Enhanced Sensitivity of Electrocorticography During Awake Craniotomy Using a Novel Circular Grid Electrode
Brin Freund1, Anteneh Feyissa2, Aafreen Khan3, Joseph Sirven2, Sanjeet Grewal1, David Sabsevitz1, Diogo Moniz-Garcia1, Alfredo Quinones-Hinojosa1, William Tatum2
1Mayo Clinic Florida, 2Mayo Clinic, 3Tower Health
Objective:
To determine the utility of using a novel 22-contact circular grid for electrocorticography (ECoG) during intraoperative functional brain mapping (FBM) for awake craniotomy.
Background:
Awake craniotomy with FBM neuropsychological testing is an important technique used to optimize resective brain surgeries near eloquent cortex. Awake craniotomy performed with ECoG and direct electrical stimulation (DES) for FBM can delineate eloquent cortex from lesions and epileptogenic regions. However, current electrode technology demonstrates spatial limitations. Our group has developed a novel circular grid with the goal of improving spatial recording of ECoG to enhance detection of ictal and interictal activity.
Design/Methods:
This retrospective study was approved by the institutional review board at Mayo Clinic Florida. We analyzed patients undergoing awake craniotomy with ECoG and DES and compared ECoG data obtained using the 22-contact circular grid to standard 6-contact strip electrode.
Results:
We included 144 cases of awake craniotomy with ECoG, 73 using circular grid and 71 with strip electrode. No significant differences were seen regarding preoperative clinical and demographic data, duration of ECoG recording (p=0.676) and use of DES (p=0.926). Circular grid was more sensitive in detecting periodic focal epileptiform discharges (PFEDs) (p=0.004), PFEDs plus (p=0.032), afterdischarges (ADs) per case (p=0.022) at lower minimum (p<0.001) and maximum (p=0.002) intensity stimulation, and seizures (p=0.048). PFEDs (p<0.001), PFEDs plus (p<0.001), and HFOs (p<0.001) but not ADs (p=0.255) predicted electrographic seizures.
Conclusions:
We demonstrate higher sensitivity in detecting ictal and interictal activity on ECoG during awake craniotomy with a novel circular grid compared to strip electrode, likely due to better spatial sampling during ECoG. We also found association between PFEDs and intraoperative seizures.