Postoperative Determination of Directional Deep Brain Stimulation (DBS) Lead Orientation Using Rotational Fluoroscopy: Interobserver Agreement and Comparison with CT-Based Software

BackgroundDirectional deep-brain stimulation (DBS) requires knowledge of lead orientation to maximize benefit and minimize side effects. While CT-based software is widely used, its accuracy may decrease with the use of oblique leads. Rotational fluoroscopy using the Iron Sight method offers an alternative; however, its reliability in clinical practice has not been fully established. ObjectiveTo assess the reliability of the Iron Sight method for postoperative lead orientation and compare it with CT-based software (Brainlab Elements). MethodsWe 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. ResultsObservers using the Iron Sight method produced highly consistent measurements, differing on average by <1{degrees} and rarely more than {+/-}7{degrees}. Compared with CT-based analysis, the Iron Sight method showed good agreement, with differences typically within {+/-}15{degrees}. These margins correspond to <1.5 mm displacement around the lead -- well within clinically acceptable limits for programming. ConclusionRotational fluoroscopy, combined with the Iron Sight method, provides clinicians with a reliable and reproducible tool to confirm lead orientation. It may be especially valuable when CT-based software is unavailable, inconclusive, or requires corroboration.