Comparison of Three-Dimensional Fluoroscopy versus Postoperative Computed Tomography for the Assessment of Accurate Screw Placement after Instrumented Spine Surgery

Abstract

While intraoperative three-dimensional fluoroscopy does not possess the resolution and image quality of computed tomography (CT), it may provide adequate information about screw placement to guide intra- and postoperative decision making. We compared the accuracy of intraoperative three-dimensional fluoroscopy visualization of proper screw placement with that of postoperative CT. We retrospectively reviewed spinal instrumentation procedures done using the O-arm (Medtronic, Minneapolis, MN, USA) that also had postoperative CT. All screws were assessed for placement accuracy on O-arm and CT images on a 4-point scale. In this study, 20 cases met the inclusion criteria. Thirteen breaches (11 grade 1 and 2 grade 2) were identified on O-arm images, and 14 breaches (10 grade 1, 3 grade 2, and 1 grade 3) were identified on CT. Sensitivity, specificity, and positive and negative predictive values were 93, 99, 99, and 98%, respectively. The Kappa value (0.96) suggested a very high degree of agreement between three-dimensional fluoroscopy and CT in determining accuracy of screw placement. These findings may allow less frequent use of postoperative CT scans, improving cost effectiveness in patients who require spinal instrumentation procedures and potentially decreasing the number of patients who require replacement of an inappropriately positioned screw.

A new 3-dimensional method for measuring precision in surgical navigation and methods to optimize navigation accuracy

“…Also, with the added confidence of the navigation, screw placement was attempted in all pedicles, even if they may have otherwise been deemed too small or difficult without the navigation. In the end, the accuracy of O-arm images for evaluation of instrumentation placement has been found to be comparable to a postoperative CT scan [41][42][43], and the number of screws felt to be in an appropriate position was comparable to previously reported data. All grade III/IV breaches were noted to be lateral, which is likely due to the ability for direct visualization of more difficult pedicles and placement of instrumentation toward the safer lateral cortex.…”

Economics of image guidance and navigation in spine surgery

“…[ 29 ] Reoperation rates were reported to be 0% in four of the seven studies (57.14%). [ 7 8 9 32 ] Only two of the six studies revealed whether the costs reported were inclusive of the entire hospital stay or solely for the operation. [ 6 29 ] There was only one study that we were able to find that performed an incremental cost-effectiveness ratio (ICER),[ 6 ] which found no significant cost-effective difference in the use of preoperative spiral CT scan and intraoperative O-arm.…”

“…Although many authors have shown support for the use of IGS, there is a scarcity of literature reporting the costs associated with spinal navigation or comparative studies showing cost differences between various interventions. [ 1 2 3 7 13 17 21 27 ] The biggest advantage of spinal navigation is the decreased rate of reoperation. Four of the seven studies analyzed show a zero rate of reoperation.…”

Accuracy of pedicle screw placement in the thoracic and lumbosacral spines using O-arm-based navigation versus conventional freehand technique

“…Previous studies demonstrated that the O-arm imaging system combined with the StealthStation navigation system could markedly increase the accuracy of pedicle screw placement and clinical outcomes [2,3,5,6,[9][10][11][12][13]. Rivkin et al [6] performed a retrospective review of 266 patients who underwent thoracolumbar pedicle screw fixation utilizing the O-arm-guided navigation system and concluded that the overall breach rate was 5.3% (87/1651), including 6.6% thoracic pedicle screws and 5.1% lumbar pedicle screws.…”

“…Recently, to reduce the need for, and perhaps avoid, reoperative screw revision, surgeons have begun to perform intraoperative O-arm scanning after screw insertion (instead of postoperative CT) to evaluate the position along the screw trajectory with axial, sagittal, and coronal views, thereby allowing revision of suboptimal screw position prior to leaving the operating room [5,10,11,16,17] (Fig. 2).…”