Epilepsy surgery in children with tuberous sclerosis complex: Presurgical evaluation and outcome

Purpose: Children with tuberous sclerosis complex (TSC) benefit from excisi onal surgery if seizures can be localized to a single tuber. We evaluated t he role of noninvasive studies to localize the epileptogenic tuber/region ( ET/R) and the outcome of focal resection. Methods: We identified 21 children with TSC, ages 3 months to 15 years (mea n 4.8 years). All had video-(electroencephalogram) EEG and magnetic resonan ce imaging (MRI) scans, and 18 also had ictal single photon emission-comput ed tomography (SPECT) studies. An ET/R was localized in 17 patients. Thirte en patients underwent resection guided by intraoperative electrocorticograp hy (n = 7) or subdural monitoring (n = 6). Results: Interictal EEG revealed a principal spike focus (PSF) that corresp onded to the ET/R in 14 children. In seven, PSFs occurred in rhythmic runs. PSFs were not observed remote from the ET/R. Focal polymorphic slowing and attenuation occurred in the region of the PSF in 11 patients. Sixteen pati ents demonstrated an ictal focus corresponding to the ET/R. Ictal SPECT rev ealed focal hyperperfusion correlating with the ET/R in 10 patients. Althou gh the MRIs in all children revealed multiple tubers, the ET/R corresponded to a large discrete tuber in 8 patients and a calcified tuber in 13 patien ts. Patchy calcified tubers were also seen elsewhere in six patients. At a mean follow-up of 26 months, 9 of the 13 children who underwent surgery wer e seizure-free, one had greater than 75% reduction in seizures, two were un changed, and one was lost to follow-up. New seizures developed in one child from a contralateral tuber. Conclusions: Surgical resection of an ET/R alleviates seizures in most chil dren with TSC and intractable epilepsy, The scalp EEG and MRI help define t he ET/R and improve case selection when ictal SPECT is nonlocalizing.