Authors :
Presenting Author: Mariam Josyula, BA – University of Pennsylvania
Gabriela Bustamante, MPH, RN – Perelman School of Medicine, University of Pennsylvania
Kathryn Davis, MD – Center for Neuroengineering and Therapeutics and Penn Epilepsy Center, Department of Neurology, University of Pennsylvania
Catherine Kulick-Soper, MD – Perelman School of Medicine, University of Pennsylvania
Rationale:
Pre-surgical evaluation for patients with drug resistant epilepsy (DRE) typically includes ictal EEG, MRI brain, fMRI (or other determination of language lateralization), PET, and neuropsychological testing. At most epilepsy centers, these data are reviewed at a multidisciplinary epilepsy surgical conference (MESC) to form a consensus regarding the hypothesized seizure onset zone (SOZ) and next steps. Although this general approach is used at many centers, the impact of MESC on data interpretation and surgical planning remains under-studied. This study aimed to evaluate the influence of MESC on SOZ hypothesis and surgical plan.Methods:
Scales assessing the lateralizing and localizing value of each individual pre-surgical study, SOZ hypothesis, and plan were completed both pre- and post-MESC by a total of 16 epileptologists for 196 DRE patients seen at the Hospital of the University of Pennsylvania between 2023-2025 (Figure 1). Extracted variables included SOZ lateralization/localization, 3T MRI lateralization/localization, and plan to pursue additional noninvasive studies, intracranial EEG (iEEG), ablation/resection, or neuromodulation (Table 1). A logistic regression was performed to determine which characteristics were most predictive of post-MESC recommendation to proceed to ablation/resection.
Results:
Of 196 patients, 50 (25.5%) had right-lateralizing seizures, 73 (37.2%) were left-lateralizing, and 73 (37.2%) were non-lateralizing/bilateral; 114 (58.2%) had temporal-localizing seizures, 34 (17.4%) were extratemporal, and 48 (24.5%) were diffuse/multifocal. The 3T MRI results included 28 (14.3%) right-lesional, 39 (19.9%) left-lesional, and 129 (65.8%) non-lesional/bilateral. Post-MESC plans included 32 (16.3%) requiring additional studies, 83 (42.4%) proceeding to iEEG, 38 (19.4%) ablation/resection, and 55 (28.1%) neuromodulation. When comparing pre- vs post-MESC responses, SOZ lateralization was changed for 2 (1.0%) patients and localization for 16 (8.2%) cases. The plan was changed for 65 (33.2%) patients. For 15 (7.7%) patients, this change was that additional studies were required prior to proceeding further. For 16 (8.2%) patients, additional studies were no longer needed. Seven (3.6%) patients were able to skip additional studies or iEEG and proceed straight to ablation/resection, whereas iEEG was added to the plan for 14 (7.1%) patients. Three (1.5%) patients were re-categorized as neuromodulation candidates only, and 2 (1.0%) were re-categorized as candidates for iEEG or ablation/resection. A logistic regression showed that a temporal lobe MRI lesion (B=1.540, p=0.039) and right-lateralizing seizures (B=1.710, p=0.026) significantly increased the likelihood of recommending ablation/resection post-MESC. Conclusions:
We found that MESC led to a change in the hypothesized SOZ or plan in 109 (55.61%) of patients, highlighting the importance of this step in the pre-surgical pathway. Temporal lobe MRI lesions and right-sided seizure lateralization significantly increased the likelihood of recommending ablation/resection post-MESC.
Funding: N/A