Endoscopic Hemispherotomy for Nonatrophic Rasmussen's Encephalopathy.

<bold>Background: </bold>Hemispheric disconnection represents a challenging and major epilepsy surgical procedure. This procedure in experienced hands offers excellent results in terms of seizure outcomes, especially for hemispheric pathologies such as Rasmussen's encephalitis, hemispheric dysplasias, hemimegalencephaly. The technique of hemispherotomy has witnessed various modifications over the years, beginning from anatomical hemispherectomy to the current era of minimally invasive functional hemispheric disconnections.<bold>Objective: </bold>This study aimed to describe the technique of performing endoscopic vertical hemispherotomy using interhemispheric corridor developed by the senior author.<bold>Materials and Methods: </bold>A 12-year-old girl with seizure onset at the age of 10 years presented with an aura of fear and nausea followed by tonic deviation of eyes to the right and blinking with speech arrest. There were tonic-clonic movements of the right-sided limbs along with ictal spitting and occasional deviation of the angle of mouth to the right. The patient had loss of awareness for the event along with postictal confusion lasting few minutes.<bold>Results: </bold>Video electroencephalography (VEEG) revealed left parietocentral and left temporal localization. Serial magnetic resonance imaging (MRI) brain over 3 years revealed progressive left hemispheric changes suggestive of Rasmussen's encephalitis. The patient underwent left-sided endoscopic hemispherotomy. At 2 years follow-up, the patient is seizure-free (ILAE [International League Against Epilepsy] Class 1).<bold>Conclusion: </bold>Endoscopic hemispherotomy using the interhemispheric approach is an elegant, minimally invasive, reproducible, safe, and efficacious technique. [ABSTRACT FROM AUTHOR]