Abstract
Background: Relaxation of paraspinal muscles at the end of flexion range of motion known as flexion-relaxation phenomenon is not present in patients with chronic low back pain (CLBP). Persistent activation of erector spinae muscles throughout flexion in CLBP patients (i.e. lack of FRR) may be a muscular adaptation and or protective strategy indicating patients’ attempt to enhance trunk stiffness and subsequently provide spine stability. It is hypothesized that loss of deep intrinsic muscles control can lead to erector spine muscles hyperactivity. Lumbosacral orthoses (LSO) are expected to decrease erector spinae muscle activity through providing passive trunk stiffness and trunk stability, and thereby return the normal flexion-relaxation pattern.
Objectives: This study aimed to investigate the effects of extensible and non-extensible lumbosacral orthoses (LSO) on clinical outcomes and erector spinae muscles performance in patients with CLBP.
Methods: A randomized clinical trial without a control group, recruiting 40 patients with CLBP was conducted. The patients were randomly allocated to two groups: extensible or non-extensible LSO. Pain intensity (Visual Analog Scale: VAS), physical function (Oswestry Disability Index: ODI), fear of movement (Kinesiophobia), back extensors endurance, and flexion-relaxation ratios were measured at baseline, and after four weeks of intervention in both groups.
Results: Based on mixed-model ANOVA, time × group interactions were not significant for any of the outcome measures. The main effect of time (pre versus post) was significant for pain (F = 62.06, P < 0.001, ηp² = 0.62), physical activity (F = 48.27, P < 0.001, ηp² = 0.56), fear of movement (F = 9.79, P = 0.003, ηp² = 0.2), and back extensors endurance (F = 22.44, P < 0.001, ηp² = 0.37). However, no significant effect of group was observed for any of the outcome measures.
Conclusion: Wearing an LSO, extensible or non-extensible, for 4 weeks significantly improved pain, physical function, kinesiophobia, and extensors endurance. There was no adverse effect on muscle performance, however, it was not able to return normal flexion relaxation pattern in this population.
Keywords
Low Back Pain Orthotic Devices Electromyography Back Muscles
Copyright
© 2024, Author(s). This open-access article is available under the Creative Commons Attribution 4.0 (CC BY 4.0) International License (https://creativecommons.org/licenses/by/4.0/), which allows for unrestricted use, distribution, and reproduction in any medium, provided that the original work is properly cited.