Abstracts

Rationale: Intractable Epilepsy is one of many complications from Tuberous Sclerosis Complex (TSC) and is known to be adversely affecting the developmental outcome and the overall quality of life in the affected children. Epilepsy surgery can provide successful outcome in the selected children with well-localized tubers situated in the relatively non-eloquent areas. However, a surgery is commonly discouraged when the tubers are near or on the presumed functional cortex or when there is lack of pre-surgical functional map due to the limited cooperation from the young children. Methods: We identified 12 consecutive patients with TSC and intractable epilepsy who underwent epilepsy surgery at the Cincinnati Children's Hospital Medical Center from Sep 2006 to Dec 2007. The demographic data, results of pre-surgical and surgical evaluation including scalp EEG monitoring, MRI, PET, SPECT/SISCOM, MEG, and the intracranial EEGs were retrospectively reviewed if available. The epileptogenic zone was determined based on the ictal onset zone from the intracranial EEG and the anatomical/functional imaging results. The surgical outcome was assessed at 6 mo and 1 year post-op visit using Engel's classification. Neuropsychological function was evaluated at the same time and compared to the pre-op evaluation. Results: Among the 12 consecutive patients with TSC and intractabl partial epilepsy who has undergone a resective surgery, 7 (M:F = 3:4, age 1.5 - 13 yrs) had epileptogenic tubers localized to the eloquent areas: Rolandic (orofacial motor) area, 4; limb motor area, 2; Rolandic motor and sensory cortex, 1. Non-invasive functional mapping for the suspected epileptogenic zone was available only in 2 patients. Six patients underwent prolonged video-intracranial EEG monitoring with subsequent localization of the ictal onset zone and functional mapping using combination of cortical stimulation and evoked potential studies. One patient had a tuberectomy with intra-operative electrocorticogram without prolonged intracranial EEG. Three out of 7 patients (42%) became seizure free as of 1 year post-op visit. The other 4 patients had significant improvement in seizures (Engel's Class 2). Two patients had transient functional deficits (swallowing difficulty 1, speech impairment 1) immediately following surgery with a full recovery within a month. Conclusions: Our data showed that the functional impairment following the removal of epileptogenic tubers in the "presumed" eloquent cortex is minimal and recoverable. Early onset of intractable seizures and the presence of tubers since early life may be responsible for this finding. Resective surgery should not be discouraged solely based on the location of the suspected epileptogenic tubers in these children.