3D Topographic Measurements to Assess Spinal Mobility in Adolescent Idiopathic Scoliosis Patients

Adolescent Idiopathic Scoliosis (AIS) patients are often exposed to ionizing radiation which may contribute to the 3-4 times greater incidence of cancer in this population. Here we seek to compare lateral and forward flexion measurements using a 30 camera stereo-photogrammetric system (3dMD) between AIS patients and controls as a first step towards establishing a new set of trunk measurements that does not require ionizing radiation.

Informed consent was obtained from patients with spinal deformity and matching controls to undergo 3dMD based scans. A finger to floor scan was performed after positioning the patient in Adam’s forward bending posture whereby they were instructed to reach for the floor to their maximum extent. A lateral bending scan was performed after positioning the patient in the A-pose. The subject was asked to bend to the left to their maximum extent and then bend to the right to their maximum extent while reaching their fingers to the floor. An analysis of covariance (ANCOVA) was used to test the hypothesis that AIS patients and controls would exhibit differences in these bending parameters.

80 AIS patients and 29 controls were included in this analysis of four lateral bending measures and two forward bending measures. The finger to floor coronal asymmetry (p=0.01), AC coronal asymmetry (p=0.003), and angle coronal asymmetry (p=0.006) were significantly different between AIS patients and controls whereby the patients exhibited more asymmetry. The coronal angle ROM (p=0.223), forward sagittal angle normalized (p=0.137) and forward AC to floor average (p=0.195) were not significantly different between groups.

3D topographic scanning of the trunk during bending was shown to distinguish AIS patients from controls and is an efficient and safe measure of spine range of motion that can be incorporated in the management of AIS patients.