The Use of Back Belts to Increase Intraabdominal Pressure as a Means of Preventing Low Back Injuries: A Survey of the Literature

The Use of Negative Acceleration as Accessory Force during Lifting

OBJECTIVES

Injury associated with lifting, especially low back injury, is a big problem in industry that accounts for loss of work and high medical expenses. Studies of biomechanics of lifting provide a basis for optimization of lifting. The aim of the study was to further investigate the role of the upward force due to negative acceleration during a lift.

METHODS

Nine healthy subjects lifted an empty box and a box with additional load of 10, 20, and 25 lb. Kinematic data were recorded during the lifts and accelerations were calculated, and angular positions of the trunk and knee were obtained during the lifting when negative accelerations were used.

RESULTS

Negative acceleration assisted the quadriceps when the thighs were at approximately 90° and the hips when the trunk was rotating toward standing position. Negative acceleration was present during lifts of different loads.

CONCLUSION

The outcome of the study suggests that enhancing the use of negative acceleration could be a strategy to improve the quality of lifting and minimize a probability of low back injury.

The orthotic treatment of acute and chronic disease of the cervical and lumbar spine

BACKGROUND

Orthoses are external aids that are often used to treat pain and diseases affecting the spine, such as lumbago, whiplash, and disc herniation. In this review, we assess the effectiveness and complications of orthotic treatment for typical spinal conditions and after spinal surgery. The orthotic treatment of fractures and postural abnormalities are beyond the scope of this article.

METHOD

This review is based on a selective search in the Medline database with consideration of controlled trials, systematic reviews, and the recommendations of the relevant medical societies.

RESULTS

Three relevant systematic reviews and four controlled trials were found. Very few controlled trials to date have studied the efficacy of orthotic treatment compared to other conservative treatments and surgery. No definitive evidence was found to support the use of orthoses after surgery, in lumbar radiculopathy, or after whiplash injuries of the cervical spine. In a single trial, short-term immobilization was an effective treatment of cervical radiculopathy. Orthoses are not recommended for nonspecific low back pain. The potential complications of cervical orthoses include pressure-related skin injuries and dysphagia.

CONCLUSION

No definitive evidence as yet supports the use of orthoses after spinal interventions or in painful conditions of the cervical or lumbar spine. They should, therefore, be used only after individual consideration of the indications in each case.

Effects of the pelvic compression belt on gluteus medius, quadratus lumborum, and lumbar multifidus activities during side-lying hip abduction

The aims of this study were to assess the effect of the pelvic compression belt on the electromyographic (EMG) activities of gluteus medius (GM), quadratus lumborum (QL), and lumbar multifidus (LM) during side-lying hip abduction. Thirty-one volunteers (15 men and 16 women) with no history of pathology volunteered for this study. Subjects were instructed to perform hip abduction in side-lying position with and without applying the pelvic compression belt. The pelvic compression belt was adjusted just below the anterior superior iliac spines with the stabilizing pressure using elastic compression bands. Surface EMG data were collected from the GM, QL, and LM of the dominant limb. Significantly decreased EMG activity in the QL (without the pelvic compression belt, 60.19±23.66% maximal voluntary isometric contraction [MVIC]; with the pelvic compression belt, 51.44±23.00% MVIC) and significantly increased EMG activity in the GM (without the pelvic compression belt, 26.71±12.88% MVIC; with the pelvic compression belt, 35.02±18.28% MVIC) and in the LM (without the pelvic compression belt, 30.28±14.60% MVIC; with the pelvic compression belt, 37.47±18.94% MVIC) were found when the pelvic compression belt was applied (p<0.05). However, there were no significant differences of the EMG activity between male and female subjects. The findings suggest that the pelvic compression belt may be helpful to prevent unwanted substitution movement during side-lying hip abduction, through increasing the GM and LM and decreasing the QL.

Back belt use for prevention of occupational low back pain: a systematic review

BACKGROUND

Back pain continues to be the leading overall cause of morbidity and lost productivity in the workplace. Recently, there has been a renewed interest in the use of back belts by industry to reduce occupational low back pain (LBP).

