Answer to the Letter to the Editor of F. Xiao, et al. concerning “Reliability and accuracy of scoliotic parameters on using a wireless handheld 3D ultrasound for children with adolescent idiopathic scoliosis: a pilot study” by Nguyen TNN, et al. (Eur Spine J [2024]; doi:10.1007/s00586-024-08445-w)