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Objective: Numerous studies have examined epilepsy surgery outcomes, yet the variability in the level of detail reported hampers our ability to apply these findings broadly across patient groups. Established reporting standards in other clinical research fields enhance the quality and generalizability of results, ensuring that the insights gained from studying these surgeries can benefit future patients effectively. This study aims to assess current reporting standards for epilepsy surgery research and identify potential gaps and areas for enhancement. Methods: The Enhancing the Quality and Transparency of Health Research (EQUATOR) repository was accessed from inception to April 27, 2023, yielding 561 available reporting standards. Reporting standards were manually reviewed in duplicate independently for applicability to epilepsy and/or neurosurgery research. The reporting standards had to cover the following aspects in human studies: (1) reporting standards for epilepsy/epilepsy surgery and (2) reporting standards for neurosurgery. Disagreements were resolved by a third author. The top five neurosurgery, neurology, and medicine journals were also identified through Google Scholar's citation index and examined to determine the relevant reporting standards they recommended and whether those were registered with EQUATOR. Results: Of the 561 EQUATOR reporting standards, 181 were pertinent to epilepsy surgery. One was related to epilepsy, six were specific to surgical research, and nine were related to neurological/neurosurgical research. The remaining 165 reporting standards were applicable to research across various disciplines and included but were not limited to CONSORT (Consolidated Standards of Reporting Trails), STROBE (Strengthening the Reporting of Observational Studies in Epidemiology), and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta‐Analyses). None of these required reporting factors associated with epilepsy surgery outcomes, such as duration of epilepsy or magnetic resonance imaging findings. Significance: Reporting standards specific to epilepsy surgery are lacking, reflecting a gap in standards that may affect the quality of publications. Improving this gap with a set of specific reporting standards would ensure that epilepsy surgery studies are more transparent and rigorous in their design. [ABSTRACT FROM AUTHOR]

Objective: A third of the patients who undergo intracranial EEG (iEEG) for seizure‐onset zone (SOZ) localization do not proceed to resective surgery for epilepsy, and over half of those who do continue to have seizures following treatment. To better identify candidates who are more likely to see benefits from undergoing iEEG, we investigated preoperative and iEEG peri‐operative features associated with the localization of a putative SOZ, undergoing subsequent surgical treatment, and seizure outcomes. Methods: We conducted a retrospective cohort study of consecutive patients who underwent iEEG from 2001 to 2022 at two institutions. Outcomes included SOZ identification, proceeding to surgical treatment (resection vs. neuromodulation), and subsequent seizure freedom. Results: We identified 329 unique patients who were followed for a median of 3.9 (IQR:7) years, with a minimum of 2‐year follow‐up for seizure outcomes analyses. Multivariate analysis identified lateralized and lobar localization on scalp EEG (OR 3.8, p = 0.001) to be associated with SOZ localization. Patients with unilateral localization on scalp EEG (OR 3.0, p = 0.003), unilateral preimplantation hypothesis (OR 3.1, p = 0.001), and lesional preoperative MRI (OR 2.1, p = 0.033) were more likely to undergo resection than neuromodulation. Similarly, a unilateral pre‐implantation hypothesis (OR 2.6, p < 0.001) favored seizure freedom, whereas prior neuromodulation (OR 0.3, p = 0.013) decreased the odds. Larger number of preoperative anti‐seizure medications (ASMs) did not influence seizure freedom rates but did decrease favorable (Engel I, II) seizure outcomes (OR 0.7, p = 0.026). Interpretation: Non‐invasive localization data prior to iEEG are associated with subsequent resection and seizure freedom, independent of iEEG localization. Factors predictive of SOZ localization are not necessarily predictive of post‐operative seizure freedom. [ABSTRACT FROM AUTHOR]

Patients considering therapeutic epilepsy surgery often seek to decrease the number of anti-seizure medications (ASMs) they need. Predicting such reductions remains challenging. Although predictors of seizure freedom after epilepsy surgery are well-established, long-term outcomes remain modest and factors associated with ASM reduction, even in the absence of seizure freedom, may improve surgical planning to align with patient goals. We studied a large multi-institutional cohort of patients who underwent epilepsy surgery between 2001 and 2022, with a minimum of two years follow-up. Preoperative features, including duration of epilepsy, epilepsy etiology, non-invasive investigation data, and total number of ASMs prescribed immediately prior to surgery were extracted for each patient. Primary endpoints included likelihood of ASM reduction and ASM freedom at multiple post-operative time points up to 15 years and stratified by seizure control. A total of 250 patients were followed for a median of 6.0 (range 2, 22) years after intracranial EEG (iEEG) surgery. Significant ASM reduction was only observed in those who underwent subsequent resection, whereas those undergoing neuromodulation saw their ASM usage maintained. Engel I outcomes were the strongest driver of ASM reduction. In patients with persistent seizures, patients with lateralized seizure onset zones (SOZs) also achieved sustained ASM reduction over time. Similarly, an increased number of preoperative ASMs also corresponded to a higher likelihood of ASM reduction across all follow-up periods. Other preoperative factors, including seizure etiology, did not independently influence ASM reduction. Even patients with persistent seizures after epilepsy surgery can observe meaningful ASM reduction during long-term follow-up. ASM reduction may be a relevant secondary outcome measure for epilepsy surgery. • ASM reduction following surgery is only observed in patients undergoing resection, and not neuromodulation • Engel outcomes is the strongest predictor of ASM reduction following surgery • Independent of seizure outcomes, a well localized SOZ and larger number of preoperative ASMs predicts ASM reduction [ABSTRACT FROM AUTHOR]

