Cerebral hemispherectomy

Abstract

Cerebral hemispherectomy has become a routine surgical procedure for control of intractable seizures, especially in young patients at risk for epileptic encephalopathies. Pediatric centers report that 20%–40% of patients undergoing surgery have a hemispherectomy.1,2 Despite preexisting neurologic deficits, many patients achieve substantial cognitive benefits, particularly from early seizure control, leading to productive lives and even attendance at college or vocational schools (www.hemifoundation.intuitwebsites.com).3 Cerebral hemispherectomy is justified in individuals with seizures from static and progressive unihemispheric etiologies, such as cortical dysplasia, perinatal infarcts, Sturge-Weber syndrome, and Rasmussen encephalitis (figure, A). More controversial and still in clinical evolution is what to do when neuroimaging indicates asymmetric bihemispheric epileptogenic lesions (figure, B) or no abnormal findings by MRI (figure, C). Figure Spectrum of neuroimaging abnormalities observed in cerebral hemispherectomy patients All cases presented are seizure-free after surgery. (A) Unihemispheric MRI abnormality. Right peri-Sylvian atrophy is observed from Rasmussen encephalitis. The left hemisphere is normal by MRI. (B) Bihemispheric asymmetric MRI abnormality. Infant with right-sided hemimegalencephaly (short arrows) associated with mostly right but bihemispheric EEG interictal and ictal findings. In addition to a smaller left hemisphere compared with the right, there is a left mesial frontal area of cortical dysplasia (long arrow). Because of a significant risk of an epileptic encephalopathy, this child proceeded to right …