Discriminant analysis of neuromuscular variables in chronic low back pain

Background: Investigation and discrimination of neuromuscular variables related to the complex aetiology of low back pain could contribute to clarifying the factors associated with symptoms. Objective: Analysing the discriminative power of neuromuscular variables in low back pain. Methods: This study compared muscle endurance, proprioception and isometric trunk assessments between women with low back pain (LBP, n=14) and a control group (CG, n=14). Multivariate analysis of variance and discriminant analysis of the data were performed. Results: The muscle endurance time (s) was shorter in the LBP group than in the CG (p=0.004) with values of 85.81 (37.79) and 134.25 (43.88), respectively. The peak torque (Nm/kg) for trunk extension was 2.48 (0.69) in the LBP group and 3.56 (0.88) in the GG (p=0.001); for trunk flexion, the mean torque was 1.49 (0.40) in the LBP group and 1.85 (0.39) in the CG (p=0.023). The repositioning error (degrees) before the endurance test was 2.66 (1.36) in the LBP group and 2.41 (1.46) in the CG (p=0.664), and after the endurance test, it was 2.95 (1.94) in the LBP group and 2.00 (1.16) in the CG (p=0.06). Furthermore, the variables showed discrimination between the groups (p=0.007), with 78.6% of the individuals with low back pain correctly classified in the LBP group. In turn, variables related to muscle activation showed no difference in discrimination between the groups (p=0.369). Conclusion: Based on these findings, the clinical management of low back pain should consist of both resistance and strength training, particularly in the extensor muscles.

Self-reported moderate-to-vigorous leisure time physical activity predicts less pain and disability over 12 months in chronic and persistent low back pain

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Prevalence of low back pain and associated factors in adults from a middle-size Brazilian city

Objective: To determine the prevalence of low back pain and some related variables among adults of both genders. Methods: Was conduct a cross-sectional study of population-based in the urban area of Presidente Prudente, São Paulo. The sample consisted of 743 adult residents for over two years in this city. Low back pain, quality of sleep and physical activity were collected through face to face interview at the residence of respondents. Was used the chi-square test to analyze the association between variables, later was created tree multivariate models with hierarchical inclusion of confounding factors. Results: The prevalence of low back pain reported last year was 50.2% (95% CI: 46.6, 53.8), and the last week 32.3% (95% CI: 28.9, 35.6). Was association among low back pain and females (p-value = 0.031), older age, lower education, altered sleep and overweight, the adjusted model found that people over the age of 45 years (45 to 59.9 years, OR = 13.1 [1.72-98.5] and ≥ 60 years, OR = 9.10 [1.15-71.7]), with some alteration of sleep (OR = 3.21 [1.84-5.61]) and obese (OR = 2.33 [1:26 to 4:33]) seems to be a risk group for low back pain. Conclusion: The prevalence of low back pain is high and obese people aged over 45 years, with any sleep disturbance are a group at higher risk for low back pain.

Relationship between therapeutic alliance and deep abdominal muscle recruitment in nonspecific low back pain sufferers

Chronic low back pain is a difficult condition to be treated. As some patients respond positively to treatment and others do not present any improvements, one can think there are others conditional factors that need to be elucidated. By means of this study, we sought to investigate the association between the occurrence of the formation of a positive relationship between patient and therapist, assessed by the therapeutic alliance inventory, and the adequate recruitment of the deep abdominal muscles, as well as to verify the effect of a protocol intervention based on motor control exercises on levels of pain and disability. The recruitment of the transverse abdominal and internal oblique muscles was examined by ultrasound imaging in 12 subjects with nonspecific chronic low back pain before and after implementation of a protocol for motor control exercises, with subsequent application of the therapeutic alliance inventory questionnaire. No association was found between the level of therapist/patient alliance and muscle recruitment. The proposed protocol was effective in reducing the levels of pain and disability; however, recruitment of transverse abdominal and internal oblique muscles showed no significant changes in the end of the intervention. Based on these findings, we verified that the therapeutic alliance has no association with muscle recruitment in the short term. However, although there were no changes in muscle recruitment after the intervention program, the level of pain and disability was reduced.

