METHODS: We conducted a retrospective observational study at Children's Hospital Boston. Cases were ascertained from a research database of patients who underwent
epilepsy surgery from 1997 to 2011. Data were obtained from electronic medical records and office charts. Outcome after surgery was defined as improvement in
seizures (quantity and severity) represented by the Engel classification score measured at last follow-up, with a minimum of 12 months of follow-up. The need for reoperation for completion of hemispheric disconnection. We also examined whether placement of
ventriculoperitoneal shunt was required after
hemispherectomy was a secondary outcome.
RESULTS: We identified 36 patients who underwent
hemispherectomy for severe, medically
intractable epilepsy. Group 1 (n = 14) had static acquired lesions, and group 2 (n = 22) had
malformations of cortical development. Mean age at surgery for group 1 was 9 years (S.D. 5.5) and 2.77 years for group 2 (S.D. 4.01; P < 0.001). The seizure outcome was good in both groups (Engel score I for 25, II for three, III for six, and IV for two patients) and did not differ between the two groups. In group 1, five patients underwent anatomic
hemispherectomy (one had prior focal resection), four underwent
functional hemispherectomy, and five underwent peri-insular hemispherotomy; none required a second procedure. In group 2, a total of 14 patients had anatomic
hemispherectomy (of these, three had had limited prior focal resection), five had
functional hemispherectomy, and three had peri-insular hemispherotomy. Among the patients in group 2 who had had
functional hemispherectomy, one required reoperation to complete the disconnection and one required peri-insular hemispherotomy because of persistent
seizures. In group 1, three patients underwent a
ventriculoperitoneal shunt, and from these patients two underwent anatomic
hemispherectomy and one had
functional hemispherectomy. In group 2, 12 patients had
ventriculoperitoneal shunt, and all of them had anatomic
hemispherectomy as a first or second procedure.
CONCLUSION: Seizure outcome after
hemispherectomy is good in patients with acquired lesions and with developmental malformations. Although the seizure outcome was similar in the three procedures, the complication rate was higher with anatomic
hemispherectomy than with the more recent
functional hemispherectomy and peri-insular hemispherotomy. The group with cortical malformations generally had surgery at a younger age; two patients with
malformations of cortical development who underwent
functional hemispherectomy required second surgeries. The need for reoperation in these cases may reflect the anatomic complexity of developmental hemispheric malformations, which may lead to incomplete disconnection.