Accuracy, Safety, and Workflow of Frameless Neuronavigation-Guided Stereoelectroencephalography in Drug-Resistant Epilepsy: A Single-Center Cohort Study

BACKGROUND AND OBJECTIVES: Stereoelectroencephalography (SEEG) is central to invasive presurgical evaluation in drug-resistant epilepsy (DRE). We evaluated the accuracy, safety, and workflow efficiency of frameless neuronavigation-guided SEEG in routine clinical practice. METHODS: This retrospective single-center cohort included consecutive adult and pediatric patients with DRE who underwent SEEG between July 2016 and August 2025. Entry-point and target-point deviations were measured on postoperative computed tomography fused to the preoperative planning data set. Safety end points were perioperative complications. Operative duration and time per electrode were recorded. Comparative analyses between AdTech and Dixi systems were restricted to the primary-surgery cohort to maintain independent samples. A subgroup analysis examined procedures performed by experienced surgeons, defined as more than 250 implanted electrodes. RESULTS: Seventy-seven patients underwent 82 SEEG procedures. Across all procedures, 984 electrodes were implanted. The median number of electrodes per surgery was 13. The median entry-point and target-point deviations were 2.1 and 1.8 mm, respectively. Entry-point deviation did not differ between AdTech and Dixi electrodes in the primary-surgery cohort (2.1 vs 2.1 mm; P = .579), whereas target-point deviation was slightly lower with Dixi (1.6 vs 1.9 mm; P = .030). The duration of Dixi procedures was shorter than AdTech procedures (102 vs 186 minutes P < .001) and had lower time per electrode (10 vs 14 minutes; P < .001). Four minor hemorrhagic complications occurred (4.9%/procedure; 0.4%/electrode); no permanent neurological deficits, reoperations, hardware-related complications, or procedure-related deaths occurred. A seizure-onset zone was localized in 48 patients (62%), enabling subsequent resective or disconnective surgery. CONCLUSION: Frameless neuronavigation-guided SEEG achieved reproducible millimetric accuracy, low morbidity, and efficient workflow in a consecutive real-world cohort. These findings support frameless neuronavigation as a safe and scalable option for invasive presurgical evaluation in DRE.