Authors :
Anthony Lee, University of California, San Francisco; Noah Nichols - University of California, San Francisco; Benjamin Speidel - University of California, San Francisco; Joline Fan - University of California, San Francisco; Robert Knowlton - University of
Rationale:
There is currently an emerging debate over the optimal approach between subdural grids and stereoelectroencephalography (SEEG) for invasive epilepsy monitoring. We utilize two strategies for intracranial EEG recordings: 1) a “hybrid” approach, whereby patients receive combined subdural grid and depth electrode implantations, and 2) SEEG. This study compares the risks and benefits between both approaches.
Method:
A retrospective review was performed on consecutive patients that underwent hybrid or SEEG implantation from July 2012 to July 2019 at an academic epilepsy center by a single surgeon. Outcomes included hemorrhagic and non-hemorrhagic complications, neurological deficits, and electrode locations. Results99 hybrid and 44 SEEG procedures were performed. Hemorrhagic complication rates were similar (SEEG: 8%; hybrid: 7.1%, p=0.96). SEEG hemorrhages were all intra-axial, whereas hybrid hemorrhages were all extra-axial. Neurological deficits from hybrid cases were quickly reversed with prompt hematoma evacuation, while SEEG was associated with more severe deficits (p< 0.01). There was no difference in non-hemorrhagic complications (p=0.24). Hybrid cases had higher density of electrode contacts (hybrid: 122.1±28.5, SEEG: 89.8±34.2, p< 0.01), with more sampling of eloquent cortices. SEEG electrodes were more likely to be located in white matter (SEEG: 34.0%, hybrid: 9.2%, p< 0.01).
Conclusion:
Both approaches resulted in similar, relatively low hemorrhage rates. However, SEEG-related hemorrhages in eloquent brain regions resulted in lasting neurological deficits, whereas deficits from grid-related subdural hematomas resolved quickly after evacuation. The decision to use hybrid or SEEG should tailor the characteristics of either approach to the localization question and risk/benefit profile for a given patient.
Funding:
:No funding was used to support this research.
FIGURES
Figure 1