Abstracts

Stereoelectroencephalography versus Subdural Electrode Implantations for Drug Resistant Epilepsy: Comparisons of Surgical and Non-Surgical Candidates after Invasive Investigations

Abstract number : 3.445
Submission category : 9. Surgery / 9C. All Ages
Year : 2022
Submission ID : 2232923
Source : www.aesnet.org
Presentation date : 12/5/2022 12:00:00 PM
Published date : Nov 22, 2022, 05:28 AM

Authors :
Paule Lessard Bonaventure, MD MSc FRCSC – CHU de Québec-Université Laval; Jorge Burneo, MD, MSPH, FRCPC – University of Western Ontario; Alan Chalil, MD – University of Western Ontario; David Steven, MD, MPH, FRCSC, FACS – University of Western Ontario

This is a Late Breaking abstract

Rationale: Intracranial electroencephalography is frequently needed to help localize the epileptogenic zone of candidates for epilepsy surgery. While subdural grid/strips electrodes (SDE) have been the mainstay for many years, a recent shift toward stereoencephalography (SEEG) is trending worldwide. Some direct comparative studies of SEEG and SDE have shown that the safety profile and seizure outcomes are similar. However, some epilepsy centers have noticed a decrease in the proportion of resective surgery offered  after invasive investigations since the adoption of SEEG. Our objectives were to perform a comparative analysis of non-surgical candidates following SEEG vs SDE and to identify factors associated with the non-surgical cases in both groups.

Methods: A single center retrospective cohort study from 2006-2021 of all cases who underwent intracranial investigations for drug resistant epilepsy at the London Health Science Center, Ontario. Means of continuous variables were compared using T-Test or Mann-Whitney U test and Chi-squared test was used to compare proportions and categorical variables. The probability of surgical candidacy was assessed using univariate and multivariate logistic regression models.

Results: A total of 363 patients underwent 397 intracranial evaluations. Our practice transitionned from SDE to SEEG in 2014. SDE (n=182) and SEEG (n=213) groups were similar in age (33.1 vs. 34.1 years,) sex (49.2 vs. 49.3% male), duration of epilepsy (17.3 vs. 18.7 years) and radiological findings (MRI non-lesional in 32.9% vs. 40.1%). A greater proportion of SEEG vs SDE cases had previous cranial surgery (29.1 vs. 19.7%, p=0.03). Resective surgery was offered to 57.7% of SDE cases and  64.8% of SEEG cases. A higher proportion of SDE cases needed additional electrodes (13% vs. 0%, p=0.001). Reasons precluding resective surgery after implantation differed between the two groups. More SDE cases had multifocal origin of seizures (48.0 vs. 26.0%) and incomplete/unprecise investigations (19.75 vs. 13.66%) while SEEG cases had greater proportions of bitemporal seizures (39.73 vs. 22.67%) and non-epileptic seizures (5.48 vs. 0%). Both groups had similar proportion of eloquent cortex seizures (9.3 vs. 13.7%). After adjustments for confounding factors, a bilateral implantation (OR 2.6, p= < 0.001) and a non-lesional MRI (OR 2.0, p=0.004) were associated with a higher odd of non-surgical outcome. The odds of not being a surgical candidate was 1.4 time the odds of surgical candidate for every additional week of monitoring with intracranial electrodes.
Surgery