Supplementary Material for: Postoperative Determination of Directional DBS Lead Orientation: A Comparison of CT-Based Software and Rotational Fluoroscopy

Introduction: During evaluation of the Brainlab Elements™ software for postoperative determination of directional deep brain stimulation (DBS) lead orientation, we noted a lack of published in vivo comparative agreement data. At the same time, prior reports have described substantial variability in implanted lead rotation angles, underscoring the need to verify software-based estimates. We therefore compared Brainlab Elements™ with 3D rotational fluoroscopy, analyzed using the “Iron Sights” method (ISM), by two independent observers. Objective: To assess the concordance between lead position estimations by the image-guided software (Brainlab Elements™) and ISM. Methods: We prospectively analyzed 70 directional leads implanted at our center (2022–2024). Orientation was measured on postoperative rotational fluoroscopy by two independent observers and compared with postoperative CT analyzed in Brainlab Elements™. The agreement was evaluated using established reliability statistics. Results: Observers using the ISM produced highly consistent measurements, differing on average by <1° and rarely more than ±7°. Compared with CT-based analysis, the ISM showed good agreement, with differences typically within ±15°. These margins correspond to <1.5 mm displacement. at. Conclusion: Interobserver agreement using the ISM was excellent [ICC(2,1) = 0.983]. Brainlab Elements™ estimations [ICC(3,1) = 0.864; limits of agreement ≈ ±15°] correlated well with the ISM.