Morphometric characteristics of pedicles of the immature spine.

The morphometric characteristics of pedicles from T12 to S1 were measured from a review of 203 computerized tomographic scans of children 3 to 20 years of age. The pedicles of the lower lumbar spine (L4, L5, and S1) reached transverse extracortical pedicle diameters of 1 cm by the time the child reached 7 years of age. The pedicles of the upper lumbar spine (T12, L1, L2, and L3) did not reach similar size until the child reached 12 years of age. The data from this study suggest pedicular screw insertion, especially of the L5 and S1 vertebrae, is technically possible in young children.