Chapter 15 - Multiple Subpial Transection in the Treatment of Neuronal Migration Disorders: Basic and Clinical Approaches

Abstract

This chapter describes the effect of multiple subpial transection (MST) in an exerimental model of focal cortical seizures and in patients with neuronal migrational disorders, especially with focal cortical dysplasia. Intra-amygdala injection of kainic acid (KA) acutely induces limbic seizure status as well as spontaneous secondarily generalized seizure. The cortical epileptic focus was produced in six cats by the injection of KA into the cerebral cortex. It is found that hemosiderin deposit in the cortical layer around MST and gliosis further progressed to form cicatrix with localized atrophy of the cerebral cortex. MST is a good alternative for treating intractable focal epilepsy, when an epileptogenic focus is located in an unresectable eloquent cortex, such as the motor, sensory, visual, or speech cortex. Unilateral KA injection into the sensorimotor cortex in cats resulted in a transient focal motor status with occasional secondary generalization for a period of 5 hour. In patients with focal cortical dysplasia, MST was performed when the epileptogenic focus overlapped with eloquent cortex. Post-MST electrocorticographic demonstrated a good suppression of the spikes. These results suggest that MST is an effective surgical procedure for focal epilepsy.