IMU-Driven Dynamic Spine Model Based on Kinematics and CT for Home-Based PSSE of Idiopathic Scoliosis

Idiopathic scoliosis (IS) is a prevalent spinal deformity that impairs posture and psychosocial health. Physiotherapeutic scoliosis-specific exercise (PSSE) is an effective conservative treatment that needs long-term and regular training. However, academic demands, geographic barriers, and time constraints limit frequent clinic visits, making home-based PSSE the mainstay of care. Also, the lack of supervision makes correct execution and sustained adherence difficult, posing a major challenge in spinal rehabilitation. To address this issue, we innovatively equate the spine as an open-chain spatial multibody kinematic mechanism and propose an IMU-driven, kinematics- and CT-integrated dynamic spine model (KCT-DSM). By fusing real-time motion data with CT-derived anatomical information, KCT-DSM enables continuous tracking of spinal kinematics. Further, we develop a home-based PSSE rehabilitation training system integrating KCT-DSM and PSSE. A preliminary feasibility evaluation was conducted in patients with IS. The Cobb-like angle derived from KCT-DSM differs from X-ray measurements by 1.56$^{\circ }$, suggesting that KCT-DSM provides motion tracking of spinal deformity with different scoliosis patterns. In addition, when using the training system, the effective duration of standard rehabilitation exercises increased by 45.7% in the pilot cases. Overall, the proposed system has potential for providing quantitative feedback and supporting home-based PSSE training.