The Importance of the Pars Interarticularis as a Landmark for Safe Lumbar Pedicle Screw Placement: Technical Note.

The use of navigational adjuncts for pedicle screw placement has increased in popularity among surgeons with access to this technology. However, it remains important to have a comprehensive understanding of posterior bony element anatomy with respect to the location of the pedicle in order to ensure safe placement of pedicle screws. Proper exposure and identification of the pars interarticularis provide a helpful landmark during pedicle screw placement in order to confirm navigation accuracy and avoid misplaced instrumentation. In this technical note, we highlight the surgical anatomy of the pars interarticularis of the lumbar spine and its relationship to the lateral, inferior, and medial borders of the pedicle using diagrams and cadaveric dissections.