Abstracts

Rationale: In children with drug resistant epilepsy, a subset of children required multilobar resections. “Subtotal” hemispherectomy sparing the primary sensorimotor cortex was reported to control intractable focal epilepsy, instead of hemispherectomy. We have experience with multilobar resections in children with generalized interictal epileptiform discharges and normal/subtle MRI findings. We evaluated the characteristics of the clinical features and intracranial video EEG (VEEG) in children who underwent “Rolandic sparing” subtotal hemisperectomy in comparison to those with multilobar resections without “Rolandic sparing”.Methods: We performed a retrospective health record analysis of children with drug-resistant multi-lobar onset epilepsy who underwent intracranial video EEG monitoring at the Hospital for Sick Children between June 2009 and December 2013. We divided the patients into group A; fronto-temporo-parietal resections sparing Rolandic cortex and group B; double/multi-lobar resections without Rolandic cortex sparing. We analyzed seizure semiology, scalp VEEG, MRI, MEG, PET and seizure outcome.Results: We collected 13 patients in Group A with Rolandic sparing, subtotal hemispherectomy’s. Eleven patients in Group B underwent multilobar resections including occipito-temporo-parietal (6), fronto-temporal (2), temporo-parietal (2) and temporo-occipital (1) without Rolandic cortex sparing. Motor deficit and cognitive delay were found equally in A (1) and B (1). The epileptic spasms occurred more frequently in A (5) than B (1). Normal MRI was found in A (4) and B (1). PET abnormality was found in A (8) and B (4). Histopathology showed focal cortical dysplasia (FCD) type I, in A (5) and B (1), oligodendrogliosis in A (3) and B (1). There was no difference regarding partial seizures (11 vs. 10), MRI abnormality (9 vs. 10), MEG spike clusters (12 vs. 10) and FCD type II (1 vs. 2). The resection areas were decided by motor function mapping, distributions of MEG spike clusters, interictal and ictal high frequency oscillations, and seizure onset zone. Postoperative hemiparesis was temporarily seen in 3/13 (A) and 1/11 (B).Ten (77%) out of 13 patients (A) and 8/11 (73%) patients (B) became seizure free after the resective surgery.Conclusions: The Rolandic sparing subtotal hemispherectomy can be offered to control drug-resistant epilepsy without cognitive and motor dysfunction in children. Epileptic spasms, abnormal PET and normal MRI are suggestive of FCD type I or oligodendrogliosis and might extend the fronto-temporo-parietal epileptogenic zone while sparing Rolandic cortex.