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

Abstract

Summary:Purpose: Because the number and variety of patients at any single facility is not sufficient for clinical or statistical analysis, data from six major epilepsy centers that performed multiple subpial transections (MSTs) for medically intractable epilepsy were collected.Methods: A meta-analysis was performed to elucidate the indications and outcome, and to assess the results of the procedure. Overall, 211 patients were represented with data regarding preoperative evaluation, procedures, seizure types and frequencies before and after surgery, postoperative deficits, and demographic information. Fifty-three patients underwent MST without resection.Results: In patients with MST plus resection, excellent outcome (>95% reduction in seizure frequency) was obtained in 87% of patients for generalized seizures, 68% for complex partial seizures, and 68% for simple partial seizures. For the patients who underwent MST without resection, the rate of excellent outcome was only slightly lower, at 71% for generalized, 62% for complex partial, and 63% for simple partial seizures. EEG localization, age at epilepsy onset, duration of epilepsy, and location of MST were not significant predictors of outcome for any kinds of seizures after MST, with or without resection. New neurologic deficits were found in 47 patients overall, comparable in MST with resection (23%) or without (19%).Conclusions: These preliminary results suggest that MST has efficacy by itself, with minimal neurologic compromise, in cases in which resective surgery cannot be used to treat uncontrolled epilepsy. MST should be investigated as a stand-alone procedure to allow further development of criteria and predictive factors for outcome. Key Words: Epilepsy surgeryMultiple subpial transection-MST-Refractory epilepsy.Based on anatomic and functional considerations, and on physiological observations in animal models, Morrell et al. (1) introduced the procedure of multiple subpial transections (MSTs) for the treatment of medically uncontrolled epilepsy. 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 (4-13).A confounding aspect of such reports is the tendency to combine MST with some cortical resection, such that the efficacy and the neurologic compromise associated with either component of the approach cannot easily be separately assessed. The variable nature and distribution of underlying substrate, coupled with small numbers of patients at any one center, limit valid multivariable analyses of factors predictive of response, or even a consideration of differential efficacy. Whether MST provides substantial reduction in a specific seizure type, whether this benefit is achieved...

Efficacy of Vagus Nerve Stimulation (VNS) after Multiple Subpial Transections (MST) for Extra-Temporal Seizure Foci

“…This is greater than 50% reduction in seizures in 86% of the patients at 2 years follow-up [12]. Similar results were seen in patients who had MST as the primary procedure for extra-temporal onset seizures [1,[3][4][5][6]. Effectiveness of VNS therapy as a primary surgical intervention for intractable epilepsy has been reported in several publications.…”

“…This is especially true for multifocal multi-lobar seizure onset seizures [1,3,4]. Multiple subpial transections (MST) is useful in these cases, but a small percentage of patients have suboptimal outcomes [5,6]. These patients could, potentially, benefit from VNS therapy.…”

Stereoelectroencephalography-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) in patients with drug-resistant focal epilepsy

“…In patients with drug-resistant epilepsy, the chance of achieving seizure freedom with subsequent antiepileptic drug treatments is modest [1] . Compared with other palliative treatments [2][3][4] such as vagus nerve stimulation (VNS) and deep brain stimulation (DBS), conventional open surgery is a better treatment option [5,6] .…”

“…In contrast to other palliative [2,3] treatments such as vagus nerve stimulation (30%-63% reduction of >50% of seizures) [4][5][6] , multiple subpial transection [32] , callosotomy [33] , or deep brain stimulation of the anterior nucleus of the thalamus (54% reduction of >50% of seizures) [6] , SEEG-guided RF-TC is a focal treatment targeted selectively at the epileptogenic zone (as is radiosurgery) [34,35] . Furthermore, SEEG-guided RF-TC efficacy is a predictor of outcome in patients who undergo conventional open surgery [17] .…”

How eloquent is eloquent?

“…Having performed eight resections of the SMA would account for >10% of (transient) deficits alone. Even the literature on multiple subpial resection (MST) alone indicates higher rates of transient neurological worsening [3,4].…”