Abstracts

Rationale: Stereo EEG (sEEG) is a technique introduced in France in 1974 requiring no craniotomy for implantation of invasive electrodes for presurgical monitoring. This technique has become more widely used at epilepsy centers internationally over the past ten years. We have used this technique at Wake Forest Comprehensive Epilepsy Center in selected cases for the past two years.Methods: We reviewed all Phase II Presurgical cases between March 2013 and April 2015, which consisted of 13 traditional implants and 9 sEEG implants. We compared these two approaches in 4 categories: post-implant ICU stay, use of opioid pain medications, return to OR for revision or replacement of electrodes, and number of days to first seizure post implant.Results: Seven of the nine sEEG patients came directly to the Epilepsy Monitoring Unit (EMU) following electrode placement. One patient went to PICU following implant due to staffing issues in the EMU. The other went to ICU for closer postoperative respiratory monitoring. Twelve of the thirteen cases with traditional implants went to ICU for >15 hours prior to coming to EMU. One traditional implant patient who had only burr holes for placement of strips/depths came directly to EMU postoperatively. SEEG patients required far fewer doses of opioid pain medication, with 5 of the 9 patients requiring no opioids during their monitoring. The other 4 cases had an average of 8.5 doses of opioid medication during monitoring (range 2-20). In contrast, the traditional implant cases averaged 31 doses of opioid medication during monitoring (range 7-93). The mean time to first recorded seizure was similar in both groups, 3.5 days for sEEG implants vs. 3.3 days for traditional. The average days monitored for sEEG implants were 7.5 days compared to 9.1 days for traditional. 3 traditionally implanted patients had no seizures captured during their monitoring. Three sEEG patients returned to the OR for expanded coverage or replacement of lost electrodes. None of those patients required ICU care following OR. None of the traditional implanted patients had a revision of their implant during their admission. The number of patients proceeding to resection was similar in both groups.Conclusions: SEEG is a well-tolerated technique for localization of epileptic foci in surgical patients. In addition, the minimization of ICU care increases the efficiency of diagnostic time and potentially the cost effectiveness of epilepsy monitoring. Reduction in the need for sedating narcotics also optimizes the ability to complete the diagnostic procedure following electrode implantation. The ability to refine localization by adding electrodes in a second OR procedure without interruption by an ICU stay or need for narcotic sedation is an argument in favor of its much greater tolerability than traditional grid placement by craniotomy. When appropriate, this is a well-tolerated and highly successful technique. Further study is needed to determine if this procedure with improved tolerability can successfully influence more patients to consider presurgical evaluation.