[Destruction of apical dendritic layers in penicillin-induced cortical epileptic focus]

It has been generally accepted that topectomy is a choice of treatment for patients who have an intractable cortical epileptic focus. However, the surgery is not indicated in the cases whose focus is functionally involved in the vital cortical regions. We have experienced a case of intractable traumatic cortical epilepsy, in which the patient underwent cortical surface coagulation on his motor cortex during the dissection of his wide-spread durocortical adhesion. Subsequently, his epileptic attacks have been abolished completely for over 7 years without motor deficit. It is the purpose of this work to confirm experimentally that destruction of apical dendrites on the epileptic focus may prevent occurrence of abnormal spike epileptic discharges without vital neuronal deficit. Fifty dogs were used in this study. In normal dogs, the antidromic cortical response, after stimulation of the internal capsule, showed three predominant negative waves axonal (the first), cortical neuronal (the second) and apical dendritic potentials (the third) by surface recordings. Upon creation of the penicillin-induced cortical epileptic focus, spike discharges appeared on the corticogram, and the third wave of the antidromic cortical response shifted from negative to positive. Selected destruction of the dendrites, in the first and the second cortical layers, in the area of the epileptic focus brought about disappearance of the third wave, to isopotentially, and a marked inhibition or complete disappearance of spikes on the corticograms. The possibility exists, as been suggested by our experiment, to clinically apply this method as a treatment for intractable cortical epilepsy with foci in the functionally vital regions, although there are yet many problems to be solved.