The relationship between obesity, low back pain, and lumbar disc degeneration when genetics and the environment are considered: a systematic review of twin studies

BACKGROUND CONTEXT: The relationships between obesity and low back pain (LBP) and lumbar disc degeneration (LDD) remain unclear. It is possible that familial factors, including genetics and early environment, affect these relationships.PURPOSE: To investigate the relationship between obesity-related measures (eg, weight, body mass index [BMI]) and LBP and LDD using twin studies, where the effect of genetics and early environment can be controlled.STUDY DESIGN: A systematic review with meta-analysis.METHODS: MEDLINE, CINAHL, Scopus, Web of Science, and EMBASE databases were searched from the earliest records to August 2014. All cross-sectional and longitudinal observational twin studies identified by the search strategy were considered for inclusion. Two investigators independently assessed the eligibility, conducted the quality assessment, and extracted the data. Metaanalyses (fixed or random effects, as appropriate) were used to pool studies'estimates of association.RESULTS: In total, 11 articles met the inclusion criteria. Five studies were included in the LBP analysis and seven in the LDD analysis. For the LBP analysis, pooling of the five studies showed that the risk of having LBP for individuals with the highest levels of BMI or weight was almost twice that of people with a lower BMI (odds ratio [OR] 1.8; 95% confidence interval [CI] 1.6-2.0; I-2 = 0%). A dose-response relationship was also identified. When genetics and the effects of a shared early environment were adjusted for using a within-pair twin case-control analysis, pooling of three studies showed a reduced but statistically positive association between obesity and prevalence of LBP (OR 1.5; 95% CI 1.1-2.1; I-2 = 0%). However, the association was further diminished and not significant (OR 1.4; 95% CI 0.8-2.3; I-2 = 0%) when pooling included two studies on monozygotic twin pairs only. Seven studies met the inclusion criteria for LDD. When familial factors were not controlled for, body weight was positively associated with LDD in all five cross-sectional studies. Only two cross-sectional studies investigated the relationship between obesity-related measures and LDD accounting for familial factors, and the results were conflicting. One longitudinal study in LBP and three longitudinal studies in LDD found no increase in risk in obese individuals, whether or not familial factors were controlled for.CONCLUSIONS: Findings from this review suggest that genetics and early environment are possible mechanisms underlying the relationship between obesity and LBP; however, a direct causal link between these conditions appears to be weak. Further longitudinal studies using the twin design are needed to better understand the complex mechanisms underlying the associations between obesity, LBP, and LDD.

Massage application for occupational low back pain in nursing staff

This is a clinical trial which aims to evaluate the efficiency of massage in the reduction of occupational low back pain, and its influence on the performance of work and life activities for the nursing team. The sample consisted of 18 employees who received seven to eight sessions after their work period. From the Numerical Pain Rating Scale, significant improvements were found between the 3rd and 1st evaluations (p=0.000) and between the 3rd and 2nd (p=0.004), using the Wilcoxon test. Regarding the Oswestry Disability Index, the paired t test showed a statistical difference (p=0.02) between the baseline, with a mean of 21.33% and the second evaluation (18.78%), which was also seen between the second and third evaluation (16.67%). The score for the Handling and Transfer Risk Evaluation Scale was 18 points (medium risk). It is concluded that massage was effective in reducing occupational low back pain, and provided improvement in activities of work and life. Clinical Trials Identifier: NCT01315197.

EFFECTS OF MUSCULAR STRETCHING AND SEGMENTAL STABILIZATION ON FUNCTIONAL DISABILITY AND PAIN IN PATIENTS WITH CHRONIC LOW BACK PAIN: A RANDOMIZED, CONTROLLED TRIAL

Objective: The purpose of this study was to compare the effects of 2 exercise programs, segmental stabilization exercises (SSEs) and stretching of trunk and hamstrings muscles, on functional disability, pain, and activation of the transversus abdominis muscle (TrA), in individuals with chronic low back pain. Methods: A total of 30 participants were enrolled in this study and randomly assigned to 1 of 2 groups as a function of intervention. In the segmental stabilization group (SS), exercises focused on the TrA and lumbar multifidus muscles, whereas in the stretching group (ST), exercises focused on stretching the erector spinae, hamstrings, and triceps surae. Severity of pain (visual analog scale and McGill pain questionnaire) and functional disability (Oswestry disability questionnaire) and TrA muscle activation capacity (Pressure Biofeedback Unit, or PBU) were compared as a function of intervention. Interventions lasted 6 weeks, and sessions happened twice a week (30 minutes each). Analysis of variance was used for intergroup and intragroup comparisons. Results: As compared with baseline, both treatments were effective in relieving pain and improving disability (P < .001). Those in the SS group had significantly higher gains for all variables. The stretching group did not effectively activate the TrA (P = .94). Conclusion: Both techniques improved pain and reduced disability. In this study, SS was superior to muscular stretching for the measured variables associated with chronic low back pain. (J Manipulative Physiol Ther 2012;35:279-285)

Efficacy of graded activity versus supervised exercises in patients with chronic non-specific low back pain: protocol of a randomised controlled trial

