups and sexes.ResultsThe endurance time in young men was significantly shorter than in young women. The slopes of MF and MPF in young men were significantly higher than in young women. There were no significant differences in MF and MPF slopes of elderly men and elderly women. Furthermore, the MF and MPF slopes were significantly lower in elderly men than young men but similar in the two women groups.ConclusionsAge-related changes in the slopes of MF and MPF of erector spinae muscle occur in healthy men but not in healthy women.     

Back extensor muscle fatigue in patients with lumbar disc herniation

We investigated back muscle fatigue and endurance in patients with lumbar disc herniation before and after surgery, and established the degree of association between perceived fatigue and objectively measured fatigue. Additionally, the relationships between muscle fatigue and endurance time on the one hand, and activity, participation, self-efficacy and health on the other, were investigated to clarify the grades of association between these factors. Forty-three consecutive patients with lumbar disc herniation were tested before surgery and 4 weeks after surgery. The protocol comprised an isometric endurance test (modified Sørensens test) with concomitant measures of electromyography, and Borg ratings of pain and fatigue. To measure activity, participation, self-efficacy and health, the patients also filled in questionnaires. Results showed a post-operatively significant improvement in lumbar muscle fatigue expressed as a flatter L5 slope for the men. No significant improvement was found for endurance times or for Borg ratings. Endurance time correlated with questionnaire answers on physical activity, the Roland–Morris, the Oswestry, self-efficacy and some items of the SF-36 with correlation coefficients ranging from 0.52 to 0.91. The L5 slope correlated with the Roland–Morris, the Oswestry and some items of the SF-36 only in women with correlation coefficients between 0.53 and 0.77. We conclude that the effects of surgery reduced muscle fatigue for the men. There is an association between muscle fatigue and endurance with activity limitations, participation restrictions, self-efficacy and health in patients undergoing surgery for lumbar disc herniation.     

超声引导下竖脊肌平面阻滞临床应用及研究进展

超声引导下竖脊肌平面阻滞(erector spinae plane block,ESPB)是一项新颖的筋膜间隙阻滞技术,可以应用于胸腰部手术后镇痛,具有操作简单安全、镇痛可靠、并发症少等诸多优点。ESPB自2016年提出以来,得到广泛关注。文章介绍了超声引导下ESPB的解剖基础,阐述了ESPB起效的理论学说,归纳了ESPB在胸腹部及腰椎等手术的临床应用,总结了ESPB的优缺点及并发症,并将ESPB与胸腰部其他常用镇痛阻滞方法进行对比,分析了各自的特点。超声引导下ESPB具有诸多的优点、极少的并发症及禁忌证,在麻醉和疼痛领域存在广阔的应用空间,能提高麻醉效果和麻醉安全性。文章旨在探究ESPB的临床研究及未来发展方向,为其临床应用提供依据。     

Effects of the forearm support band on wrist extensor muscle fatigue

STUDY DESIGN: A crossover experimental design with repeated measures. OBJECTIVE: To determine whether the forearm support band alters wrist extensor muscle fatigue. BACKGROUND: Fatigue of the wrist extensor muscles is thought to be a contributing factor in the development of lateral epicondylitis. The forearm support band is purported to reduce or prevent symptoms of lateral epicondylitis but the mechanism of action is unknown. METHODS AND MEASURES: Fifty unimpaired subjects (36 men, 14 women; mean age = 29 +/- 6 years) were tested with and without a forearm support band before and after a fatiguing bout of exercise. Peak wrist extension isometric force, peak isometric grip force, and median power spectral frequency for wrist extensor electromyographic activity were measured before and after exercise and with and without the forearm support band. A 2 x 2 repeated measures multivariate analysis of variance was used to analyze the data, followed by univariate analysis of variance and Tukey's multiple comparison tests. RESULTS: Peak wrist extension isometric force, peak grip isometric force, and median power spectral frequency were all reduced after exercise. However, there was a significant reduction in peak grip isometric force and peak wrist extension isometric force values for the with-forearm support band condition (grip force 28%, wrist extension force 26%) compared to the without-forearm support band condition (grip force 18%, wrist extension force 15%). CONCLUSIONS: Wearing the forearm support band increased the rate of fatigue in unimpaired individuals. Our findings do not support the premise that wearing the forearm support band reduces muscle fatigue in the wrist extensors.     

Fat infiltration in the lumbar multifidus and erector spinae muscles in subjects with sway-back posture

Aim

Decreased activity of the lumbar stabilizer muscles has been identified in individuals with sway-back posture. Disuse can predispose these muscles to atrophy, which is characterized by a reduced cross-sectional area (CSA) and by fat infiltration. The aim of this study was to evaluate the amount of fat infiltration in the lumbar multifidus and lumbar erector spinae muscles as a sign of the muscle atrophy in individuals with sway-back posture, with and without low back pain.

