Radiation-free 3D assessment of back height differences via three-dimensional depth sensing in adolescent idiopathic scoliosis: prospective, single-center, observational study

Abstract

Purpose: Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) spinal deformity that can lead to serious physical and psychological effects, making early and accurate detection essential. Back height difference (BHD) represents a promising parameter for non-invasive scoliosis assessment using 3D depth-sensing systems. This study aimed to evaluate the reliability and clinical utility of BHD using a 3D depth-sensing imaging system to assess AIS and its correlation with clinical indicators. Methods: This study is a prospective, single-center, observational study. Thirty-six patients with AIS were enrolled to compare the reliability between the scoliosis measuring scale and a 3D depth-sensing imaging system. Additionally, 128 patients were included to evaluate the correlation of BHD with the angle of trunk rotation (ATR) and the Cobb angle. Results: BHD showed excellent reliability (intraclass correlation coefficient > 0.90), strong correlation with ATR (R ≤ 0.874; p < 0.001), and moderate correlation with Cobb angle (R ≤ 0.653; p < 0.001). Subgroup analyses showed the highest correlation in thoracic curves. BHD was sensitive in detecting advanced deformities and maintained strong correlations in mild curves. Conclusion: Although not a substitute for radiographs, BHD provides a radiation-free tool for early AIS screening and management, with good reproducibility and alignment with radiographic and trunk rotation measures. Notably, its radiation-free nature aids in reducing exposure among pediatric cohorts. Trial registration: Clinicaltrials.gov NCT06717568 (20241205).