Surgical management of medically refractory epilepsy due to early childhood stroke

Abstract

OBJECT.: The risk of developing epilepsy after perinatal stroke, hypoxic/ischemic injury, and intracerebral hemorrhage is significant, and seizures may become medically refractory in approximately 25% of these patients. Surgical management can be difficult due to multilobar or bilateral cortical injury, nonfocal or poorly lateralizing video electroencephalography (EEG) findings, and limited functional reserve. In this study the authors describe the surgical approaches, seizure outcomes, and complications in patients with epilepsy due to vascular etiologies in the perinatal period and early infancy.

Methods: The records were analyzed of 19 consecutive children and adults with medically refractory epilepsy and evidence of perinatal arterial branch occlusions, hypoxic/ischemic insult, or hemorrhagic strokes, who underwent surgery at the Comprehensive Epilepsy Center of Beth Israel Medical Center and St. Luke's-Roosevelt Hospital Center. Preoperative findings including MRI, video EEG, functional MRI, and neuropsychological testing were analyzed. The majority of patients underwent staged operations with invasive mapping, and all patients had either extra- or intraoperative functional mapping.

Results: In 7 patients with large porencephalic cysts due to major arterial branch occlusions, periinsular functional hemispherotomy was performed in 4 children, and in 3 patients, multilobar resections/disconnections were performed, with 1 patient undergoing additional resections 3 years after initial surgery due to recurrence of seizures. All of these patients have been seizure free (Engel Class IA) after a mean 4.5-year follow-up (range 15-77 months). Another 8 patients had intervascular border-zone ischemic infarcts and encephalomalacia, and in this cohort 2 hemispherotomies, 5 multilobar resections/disconnections, and 1 focal cortical resection were performed. Seven of these patients remain seizure free (Engel Class IA) after a mean 4.5-year follow-up (range 9-94 months), and 1 patient suffered a single seizure after 2.5 years of seizure freedom (Engel Class IB, 33-month follow-up). In the final 4 patients with vascular malformation-associated hemorrhagic or ischemic infarction in the perinatal period, a hemispherotomy was performed in 1 case, multilobar resections in 2 cases, and in 1 patient a partial temporal lobectomy was performed, followed 6 months later by a complete temporal and occipital lobectomy due to ongoing seizures. All of these patients have had seizure freedom (Engel Class IA) with a mean follow-up of 4.5 years (range 10-80 months). Complications included transient monoparesis or hemiparesis in 3 patients, transient mutism in 1 patient, infection in 1 patient, and a single case of permanent distal lower-extremity weakness. Transient mood disorders (depression and anxiety) were observed in 2 patients and required medical/therapeutic intervention.

Conclusions: Epilepsy surgery is effective in controlling medically intractable seizures after perinatal vascular insults. Seizure foci tend to be widespread and rarely limited to the area of injury identified through neuroimaging, with invasive monitoring directing multilobar resections in many cases. Long-term functional outcomes have been good in these patients, with significant improvements in independence, quality of life, cognitive development, and motor skills, despite transient postoperative monoparesis or hemiparesis and occasional mood disorders.

Keywords: AED = antiepileptic drug; EEG = electroencephalography; MCA = middle cerebral artery; MTS = mesial temporal sclerosis; PCA = posterior cerebral artery; electrocorticography; epilepsy; fMRI = functional MRI; mRS = modified Rankin Scale; perinatal; porencephalic; stroke; vascular disorders.