Fig. 1

Morphologic imaging evaluation using 3D reconstruction software (Synapse Vincent® version 6.1; FUJIFILM Medical Co., Ltd., Tokyo, Japan). a The software automatically generated a three-dimensional (3D) reproduction of the whole spine. b The observer manually isolated the vertebral bodies and cuts out the pedicles in a plane perpendicular to the pedicle axis through the isthmus. c The pedicle height and width in both the cortical and cancellous bones in APEX±1 and NV ± 1 were measured using the cross section of the pedicles of the 3D spinal model. APEX±1, the region of the apical vertebra and its two adjacent vertebrae; NV ± 1, the region of the cranial NV and its two adjacent vertebrae; H, cortical pedicle height; h, cancellous pedicle height; W, cortical pedicle width; w, cancellous pedicle width. d Overview of the thoracic model bone. e T10 thoracic vertebra image was cut in a plane containing isthmus, orthogonal to the anatomical pedicle axis. H, pedicle height; W, pedicle width. The laterality ratio of the pedicle diameter of the cortical bone width was defined as Lt.W/Rt.W, and the laterality ratio of the pedicle diameter of the cancellous bone width was defined as Lt.W/Rt.W. The laterality ratio of the pedicle diameter of the cortical bone height was defined as Lt.H/Rt.H, and the laterality ratio of the pedicle diameter of the cancellous bone width was defined as Lt.h/Rt.h