Right Peri-insular Hemispherotomy: 2-dimensional operative video

Abstract

This is a surgical technique video of a right peri-insular hemispherotomy in a child with Rasmussen’s encephalitis. The patient is a 5-year-old boy with focal onset impaired awareness seizures started 6 months before surgery, developing different subtypes of focal seizures and evolving to drug-resistant epilepsy. In neurological examination, he already had a left-sided hemiparesis with pyramidal signs. Magnetic resonance imaging showed right-sided cortical atrophy and fronto-insular subcortical hyperintensity signal areas. The preoperative electroencephalogram revealed frequent right-sided central mid temporal spikes. The history and complementary exams raised a hypothesis of Rasmussen’s encephalitis, a rare neurological condition, characterized by unilateral chronic inflammation of the cerebral cortex, causing drug-resistant epilepsy, and evolving to progressive neurological decline1. The hemispherotomy is an effective procedure aimed to isolate the entire hemisphere functionally with minimal removal of brain tissue, and remains the only cure for seizures caused by Rasmussen’s encephalitis2,3. Long-term seizure freedom may be achieved in around 80% of patients and improves quality of life4. It’s already accepted that briefer duration of epilepsy preceding the surgery is associated to better adaptive functioning postoperatively due to the high neuroplasticity of young patients4. Three years after surgery, the patient remains seizure free, walking without help.