Evaluation of Movement Restriction of Spinal Orthoses Using Inertial Measurement Units

Despite the frequent use of orthopedic braces or spine stabilizers in diseases such as kyphosis, lordosis, and scoliosis, as well as in the case of injuries and rehabilitation after surgeries, there is no clear evidence of their proper stabilization of the spine while carrying out daily activities. This study sought to assess the spine's mobility while wearing three different orthopedic braces while performing basic tasks. Ten healthy subjects were enrolled. Three Inertial Measurement Units (IMUs) were attached superficially along the spine at approximate levels: cervical (C7), between thoracic (T8) and lumbar (L3), and sacrum. The angle between sensors was monitored to provide data on the sagittal profile. In addition, the displacement of the spine's longitudinal axis was measured (rotation). There are three types of orthopedic braces: the semi-rigid Hohmann corset, the Jewett brace, and the Thoracolumbar Fixed Spinal Orthosis (TLSO). Four tasks were monitored: standing, sitting, walking, and picking up an item from the floor with one hand. All braces provided a similar level of stability in both the sagittal plane and rotational axis while lifting an object. On the other hand, while walking and sitting, the TLSO was the only orthosis providing a statistically significant rigidity in the sagittal plane. When performing a more voluntary task, the measured rigidity of softer braces was significantly increased when compared with more involuntary tasks. A certain degree of motion restriction with spinal orthoses may come from the feedback pressure, which stimulates paraspinal muscles to contract and thus increases the overall rigidity of the trunk.