title: Intracranial evaluation and laser ablation for epilepsy with periventricular nodular heterotopia.
abstract: Surgical treatment of focal epilepsy in the presence of periventricular nodular heterotopia (PVNH) poses a challenge, as the relative roles of the nodular tissue and the overlying cortex in the generation of seizures can be complex and variable. Here, we review the literature on chronic invasive EEG recordings in humans with this substrate and present two illustrative cases from our practice. We found that while inter-ictal spiking from nodules is common, clinical seizures rarely arise solely from nodular tissue. More typically, ictal onset is simultaneous with overlying neocortex or mesial temporal structures. Surgical outcome is more favorable in cases with unilateral (as opposed to bilateral) PVNH, and when a substantial or complete ablation of PVNH is performed. In rare cases, nodular ablation alone may be sufficient, as may be completed by MRI-guided laser interstitial thermal therapy. The mechanism(s) by which PNVH interacts with overlying cortex are not fully understood, but we suggest that PVNH either orchestrates or amplifies local network epileptogenicity. At present, invasive recordings with penetrating depth electrodes are required prior to surgical therapy, as illustrated in our cases.
authors.affiliation: Department of Neurology, University of Texas Medical School, Houston, TX, United States. Electronic address: Stephen.A.Thompson@uth.tmc.edu.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Thompson
authors.affiliation: Department of Neurology, University of Texas Medical School, Houston, TX, United States.
authors.forename: Giridhar P
authors.initials: GP
authors.lastname: Kalamangalam
authors.affiliation: Vivian L Smith Department of Neurological Surgery, University of Texas Medical School, Houston, TX, United States; Mischer Neuroscience Institute, Texas Medical Center, United States.
authors.forename: Nitin
authors.initials: N
authors.lastname: Tandon
mesh_terms: D000328:Adult; D058256:Brain Waves / Q000502:physiology; D004569:Electroencephalography; D004827:Epilepsy / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D054091:Periventricular Nodular Heterotopia / Q000000981:diagnostic imaging / Q000601:surgery*
keywords: MCD; MRgLITT; Medically intractable epilepsy; Migrational abnormality; SEEG; Seizure surgery; Visualase