Multiple subpial transection for intractable partial seizures: Seizure outcome

We studied 21 patients who underwent multiple subpial transections (MST) for the surgical treatment of intractable partial-onset seizures in whom the epileptogenic focus overlapped with primary sensorimotor or language cortex. All patients had intracranial EEG localization of seizures and functional mapping with electrical stimulation before surgery. Eighteen patients had cortical resections in addition to MST. At an average follow-up of 21 months, 13 patients either are seizure-free or are experiencing auras or simple partial seizures (SPS) only, 6 patients have had greater than 50% reduction in seizure frequency, 1 patient has had a modest reduction in seizures, and 1 patient is unchanged. MST in the 3 patients who did not undergo cortical resections reduced seizure frequency in all 3, although none are seizure- free. MST, combined with cortical resection, appears to be a safe and effective alternative to subtotal resection of the epileptogenic zone. MST alone, although not curative, reduced seizure frequency in all patients who underwent the procedure.