P.128 Percutaneous cortical screws: a novel approach to posterior spinal stabilization

Abstract

Background: Pedicle screw (PS) fixation is considered the gold-standard for spine stabilization. However, minimally invasive surgery (MIS) and cortical screw (CS) fixation have become commonplace. The biomechanical and safety profiles of CS compared to PS have yet to be determined. To our knowledge, this is the first study to describe a novel percutaneous CS approach and compare its safety and accuracy to PS fixation. Methods: Standard percutaneous PS fixation was performed using fluoroscopy from L1-L5 on one-side with percutaneous CS being placed on the other-side (10-instrumented PS and CS levels each). Anatomical confirmation and comparison of pedicle breach incidence was performed afterward via open dissection. Results: Dissection revealed no breaches of either construct. As such, no statistical comparison was possible. At one-level however, a CS was seen breaching the posterior-third lateral vertebral body under the superior end-plate. A couple of exposed screw threads were visualized well away from any entering and/or exiting foraminal or extra-spinal neurovascular structures. Conclusions: MIS and CS-based constructs are relatively new fixation techniques. We describe a novel percutaneous CS technique incorporating advantages of both MIS and CS-constructs. Although no difference was found in pedicle breach incidence, further study comparing these techniques and rigorous patient selection for application are necessary.