Abstracts

Polymicrogyria often affects the perisylvian regions uni or bilaterally, and may lead to refractory partial seizures. Resective surgical approaches are usually not considered due to involvement of eloquent cortex by the malformation. We report two adult patients with disbling partial epilepsy associated with unilateral perisylvian polymicrogyria, in whom partial lesion resection led to significant seizure control. Two women, 28 and 51 years-old, respectively, with disabling, daily, complex and motor partial and secondarily generalized seizures for more than 20 years, underwent a noninvasive presurgical protocol. MRI showed extensive unilateral perisylvian polymicrogyria in the right hemisphere, involving portions of the insula, as well as of the temporal and frontal lobe. Ictal and interictal EEGs localized the abnormalities to the lesioned hemisphere. The younger patient had a mild contralateral hemiparesis. Resective surgery was guided by acute EcoG and cortical stimulation. Acute ECoG showed a massive predominance of interictal discharges in the temporal lobe in one, and in the temporal lobe and the inferior portion of the suprasylvian region in the other. A resection of the polymicrogyric cortex involving the temporal lobe, including the depths of the first temporal gyrus, was performed in both patients. The younger patient had, in addition, subpial resection of the inferior third of the pre and post-central gyrus and of the lateral opercular frontal cortex. After 18 months of follow up, the younger patient has only occasional simple partial motor seizures involving the left hand, and the older one has only auras, without disconnection from the environment. Resection of the most epileptogenic portions of large perysilvian polymicrogyric lesions can lead to significant seizure control without surgical complications.