Abstract
Hemispherectomy and its modifications are the most effective treatment for intractable epilepsy with hemispheric foci. In this article, those procedures were historically overviewed, and then the anatomical background and surgical techniques of the latest modification, hemispherotomy, were illustrated along with our refinements. The major anatomical components to be disconnected in hemispherotomy are the corpus callosum and the projection fibers. For each, we compared the approaches we adopted. The interhemispheric callosotomy enabled more reliable disconnection of the callosal fibers than transventricular callosotomy and was especially advantageous for anomalous and asymmetric callosum frequently found in hemimegalencephaly. Transopercular disconnection of the projection fibers overcame the problems encountered in peninsular disconnection but resulted in a higher occurrence of impaired CSF circulation. Reviewing these results we recently adopted vertical hemispherotomy for use with our modification.
