Background: Wearing lumbosacral orthosis (LSO) is one of the most common treatments prescribed for conservative management of low back pain. Although the results of randomized controlled trials suggest effectiveness of LSO in reducing pain and disability in these patients, there is a concern that prolonged use of LSO may lead to trunk muscle weakness and atrophy.
Purpose: The present review aimed to evaluate available evidence in literature to determine whether LSO results in trunk muscle weakness or atrophy.
Study design: This is a systematic review.
Methods: A systematic search of electronic databases including PubMed, Scopus, ScienceDirect, and Medline (via Ovid) followed by hand search of journals was performed. Prospective studies published in peer-reviewed journals, with full text available in English, investigating the effect of lumbar orthosis on trunk muscle activity, muscle thickness, strength or endurance, spinal force, and intra-abdominal pressure in healthy subjects or in patients with low back pain, were included. Methodological quality of selected studies was assessed by using the modified version of Downs and Black checklist. This research had no funding source, and the authors declare no conflicts of interest-associated biases.
Results: Thirty-five studies fulfilled the eligibility criteria. The mean and standard deviation of the quality score was 64±9.7%. Most studies investigating the effect of lumbar orthosis on electromyographic activity (EMG) of trunk muscles demonstrated a decrease or no change in the EMG parameters. A few studies reported increased muscle activity. Lumbosacral orthosis was found to have no effect on muscle strength in some studies, whereas other studies demonstrated increased muscle strength. Only one study, which included ultrasound assessment of trunk muscle stabilizers, suggested reduced thickness of the abdominal muscles and reduced cross-sectional area of the multifidus muscles. Out of eight studies that investigated spinal compression load, the load was reduced in four studies and unchanged in three studies. One study showed that only elastic belts reduced compression force compared to leather and fabric belts and ascribed this reduction to the elastic property of the lumbar support.
Conclusion: The present review showed that the changes in outcome measures associated with muscle work demands were inconsistent in their relation to the use of lumbar supports. This review did not find conclusive scientific evidence to suggest that orthosis results in trunk muscle weakness.
Keywords: Compression load; Electromyography; Intra-abdominal pressure; Lumbosacral orthoses; Muscle weakness; Systematic review.
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