Hemispherectomy for intractable unihemispheric epilepsy - Etiology vs outcome

Background: Surgical removal of one hemisphere has been performed for several decades to treat intractable unihemispheric epilepsy. A prior case series focused on the outcomes after 58 surgeries at Johns Hopkins Hospital in 1997. This series, and an additional 53 cases, were reviewed to bring the outcomes up to date. Methods: Charts of the 111 patients undergoing hemidecortications at the Pediatric Epilepsy Center from 1975 to 2001 were reviewed and families were contacted. Three children died in the immediate perioperative period and three were lost to follow-up immediately after surgery. Follow-up ranged from 3 months to 22 years. Results: Two children died several years later due to intractable seizures. Overall, 65% are seizure-free, 21% have occasional, non-handicapping seizures, and 14% have troublesome seizures. Eighty percent are on one anticonvulsant or none and 89% are able to walk without assistance. Etiology strongly predicted seizure outcome. Patients with migrational disorders are less likely to be seizure-free than all other etiologies (predominantly Rasmussen and congenital vascular injuries) combined (51% vs 71%, p = 0.05). Conclusions: Hemidecortication continues to be a beneficial procedure in reducing seizure frequency in cases of unilateral cortical epilepsy. Fewer children with migrational disorders are seizure-free.