Is intraoperative electrocorticography (ECoG) for Long Term Epilepsy Associated Tumors (LEATs) more useful in children?-A Randomized controlled trial
Authors: Rajeev Sreenath , Darshan HR , Vilanilam George , Abraham Mathew , Venkat Easwer Hariharan , Stanley Antony , Menon Ramshekhar N , Radhakrishnan Ashalatha , Cherian Ajith , Narasimaiah Deepti , Thomas Bejoy , Kesavadas Chandrasekhar , Vimala Smita 
Published: September 2023

Objectives
The utility of intra operative electrocorticography (ECoG) guided resective surgery for pediatric Long-Term Epilepsy Associated Tumors (LEATs) with anti-seizure medication (ASM) resistant epilepsy, is not supported by robust evidence. As epilepsy networks and their ramifications are different in children from those in adults, the impact of intraoperative ECoG based tailored resections in predicting prognosis and influencing outcomes, may also differ. We evaluated this hypothesis by comparing the outcomes of resections with and without the use of ECoG in children and adults by a randomized study.
Methods
From June 2020 and Jan 2022, 42 patients (17 children and 25 adults) with LEATs and anti-seizure medication (ASM) resistant epilepsy were randomly assigned to one of the 2 groups (ECoG or no ECoG) prior to surgical resection. The no ECoG arm underwent gross total resection (GTR) without ECoG guidance and the ECoG arm underwent GTR with ECoG guidance and further additional tailored resections, as necessary. Factors evaluated were tumor location, size, lateralization, seizure duration, preoperative antiepileptic drug therapy, pre and post resection ECoG patterns and tumor histology. Postoperative Engel score, and adverse event rates were compared in the pediatric and adult groups of both arms. Eloquent cortex lesions and re-explorations were excluded.
Results
Forty-two patients were included in the study of which 17 patients were in the pediatric cohort (age < 18 years) and 25 in the adult cohort. The mean age in the pediatric group was 11.11 (SD 4.72) and in the adult group was 29.56 (SD 9.29). The mean duration of epilepsy was 9.7 years (SD 4.8) in the pediatric group and 10.96(SD 8.8) in the adult group and in the adult group. The ECoG arm of LEATs resections had 23 patients (9 children, 14 adults) and the non ECoG arm had 19 patients (8 children ,11 adults). Three children and 3 adults from the ECoG group further underwent tailored resection (average 1.33 additional tailored resection/per patient.).The histology of the tailored resection specimen was unremarkable in 3/6(50%).Overall the commonest histology in both groups was ganglioglioma and the temporal lobe the commonest site of the lesion. 88.23% of pediatric cases (n=15/17) had an excellent outcome(Engel Ia) following resection compared to 84% of adult cases (n=21/25) at a mean duration of follow up of 12 months(p-0.405).There was no significant difference in seizure outcomes between the ECoG and no ECoG group both in children and adults respectively(p > 0.05).Additional tailored resection did not offer any seizure outcome benefit when compared to the non-tailored resections.
Conclusions
The use of intraoperative electrocorticography in LEATs did not contribute to post operative seizure outcome benefit in children and adults. No additional advantage or utility was offered by ECoG in children when compared to its use in adults. ECoG guided additional tailored resections did not offer any additional seizure outcome benefit both in children and adults.