Feasibility Trial of Novel Headset-Based Augmented Reality Navigation System in Thoracic Pedicle Screw Placement

Introduction: Augmented reality (AR) navigation is an emerging technology with significant potential to enhance the accuracy and safety of surgical procedures. Placement of thoracic pedicle screws is a common but complex surgical technique with inherent risk of screw malposition, which can lead to poor patient outcomes. This study aims to determine the feasibility of a novel headset-based AR navigation system to assist in thoracic pedicle screw placement in comparison to traditional anatomic freehand technique.

Methods: A total of 21 thoracic vertebral levels across 2 cadavers were 3D modeled based on preoperative CT and registered to their corresponding specimens. Pre-planned start and end points for pedicle screw trajectory were labeled on each 3D model. One side of the exposed cadaveric vertebral level was instrumented utilizing the AR system, and the contralateral side was instrumented using traditional freehand technique. Postoperative CT scans of the specimens were obtained and analyzed for pedicle screw accuracy. Acceptability of the thoracic screw implants was determined by Gertzbein-Robbins scoring grade "A" or "B", and the groups were compared using Fisher exact test. Technical accuracy of the AR system was determined by measuring deviation in millimeters (mm) from the pre-planned start point to the actual pedicle screw position on postoperative CT.

Results: The technical accuracy of the AR system was 3.18 +/- 1.87 mm. The AR group resulted in 18/21 screws deemed acceptable (85.7% success rate), and the traditional anatomic freehand group resulted in 15/21 screws deemed acceptable (71.4% success rate). These groups were not significantly different based on Fisher exact testing (p = 0.4537).

Conclusion : This cadaveric pilot study supports the technical feasibility of this novel AR navigation technology for thoracic pedicle screw implantation and demonstrates potential for a future portable spinal navigation system. Future studies aim to improve accuracy, workflow, and expand to lumbar and cervical applications.