Postural recovery following voluntary arm movement is impaired in people with chronic low back pain

Study design

Recovery of postural equilibrium following bilateral voluntary arm movement was evaluated using a case-control study, with 13 subjects with chronic LBP and 13 age- and gendermatched control subjects.

Objectives

To evaluate control of the centre-of-pressure (COP), as a marker of the quality of control of postural equilibrium associated with voluntary arm movements, in people with and without LBP. Summary of background data. When healthy individuals perform rapid voluntary arm movements, small spinal movements (preparatory movement) opposite to the direction of the reactive moments precede voluntary arm movements. Evaluation of trunk movement in people with LBP suggests that this strategy is used infrequently in this population and is associated with an increased spinal displacement following arm flexion. As the preparatory spinal movement was also thought to be an anticipatory mechanism limiting postural perturbation caused by arm movements, we hypothesized that LBP subjects would have compromised control of postural equilibrium following arm flexion.

Methods

Subjects performed bilateral voluntary rapid arm flexion while standing on support surface of different dimensions with eyes opened or closed.

Results

Results indicated that people with LBP consistently took longer to recover postural equilibrium and made more postural adjustments in different stance conditions. However, there was no increase in the excursion of the COP during the recovery period in the LBP group.

Conclusion

These data suggest that while COP is tightly controlled during postural recovery, the finetuning of the control of postural equilibrium is compromised in people with LBP. Postural control dysfunctions should be considered in the management of chronic low back pain.     

Postural sway in children: A literature review

Background and aimStatic posturography can serve as an easy and fast way to determine whether a child possesses sufficient balance control in different sensory conditions. Therefore, the aim of this review is to map age-related differences in postural sway during childhood in typically developing children, using static posturography and to provide an overview of the available (age-specific) reference values in scientific literature.MethodsThe search strategy was performed in five databases (Pubmed, Web of Science, ScienceDirect, Cochrane Clinical Trials, Medline (Ovid)) November 2nd 2014 and updated twice: March 16th 2015 and July 20th 2015. The following keywords were used: (children OR child) AND (“postural control” OR “postural stability” OR equilibrium OR posture OR “postural balance”[mesh]) AND (“quiet stance” OR standing OR stance OR “quiet stance” OR static) AND (“postural sway” OR posturography OR “body sway” OR stabilography OR “trunk sway” OR “medio-lateral sway” OR “antero-posterior sway”). Relevant studies were identified using predefined selection criteria, applied on title and abstract (phase 1) and on full text (phase 2), supplemented with reference screening after the second phase.ResultsA total of 14 studies met the criteria. This review showed three main findings: 1) during natural bipedal stance with the eyes open, all studies reported a decrease in postural sway with increasing age, with conflicting results on the (non-)linearity of its development, 2) with eyes closed, all children show more sway than with eyes open and 3) only four studies reported numeric sway values that could serve as reference values, mainly focusing on children aged five and older.ConclusionConsiderable disagreement exists on the (non-)linearity of the development of postural sway in children. By choosing arbitrary age categories, it remains unclear between which age groups differences are situated. Future research is necessary to determine for which age groups age-specific reference values are relevant.     

Influence of dual tasks on sitting postural sway in children and adolescents with myelomeningocele

Performing dual tasks, e.g. cognitive and motor tasks simultaneously, may be especially challenging to children with motor disorders. Changes in postural sway have been used to evaluate the effect of dual tasks. Increases in postural sway frequency and concurrent decrease in sway amplitude have been interpreted as tighter control of postural sway. The purpose of this study was to analyze postural sway under single and dual task conditions, while sitting. Thirteen children and adolescents with myelomeningocele and a matched control group were included in the study. The participants performed two single and two dual tasks each. The single task was a sitting still task. The dual tasks were one visual-spatial task and one executive task while simultaneously sitting still. Amplitude, velocity and frequency of center of pressure displacement of postural sway were analyzed between tasks and between groups. The results of the cognitive tasks were analyzed as well. The results revealed different patterns in the groups. During single tasks, the MMC group displayed significantly lower frequencies and velocities of center of pressure displacement compared to the control group. Adding the visual-spatial task influenced postural sway significantly in the control group, while adding the executive task influence the postural sway significantly in the MMC group. The myelomeningocele group confirmed our clinical experience by performing the cognitive tasks slowly but accurately. Further studies are needed to evaluate whether motor function, sensory function, structural anomalies in the brain or any other causes, separately or together, may explain the observed differences in the groups.     

