Abstracts

Rationale: Children with unilateral cortical dysplasia may present with intractable focal seizures in infancy or early childhood that are refractory to anti-epileptic drugs (AEDs). Uncontrolled seizures can be associated with stagnation or regression of neuro-cognitive development likely secondary to a combination of seizures and polytherapy with AEDs. In such children epilepsy surgery can be a successful treatment option. Methods: The medical records of patients who underwent functional hemispherectomy for intractable epilepsy secondary to cortical dysplasia between 2006 and 2012 at a large tertiary care academic center were reviewed. Results: Six cases were identified. - 4 patients had focal cortical dysplasia, 1 hemimegalencephaly and 1 had diffuse dysplasia of the right hemisphere. - Ages ranged from 8 months to 6.5 years with median age of 2.8 years. - 4 of 6 patients had cortical dysplasia involving the left hemisphere. - 3 of 6 patients had undergone previous focal frontal resections prior to hemispherectomy. - 1 patient required additional resection after functional hemispherectomy for residual tissue. - Follow-up ranged from 2 months to 4 years, average 2 years. 4 of 6 patients had an Engel class 1a outcome and 2 of 6 patients had an Engel class 1b outcome. - 4 of 6 patients had mild to moderate hemiparesis prior to hemispherectomy. (2 of them subsequent to a focal frontal resection). - Post-operatively contralateral hemiplegia slowly improved in all patients with arm recovery being incomplete. All 6 were ambulating independently at follow up. - Significant improvement in cognitive and developmental abilities was noted after surgery. 4/6 patients underwent left hemispherectomy. 3 of these 4 patients had improved language function at follow up (1y 3m and 4 years). - EEG in 3/6 patients showed multifocal or generalized spikes, although imaging and clinical exam did not show evidence of migrational abnormality in the contralateral hemisphere. - Pathology confirmed focal cortical dysplasia in all 6 cases. - Complications were limited to expected hemiplegia. Conclusions: 1. Very early hemispherectomy has been reported in literature in children as young as 2 months. Based on our series early surgery should be considered in well selected infants and young children with severe epilepsy and unilateral hemispheric cortical dysplasia to optimize seizure control and to minimize the effect of catastrophic epilepsy on the developing brain. 2. Epilepsy surgery in the presence of multifocal or generalized epileptiform discharges in a child with unihemispheric cortical dysplasias is compatible with good outcome for seizure control. Clinical examination, MRI findings and other imaging data should however be concordant. The diffuse electrographic abnormalities may be due to the impact of the epileptogenic lesion on the developing brain. 3. Hemispherectomy may be considered after failed focal resections of cortical dysplasia.