Intraoperative Accuracy of Sacroiliac Joint Fusion Implant Placement Using 3D Computed Tomography-Guided Imaging for Primary Sacroiliac Arthropathy.

BACKGROUND: Placement of iliosacral screws is technically challenging. This is especially the case with dysmorphic anatomy. Intraoperative computer navigation can be used to facilitate. No studies have evaluated computer navigation accuracy for minimally invasive sacroiliac joint (SIJ) fusion using iliosacral screws. We sought to evaluate the outcomes of navigated SIJ fusion and the accuracy of virtual screw placement (navigation projection) compared with actual screw placement across the SIJ. METHODS: We retrospectively reviewed consecutive minimally invasive SIJ fusions at our institution from July 2020 to November 2023. The virtual trajectory of the iliosacral screws on the computer-guided navigation (Stealth Navigation, Medtronic, Fridley, MN, USA) was compared with actual intraoperative cone beam (O-arm) imaging of the iliosacral screws after placement. The virtual iliosacral screw and actual iliosacral screw angulation and trajectories were compared with respect to the SIJ. RESULTS: Thirteen patients (4 men and 9 women) with 38 total iliosacral screws were analyzed. Five patients (38%) had dysmorphic anatomy. No iliosacral screw malpositions were identified, and no complications occurred. The mean axial angular difference (% variation) between the Stealth projections and the actual iliosacral screw placement was 0.3° (2.7%) on axial images (P = 0.69). The mean coronal angular difference (% variation) between the Stealth projections and the actual iliosacral screw placement was 0.1° (2.6%) on coronal images (P = 0.76). CONCLUSION: The Stealth navigation iliosacral screw projections accurately represented final implant placement within 1° in this cohort. Results suggest that SIJ fusion iliosacral screw placement using intraoperative Stealth navigation is accurate and reliable. CLINICAL RELEVANCE: This study provides evidence supporting the accuracy of intraoperative computer navigation for iliosacral screw placement in iliosacral fusion procedures. The findings demonstrate precision, with minimal average angular differences of iliosacral fusion implants in the axial and coronal views. Intraoperative navigation systems can offer an advantage in achieving optimal implant positioning, especially in patients with anatomically complex, dysmorphic anatomy.