MULTIPLE SUBPIAL CORTICAL TRANSECTION (MST) FOR THE TREATMENT OF EXTENSIVE SEIZURE FOCI

Multiple subpial transection (MST) was used to treat 7 patients who ha d intractable epilepsy with extensive seizure foci involving more than one lobe and both hemispheres, and who have had a follow-up of at lea st 2 years. The longest follow-up is 61 months, with a median of 43 mo nths. Preoperative investigations included magnetic resonance scans, p ositron emission tomography scans, single photon emission computed tom ography scans, and video-EEG monitoring with scalp and subdural electr odes. Two patients' seizure foci were in both hemispheres, and 5 patie nts' foci were in 2 lobes of 1 hemisphere. The motor cortex was involv ed in 5 patients and the speech areas in 1 patient. MST at an interval of 4 mm was performed over all areas that showed seizure foci. Two pa tients are free of seizures, 1 patient is free of seizures involving t he operated hemisphere, 1 has rare seizures, 1 has >90% reduction in s eizure frequency, 1 has >70% reduction in seizure frequency, and 1 did not respond to MST. MST alone was able to control seizures to varying degrees, without producing a permanent deficit, in 84% of patients wi th intractable seizures originating from large areas of the cortex. (C ) 1997 by Elsevier Science Inc. All rights reserved.