Materials and methods

Forty-five sedentary individuals between 16 and 40 years old participated in this study. The sample was divided into three groups: symptomatic sway-back (SSBG) (n = 15), asymptomatic sway-back (ASBG) (n = 15), and control (CG) (n = 15). The individuals were first subjected to photographic analysis to classify their postures and were then referred for a magnetic resonance imaging (MRI) examination of the lumbar spine. The total (TCSA) and functional (FCSA) cross-sectional areas of the lumbar erector spinae together with lumbar multifidus and isolated lumbar multifidus muscles were measured from L1 to S1. The amount of fat infiltration was estimated as the difference between the TCSA and the FCSA.

Results

Greater fat deposition was observed in the lumbar erector spinae and lumbar multifidus muscles of the individuals in the sway-back posture groups than in the control group. Pain may have contributed to the difference in the amount of fat observed in the groups with the same postural deviation. Similarly, sway-back posture may have contributed to the tissue substitution relative to the control group independently of low back pain.

Conclusions

The results of this study indicate that individuals with sway-back posture may be susceptible to morphological changes in their lumbar erector spinae and lumbar multifidus muscles, both due to the presence of pain and as a consequence of their habitual posture.     

1987 Volvo award in basic science. The morphology of the lumbar erector spinae

The lumbar erector spinae consists of two muscles--iliocostalis lumborum and longissimus thoracis--each with distinct thoracic and lumbar parts. The thoracic parts consist of tiny muscle bellies with segmental origins from the thorax and long caudal tendons that form the erector spinae aponeurosis. The lumbar fibers arise from the lumbar accessory processes and the L1-4 transverse processes, and insert independently of the erector spinae aponeurosis into the ilium. The intrinsic lumbar fibers of the erector spinae are poorly described in the literature, and the existence of the iliocostalis lumborum pars lumborum has rarely been recognized even though it constitutes a substantial portion of the total muscle mass acting directly on the lumbar vertebrae.     

Biopsy samples from the erector spinae of persons with nonspecific chronic low back pain display a decrease in glycolytic muscle fibers

BACKGROUND CONTEXTLow back pain (LBP) in Western Europe was classified as having the highest disability and overall burden among 291 studied conditions. For an extensive period of time, evidence related to morphological changes (eg, atrophy and fat infiltration) of the paraspinal muscles in persons with LBP has accumulated. Despite this evidence, there is limited knowledge on muscle fiber type composition of these muscles, and their relation to LBP.PURPOSEThe aim of the study is to investigate differences in muscle fiber type composition between persons with nonspecific chronic low back pain (NSCLBP) and healthy controls for the lumbar erector spinae (ES) and multifidus (MF) muscle.STUDY DESIGN AND SETTINGA cross-sectional study took place in the REVAL Rehabilitation Research Center, Hasselt University, Diepenbeek, Belgium.PATIENT SAMPLETwenty persons with NSCLBP (age: 44.5±7.42) and 18 healthy controls (age: 39.89±7.90) participated in this study.OUTCOME MEASURESThe primary outcome measure was paraspinal muscle fiber type composition. Secondary outcomes consisted of physiologic measures (maximal aerobic capacity and back muscle strength) and functional measures (activity level).METHODSBiopsy samples were taken from the lumbar ES and MF muscle at the L4 spinal level. These samples were stained using immunofluorescent antibodies against myosin heavy chains. In each sample, number and size (CSA) of type I, I/IIa, IIa, IIa/x, and IIx muscle fibers were quantified. From these data the relative cross-sectional fiber areas (RCSA) were calculated. To analyze differences in fiber type composition between healthy persons and persons with NSCLBP, a repeated measurements analysis of variance was used. Secondary outcome measures were analyzed using a Student's t test, and Wilcoxon test. This study was supported by the research fund of Hasselt University without potential conflict of interest.RESULTSThere were no significant differences between both groups regarding anthropometric data. There were no significant between group differences for CSA in the ES. Persons with NSCLBP displayed a nonsignificant (p=.0978) increase in the number of type I muscle fibers, and a significant decrease (p=.0019) in the number of type IIx muscle fibers in the ES muscle. Persons with NSCLBP also displayed a trend toward a higher (p=.0596) RCSA for type I fibers and a significantly lower RCSA for type IIx fibers (p=.0411). There were no significant between group differences within the MF. Regarding the secondary outcome measures, there was a significant between group difference in activity level (p=.0004) and isokinetic back muscle strength (p=.0342).CONCLUSIONSThis is the first study to examine muscle fiber type characteristics in both the ES and MF muscle of persons with NSCLBP. Based on muscle fiber characteristics, the paraspinal muscles of persons with NSCLBP seems to display a larger oxidative potential based on an increase of the number type I fibers at the expense of type IIx glycolytic fibers.