Epidural grid, a new methodology of invasive intracranial EEG monitoring: A technical note and experience of a single center

So Hee Park, In ho Jung, Kyung Won Chang, Maeng Keun Oh, Jin Woo Chang, Se Hee Kim, Hoon Chul Kang, Heung Dong Kim, Won Seok Chang

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Introduction: Subdural grid monitoring (SDG) has the advantage to provide continuous coverage over a larger area of cortex, direct visualization of electrode location and functional mapping. However, SDG can cause direct irritation of the cortex or postoperative headaches due to cerebrospinal fluid (CSF) leakage. Epidural grid monitoring (EDG) without opening the dura is thought to reduce the possibility of these complications. We report our experience with EDG. Methods: We described our surgical technique of EDG in invasive intracranial electroencephalography (iEEG) monitoring. A retrospective review of 30 patients who underwent grid placement of iEEG between March 2019 and December 2020 was performed to compare SDG and EDG. Results: Of the 30 patients, 10 patients underwent SDG and 20 patients underwent EDG. There was no difference in age between SDG and EDG groups (p = 0.13). Also, there was no difference in the number of grid electrodes, craniotomy size, number of electrodes per craniotomy area and postoperative complication rate (p = 0.32, 0.84, 0.58 and 0.40). However, the maximum number of electrodes that have been undermined from the bone margin was much higher in SDG group (SDG 4.6 ± 2.2 vs. EDG 2.0 ± 0.9; p = 0.001). The demand for postoperative analgesics was significantly lower in EDG group (SDG 13.4 ± 9.1 vs. EDG 4.1 ± 4.3; p = 0.012); and the demand for postoperative antiemetics also tended to be low (SDG 4.6 ± 3.6 vs. EDG 1.8 ± 1.6; p = 0.078). Conclusions: There was no significant difference in craniotomy and electrode insertion between the two groups; however, the EDG group showed less postoperative headache and nausea. Though not in direct contact with the cortex, the quality of the electrophysiological signal received through the electrode in EDG is comparable to that of the SDG. The EDG enables to detect the onset of seizure and delineate the epileptogenic zone sufficiently. Moreover, functional mapping is possible with EDG. Therefore, EDG has the sufficient potential to replace SDG for monitoring of the lateral surface of brain.

Original languageEnglish
Article number106912
JournalEpilepsy Research
Publication statusPublished - 2022 May

Bibliographical note

Funding Information:
This research was funded by the National Research Foundation of Korea (NRF), (NRF 2020R1A2C2008480 ). Additionally, this work was supported by Korea Medical Device Development Fund (Project Number: KMDF_PR_20200901_0103 and KMDF_PR_202011D25 ).

Publisher Copyright:
© 2022

All Science Journal Classification (ASJC) codes

  • Neurology
  • Clinical Neurology


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