Feasibility of Merging Sacroiliac Fusion Computed Tomography Preoperative Planning to Original Computed Tomography Scans

Background: Spinal merging has been done with preoperative CT scans merged with fluoroscopic imaging. However, preoperative and intraoperative CT scans have not been merged for the purposes of transferring a plan. If spine surgeons can create the optimal surgical pathway before surgery and then merge the pre-planned pathway onto the real patient CT scan in the operating room, the result will be efficiency and better time management for the spine surgeon. Our objective was to analyze the feasibility of merging computed tomography (CT) preplanned with sacroiliac fusion iliosacral screw trajectories with the original CT scans. Methods: Twenty-seven patients were identified from the institutional Faculty Group Practice who had undergone CT scans in the pelvic region. The pelvic CT scans were transferred to Medtronic’s StealthStation, which allowed for analysis in coronal, sagittal, and axial sections. Three trajectories were mapped out, representing three working pathways for fixation. The position of the trajectories was localized by measuring their distance from anatomic landmarks. The CT scan with the planned trajectories was merged with the original CT scan. The same measurements made pre-merge were performed post-merge to check for the accuracy of the merging process. Results: Post-merge measurements were nearly identical to pre-merge measurements, with a maximum difference of ± 0.1 mm. No significant differences existed between pre-merge and post-merge measurements for any of the trajectories Conclusion: The merging of preplanned trajectory CT scans with intraoperative CT scans is a highly accurate technique. Clinical relevance: If this technique can be replicated by merging actual pre-operative CT scans with actual intraoperative scans, it could save time and expense. This would benefit the patient because time under anesthesia would be reduced.