Fig. 1

A On an axial CT scan, the axial location of pedicle screw implantation in the medio-lateral direction (indicated by the red line) and the anterior–posterior direction (indicated by the green line) within the vertebral body. B On CT axial view, the distribution of cement within the vertebral body was classified into four zones. C–F. A magistral form of basivertebral foramen (a large, single centrally located foramen with a width/height of ≥ 5 mm). D–H. A disperse form of basivertebral foramen (multiple small nutrient foramina). I. Local ECL on axial CT image (cement meniscus only at the nutrition foramen). J. Extensive ECL on axial CT image (cement mass surpassing the limits of the nutrition foramen in the posterior wall of the vertebral body, or leakage in the canal measuring over 2 mm in thickness). ECL epidural cement leakage