P21. Lumbar percutaneous pedicle screw breach rates: a comparison of robotic navigation versus conventional techniques

Abstract

BACKGROUND CONTEXT Pedicle screw fixation is an established means of stabilizing the thoracic and lumbar spine. Computer-assisted navigation has been demonstrated to improve the accuracy of pedicle screw placement. Few studies have compared screw breach rates using navigated robotic platforms. PURPOSE The goal of this study is to determine if the use of a navigated robotic platform, Excelsius GPS™ (Globus Medical, Inc., Audubon, PA), minimizes pedicle breach in comparison to conventional techniques, and to determine why breach rates differ between these two techniques. STUDY DESIGN/SETTING Cadaveric study. METHODS Ten board-certified neuro- and orthopaedic spine surgeons inserted 80 percutaneous lumbar screws in 10 unembalmed human cadavers. Forty screws were inserted using conventional fluoroscopic guidance; 40 were inserted using a navigated robotic platform. None of the participating surgeons had prior experience with navigated robotic spine surgery. At the end of the study, each screw was assessed with CT scans, plain radiographs, and visual inspection to determine the presence or absence of pedicle breaches. RESULTS Forty percent (16/40) of screws inserted using conventional fluoroscopic guidance breached the pedicle compared to 2.5% (1/40) of screws inserted with robot assistance (p=0.00005). High-grade breaches accounted for 17.5% (7/40) of screws inserted using fluoroscopic guidance. No high-grade breaches were observed in screws inserted using robotic assistance. High-grade breaches were defined as Gertzbein-Robbins grade C, D or E. Lateral breaches accounted for 88.2% (15/17) of all breaches. A subgroup analysis was performed of the 14 fluoroscopic screws that breached laterally. Detailed analyses revealed that the starting points of screws that breached laterally were significantly more lateral than those of the contralateral accurate screws (p=0.016). Pedicle screw diameter, length, and angulation in the transverse plane did not differ significantly between accurate screws and those that breached (p>0.05). Of the total 80 screws placed, robotic navigation allowed for use of both larger diameter (6.3±0.5mm vs. 6.6±0.6mm, p CONCLUSIONS Use of a navigated robotic platform allows surgeons to identify an appropriate entry point, plan the pedicle screw trajectory based on that entry point, and execute insertion of the pedicle screw in a safe manner, which in the context of the current study resulted in a significantly lower pedicle breach rate compared to conventional techniques. FDA DEVICE/DRUG STATUS Excelsius GPS (Approved for this indication).