Influence of dual tasks on sitting postural sway in children and adolescents with myelomeningocele

Performing dual tasks, e.g. cognitive and motor tasks simultaneously, may be especially challenging to children with motor disorders. Changes in postural sway have been used to evaluate the effect of dual tasks. Increases in postural sway frequency and concurrent decrease in sway amplitude have been interpreted as tighter control of postural sway. The purpose of this study was to analyze postural sway under single and dual task conditions, while sitting. Thirteen children and adolescents with myelomeningocele and a matched control group were included in the study. The participants performed two single and two dual tasks each. The single task was a sitting still task. The dual tasks were one visual-spatial task and one executive task while simultaneously sitting still. Amplitude, velocity and frequency of center of pressure displacement of postural sway were analyzed between tasks and between groups. The results of the cognitive tasks were analyzed as well. The results revealed different patterns in the groups. During single tasks, the MMC group displayed significantly lower frequencies and velocities of center of pressure displacement compared to the control group. Adding the visual-spatial task influenced postural sway significantly in the control group, while adding the executive task influence the postural sway significantly in the MMC group. The myelomeningocele group confirmed our clinical experience by performing the cognitive tasks slowly but accurately. Further studies are needed to evaluate whether motor function, sensory function, structural anomalies in the brain or any other causes, separately or together, may explain the observed differences in the groups.     

Postural sway following cryotherapy in healthy adults

In light of the wide use of cryotherapy and its potential negative effects on postural stability, little is known about how postural sway is affected, particularly when the whole lower limb is immersed. The purpose of this study was to analyze the influence of cryotherapy on postural sway in healthy males. Twenty-six subjects were randomly assigned into two intervention groups: control (tepid water at ∼26 °C) or ice (cold water at ∼11 °C). Postural sway was measured through the center of pressure (COP) position while they stood on a force plate during bipedal (70 s) and unipedal (40 s) conditions before and after the subjects were immersed in a water tub up to the umbilical level for 20 min. COP standard deviation (SD) and COP velocity were analyzed in the anterior–posterior (AP) and medial–lateral (ML) directions. Statistical analysis showed that in the bipedal condition cryotherapy increased the COP SD and COP velocity in the ML direction. During the unipedal condition, a higher COP velocity in the AP and ML directions was also reported. Our findings indicate that cryotherapy by immersing the whole lower limb should be used with caution before engaging in challenging postural control activities.     

Patients with chronic non-specific low back pain have altered movement coordination during functional reaching tasks

BackgroundIdentifying altered motor control patterns during functional movements in patients with chronic non-specific low back pain (LBP) has important clinical implications for reducing the risk of recurrence. While prior research has shown that magnitudes of lumbar and hip motion are not altered in patients with chronic non-specific LBP, it is possible that outcomes which describe coordination could provide greater discriminatory information between pathological and healthy movement.Research questionDetermine the effect of biological sex and chronic non-specific LBP on coordination between hip and lumbar motion during cyclic and discrete reaching.MethodsTwenty participants with chronic non-specific LBP (11 male/9 female, 23.5 ± 4.9 years old) and 21 control participants (12 male/9 female, 22.9 ± 6.1 years old) completed discrete and cyclic reaching tasks to a target in the mid-sagittal plane, while whole-body kinematics were collected using a three-dimensional motion capture system. Movement time, lumbar motion, hip motion, and the ratio between lumbar and hip motion were compared between participants with and without chronic non-specific LBP and between men and women using two-way mixed ANOVAs.ResultsParticipants with chronic non-specific LBP had reduced lumbar-hip ratios relative to control participants during both the cyclic (F = 4.779, p = 0.035, η² = 0.114) and discrete tasks (F = 4.743, p = 0.036, η² = 0.119), however group differences were not observed for hip or lumbar excursion during either task (p > 0.05). Participants with chronic non-specific LBP had slower reaching times relative to controls during the discrete reaching task (F = 4.795, p = 0.035, η² = 0.115). No significant effects of sex, and no interactions between group and sex were observed for any outcome.SignificanceReduced lumbar-hip ratios during reaching likely reflect a compensatory movement strategy that could play an important role in the development and progression of LBP.     

