Abstracts

Rationale: According to current literature, 80-90% of patients with Tuberous sclerosis complex (TSC) have epilepsy, often with seizure onset in the first 12 months of life, and a large proportion intractable to anticonvulsant medications.  Previous studies have demonstrated that surgical resection of the epileptogenic zone can achieve seizure freedom in children with TSC in 22-67% of cases, and that early control of seizure burden has a positive impact on development and cognitive outcome. Despite frequent multifocal or generalized electrographic findings or generalized seizure semiology, many can become candidates for epilepsy surgery if epileptic foci can be targeted by detailed pre-surgical evaluation.  Here we report our institutional experience in a case series of children with TSC and epilepsy surgery. Methods: A retrospective review was performed of all children with a clinical diagnosis of TSC and epilepsy surgery at the McGovern Medical School UT Health at Houston from January 2006 to May 2017. A total of 23 cases were identified, and findings including presurgical testing, surgeries performed, and seizure outcomes were evaluated. Results: The range for age of seizure onset was 1 day to 13 months old.  Epileptic spasms were identified in 15 cases and 65% of patients had 3 or more seizure types. All but one case had at least one type of seizure that was clinically categorized as generalized. Magnetoencephalography (MEG) was performed in 19 patients, and 8 patients (35%) had invasive intracranial monitoring with subdural grids or SEEG. The age at first surgery ranged from 7 weeks to 12 years. 10 patients had a single resective surgery, 2 had partial or complete corpus callosotomy alone, and multiple surgeries were performed in 11 cases.  Favorable seizure outcomes were found in 76% of cases (17/23), with 73% having Engel I or 2 outcome, with a range of time of follow up after the last surgery from 4 months to 9 years. Of the 11 cases with generalized or multifocal discharges on scalp EEG, 8 patients had good outcomes, with 4 becoming seizure free after 1 to 3 surgical procedures. Identification of a single seizure focus on MEG was associated with a seizure-free outcome in 60% of cases. Invasive monitoring was associated with seizure-free outcome in all but one case.  90% of cases with multiple surgical procedures had Engel I or II outcomes (Engel I in 36%, Engel 2 in 54%). Conclusions: This single center retrospective study demonstrates that favorable outcomes can be achieved with epilepsy surgery in children with TSC despite multifocal or generalized EEG findings, or non-focal seizure semiology.  Characterizing ictal onset on VEEG and use of other non-invasive testing such as magnetoencephalography can provide critical information that identifies surgical candidates, and intracranial monitoring and a multi-staged surgical process that targets the epileptic network is sometimes necessary to achieve favorable long-term outcome. Funding: None