Fatemeh Azadinia - Department of Orthotics and Prosthetics, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
Ismail Ebrahimi-Takamjani - Department of Physical Therapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
Mojtaba Kamyab - Department of Orthotics and Prosthetics, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
Morteza Asgari - Department of Mechanical Engineering, Sharif University of technology, Tehran, Iran

Background: Lumbosacral orthosis (LSO) is commonly used for the treatment of back pain. The clinical andmechanical effectiveness of this device has been repeatedly investigated in several studies; however, its sensorimotoreffectiveness has been rarely considered. Regarding this, the aim of the current study was to investigate the effect ofa non-extensible LSO on postural stability (as a construct of sensorimotor function) in patients with nonspecific chroniclow back pain (LBP).Methods: This preliminary study was conducted on 17 patients with nonspecific chronic LBP using a single-groupquasi-experimental design. Postural stability was measured while the participants were placed in a quiet standingposition, under the combined conditions of base of support (rigid and foam surface), visual input (open eyes and closedeyes), and LSO (with and without orthosis).Results: The findings demonstrated that wearing orthosis during the most challenging postural task (i.e., blindfoldedwhile standing on a foam surface) significantly reduced postural sway parameters related to the position anddisplacement of the center of pressure (COP; the sway area and sway amplitude in the anteroposterior direction;P<0.001). However, the use of this device had no significant effect on COP velocity.Conclusion: As the findings of the present study indicated, the use of a non-extensible LSO decreased the COPdisplacement; however, it did not affect the COP velocity. Therefore, our data could not utterly support the effectivenessof non-extensible LSO on postural stability as a construct of sensorimotor function. Postural control is an appropriateindicator for assessing the global functioning of the sensorimotor system due to its dependence upon the interactionbetween the neural and musculoskeletal systems. Consequently, further studies are needed to elucidate the positiveeffects of LSO on the aspects of sensorimotor function.Level of evidence: III

LBP, orthotic device, Postural balance