Seizure outcomes and complications associated with stereoelectroencephalography versus subdural electrodes for invasive monitoring in epilepsy surgery: A meta-analysis

Nallammai Muthiah¹Hope M Reecher²Seyed Farzad Maroufi³Alireza Mansouri⁴Taylor J Abel^5*

• ¹Department of Neurosurgery, School of Medicine, Washington University in St. Louis, Saint Louis, Missouri, United States
• ²Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
• ³Department of Neurosurgery, Shool of Medicine, Tehran University of Medical Sciences, Tehran, Alborz, Iran
• ⁴Department of Neurosurgery, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania, United States
• ⁵Department of Neurological Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States

Introduction: Approximately 1.2% of people in the United States have epilepsy. Accurate identification of seizure origin is critical for clinical management. Yan et al. published a systematic review up to 2018 comparing SDE and SEEG (two invasive monitoring modalities) on clinical effectiveness and safety. However, meta-analysis was not performed, and multiple centers have published key SDE and SEEG data since 2018. Methods: We performed an updated literature search from Yan et al., through June 2023, of studies on patients who underwent SEEG or SDE for seizure focus localization. Inclusion criteria were: 1) randomized control trial, prospective or retrospective cohort study, or case series >5 patients, 2) at least one patient who underwent seizure focus resection, 3) outcomes of either seizure freedom or complications. Meta-analytic methods were utilized for data analysis. Results: An initial search resulted in 4,647 records; 81 studies were included, reflecting 3,482 SEEG and 2,816 SDE patients. Compared to SEEG, SDE exhibited similar operative time (164 vs. 185 minutes, p=0.50), inpatient monitoring time (8.7 vs. 8.9 days, p=0.81), and length of hospital stay (11.8 vs. 9.7 days, p=0.17). Seizure foci were identified in 95.4% of SEEG patients and 91.9% of SDE patients (p=0.25). A higher proportion of SDE patients underwent resective surgery (85.6% vs. 74.0%, p<0.01). Overall, 8.0% of SEEG patients and 10.6% of SDE patients experienced adverse events (p=0.22). Incidence of infection was higher for SDE (1.8%) than for SEEG (0.3%, p<0.01). Overall, 62.7% of SEEG patients and 63.4% of SDE patients achieved seizure freedom (p=0.87). Among studies which directly compared SEEG to SDE, there were no differences in seizure freedom attainment or overall morbidity. Conclusions: SEEG and SDE are safe and effective modalities to localize seizure foci. SDE was associated with higher rates of subsequent resection, but infection rate was higher for SDE than SEEG.