Mobile device-based 3D scanning is superior to scoliometer in assessment of adolescent idiopathic scoliosis

Purpose: Screening for adolescent idiopathic scoliosis (AIS) currently relies on clinical evaluations by trained practitioners, most commonly using a scoliometer. Modern structured light 3D scanning can generate high-quality 3D representations of surface anatomy using a mobile device. We hypothesized that a mobile-based 3D scanning system would provide accurate deformity assessments compared to a scoliometer.

Methods: Between August 2020 and June 2022, patients 10-18 years being evaluated for AIS in our clinic with a scoliosis radiograph obtained within 30 days of clinic evaluation and no history of spinal surgery were enrolled. Patients had 3D scans taken in the upright and forward bend positions, and the largest angle of trunk rotation (ATR) was measured by a scoliometer. Image processing software was used to analyze trunk shift (TS), coronal balance (CB), and clavicle angle (CL) in the upright position and the largest ATR in the forward bend position. 3D and scoliometer measurements were correlated to major curve magnitude. Multiple logistic regression models were created based on 3D and scoliometer measurements, controlling for demographic covariates.

Results: Two hundred and fifty-eight patients were included in this study. Mean coronal major curve magnitude was 25.7° (range 0-100), and 59% had a thoracic major curve. There were good-to-excellent correlations between 3D and radiographic measures of TS, CB, and CL (r = 0.79, rs = 0.80, and r = 0.64, respectively, p < 0.001). Correlations between 3D and radiographic measures of largest lumbar and thoracic ATR also demonstrated good correlations (r = 0.64 for both, p < 0.001). Using Akaike's Information Criterion (AIC), a multivariable logistic regression model based on 3D scanning outperformed a scoliometer model.

Conclusions: Mobile device-based 3D scanning of TS, CB, and TS identifies clinically relevant scoliotic deformity and is more predictive of radiographic curve magnitude than scoliometer in this population. This new modality may facilitate scoliosis screening by decreasing the need for trained personnel or dedicated equipment and clinical space to perform screening tests.

Level of evidence: II.