Stereoelectroencephalography (SEEG)-guided insula resections: is it “Reily” worth it?

Objective: Stereoelectroencephalography (SEEG) is widely used to characterise epileptic networks and guide resection in paediatric epilepsy surgery programmes. The insula, with its extensive connectivity with temporal and extratemporal structures, has increasingly been seen as a possible surgical target. We report our seizure outcomes after SEEG-guided resection of the insula in a paediatric cohort. Methods: From our paediatric epilepsy surgery database of patients aged 0–19 years, we analysed demographic and clinical data of those who underwent SEEG-guided insula cortex resection. Results: In total, 11 children (7 females, 4 males) who underwent SEEG-guided resection were identified. The mean age at first SEEG was 13 years old. Mean age at seizure onset was 4.3 years; seizure frequency ranged from 50/day to 2/week. Four children required 1 SEEG study, 6 children 2 SEEG, and 1 child underwent 3 SEEG recordings. The mean follow-up duration was 2.1 years; at the latest follow-up, three children had Engel I, 2 children Engel III, and 6 children Engel IV. One child classified as an Engel IV outcome for insular surgery had Engel class I after 2 failed insula surgeries, after an occult frontal focal cortical dysplasia was later identified and resected. No major complications were noted. Conclusions: In our paediatric series, one third of the patients undergoing insula cortex surgery after SEEG became seizure free but this may require repeat SEEG implantation, repeat resective surgery and the possibility of changing hypothesis from the insula cortex to nearby foci.