Depth electroencephalography in selection of refractory epilepsy for surgery

Area of Science:

• Neurology
• Neurosurgery
• Epileptology

Background:

• Medically refractory epilepsy often requires surgical intervention for seizure control.
• Depth electroencephalography (EEG) is a controversial tool used in pre-surgical evaluation.
• Surgical success rates for epilepsy range from 60-80% but are not improved at centers using depth EEG.

Purpose of the Study:

• To evaluate the potential impact of depth EEG on surgical decision-making in patients with medically refractory epilepsy.
• To compare the utility of depth EEG versus scalp EEG in identifying epileptogenic foci.

Main Methods:

• Systematic review of published literature comparing depth EEG and scalp EEG results.
• Analysis of 178 patients to assess how depth EEG could have altered surgical candidacy.
• Evaluation of depth EEG's potential to identify single or multiple epileptogenic foci.

Main Results:

• Depth EEG could have identified suitable candidates for surgery in an additional 36% of patients by pinpointing previously unidentifiable foci.
• Depth EEG could have prevented unnecessary surgery in 18% of patients by revealing additional or different epileptogenic foci.
• The overall potential to alter surgical decisions was observed in over 50% of patients reviewed.

Conclusions:

• Depth EEG has a significant potential to refine surgical candidate selection for epilepsy.
• Discrepancies in surgical success rates may be due to differences in patient populations evaluated at various centers.
• Further research is needed to optimize the role of depth EEG in epilepsy surgery protocols.