Multiple Subpial Transection for Control of Epileptic Seizures: Effectiveness and Safety

Abstract

Summary:Purpose: To assess the efficacy and safety of multiple subpial transection (MST), a new technique in epilepsy surgery, alone and in combination with resection.Methods: MST was performed in 22 patients with intractable epilepsy, 10 of whom were treated with a combination of a resection and MST in functionally important cortex, 6 of whom were treated with a combination of a resection and MST performed outside functionally important cortex, and 6 of whom were treated with MST alone.Results: Of the 6 patients who received MST alone, none became seizure free and 4 showed >50% reduction of all seizure types. In 2 patients, including 1 with Rasmussen's encephalitis, no change in seizure frequency or intensity occurred. Of the 16 patients in whom MST was combined with a resection, 9 (56%) became seizure free. Six of the remaining 7 patients showed >95% reduction of all seizure types. Disappearance of epileptiform potentials in the postoperative EEG correlated significantly with complete relief from seizures.Subtle, permanent neurological deficits remained in 5 of 14 patients who received MST in functionally important brain areas.Conclusions: Reduction of the seizure frequency was substantial in 4 of 6 patients who received MST alone, but complete seizure control was not observed. MST surrounding a lesionectomy may be a new surgical approach which would minimize the excised volume and improve seizure control. Key Words: Epilepsy surgery-Epileptogenic zone-Multiple subpial transection-Electrocorticography-Seizure outcome.In multiple subpial transection (MST), a new technique in epilepsy surgery (l), the main objective is to extend the surgical procedure into epileptogenic brain areas of high functional importance, such as the primary motor or speech areas, while avoiding unacceptable neurological deficits. In theory, MST disrupts horizontal neuronal interconnections essential for seizure spread, while preserving the descending vertical neuronal colstructural abnormality detected by magnetic resonance imaging (MRI) or intraoperatively. We wished to evaluate whether seizure control achieved by this method is similar to that achieved by a more extensive resection of a lesion and the perilesional epileptogenic cortex. If so, MST may prove to be a new approach to epilepsy surgery of circumscribed epileptogenic lesions. umns largely responsible for the underlying neuronal function. Recent studies have demonstrated efficacy of MST in seizure control without producing major neurological dysfunction (2-6). However, few patients have been treated exclusively with MST and separate data concerning this subgroup are frequently lacking (2,6). In the present study, we assessed seizure control and safety aspects in patients treated with MST alone or in combination with a resection. In a subgroup of patients, MST was performed outside functionally important brain areas surrounding a lesionectomy limited to the extent of a PATIENTS AND METHODSMST was performed in 22 patients (12 men, 10 women) aged 7 to 45 years (mean, 26 years) wi...

Multiple Subpial Transection for Intractable Partial Epilepsy: An International Meta‐analysis

“…Most previous reports found better results when resection was combined with MST than when MST was performed alone (4,5). We observed this discrepancy only for generalized seizures.…”

“…The approach was conceived and advocated for the specific situation in which resective surgery was precluded by the likelihood of neurologic compromise, and was later adapted for the treatment of some specific syndromes (2,3). Subsequently MST has been slowly (and somewhat randomly) adopted at many centers around the world, some of which have published experience with specific patient selection, seizure outcome, and neurologic status (4)(5)(6)(7)(8)(9)(10)(11)(12)(13).…”

“…Two thirds of the centers were in northeastern locations in the United States, and one European center contributed the largest number of patients (Table 1). Most centers included at least some previously published patients (4)(5)(6)8,12,14,15).…”

Epileptiform Propagation Patterns Mediated by NMDA and Non‐NMDA Receptors in Rat Neocortex

“…Multiple subpial transection (MST) is an increasingly popular surgical treatment for certain intractable forms of epilepsy (35)(36)(37)(38). The aim of MST is to sever critical sets of horizontal axons that mediate seizure spread, while sparing vertical columns of cortical neurons and connections that are thought to mediate the most essential aspects of neocortical function (39-42).…”

“…Slight technical variations of MST have been published by Morrell et al (36), Kaufman et al (43), and Hufnagel et al (35), and the efficacy of MST has been demonstrated when used alone and in conjunction with resection (35)(36)(37). But the success of MST must be assessed by considering both seizure control and postoperative neurologic function.…”