Is Epilepsy Surgery on both Hemispheres Effective?

Abstract

Background: Patients with bilateral independent seizure foci are poor candidates for conventional resective epilepsy surgery. The authors have therefore used minimally invasive procedures to treat such patients. In this paper, the result of a large series of patients treated by this approach is examined to determine the effectiveness of this approach. Materials and Methods: The series had 61 patients. The range of follow-up was 15–90 months. The mean follow-up was 41.5 months with a median of 37 months. Patients’ ages at the time of surgery ranged from 3 to 54 years, with a mean of 11.3 and median of 6. Male to female ratio was 39/22. Fifty patients had complex partial seizures, 3 had Lennox-Gastaut syndrome, 4 had myotonic seizures, 2 had infantile spasm, and 2 had myoclonic seizures. Preoperative evaluation included: video electroencephalogram (EEG) monitoring using scalp electrodes, neuropsychological evaluation, magnetic resonance scans, positron emission topography and/or single photon emission computed tomography scans, magnetoencephalogram, Wada test and video EEG recording using subdural electrodes. Multiple subpial transection (MST) was the principle procedure. This procedure was supplemented (17 patients) with minimal cortical resection when intraoperative electroencephalogram indicated that an area failed to respond to MST. When an additional epileptogenic focus was present in the amygdala-hippocampus complex (5 patients), it was treated with stereotactic amygdala-hippocampotomy. The eloquent cortex was treated in 51 patients. The number of lobes treated was 2 in 5 patients, 3 in 5 patients, 4 in 10 patients, 5 in 2 patients, 6 in 38 patients and 8 in 1. Results: Seizure outcome based on Engel’s modified classification was as follows: 32 patients (52.45%) were class I, 5 (8.2%) were class II, 15 (24.59%) were class III, 3 (4.9%) were class IV and 6 (9.83%) were class V. There was no statistical difference between those who were operated on of the first half of the series and those who were operated on of the second half of the series (p = 0.1636). Similarly, there was no statistical difference between this series and two large series in which MST had been performed on one hemisphere (p values of 0.6863 and 0.7337). There was no statistical difference between those who had MST alone and those who had MST plus minimal cortical resection (p = 0.1698). There was no permanent neurological complication in this series. Conclusion: Patients with intractable epilepsy with independent seizure foci in both hemispheres can be safely treated with the approach described in this paper, and seizure control achieved by this approach is fairly satisfactory and similar to that reported in patients with surgery on one hemisphere.

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.…”

“…Further-more, the outcome is better than those who had MST alone, resection alone, or VNS therapy alone for extra-temporal onset epilepsy. The result of patients who had MST alone at our center has been described in our previous publications [1,3,4]. In addition, the improvement with VNS therapy after MST as the primary operation is significantly better that those who had VNS therapy following major resective surgery for extra-temporal seizures.…”

“…Treatment of medically intractable epilepsy is challenging [1]. Many surgical approaches have been devised to treat patients with intractable epilepsy.…”

“…Surgical treatment of extra-temporal onset seizures remains a challenge. 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].…”

Contradictory imaging and EEG results in resection surgery of bitemporal lobe epilepsy: A case report

“…This is a recently developed method for the treatment of epilepsy that reduces the frequency of disabling partial seizures and monitors epileptic discharges long enough to judge the side of the majority of the seizures, therefore enabling the modification of the surgical strategy (5,16–18,19). If epileptic activities of either side arise from the temporal neocortex, it is suggested that bipolar coagulation on functional cortices (BCFC) or multiple subpial transection (MST) are combined with selective amygdalohippocampectomy (SAH), respectively, according to the sites of the epileptogenic foci, i.e., in the amygdalohippocampal complex or temporal neocortex (20,21). Furthermore, it is suggested that additional points of view are sought in the treatment of similar cases of epilepsy.…”