[Surgical treatment of epileptogenic hemimegalencephaly]

Abstract Thirteen children affected by hemimegalencephaly were observed in the Pediatric Section of the Institute of Neurosurgery of the Catholic University of Rome in the last six years. Nine of them were operated because of an intractable epilepsy. Seven were males and 2 females; the age at operation ranged between 7 months and 11 years (mean: three years and five months); the follow-up period varied between 1 and 6 years (mean 3 years and 10 months). All the patients had a clinical history of daily epileptic seizures not responsive to medical treatment; all of them presented with severely delayed psychomotor development. At neurological examination, six children showed a motor deficit of variable severity contralateral to the affected hemisphere and two patients a severe tetraparesis. The remaining child did not present with motor deficit. In all the cases the diagnosis had been obtained by CT scan and MRI. One of the cerebral hemispheres was abnormally enlarged with associated dilation of the lateral cerebral ventricle. The cortical architecture was obviously deranged with several areas of heterotopia of the gray substance suggesting an alteration of the neuronal cell migration. All the children underwent an extrathalamocaudato hemispherectomy. A post-operative ventriculo-peritoneal shunt was required in two cases. There were neither operative, nor late deaths. A dramatic reduction in the frequency and severity of epileptic seizures was observed in all but one of the patients of the series