Correlation Analysis between Idiopathic Scoliosis and Pelvic Asymmetry Using Sitting Posture Measurement System

The effects of pelvic asymmetry and idiopathic scoliosis on postural balance sitting were studied by measuring inclination angle and electromyography. Subjects were classified into a control group, pelvic asymmetry group, scoliosis group, and scoliosis with pelvic asymmetry and then performed anterior, posterior, and left-right pelvic tilting while sitting on the sitting posture measurement system for 5 seconds to assess their postural balance. Inclination and obliquity angles between the groups were measured by an accelerometer located on the system. Surface electrodes were attached to the erector spinae muscles of each participant. Inclination and obliquity angles increased more symmetrically in participants with both pelvic asymmetry and scoliosis than with pelvic asymmetry or scoliosis alone. Muscle contraction patterns of erector spinae muscles may be influenced by spine curve type and region of idiopathic scoliosis. Asymmetrical muscle activities were observed on the convex side of scoliotic patients and these muscle activity patterns were changed by the pelvic asymmetry. From these results, sitting posture measurement system may be utilized to assess the effects of asymmetrical postural balance and muscle activity caused by pelvic asymmetry and scoliosis on the physical activity of adolescent patients in their daily lives.