A Prospective Multicenter Registry on Clinical Value of the O-Arm® Imaging System and StealthStation® Navigation for Improving the Rate of Correct Thoracolumbar Pedicle Screw Placement

The reported accuracy of pedicle screw placement varies according to the used imaging technique. Anteroposterior and lateral fluoroscopy results in up to 40% of misplaced screws. The use of 2D fluoroscopic navigation reduces this to 4%. Also intra-operative neurophysiological monitoring is used to further reduce the incidence of screw misplacement. The final screw placement is only seen on a postoperative CT-scan. The O-arm 3D imaging combined with a navigation system increases the accuracy of screw placement, an intra-operative 3D scan indicates the need for adjustment of the screw placement before wound closure. Recently, some retrospective small sized clinical reports confirmed the great accuracy of pedicle screw placement, when using the navigation-O-arm combination. A cadaver study compared the intra-operative 3D O-arm images of the screw trajectory with the screw placement observed upon dissection. And the intra-operative surgeon’s perception of accurate screw placement, when the pedicle screw track was made with the help of O-arm based navigation. Surgeon’s perception matched the dissection results in 85% of the thoracic screws and in 88% of the lumbosacral screws, whereas intra-operative CT imaging only matched with the dissection findings in 81 % of cases. As such, the value of intra-operative CT-imaging as ultimate proof of correct pedicle screw placement can be questioned. Moreover, some authors and many clinicians are concerned about the radiation exposure for both patients and staff.