Abstracts

Rationale: In patients with medically refractory epilepsy where the epileptogenic zone (EZ) is located in cortical areas not suitable for surgical resection, neuromodulation is a palliative option. Thalamic pulvinar areas, which are highly connected with posterior quadrant regions, may represent a feasible, safe and effective target for deep brain stimulation for bilateral posterior quadrant epilepsies.

Methods: This a single case report of a 20-year-old woman with medically refractory epilepsy for approximately 18 years. The patient’s semiology is a poorly described aura of “ringing in her ears” or “vibration in her head,” followed by behavioral arrest, forced eye deviation, and convulsion, with two recent episodes of status epilepticus reported. Her MRI is normal. Interictal EEG shows abundant spikes O2 >O1, frequent generalized bursts of spike-and-wave, and occasional sharp waves in the bilateral temporal-parietal-occipital regions. Several seizures were captured on video-EEG with onset in the posterior quadrant bilaterally. MEG showed independent irritative zones in the bilateral occipital lobes. She was not a candidate for resection given the bilateral independent EZ. She underwent robotic placement of bilateral DBS leads targeting the posterior pulvinar with electrodes implanted orthogonally in relation to the midsagittal plane.

Results: Intra-operatively, the patient was monitored with EEG while bipolar stimulation was performed with an amplitude of 3mA, a rate of 145 Hz, and pulsewidth of 90 usec. During stimulation using contact 2 as the cathode, the EEG showed slowing of the background bilaterally for a duration of 20-30 seconds before the normal rhythm restored. The electrodes were implanted without complication and the patient was discharged home the following day, returning 2 weeks later for placement of the pulse generator. Her DBS was enabled using monopolar stimulation with contact 2 as the cathode at 3 mA, 145 Hz, 90 usec, and cycling with 1 minute of stimulation on followed by 1 minute off. At the 2-month follow up since her DBS was turned on, she reported no FBTC seizures and is unsure whether there has been a reduction in frequency of FIAS. She has recovered well from surgery.

Conclusions: Bilateral deep brain stimulation of the pulvinar is a feasible palliative surgical treatment for intractable posterior quadrant epilepsies. The safety and efficacy profiles are still unclear and further studies are necessary.

Funding: Please list any funding that was received in support of this abstract.: None.