Prevalence of Temporal Lobe Epilepsy (TLE) Subtypes and Response to Resective Surgery in Patients with Presumed TLE Undergoing Limbic and Paralimbic Network Exploration with Stereoelectrodes
Abstract number :
3.311
Submission category :
9. Surgery / 9A. Adult
Year :
2021
Submission ID :
1825889
Source :
www.aesnet.org
Presentation date :
12/9/2021 12:00:00 PM
Published date :
Nov 22, 2021, 06:50 AM
Authors :
Irina Podkorytova, MD - University of Texas Southwestern Medical Center, Dallas, TX; Ryan Hays – Associate Professor, Neurology, University of Texas Southwestern Medical Center, Dallas, TX; Kan Ding – Associate Professor, Neurology, University of Texas Southwestern Medical Center, Dallas, TX; Bradley Lega – Associate Professor, Neurosurgery, University of Texas Southwestern Medical Center, Dallas, TX; Ghazala Perven – Assistant Professor, Neurology, University of Texas Southwestern Medical Center, Dallas, TX
Rationale: Temporal lobe epilepsy (TLE) responds well to surgical treatment, although about 45% of patients experience seizure recurrence after resection. Relapse from the contralateral mesial temporal lobe, extratemporal lobe epilepsy mimicking TLE, or temporal plus epilepsy might account for surgical failures. We investigated prevalence of TLE subtypes in patients with presumed TLE who underwent stereoelectroencephalographic (SEEG) evaluation, and response of each group to resective surgery.
Methods: We included patients with a preimplantation hypothesis suggesting TLE, who underwent SEEG evaluation at our institution and had an individual SEEG exploration paradigm with at least twelve stereoelectrodes (SE) placed to sixteen brain regions allowing exploration of limbic and paralimbic networks. The mesial SE contacts sampled the anterior and posterior hippocampus, amygdala, entorhinal cortex, precuneus, anterior and posterior insula, orbitofrontal cortex, anterior and posterior cingulate, fusiform gyrus, and contralateral hippocampus; lateral SE contacts sampled temporal, frontal, parietal and contralateral temporal neocortex. Patients who did not have sampling of at least one of these regions with SE or who underwent previous temporal lobectomy were excluded. We analyzed prevalence of TLE subtypes based on ictal onset localization with SEEG, and response to resective surgery.
Results: Twenty-four out of 179 SEEG subjects met inclusion criteria. Fourteen patients had MRI lesions; in five, the MRI lesion was related to the SEEG ictal onset zone, and in nine patients, the MRI lesion was unrelated to the SEEG ictal onset zone. Seven patients (29%) had unilateral mesial temporal epilepsy (UMTE), five (21%) – bilateral mesial temporal (BMTE), five (21%) – unilateral neocortical temporal (UNTE), six (25%) – temporal-plus (TPE), and one (4%) – extratemporal epilepsy (ETE). Most patients, representing each subgroup, have undergone resective surgery. The following characteristics were analyzed: presence of MRI lesion (L) vs non-lesional MRI (NL) related to SEEG ictal onset zone, Engel outcome, and average follow-up duration. The results are as follows: UMTE – all seven patients, NL, Engel I, 21 months (mo); BMTE – one out of five, NL, Engel I, 17 mo; UNTE – three out of five, one L, Engel I, 25 mo; TLE mimic (ETE) – one, NL, Engel I, 15 mo; TPE – all six patients, two L, Engel I –three (one L), Engel III – two (one L), Engel IV – one (NL), 19.5 mo.
Conclusions: In our SEEG study, MRI-non-lesional UMTE was the most frequent TLE subtype (29%), and all patient proceeded to resective surgery with good outcome. TPE comprised a substantial component (25%) of this cohort with initially (pre-SEEG) presumed TLE, who ultimately had the worst response to resection. Larger studies are needed to create guidelines for rational counseling of patients with presumed TLE regarding surgical outcomes, and overall to improve reliability of prognosis regarding epilepsy surgery results in this patient cohort.
Funding: Please list any funding that was received in support of this abstract.: None.
Surgery