Abstracts

Rationale: Catastrophic epilepsy in infants, often due to extensive cortical dysplasia, has devastating consequences with respect to the brain development. Therefore, early epilepsy surgery during the period of brain plasticity to relieve the brain of seizure burden is critical (1). Removal of larger tissue volumes does not always guarantee better seizure outcome versus removal or disconnection of the epileptogenic region. We present 4 infants with catastrophic epilepsy who benefited from individualized tailored surgical disconnections of the epileptogenic zone, based on hypothesis of epileptogenic zone after intensive presurgical evaluation.Methods: All cases were discussed in a multidisciplinary epilepsy surgery conference. One neurosurgeon performed all procedures. Assessment of developmental outcome was based on the neuropsychological testing, clinical evaluations by epilepsy, neurology, and pediatrics. Surgical techniques: Patient 1: A right parasagittal perisylvian hemispherotomy was performed (4), via a frontotemporal craniotomy with a supra-sylvian entry into the lateral ventricle, followed by a complete corpus callosotomy, and frontobasal and insular disconnections. Mesial temporal structures were resected via extension from the temporal horn of the lateral ventricle. Patient 2: A right temporo-parieto-occipital TPO disconnection (2; Figure 1I: C, D) was done with modification of the peri-insular hemispherotomy, such that the suprasylvian portion of the case procedure consisted only of a leucotomy along the postcentral sulcus to the midline with posterior callosotomy to disconnect the temporal, occipital, and posterior parietal lobes while preserving frontal and central structures. The infrasylvian disconnection was done as with Patient 1. Patient 3: A left perisylvian parasagittal hemispherotomy (3) allowed access to the lateral ventricle through the posterior frontal lobe, followed by a total corpus callosotomy, transection of the ipsilateral fornix, and a leucotomy lateral to the thalamus to connect the frontal and temporal horns, from which the mesial temporal structures were removed, and a frontobasal disconnection completed the hemispherotomy. Patient 4: A modified parasagittal hemispherotomy was done, omitting the lateral thalamic and forniceal transaction transections, thus preserving the posterior frontal, temporal, and parietal structures. The frontobasal disconnection was performed as with Patient 3 (Figure 1II: B, C, D).Results: All patients had 90-100% seizure reduction and significantly improved neurodevelopmental outcomes (Table1). The epileptogenic zone was localized based on evidence collected during presurgical evaluation (Table1). Figure 1I, A, B illustrate neuroimaging congruence in patient 2. Figure 1II, A illustrates a left superior frontal cortical lesion in patient 4.Conclusions: Modifications of established surgical disconnection techniques, individualized to each patient’s patient's specific epileptogenic zone, optimized seizure outcomes and neurodevelopment, while minimizing the risks associated with larger surgical resections.