1468. Accuracy of pedicle screw placement using next-generation spinal robotics: evaluation of deviation from pre-planned trajectory

Authors: Bowen Jiang, MD; A Ahmed, BS; Corinna Zygourakis, MD; Alex Zhu, PA-C; Ali Bydon, MD; Neil Crawford, PhD; Nicholas Theodore, MD (Baltimore, MD)

Introduction: The ExcelsiusGPS ® (Globus Medical, Inc., Audubon, PA) is a next-generation real-time image-guided surgical robotic system approved for use in the United States. The objective of the current study is to assess pedicle screw accuracy and clinical outcomes among the first ten operative cases utilizing the ExcelsiusGPS ® robotic system and describe a novel metric to quantify screw deviation. Methods: Ten patients who underwent thoracic and/or lumbar fusion at a single institution with the ExcelsiusGPS ® surgical robot were included. Pre-operative trajectory planning was performed from an intra-operative CT scan using the O-arm (Medtronic, Inc., Minneapolis, MN). After robotic-assisted screw implantation, a post-operative CT scan was obtained to confirm ideal screw placement and accuracy with the planned trajectory. A novel pedicle screw accuracy algorithm was devised to measure screw tip/tail deviation distance and angular offset on axial and sagittal planes. Clinical variables such as symptomatology, operative data, and post-operative follow-up were also collected. Results: A total of 50 pedicle screws were instrumented in ten cases. Mean screw tip deviation was 2.7mm (range 0.5-5.2mm), mean tail deviation was 3.6mm (range 0.5-8.4mm), and mean angular offset was 4.8 degrees (range 0-16.2 degrees). There were no cases of screw revision or new post-operative deficit. 98% (49/50) of the screws were considered appropriately placed based on the Gertzbein-Robbins scale (88% Grade A and 10% Grade B). All patients experienced improvement in Frankel grade and Karnofsky Performance Status (KPS) score by 6 weeks post-op. Conclusion: The ExcelsiusGPS robot allows for accurate pedicle screw placement and acceptable execution of an intended pre-planned trajectory in the first patients to undergo robotic-assisted instrumentation with this technology.