OBJECTIVES

To examine the literature and evaluate the effectiveness of back belt use for the primary prevention of occupational LBP.

METHODS

MEDLINE, CINAHL, EMBASE, and HEALTHSTAR were searched for relevant articles published up to July 2003. Studies were included if participants were material handlers, and outcomes included the incidence and/or duration of lost time of reported LBP among workers who wore back belts compared with those who did not. The quality of the evidence was scored independently by 2 reviewers using a double rating method, first according to research design followed by an internal validity rating. Final synthesis of the evidence was performed in which the evidence was classified as good, fair, conflicting, or insufficient.

RESULTS

Ten epidemiologic studies meeting inclusion criteria were identified. Of 5 randomized controlled trials, 3 showed no positive results with back belt use; 2 cohort studies had conflicting results; and 2 nonrandomized controlled studies and 1 survey showed positive results.

CONCLUSIONS

Currently, because of conflicting evidence and the absence of high-quality trials, there is no conclusive evidence to support back belt use to prevent or reduce lost time from occupational LBP.

Mechanisms of action of lumbar supports: a systematic review

STUDY DESIGN

A systematic review and meta-analysis of studies on the putative mechanisms of action of lumbar supports in lifting activities.

OBJECTIVE

To summarize the evidence bearing on the putative mechanisms of action of lumbar supports.

SUMMARY OF BACKGROUND DATA

A restriction of trunk motion and a reduction in required back muscle forces in lifting are two proposed mechanisms of action of lumbar supports. Available studies on these putative mechanisms of action of lumbar supports have reported contradictory results.

METHODS

A literature search for controlled studies on mechanisms of action of lumbar supports was conducted. The methodologic quality of the studies was assessed. The evidence for the two proposed mechanisms of action of lumbar supports was determined in meta-analyses.

RESULTS

Thirty-three studies were selected for the review. There was evidence that lumbar supports reduce trunk motion for flexion-extension and lateral bending, with overall effect sizes of 0.70 (95% confidence interval [CI] 0.39-1. 01) and 1.13 (95% CI 0.17-2.08), respectively. The overall effect size for rotation was not statistically significant (0.69; 95% CI -0. 40-4.31). There was no evidence that lumbar supports reduce the electromyogram activity of erector spinae muscles (effect size of 0. 09; 95% CI -0.41-0.59) or increase the intra-abdominal pressure (effect size of 0.26; 95% CI -0.07-0.59).

CONCLUSION

There is evidence that lumbar supports reduce trunk motion for flexion-extension and lateral bending. More research is needed on the separate outcome measures for trunk motion before definite conclusions can be drawn about the work conditions in which lumbar supports may be most effective. Studies of trunk motion at the workplace or during specified lifting tasks would be especially useful in this regard.

Reduction of Acute Low Back Injuries by Use of Back Supports

The objective of this study was to determine the effect of a change in back-support-use policy on the occurrence of work-related low back injuries among a large cohort of employees in the retail-trade home improvement industry. Working hours of exposure, back support use, and intensity of materials-lifting requirements were collected from 1989 through 1994. Records of injury-related claims were reviewed for all documented injuries to the lower back among members of the cohort during the same period. Over 101,000,000 working hours were recorded by nearly 36,000 employees; 2,152 employees reported an acute low back injury occurring during working hours as a first report of episode, with medical-physician diagnosis and acute/abrupt onset. Incidence density rates were calculated for persons wearing and not wearing the back support. Rate ratios and prevented fractions were evaluated. Before implementation of a company-wide back-support policy, the employees had a rate of acute low back injuries of 30.6 per million working hours. After implementation, this rate fell to 20.2 per million working hours, a significant reduction of 34.0%. This effect was seen in both genders, in younger workers and in those aged 55+, with low levels of lifting as well as high lifting intensities, and in persons with one to two years of employment with the company. The authors conclude that uniform mandatory implementation of a back-support-use policy significantly reduces the incidence of acute low back injuries incurred in the workplace.