Abstract

Objective Periventricular Nodular Heterotopia (PVNH) is the most common neuronal heterotopia, frequently resulting in pharmaco-resistant epilepsy. PVNH has a deep location which renders localization of seizure onsets and traditional surgical therapy challenging and of limited success. Here we characterize variables that predict good epilepsy outcomes following surgical intervention using SEEG-informed MRgLITT.

Methods A prospectively compiled surgical epilepsy database from a single high-volume epilepsy referral center was used to identify patients who underwent SEEG evaluation for PVNH and characterize the intervention on outcomes.

Results Thirty-nine patients underwent SEEG-informed MRgLITT. Associated imaging abnormalities— mesial temporal sclerosis (MTS) or polymicrogyria (PMG) were treated based on SEEG.

SEEG-guided MRgLITT of the seizure onset zone (SoZ) in PVNH and associated epileptic tissue was carried out. PVNH and PMG were densely sampled—mean 16.5(SD=2)/209.4(SD=36.9) SEEG probes/recording contacts. A single trajectory was used in 18, two in 13, and three or more in eight patients. Volumetric analyses revealed a high percentage of PVNH SoZ ablation (96.6%, SD=5.3%) in unilateral and bilateral (92.9%, SD=7.2%) cases. Mean follow-up duration was 31.4 months (SD=20.9). Seizure freedom was excellent overall: unilateral PVNH without other imaging abnormalities—80%; PVNH with MTS or PMG—63%; Bilateral PVNH—50%. SoZ ablation percentage significantly impacted surgical outcomes (p<0.001).

Interpretation PVNH plays a central role in seizure genesis. MRgLITT represents a transformative technological advance in PVNH-associated epilepsy with seizure control outcomes consistent with those seen in focal lesional epilepsies. In localized unilateral cases and otherwise normal imaging, performing PVNH ablation without invasive recordings may be reasonable.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This study did not receive any funding

Author Declarations

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Committee for the Protection of Human Subjects (CPHS) of the University of Texas Health Science Center at Houston gave ethical approval for this work

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Data Availability

All data produced in the present work are contained in the manuscript

AbbreviationsPVNHPeriventricular Nodular HeterotopiaSEEGStereoelectroencephalographyMRgLITTMagnetic Resonance-Guided Laser Interstitial Thermal TherapyMTSMesial Temporal SclerosisPMGPolymicrogyriaSoZSeizure Onset ZoneASMAntiseizure MedicationFDG-PET2-[18F] fluoro-2-deoxy-D-glucose positron emission tomographyMEGmagnetoencephalographyATLAnterior Temporal LobectomyVNSVagal Nerve StimulatorFTBTCFocal to bilateral tonic-clonicFIASfocal impaired awareness seizuresSDESubdural Grid ElectrodeSAHSelective AmygdalohippocampectomyFCDFocal Cortical DysplasiaHSHippocampal SclerosisRNSResponsive NeurostimulationVNSVagal Nerve Stimulator