Digital twin for the analog scoliometer: advancements in telehealth for paediatric spine deformity care

In scoliosis care, a spine specialist will measure the lateral curvature of the spine from a radiograph and measure the torso rotation non-radiographically with an analog scoliometer directly on the patient at every surveillance appointment. While radiographs can be taken at any imaging centre and transferred to the treating spine clinic, the patient must visit in-person for monitoring the progression of structural rotation. Until now, distance measurement of the Angle of Trunk Rotation (ATR) has not been possible as no "virtual" scoliometer exists. This study describes the development of the first digital twin for the analog scoliometer to enable fast, gravity-independent, reliable and accurate digital ATR measurements from patient-specific 3D virtual models. It mimics the physical measurement process of the ATR using an analog scoliometer in a virtual environment. Validation of the tool showed excellent intra-user (< 0.95) and inter-user (< 0.95) reliability. The digital measurements had a high positive correlation (0.897) and agreement (92.7%) with the analog measurements made clinically. At 6° cut-off, the tool showed a high sensitivity of 90.24% and specificity of 92.31%. Larger device width was not shown to be an advantage. The development of this digital twin is significant for telehealth implementation in paediatric spine deformity management.