How Does Lumbosacral Orthosis Affect Trunk Muscles

Background: Wearing lumbosacral orthosis (LSO) is one of the most common treatments prescribed for conservative management of low back pain. While 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. The present review aimed to evaluate available evidence in literature to determine whether LSO result in trunk muscle weakness and/or atrophy.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, investigating the effect of lumbar orthosis on trunk muscle activity, muscle thickness, strength/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.Results: Thirty-five studies fulfilled the eligibility criteria. The mean and SD of the quality score was 64 ± 9.7%. Most studies investigating the effect of lumbar orthosis on electromyography activity (EMG) of trunk muscles demonstrated a decrease or no change in the EMG parameters. A few studies reported increased muscle activity. LSO was found to have no effect on muscle strength in some studies, while other studies demonstrated increased muscle strength. Out of eight studies that investigated spinal compression load, the load was reduced in four studies, and unchanged in three studies. One study revealed reduced compression force only with the use of an elastic belt compared with leather and fabric belts, so ascribed this result to the elastic property of the lumbar support.Conclusion: This review did not find conclusive scientific evidence to suggest that orthosis results in trunk muscle weakness

Keywords:

lumbosacral orthosis , trunk muscles