Patients with medication-resistant disabling epilepsy should be considered for potential epilepsy surgery. If noninvasive techniques are unable to identify the location of the seizure onset zone (SOZ), it becomes necessary to consider intracranial investigations. Stereo-electroencephalography (SEEG) is currently the preferred method for such monitoring, however foramen ovale (FO) electrodes offer a less invasive alternative that may be suitable in certain situations. Previous studies have demonstrated the effectiveness of FO electrodes in suspected mesial temporal epilepsy, nevertheless, increased experience with FO electrode use could further enhance their safety and efficacy. Therefore, we conducted an analysis of recent FO electrode investigations to assess their utility in surgical decision making, post resection outcomes, and complication rates. We conducted a retrospective analysis of 61 patients who underwent FO placement at Mass General Brigham between 2009 and 2020. Patient and seizure characteristics, preoperative investigation data, and seizures outcomes were collected. In addition, identified predictors of FO utility using logistic regression. A total of 61 patients were identified. FO evaluation localized the SOZ in 56 % of patients. Complications were encountered in 1.6 % of patients. Subsequent surgical resection was pursued by 49 % of patients, with 56 % becoming seizure free, and 67 % having favorable seizure outcomes at last follow-up. Multivariate analysis identified younger patients with a higher number of preoperative ASMs as more likely to undergo subsequent treatment, however, these features were not predictive features of SOZ localization, seizure freedom, or favorable seizure outcomes. In patients with bitemporal or cross-over onsets on scalp EEG, FO was able to identify the SOZ in 79 %, whereas in patients with discordant or unclear onset, the rates were 71 % and 45 %, respectively. In a contemporary cohort, FO electrode placement had a low complication rate and a high utility primarily in cases of unclear laterality of mesial temporal onsets or discordance between scalp EEG and other pre-FO investigation data in cases of suspected mesial temporal onsets. • We examine a large recent cohort of patient who underwent foramen ovale electrode investigations. • We aimed to identify contemporary usage of foramen ovale investigations. • We found high utility primarily in cases of unclear laterality or discordant EEG onsets. [ABSTRACT FROM AUTHOR]

• Estimates of meaningful ASM reduction or discontinuation are uncertain following epilepsy surgery. • Half of patients undergoing resection can expect ASM reduction, though only a tenth can expect to discontinue ASMs completely. • Less than a third of patients undergoing neuromodulation can expect ASM reduction. • ASM reduction decreases over long-term follow-up, which is especially notable in patients undergoing neuromodulation. • If reduction is not seen early, it likely does not occur later during long-term follow-up. Many patients pursue epilepsy surgery with the hope of reducing or stopping anti-seizure medications (ASMs), in addition to reducing their seizure frequency and severity. While ASM decrease is primarily driven by surgical outcomes and patient preferences, preoperative estimates of meaningful ASM reduction or discontinuation are uncertain, especially when accounting for the various forking paths possible following intracranial EEG (iEEG), including resection, neuromodulation, or even the absence of further surgery. Here, we characterize in detail the ASM reduction in a large cohort of patients who underwent iEEG, facilitating proactive, early counseling for a complicated cohort considering surgical treatment. We identified a multi-institutional cohort of patients who underwent iEEG between 2001 and 2022, with a minimum of two years follow-up. The total number of ASMs prescribed immediately prior to surgery, choice of investigation modality, and subsequent surgical treatment were extracted for each patient. Primary endpoints included decreases in ASM counts from preoperative baseline to various follow-up intervals. A total of 284 patients were followed for a median of 6.0 (range 2,22) years after iEEG surgery. Patients undergoing resection saw an average reduction of ∼ 0.5 ASMs. Patients undergoing neuromodulation saw no decrease and trended towards requiring increased ASM usage during long-term follow-up. Only patients undergoing resection were likely to completely discontinue all ASMs, with an increasing probability over time approaching ∼ 10 %. Up to half of resection patients saw ASM decreases, which was largely stable during long-term follow-up, whereas only a quarter of neuromodulation patients saw a reduction, though their ASM reduction decreased over time. With the increasing use of stereotactic EEG and non-curative neuromodulation procedures, realistic estimates of ASM reduction and discontinuation should be considered preoperatively. Almost half of patients undergoing resective surgery can expect to reduce their ASMs, though only a tenth can expect to discontinue ASMs completely. If reduction is not seen early, it likely does not occur later during long-term follow-up. Less than a third of patients undergoing neuromodulation can expect ASM reduction, and instead most may require increased usage during long-term follow-up. [ABSTRACT FROM AUTHOR]