Stereotactic placement of depth electrodes in medically intractable epilepsy

Object. Despite its long-reported successful record, with almost 60 years of clinical use, the technical complexity regarding the placement of stereoelectroencephalography (SEEG) depth electrodes may have contributed to the limited widespread application of the technique in centers outside Europe. The authors report on a simplified and novel SEEG surgical technique in the extraoperative mapping of refractory focal epilepsy. Methods. The proposed technique was applied in patients with medically refractory focal epilepsy. Data regarding general demographic information, method of electrode implantation, time of implantation, number of implanted electrodes, seizure outcome after SEEG-guided resections, and complications were prospectively collected. Results. From March 2009 to April 2012, 122 patients underwent SEEG depth electrode implantation at the Cleveland Clinic Epilepsy Center in which the authors' technique was used. There were 65 male and 57 female patients whose mean age was 33 years (range 5-68 years). The group included 21 pediatric patients (younger than 18 years). Planning and implantations were performed in a single stage. The time for planning was, on average, 33 minutes (range 20-47 minutes), and the time for implantation was, on average, 107 minutes (range 47-150 minutes). Complications related to the SEEG technique were observed in 3 patients. The calculated risk of complications per electrode was 0.18%. The seizure-free rate after SEEG-guided resections was 62% in a mean follow-up period of 12 months. Conclusions. The authors report on a safe, simplified, and less time-consuming method of SEEG depth electrode implantation, using standard and widely available surgical tools, making the technique a reasonable option for extraoperative monitoring of patients with medically intractable epilepsy in centers lacking the Talairach stereotactic armamentarium.