![]() C-arm) as well as the detector technology (image-intensifier vs. Furthermore, there are differences between the available CBCT systems, like gantry size and form (O-arm vs. The iCT, in general, has the advantage of a higher image resolution and a larger FOV, whereas with CBCT the radiation dose for the patient is lower and the use of the device more feasible 24, 25, 26. While CBCT has been performed for about two decades and especially the O-arm (Medtronic, Dublin, Ireland) in combination with StealthStation navigation (Medtronic, Dublin, Ireland) seems to be widely used in spine surgery, iCT-based navigation has been increasingly applied in recent years since the introduction of the mobile iCT Airo (Brainlab, Munich, Germany) and Curve navigation (Brainlab, Munich, Germany) 23. ![]() While spinal navigation solutions are available from different manufacturers, integrated imaging and navigation systems from the same manufacturer are most commonly used in combination 23. For intraoperative 3D imaging, either Cone Beam CT (CBCT) or intraoperative CT (iCT) imaging can be used and both result in the intraoperative generation of a 3D dataset, yet, besides the technical aspect, these methods differ in terms of field of view (FOV) and image quality 18, 19, 20, 21, 22. The available literature contains several studies including systematic reviews and meta-analyses showing a significantly lower risk for screw malposition in 3D navigated PS placement compared to both freehand and fluoroscopy-controlled techniques 13, 14, 15, 16, 17.įor 3D navigation, an intraoperative 3D imaging device as well as a compatible navigation system is needed. The aforementioned reasons and the trend towards minimally invasive techniques have led to the increasing use of intraoperative 2D and 3D imaging and navigation in PS placement 9, 10, 11, 12. However, the accuracy rates available in the literature differ substantially 8. The accuracy of freehand PS placement is generally considered acceptable. ![]() Another challenge is the interindividual differences in pedicle morphology, which require individual surgical planning before and possible adjustments during surgery 6, 7. Due to the close anatomical relation of the pedicle and sensitive structures, PS placement carries the risk of a number of complications, including neurological, vascular or dural injury following perforation of the pedicle wall 3, 4, 5. Pedicle screw (PS) placement has been considered a standard procedure in spine surgery for many years and is widely used for a variety of indications 1, 2. Weighted interrater reliability for Gertzbein Robbins grading was moderate for C-arm CBCT, substantial for CBCT and almost perfect for iCT. ![]() However, the exact reasons for the difference in accuracy remain unclear. Under quasi-identical conditions, higher screw accuracy was achieved with the combinations iCT/Curve and C-arm CBCT/Pulse compared with CBCT/StealthStation. Weighted interrater reliability was found to be 0.896 for iCT, 0.424 for C-arm CBCT and 0.709 for CBCT. Relevant perforations of the medial pedicle wall were only seen in the CBCT group. The differences between the different combinations were not statistically significant except for the comparison of C-arm CBCT/Pulse and CBCT/StealthStation (p = 0.003). Weighted kappa was used to calculate reliability between the observers. Grades A and B were considered acceptable and Grades C-E unacceptable. Two blinded observers classified screw placement according to the Gertzbein Robbins grading system. 470 screws were included in the final evaluation. With each combination of imaging system and navigation interface, 160 navigated screws were placed percutaneously in spine levels T11-S1 in ten artificial spine models. Thus, the objective of this study was to compare the accuracy of two combinations most used in the literature for spinal navigation and a recently approved combination of imaging device and navigation system. While different imaging and navigation devices can be used, there are few studies comparing these under similar conditions. 3D-navigated pedicle screw placement is increasingly performed as the accuracy has been shown to be considerably higher compared to fluoroscopy-guidance.
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