To determine efficacy of heterotopia laser ablation in patient with bilateral periventricular nodular heterotopia, and to compare stereo-EEG (SEEG) and Neuropace data.

Excellent epilepsy surgery outcomes are reported in patients with unilateral heterotopia, whereas for the bilateral cases, surgical outcomes are less favorable.

We report combined treatment of bilateral periventricular nodular heterotopia with laser ablation and Neuropace leads placement after stereo-EEG evaluation.

The patient with several bilateral periventricular heterotopia nodules and intractable epilepsy with clinical seizures every two weeks underwent invasive evaluation with bilateral SEEG sampling heterotopia nodules, mesial temporal structures and neocortex overlying heterotopia in both hemispheres. Her clinical seizures correlated with stereotypical complex ictal pattern showing initial changes over the left hippocampus with early involvement of heterotopia and overlying neocortex. The patient also had multiple sub-clinical seizures from both right and left heterotopic nodules as well as overlying neocortex. She underwent laser ablation of the right and left heterotopia nodules followed by Neuropace implantation with leads through the heterotopia nodule and into the hippocampus, one on each side.  Patient was clinically seizure free for a year after the ablative surgery. The Neuropace only captured two sub-clinical seizures from the left hippocampus on the day of leads placement, and the next seizure captured was a year after the laser ablation which was clinical and thought to be provoked by vaccination.

The laser ablation of the bilateral periventricular heterotopia nodules resulted in good seizure control in spite of SEEG evaluation suggesting seizure onset in the left hippocampus. Studies on a larger patient cohort are needed to identify if the heterotopia nodules have to be an initial surgical target regardless of invasive evaluation data.