Author(s): ZHANG, X., LIN, Y., LIAO, B., Institution: GUANGZHOU SPORT UNIVERSITY, Country: CHINA, Abstract-ID: 888

INTRODUCTION:
Asynchronous growth of muscle and skeleton is a well-recognized risk factor for curve progression in adolescent idiopathic scoliosis (AIS), often resulting in a vicious cycle. Studies indicate that a reduction in the paraspinal muscle mass is the primary contributor for the disparity in growth rates between muscle and skeleton. Therefore, improving the muscle mass under spinal–pelvic alignment becomes the key for treatment. Although studies have shown that the Schroth Method could control the severity of the curves, the lack of quantification of skeletal and muscle changes during exercise limits its reproducibility, as the specificity of the deformity frequently relies on the subjective experience of the therapist.We aimed to quantify the changes in the skeletal and paravertebral muscles of patients with AIS during Schroth exercise using three-dimensional ultrasound reconstruction.
METHODS:
Patients with a single type of Cobb angle in the thoracic curvature of 20°–45° were included in this cross-sectional study. We used muscle cylinder, door handle exercise, self-corrective standing, and self-corrective sitting postures to compare habitual standing with habitual sitting postures and observe changes in spinal alignment and muscle volume parameters. Metrics including paravertebral muscle volume (cm3) of the upper end vertebrae (UEV), apex vertebrae (AV), and lower end vertebrae (LEV) were captured, with simultaneous recordings of the ultrasound curve angle (UCA), ultrasound spinous process angle (SPA), and axial vertebral rotation (AVR).
RESULTS:
Overall, 15 participants were included. The results showed that all four corrective postures decreased the UCA (p < 0.05). Self-corrective standing (p = 0.01) and muscle cylinder (p = 0.01) decreased the TSPA in patients with Rigo A. Self-corrective sitting (p < 0.001), door handle exercise (p = 0.03), and muscle cylinder (p = 0.01) increased the LSPA. Door handle exercise improved the AVR (p = 0.03). Self-corrective standing increased the muscle volume on the concave (p = 0.03) and the convex (p = 0.02) of the AV, and increased the muscle volume on the concave (p = 0.02) and the convex (p = 0.04) of the UEV. Muscle cylinder increased the muscle volume on the concave (p = 0.02) and the convex (p = 0.01) of UEV. Self-corrective sitting increased the muscle volume on the convex (p = 0.03) of the LEV and the convex (p = 0.02) of the UEV. Door handle exercise increased the muscle volume on the convex (p = 0.03) of AV and the convex (p = 0.01) of UEV.
CONCLUSION:
Self-corrective standing, Muscle cylinder, Self-corrective sitting, and Door handle exercise all decreased the coronal plane angle, sagittal plane parameters, and paravertebral muscle symmetry, whereas they partially improved the horizontal plane parameters. Therefore, these postures may intensify sagittal plane and paravertebral muscle imbalances in AIS patients with Rigo A who should be cautiously treated in clinical applications.