Etiology of low back pain in athletes

Low back pain and injury is a common affliction for patients involved in athletic endeavors. For this reason, the health care professional should be cognizant of age-related and sports-specific considerations when evaluating athletes with low back complaints. An elevated index of suspicion with regard to specific etiologies of back pain proves invaluable in order to avoid the misdiagnosis of a more serious problem. Although a number of conditions exist that require more aggressive evaluation and treatment, the majority of low back pain in athletes is self-limiting. In this context, a treatment plan designed to increase low back and abdominal muscle strength, flexibility, and range of motion often proves beneficial not only in returning the athlete to competition, but also in preventing injury recurrence.     

Recurrent postdiskectomy low back pain: MR-surgical correlation

The preoperative MR findings in 11 patients, all of whom had developed recurrent low back pain after surgery for herniated lumbar intervertebral disk, were correlated with the surgical findings to determine possible criteria for distinguishing recurrent disk herniation from postoperative scar (extradural fibrosis). The preoperative MR findings agreed with the surgical findings in seven of eight patients with recurrent disk herniation and in six of nine individuals with extradural fibrosis. The most important parameters in differentiating recurrent herniated disk from extradural scar were the configuration and margination of the extradural mass rather than its signal characteristics. The most reliable MR sign for recurrent herniated disk was the presence of a sharply marginated focal polypoid disk protrusion beyond the posterior margins of the adjacent vertebral bodies shown to best advantage on sagittal T1- and T2-weighted and axial T1-weighted spin-echo MR images. Disk herniations usually maintained isointensity with the intervertebral disk of origin, while extradural fibrosis exhibited variable signal intensity. The preoperative diagnosis of extradural fibrosis on MR was based primarily on its irregular configuration and extension. This study suggests that preoperative differentiation between scar and recurrent herniated disk is possible with MR when morphology and topography are considered in addition to signal intensity.     

Functional restoration in chronic low back pain

Conventional treatments have not slowed down the ever expanding low back pain (LBP) problem. Traditional treatment has most probably contributed to the growth of the problem. Therefore, in a search for new solutions, 'functional restoration' has been devised. In connection with chronic LBP the term has been associated with a full-day program lasting from 3 to 5 weeks. it includes multidisciplinary treatment of patients in groups with intensive physical and ergonomic training, psychological pain management, back school, as well as teaching in social/work related issues. The key concepts are 'acceptance of the pain', 'activity', 'self-responsibility', 'multidisciplinary' and 'quantitative functional evaluation (QFE)'. The latter is aimed so that the participants can feel the physical improvement, encouraging them to be able to go back to work, or at least to lead a more active life style. Several controlled studies suggest a lasting effect in terms of regaining their ability to work and improving pain behavior for a good part of disabled chronic LBP patients. However, it is noteworthy that randomized studies seemingly show poorer results than studies not employing randomized controls.     

Physcial exercise and low back pain

Health care providers often prescribe exercises as treatment for nonspecific low back pain. However, the effectiveness of this treatment is poorly documented in the literature. While the evidence suggests that exercise in general is beneficial, there is a lack of knowledge about the types, frequency and duration of exercises that should be prescribed and at what stage of injury they are most helpful. In addition, few studies have dealt with exercise treatment alone rather than in combination with other treatments, making it hard to decipher the unique contribution of exercise. Inadequate study designs also make conclusions difficult. Conversely, the literature clearly shows that inactivity has detrimental effects (i.e. delayed return to normal activity, and negative physiological and psychological effects) for low back pain patients.     

战士下腰痛的流行病学研究

目的：初步掌握战士下腰痛流行病学,为防治提供参考。方法：随机整群抽取驻西南某部战士1000名,进行个人、工作、心理及下腰痛调查。对下腰痛患者另行VAS和Oswestry功能障碍指数调查。结果：该群体中下腰痛的点患病率为30.4%,年患病率为38.4%;下腰痛患者SCL-90各项因子得分均显著高于对照组;回归分析显示体重、下腰痛史、外伤史、工龄、A工种和躯体化是下腰痛的相关危险因素,焦虑是保护因素;慢性下腰痛患者Oswestry功能障碍指数和VAS评分均最高。结论：战士下腰痛患病率高;亚急性和慢性下腰痛患者心理健康状况较差,功能障碍和疼痛显著,需重点防治。     

