Comparison of motion restriction and trunk stiffness provided by three thoracolumbosacral orthoses (TLSOs)

The amounts of thoracic and lumbar spine motion restriction and passive trunk stiffness provided by three thoracolumbosacral orthoses (TLSOs) (Aspen TLSO, Boston Body Jacket, and CAMP TLSO) were compared. Ten subjects executed maximum trunk flexion, extension, and lateral bending motions. The spine motion was measured noninvasively with a thin strain gauge device (Flexducer), and passive trunk stiffness around the neutral posture was estimated from an electromyography-assisted biomechanical model. No significant differences in either the restriction of motion or the amount of added passive trunk stiffness were found between the three orthoses. The subjects also did not perceive any difference in the restriction of motion but rated the Aspen TLSO significantly more comfortable than the other two orthoses. The rigid custom orthosis design may not be important for restricting the spine motion and providing passive trunk stiffness, or there may be other measures that reflect better the function of orthoses.