Functional hemispherotomy for epilepsy in the very young

OBJECTIVE Epilepsy is one of the most common neurological disorders in children. Among very young children, one-third are resistant to medical treatment, and lack of effective treatment may result in adverse outcomes. Although functional hemispherotomy is an established treatment for epilepsy, its outcome in the very young child has not been widely reported. In this study the authors investigated seizure and developmental results after hemispherotomy in children younger than 3 years. METHODS The authors reviewed a prospective database of all children younger than 3 years with medically intractable epilepsy who underwent functional hemispherotomy at the authors’ institution during the period between 2012 and 2020. Demographic data, epilepsy history, underlying etiology, operative and transfusion details, and seizure and developmental outcomes were analyzed. RESULTS Twelve patients were included in this study. The mean age (± SD) at seizure onset was 3 ± 2.6 months and at surgery was 1.3 ± 0.77 years, with a mean follow-up of 4 years. Diagnoses included hemimegalencephaly (n = 5), hemidysplasia (n = 2), hypoxic/hemorrhagic (n = 2), traumatic (n = 1), Sturge-Weber syndrome (n = 1), and mild hemispheric structural abnormality with EEG/PET correlates (n = 1). Eleven patients achieved an Engel class I outcome, and 1 patient achieved Engel class IV at last follow-up. No deaths, infections, cerebrovascular events, or unexpected long-term neurological deficits were recorded. All children progressed neurodevelopmentally following surgery, but their developmental levels remained behind their chronological age, with an overall mean composite Vineland Adaptive Behavior Scale score of 58 (normal: 86–114, low: < 70). One patient required insertion of a subdural peritoneal shunt, 1 patient required dural repair for a CSF fluid leak, and 1 patient required aspiration of a pseudomeningocele. In 2 patients, both of whom weighed less than 5.7 kg, the first operation was incomplete due to blood loss. CONCLUSIONS Hemispherotomy in children younger than 3 years offers excellent seizure control and an acceptable risk-to-benefit ratio in well-selected patients. Families of children weighing less than 6 kg should be counseled regarding the possibility of staged surgery. Postoperatively, children continue to make appropriate, despite delayed, developmental progress.