Pedicle Screws Challenged: Lumbar Cortical Density and Thickness Are Greater in the Posterior Elements Than in the Pedicles.

Extrapedicular regions of the lumbar vertebrae, including the lamina and inferior articular process, contain denser bone than the pedicles. Since screw pullout strength relies greatly on bone density, the lamina and inferior articular processes may offer stronger fixation of the lumbar spine.