[The Current Status of Corpus Callosotomy for Epilepsies]

Surgery is considered a therapeutic option for drug-resistant epilepsies. As a first step, the epileptic focus is carefully examined using extra- and intra-cranial EEG and various neurodiagnostic imaging techniques, such as magnetic resonance imaging, intra-ictal single photon emission computed tomography, magnetoencephalography, and functional near-infrared spectoroscopy. Only when the epileptogenic focus can not be identified, callosotomy is considered as a palliative surgical method. It is indicated especially in cases with drop attacks, which severely exacerbate the patient's quality of life. Almost complete drop attack remission can be expected after callosotomy. Each year, about 40 cases of callosotomy are registered in Japan. Postsurgical split-brain syndromes are observed for several months and gradually disappear, especially in young children.