Abstract Background Low back pain is a relevant public health problem, being an important cause of work absenteeism worldwide, as well as affecting the quality of life of sufferers and their individual functional performances. Supervised active physical routines and of cognitive-behavioral therapies are recommended for the treatment of chronic Low back pain, although evidence to support the effectiveness of different techniques is missing. Accordingly, the aim of this study is to contrast the effectiveness of two types of exercises, graded activity or supervised, in decreasing symptoms of chronic low back pain. Methods/design Sample will consist of 66 patients, blindly allocated into one of two groups: 1) Graded activity which, based on an operant approach, will use time-contingent methods aiming to increase participants’ activity levels; 2) Supervised exercise, where participants will be trained for strengthening, stretching, and motor control targeting different muscle groups. Interventions will last one hour, and will happen twice a week for 6 weeks. Outcomes (pain, disability, quality of life, global perceived effect, return to work, physical activity, physical capacity, and kinesiophobia) will be assessed at baseline, at treatment end, and three and six months after treatment end. Data collection will be conducted by an investigator blinded to treatment allocation. Discussion This project describes the randomisation method that will be used to compare the effectiveness of two different treatments for chronic low back pain: graded activity and supervised exercises. Since optimal approach for patients with chronic back pain have yet not been defined based on evidence, good quality studies on the subject are necessary. Trial registration NCT01719276

Test-retest reliability of the nociceptive withdrawal reflex and electrical pain thresholds after single and repeated stimulation in patients with chronic low back pain

Recent studies have shown that the nociceptive withdrawal reflex threshold (NWR-T) and the electrical pain threshold (EP-T) are reliable measures in pain-free populations. However, it is necessary to investigate the reliability of these measures in patients with chronic pain in order to translate these techniques from laboratory to clinic. The aims of this study were to determine the test-retest reliability of the NWR-T and EP-T after single and repeated (temporal summation) electrical stimulation in a group of patients with chronic low back pain, and to investigate the association between the NWR-T and the EP-T. To this end, 25 patients with chronic pain participated in three identical sessions, separated by 1 week in average, in which the NWR-T and the EP-T to single and repeated stimulation were measured. Test-retest reliability was assessed using intra-class correlation coefficient (ICC), coefficient of variation (CV), and Bland-Altman analysis. The association between the thresholds was assessed using the coefficient of determination (r (2)). The results showed good-to-excellent reliability for both NWR-T and EP-T in all cases, with average ICC values ranging 0.76-0.90 and average CV values ranging 12.0-17.7%. The association between thresholds was better after repeated stimulation than after single stimulation, with average r (2) values of 0.83 and 0.56, respectively. In conclusion, the NWR-T and the EP-T are reliable assessment tools for assessing the sensitivity of spinal nociceptive pathways in patients with chronic pain.

The course of chronic and recurrent low back pain in the general population

Using latent class analysis (LCA), a previous study on patients attending primary care identified four courses of low back pain (LBP) over the subsequent 6 months. To date, no studies have used longitudinal pain recordings to examine the "natural" course of recurrent and chronic LBP in a population-based sample of individuals. This study examines the course of LBP in the general population and elaborates on the stability and criterion-related validity of the clusters derived. A random sample of 400 individuals reporting LBP in a population-based study was asked to complete a comprehensive questionnaire at the start and end of the year's survey, and 52 weekly pain diaries in between. The latter were analyzed using LCA. 305 individuals returned more than 50% of the diaries. Four clusters were identified (severe persistent, moderate persistent, mild persistent, and fluctuating). The clusters differed significantly with regards to pain and disability. Assessment of cluster stability showed that a considerable proportion of patients in the "fluctuating" group changed their classification over time. Three of the four clusters describing the typical course of pain matched the clusters described previously for patients in primary care. Due to the population-based design, this study achieves, for the first time, a close insight into the "natural" course of chronic and recurrent low back pain, including individuals that did not necessarily visit the general practitioner. The findings will help to understand better the nature of this pain in the general population.

Cost of low back pain in Switzerland in 2005

Low back pain (LBP) is the most prevalent health problem in Switzerland and a leading cause of reduced work performance and disability. This study estimated the total cost of LBP in Switzerland in 2005 from a societal perspective using a bottom-up prevalence-based cost-of-illness approach. The study considers more cost categories than are typically investigated and includes the costs associated with a multitude of LBP sufferers who are not under medical care. The findings are based on a questionnaire completed by a sample of 2,507 German-speaking respondents, of whom 1,253 suffered from LBP in the last 4 weeks; 346 of them were receiving medical treatment for their LBP. Direct costs of LBP were estimated at 2.6 billion and direct medical costs at 6.1% of the total healthcare expenditure in Switzerland. Productivity losses were estimated at 4.1 billion with the human capital approach and 2.2 billion with the friction cost approach. Presenteeism was the single most prominent cost category. The total economic burden of LBP to Swiss society was between 1.6 and 2.3% of GDP.