Intraoperative electrocorticography during tumor resection: impact on seizure outcome in patients with gangliogliomas

Abstract

Gangliogliomas are indolent neoplasms that are often associated with long-standing intractable seizures. The seizure-free outcome following ganglioglioma resection alone (or "lesionectomy") has been generally favorable, ranging in most series from 50% to 65%. Thus, the value of resection of epileptogenic cortex in addition to tumor with regard to seizure outcome has been the subject of controversy. The authors describe a series of 12 patients with frontal or temporal lobe gangliogliomas associated with long-standing intractable seizures. In these patients, intraoperative electrocorticography was used to guide the resection of epileptogenic cortex along with tumor. