Lumbar spine orthosis wearing. II. Effect on trunk muscle myoelectric activity

The effects of wearing commonly prescribed low-back braces and corsets on myoelectric signal levels in the erector spinae and oblique abdominal muscles were investigated. A lumbosacral corset, a chairback brace, and a molded thoracolumbosacral orthosis (TLSO) were studied. Nineteen tasks involving sitting and standing were performed by five healthy adult men. Myoelectric signal levels measured when wearing each orthosis were compared with those measured when performing the same task while wearing no orthosis. The changes in mean myoelectric signal levels ranged from a 9% reduction to a 44% increase when the lumbosacral corset was worn, from a 27% reduction to a 25% increase when the chairback brace was worn, and from a 38% reduction to a 19% increase when the TLSO was worn.     

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.     

Lumbar Corsets Can Decrease Lumbar Motion in Golf Swing

Swinging a golf club includes the rotation and extension of the lumbar spine. Golf-related low back pain has been associated with degeneration of the lumbar facet and intervertebral discs, and with spondylolysis. Reflective markers were placed directly onto the skin of 11young male amateur golfers without a previous history of back pain. Using a VICON system (Oxford Metrics, U.K.), full golf swings were monitored without a corset (WOC), with a soft corset (SC), and with a hard corset (HC), with each subject taking 3 swings. Changes in the angle between the pelvis and the thorax (maximum range of motion and angular velocity) in 3 dimensions (lumbar rotation, flexion-extension, and lateral tilt) were analyzed, as was rotation of the hip joint. Peak changes in lumbar extension and rotation occurred just after impact with the ball. The extension angle of the lumbar spine at finish was significantly lower under SC (38°) or HC (28°) than under WOC (44°) conditions (p < 0.05). The maximum angular velocity after impact was significantly smaller under HC (94°/sec) than under SC (177°/sec) and WOC (191° /sec) conditions, as were the lumbar rotation angles at top and finish. In contrast, right hip rotation angles at top showed a compensatory increase under HC conditions. Wearing a lumbar corset while swinging a golf club can effectively decrease lumbar extension and rotation angles from impact until the end of the swing. These effects were significantly enhanced while wearing an HC.

Key points

• Rotational and extension forces on the lumbar spine may cause golf-related low back pain
• Wearing lumbar corsets during a golf swing can effectively decrease lumbar extension and rotation angles and angular velocity.
• Wearing lumbar corsets increased the rotational motion of the hip joint while reducing the rotation of the lumbar spine.

Key words: Golf, back pain, motion analysis, orthosis, corset     

Lumbar spine orthosis wearing. I. Restriction of gross body motions

The effects of wearing commonly prescribed low-back braces and corsets on restriction of gross body motions were investigated. A lumbosacral corset, a chairback brace, and a molded plastic thoracolumbosacral orthosis (TLSO) were studied. Four trunk movements (flexion, extension, lateral bending, and twisting) were examined in five healthy adult men when standing and sitting. All three orthoses restricted at least some gross body motion to approximately two thirds to one half of no-orthosis values. All three orthoses failed to provide restrictions of at least 10% in at least one motion. Mean motion restriction across all eight movements studied in all five subjects were largest when wearing the TLSO and least when wearing the corset. Gross body motion restrictions relieve lumbar trunk muscle and spine loads.     

Feedforward responses of transversus abdominis are directionally specific and act asymmetrically: implications for core stability theories

STUDY DESIGN: Experimental laboratory study supplemented with a repeated case study. OBJECTIVE: To examine bilateral muscle activity of the deep abdominals in response to rapid arm raising, specifically to examine the laterality and directional specificity of feedforward responses of the transversus abdominis (TrA). BACKGROUND: Based on the feedforward responses of trunk muscles during rapid arm movements, authors have concluded that the deep trunk muscles have different control mechanisms compared to the more superficial muscles. It has been proposed that deep trunk muscles such as TrA contribute substantially to the stability of the lumbar spine and that this is achieved through simultaneous bilateral feedforward activation. These inferences are based on unilateral fine-wire electromyographic (EMG) data and there are limited investigations of bilateral responses of the TrA during unilateral arm raising. METHODS AND MEASURES: Bilateral fine-wire and surface EMG data from the anterior deltoid, TrA, obliquus internus (OI), obliquus externus, biceps femoris, erector spinae, and rectus abdominis during repeated arm raises were recorded at 2 kHz. EMG signal linear envelopes were synchronized to the onset of the anterior deltoid. A feedforward window was defined as the period up to 50 ms after the onset of the anterior deltoid, and paired onsets for bilateral muscles were plotted for both left and right arm movements. RESULTS: Trunk muscles from the group data demonstrated differences between sides (laterality), which were systematically altered when alternate arms were raised (directional specificity). This was clearly evident for the TrA but less obvious for the erector spinae. The ipsilateral biceps femoris and obliquus externus, and contralateral OI and TrA, were activated earlier than the alternate side for both right and left arm movements. This was a consistent pattern over a 7-year period for the case study. Data for the rectus abdominis derived from the case study demonstrated little laterality or directionally specific response. CONCLUSION: This is the first study to show that the feedforward activity of the TrA is specific to the direction of arm movement and not bilaterally symmetrical. The asymmetry of TrA activity during arm raising suggests that the interpretation of the role of TrA as a bilateral stabilizer during anticipatory postural adjustments needs to be revised. Future research needs to examine muscle synergies associated with the asymmetrical function of the TrA and the underlying mechanism associated with low-load stability training. LEVEL OF EVIDENCE: Therapy, level 5.     

Trunk muscle balance and muscular force

An investigation of the absolute strength of the human muscle was carried out on the in vivo erector spinae muscle using magnetic resonance tomography coupled with dynamic muscular testing. The absolute strength of the erector spinae was calculated to be 48 N/cm2. The area of the rectus abdominis was 15.1 cm2, and the area of the erector spinae was 54.5 cm2. The internal moment arm for the rectus abdominis and erector spinae muscles was 7.04 and 5.64 cm, respectively. The static force measures showed the trunk extensor moment to be only 30% greater than the flexor moment. The difference is discussed in terms of the absolute strength of muscle, and other anatomic factors.     

Effects of pregnancy on lumbar motion patterns and muscle responses

BACKGROUND CONTEXT

The kinematics of the lumbar region and the activation patterns of the erector spinae muscle have been associated with the genesis of low back pain, which is one of the most common complications associated with pregnancy. Despite the high prevalence of pregnancy-related low back pain, the biomechanical adaptations of the lumbar region during pregnancy remain unknown.

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.     

老年女性腰椎骨密度与年龄及椎旁体质成分相关性分析

目的探讨不同腰椎椎体骨密度(bone mineral density,BMD)与年龄及同层面椎旁腰大肌、竖脊肌、腹部脂肪、血管钙化情况的关系。方法收集体检中心行腰椎检查的老年女性90名,采用定量CT(quantitative CT,QCT)及后处理软件测量L2-L4椎体骨密度及三椎体同层面椎旁体质成分。统计学处理应用配对t检验、Pearson相关分析和多元逐步回归分析等。结果①3组椎体BMD均与年龄均呈负相关(P0.05),L2BMD、L3BMD均与双侧腰大肌、竖脊肌密度成正相关(r=0.233~0.301,P均0.05)。而L4BMD显示与双侧竖脊肌密度及腹部脂肪面积有良好的相关性,均呈正相关。②多元逐步回归分析显示除年龄外,肌肉是影响BMD的重要因素。年龄是唯一全部进入3组腰椎BMD回归方程,并呈负相关,是影响腰椎BMD的重要因素。结论老年女性的腰椎骨密度与椎旁腰大肌、竖脊肌密度,腹部脂肪面积及年龄密切相关,除年龄外椎旁肌肉密度对骨密度影响最大。QCT扫描更加直观、精确显示椎骨与椎旁体质成分情况,可作为测量诊断骨质疏松、体质成分的新手段。     

A universal model of the lumbar back muscles in the upright position.

A model of the lumbar back muscles was constructed incorporating 49 fascicles of the lumbar erector spinae and multifidus. The attachment sites and sizes of fascicles were based on previous anatomic studies, and the fascicles were modeled on radiographs of nine normal volunteers in the upright position. Calculations revealed that the thoracic fibers of the lumbar erector spinae contribute 50% of the total extensor moment exerted on L4 and L5; multifidus contributes some 20%; and the remainder is exerted by the lumbar fibers of erector spinae. At upper lumbar levels, the thoracic fibers of the lumbar erector spinae contribute between 70% and 86% of the total extensor moment. In the upright posture, the lumbar back muscles exert a net posterior shear force on segments L1 to L4, but exert an anterior shear force on L5. Collectively, all the back muscles exert large compression forces on all segments. A force coefficient of 46 Ncm-2 was determined to apply for the back muscles. These results have a bearing on the appreciation of the effects on the back muscles of surgery and physiotherapy.     

Response of the flexion-relaxation phenomenon relative to the lumbar motion to load and speed

STUDY DESIGN: Nonrandomized control trial. OBJECTIVE: To determine if the variations of speed and loading conditions during trunk flexion-extension could influence the times of occurrence and disappearance of the electrical silence of the erector spinae muscles, the degrees of lumbar flexion at those instants, and the relative lumbar motion time. SUMMARY OF BACKGROUND DATA: It has been suggested that varying either the speed of movement or the load on the trunk during trunk flexion-extension movements may influence the flexion-relaxation phenomenon or the kinesiologic data. However, no study dealt with the simultaneous effect of the speed of movement on the spine rhythm and on the occurrence of the electrical silence of the erector spinae. METHODS: A total of 22 pain-free volunteers performed a series of trunk flexion-extension movements varying the speed and load. The motion of the lumbar spine ( degrees ) and the integrated electromyography (microV) of erector spinae muscles were simultaneously recorded. Two measures were calculated: the percentage of the maximum lumbar spine flexion at the instants when changes of electrical activity represented the beginning and end of the electrical silence and the relative lumbar spine motion time during trunk flexion and extension movements. RESULTS: The increase in speed of movement significantly increased the relative lumbar flexion time and significantly reduced the relative lumbar extension time (t = 2.49 and t = 2.25, P < 0.05); furthermore, it significantly delayed the appearance of the electrical silence in the range of flexion (t = 3.52, P < 0.01). There was no significant effect from a change in load. CONCLUSIONS: The relative spine motion time differed depending on the direction of movement, being longer during trunk flexion and shorter during extension. The increase in speed of movement produced greater differences in the relative time between trunk flexion and extension; furthermore, it delayed the appearance of the electrical silence of the erector spinae muscles in the range of flexion.     

Erector spinae plane block combined with local infiltration analgesia for total hip arthroplasty: A randomized,placebo controlled,clinical trial

The erector spinae plane block is an emerging analgesic technique, which is gaining popularity for a large number of procedures. The majority of publications are at the thoracic level and almost all indicate some benefit to patients. However, there have been relatively few randomized controlled trials and even fewer studies at the lumbar level. The aim of this study was to assess whether the erector spinae plane block at the lumbar level would confer early analgesic benefits and improve the quality of recovery in patients undergoing elective unilateral primary hip arthroplasty. Sixty-four patients were randomized to receive an erector spinae plane block at the third lumbar vertebra with either 30milliliters (ml) of 0.2% ropivacaine or 30 ml of 0.9% saline. The patient, anesthetist and assessor were blinded to allocation. The primary outcome was pain on movement at 6 h (numeric rating scale 0–10) with a reduction of 2 points considered clinically significant. Secondary outcomes included quality of recovery (QoR-15 score), mobilization and length of stay. In this study there was no appreciable analgesic benefit to adding an erector spinae plane block to patients who already receive neuraxial blocks, local anesthetic infiltration and oral multimodal analgesia for elective primary total hip arthroplasty. Both groups were found to have relatively low pain scores and a high quality of recovery with no significant difference in mobilization or length of stay.     

Prediction of trunk muscle areas and moment arms by use of anthropometric measures

The prediction of five internal muscle variables extracted from computed tomography scans was attempted using 27 anthropometric variables. Stable regression equations are presented for the prediction of the cross-sectional area of the rectus abdominis, psoas, and erector spinae, as well as for the moment arm of the erector spinae. No stable regression equation was found for the prediction of the moment arm of the rectus abdominis, and the results indicated that the method was group dependent. These findings have implications for human modeling studies that use estimated parameters for the internal muscle variables.     

Electromyographic activity of the abdominal and low back musculature during the generation of isometric and dynamic axial trunk torque: implications for lumbar mechanics.

This study focused on the electromyographic activity of the trunk musculature, given the well-documented link between occupational twisting and the increased incidence of low back pain. Ten men and 15 women volunteered for this study, in which several aspects of muscle activity were examined. The first aspect assessed the myoelectric relationships during isometric exertions. There was great variability in this relationship between muscles and between subjects. Further, the myoelectric activity levels (normalized to maximal electrical activity) obtained from nontwist activities were not maximal despite maximal efforts to generate axial torque (e.g., rectus abdominis, maximum voluntary contraction; 22% external oblique, 52%; internal oblique, 55%; latissimus dorsi, 74%; upper erector spinae [T9], 61%; lower erector spinae [L3], 33%). In the second aspect of the study, muscle activity was examined during dynamic axial twist trials conducted at a velocity of 30 and 60 degrees/s. The latissimus dorsi and external oblique appeared to be strongly involved in the generation of axial torque throughout the twist range and activity in the upper erector spinae displayed a strong link with axial torque and direction of twist, even though they have no mechanical potential to contribute axial torque, suggesting a stabilization role. The third aspect of the study was comprised of the formulation of a model consisting of a three-dimensional pelvis, rib cage, and lumbar vertebrae and driven from kinematic measures of axial twist and muscle electromyograms. The relatively low levels of normalized myoelectric activity during maximal twisting efforts coupled with large levels of agonist-antagonist cocontraction caused the model to severely underpredict measured torques (e.g., 14 Nm predicted for 91 Nm measured). Such dominant coactivity suggests that stabilization of the joints during twisting is far more important to the lumbar spine than production of large levels of axial torque.     

A randomised controlled trial of the non-inferiority of erector spinae plane block vs. thoracic paravertebral block for laparoscopic nephro-ureterectomy

Erector spinae plane block and paravertebral block can provide analgesia for abdominal surgery. It is unclear whether erector spinae block is inferior to paravertebral block. We aimed to determine whether sufentanil dose and pain intensity (11-point scale) to 24 h after erector spinae block exceeded those after paravertebral block by no more than 5 μg and 1 point, respectively. We randomly allocated 166 adults to 0.4 ml.kg⁻¹ ropivacaine 0.375% before scheduled laparoscopic nephroureterectomy, 83 each to erector spinae or paravertebral injection. We measured incision pain and intra-abdominal pain at rest and on movement 0.5 h, 2 h, 6 h, 18 h, 24 h and 48 h after surgery. Median (IQR [range]) cumulative sufentanil dose after erector spinae block was 15 (5–30 [0–105]) μg vs. 20 (10–50 [0–145]) μg after paravertebral block, median (95%CI) difference 5 μg (0–10), erector spinae non-inferiority p < 0.001. Median (IQR [range]) pain were 1.5 (1.0–2.0 [0.0–5.3]) after erector spinae block vs. 2.0 (1.0–2.5 [0.0–6.0]) after paravertebral block, median (95% CI) difference 0.3 (0.0–0.5), erector spinae non-inferiority p < 0.001. Adverse events did not differ between groups. Erector spinae block analgesia was not inferior to paravertebral block analgesia after laparoscopic nephroureterectomy.     

Psychodynamic aspects of corset treatment in adolescents

Based on 41 psychoanalytical interviews with 14 adolescent corset patients it was intended to analyse in a pilot study the individual experience, the handling of the corset and the influence of corset therapy on the adolescent development. The indication for proceeding to corset therapy was either due to Scheuermann's disease or scoliotic disease. Contrary to the doctor's instructions all patients examined only wore the corset during certain periods of time according to a time schedule fixed with the parents only, therefore lacking any official authorization. It also happened that the therapy was interrupted without further notice and that patients openly refused wearing the corsets any longer. As for the indication of orthese therapy, the authors recommend to take psychosocial aspects into account and submits concrete proposals as far as the care for the corset patients is conserned.     

Iatrogenic injury to the erector spinae during posterior lumbar spine surgery: underlying anatomical considerations,preventable root causes,and surgical tips and tricks

The approach-related morbidity resulting from iatrogenic erector spinae injury in posterior lumbar surgery has become an increasing concern for spine surgeons. Many studies have explained the injury mechanisms and reported new surgical approaches to prevent this iatrogenic injury from their own point of views, but there is still no systemic information for a thorough understanding of this iatrogenic erector spinae injury that may give spine surgeons practical advices in their individual operations. We consequently reviewed the literature on the anatomy of erector spinae, causes of injury, and relative minimally invasive approaches. We found that the local anatomic structures make the erector spinae vulnerable to injury during posterior lumbar surgery, especially the medial multifidus which is innervated only by the medial branch of the dorsal ramus, with no intersegmental nerve supply as in the other paraspinal muscles, and the injury factors mainly include dissection, retraction, denervation, and immobility. Studies suggest that the goal of prevention is to preserve the physiological structure of erector spinae and to avoid or limit the injury causes: approaches through spatium intermusculare and approaches with endoscope and tubular retractor system can prevent the erector spinae from injury by less dissection and retraction; non-fusion techniques may prevent the erector spinae from disuse atrophy by preserving the segmental motion and the adjacent erector spinae activity.     

Impact of waist/hip ratio on the therapeutic efficacy of lumbosacral corsets for chronic muscular low back pain

 A series of 143 new outpatients who had had chronic low back pain for longer than 3 months, with neither a positive straight leg raise test nor radiographic abnormality including lumbar spondylosis, were treated for 4 weeks with a traditional lumbosacral corset or one with a front-to-back tensile band (extensile corset). Randomization was performed according to birth date. Radiographs were used to analyze the change in sacral inclination angle with and without the respective corset. Central obesity subgroups consisted of men with a waist/hip ratio (W/H) of ≥90% and women with a W/H ratio of ≥80%. Quebec Back Pain Disability Scale scores were measured at baseline and at 4 weeks. The mean changes in sacral inclination were +3.8° ± 5.4° in the extensile corset group (n = 72) and −2.6° ± 4.6° in the traditional corset group (n = 71). Thus, the extensile corset had a mechanical effect opposite to that of the traditional corset. Participants without central obesity who were treated with the extensile corset (n = 30) demonstrated significant improvement compared to participants with the traditional corset (n = 33) (P = 0.034). Central obesity should be considered when recommending corsets for patients with chronic muscular low back pain. Received: April 18, 2002 / Accepted: July 12, 2002 Offprint requests to: Y. Toda