Abstract Details

Title High-density 360-degree Circle Grid for Detection of After Discharges During Functional Brain Mapping in Patients with Glioma

Topic Epilepsy/Clinical Neurophysiology (EEG)

Presentation(s) S3 - Epilepsy/Clinical Neurophysiology (EEG) I (1:55 PM-2:06 PM)

Poster/Presentation
Number 006

Background Intraoperative FBM has been used to identify eloquent cortex during resection of brain tumors. DES may induce ADs, which may become prolonged and manifest as clinical seizures impairing FBM during awake craniotomy.

Objective We aimed to identify electrophysiological properties of after-discharges (ADs) elicited during intraoperative direct electrocortical stimulation (DES) for functional brain mapping (FBM) using a customized, high-density (HD) circular grid.

Design/Methods Intraoperative DES was performed in conjunction with a customized HD, 22-channel, ring-shaped grid; electrodes 0.3 mm diameter, spaced 5mm apart with an open center. Hand-held DES consisted of alternating current, bipolar electrical stimulation, 50 Hz, 200 ms pulse duration, in escalating amplitudes from 0.5 mA to 10 mA. Electrocorticography was reviewed by two parties independently.

Results

18 patients (mean 49.5 ± 14.7 years; 9 males) underwent resection near eloquent cortex guided by FBM; 16 Caucasian (88.9%) and 2 Hispanic (11.1%). Pathology included 11 glioblastoma (61.1%), 5 anaplastic astrocytoma (27.7%), and 2 oligodendroglioma (11.1%). ADs were elicited in 9 patients (50%, 95% CI 0.26 to 0.74), exceeded 10 seconds in 7 patients (38.8%, 95% CI 0.17 to 0.64), resulted in a clinical seizure in 1 patient (5.5%, 95% CI 0 to 0.27). The mean duration of ADs was 6.3 ± 2.2 s, comprising 25 ADs involving 7 contacts. Multi-directional ADs were present with inter- and intra-individual variation. The mean AD threshold was 3.5 mA (range = 2-5 mA). Eloquence was assessed using DES, and complications occurred in two patients (aphasia, facial weakness) following FBM.

Conclusions Using a customized circular HD-grid, DES identified that the ADs were similar to other reports of ADs in FBM. ADs were present in all directions which are unidentifiable without a 360 degree metric. Early detection of ADs may minimize intraoperative seizures during FBM.

Authors/Disclosures
Anvita Potluri, MD PRESENTER	Dr. Potluri has nothing to disclose.
Jake McKay, MD	Dr. McKay has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for UCB.
Rana Hanna AL-Shaikh, MD (Mayo Clinic Florida)	Dr. Hanna AL-Shaikh has nothing to disclose.
Anteneh M. Feyissa, MD, MSc, FAAN (Mayo Clinic)	Dr. Feyissa has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Neurelis.
	No disclosure on file
Alfredo Quinones-Hinojosa	Alfredo Quinones-Hinojosa has nothing to disclose.
William O. Tatum IV, DO, FAAN (Mayo Clinic)	Dr. Tatum has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Bioserenity. Dr. Tatum has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Natus. Dr. Tatum has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Neurelis. Dr. Tatum has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Elsevier. Dr. Tatum has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Defense Law Firm on behalf of a patient with epilepsy with funds donated to the Epilepsy Foundation of America. The institution of Dr. Tatum has received research support from Esai. The institution of Dr. Tatum has received research support from Mayo Clinic. The institution of Dr. Tatum has received research support from Liva Nova. The institution of Dr. Tatum has received research support from Engage Pharmaceuticals. The institution of Dr. Tatum has received research support from Xenon. Dr. Tatum has received intellectual property interests from a discovery or technology relating to health care. Dr. Tatum has received publishing royalties from a publication relating to health care. Dr. Tatum has received publishing royalties from a publication relating to health care. Dr. Tatum has received publishing royalties from a publication relating to health care. Dr. Tatum has a non-compensated relationship as a AAN Section Chair of Clinical Neurophysiology with AAN that is relevant to AAN interests or activities.

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