Intraoperative 3D imaging system in spine surgery: evaluation after 2 years with a retropective analysis of 586 pedicle screws

Purpose : The goals of this paper are to assess the clinical utility and accuracy of a novel intraoperative 3D imaging system for evaluation of pedicle screws positon, and to evaluate and compare the efficacy of this system versus conventional post-operative CT scan. Methods: Intraoperative 2D/3D imaging systems associated or not with navigation system was utilized to place the pedicle screws. An intraoperative 3D cbCT was obtained after all screws were inserted. Two surgeons have retrospectively and independently reviewed all the images to evaluate the position of screw according to breaches classification system. A postoperative CT scan was performed for some patients and was reviewed by a third operator with the same classification to compare the accuracy of these two imaging control. Results: The position of 586 pedicle screws was analysis. Four hundred ninety-six screwsv(84.6%) were grade 1, twenty-four screws (4.1%) were grade 2, twenty-one screws (3.6%) were grade 3, ten screws (1.7%) were grade 4, four screws (0.7%) were grade 5, five screws (0.9%) were grade 6 and twenty-six screws (4.4%) were grade 7. Total percent of breach was 15.4%. Seventeen screws were repositioned intraoperatively after the 3D control, one of us presented at follow-up paresthesia of the big toe. Test of Kappa had showed almost a prefect agreement (0.82) between gold standard (CT scan) and new intraoperative 2D/3D cbCT imaging system. Conclusion: This new intraoperative technic evaluating position of pedicle screws in cbCT images is a feasible and reliable means, and could render the postoperative CT scan control superfluou