腰骶移行椎:与下腰疼的关系

目的评估自发性骨关节炎中腰骶移行椎的发生率与程度,评估腰骶移行椎与下腰部及臀部疼痛的联系,评估腰骶移行椎分级的可重复性。材料与方法研究经单位伦理委员会批准,获得病人的知情同意。4636例自发性骨性关节炎病人(男1992例,女2804例,年龄45～80岁)进行常规立位骨盆平片检查,包括L5双侧横突,并按照Castellvi标准进行分级。评价腰骶移行椎的发病率及其与下腰和臀部疼痛的相关性。结果腰骶移行椎的发病率为18.1%(841/4636),男性发病率高于女性(分别为28.1%和11.1%,P<0.001)。在841例腰骶移行椎中,41.72%属Ⅰ型(发育不良的宽大横突),41.4%属Ⅱ型(假关节型),11.5%属Ⅲ型(融合型),5.2%属Ⅳ型(一侧横突融合一侧假关节型)。无腰骶移行椎的受试者中,53.9%存在下腰部疼痛;而在Ⅰ、Ⅱ、Ⅲ和Ⅳ型腰骶移行椎者中下腰疼的发病率分别为46%、73%、40%和66%(χ2检验,P<0.05)。Ⅱ和Ⅳ型病人下腰及臀部疼痛的发病率较高,程度更重(P<0.001)。结论Ⅱ和Ⅳ型腰骶移行椎与下腰及臀部疼痛的发病率和严重性相关。     

Postural control measured as the center of pressure excursion in young female gymnasts with low back pain or lower extremity injury

Gymnasts are known to practice and compete although suffering from injuries and pain. Pain may change strategies for postural control. The primary aim of the present study was to investigate how center of pressure (COP) measurements are influenced by low back pain and lower extremity injury in top-level female gymnasts. A secondary aim was to study the reliability of these measurements using a test-retest design, and how this depends on the duration of the test. Fifty-seven top-level gymnasts were included in four groups: non-injured (NI, n=18), low back pain (LBP, n=11), lower extremity injury (LEI, n=17) and a multiple injury group (MI, n=11). COP excursion during quiet stance was measured on a force platform, during 120s: (1) hard surface/eyes open, (2) hard surface/eyes closed, (3) foam surface/eyes open and (4) foam surface/eyes closed. The COP excursion increased, for all groups, during the foam surface/eyes closed measurement compared to the other three tests. Furthermore, the LBP group showed a 49% (p=0.01) larger COP area compared to the LEI group in the foam surface/eyes closed condition. Measurements on foam surface were in general more reliable than tests on hard surface and tests with eyes closed were more reliable than tests with eyes open. Tests during 120s were in most cases more reliable than tests during 60s. In conclusion the COP excursion is influenced by injury location. Quiet stance measurements on foam surface with eyes closed seems to be reliable and sensitive in young female gymnasts.     

Measurements and evaluations in low back pain patients

With the present review of literature, the authors intended to compare the definition terms, selection criteria, and measurement tools or methods used in different studies related to chronic low back pain (CLBP) patients. The relevance of including all the above information is that any health-care professional can use them to evaluate their treatment methods with CLBP patients or use them in study designs according to their objectives. These measurements concern pain measurements, measures that were used to describe the CLBP pain, questionnaires used to measure the CLBP patients' responses to pain, the pain effects on their living activities, and also measurements of the physical abilities and functional performance. A computerized literature search in English MEDLINE was conducted using "low back pain," and "flexibility, "strength,"evaluation,"functional level," and "measurements" as search words. Identified abstracts were scanned, and useful articles were acquired for further review. Interms of CLBP definitions, the authors concluded that is best defined as a lumbar, sacral, or lumbosacral spinal pain that is continuous or essentially continuous but low level punctuated by exacerbations of pain, each of which is characterized as "acute." In order to establish the criteria for selecting participants in a study design related to CLBP, pain characteristics and clinical diagnoses have to be taken into consideration for obtaining homogeneity of groups. Finally, the selection of measurement tools and evaluation methods is related to the study's goals, the specialization of the researchers, and their validity.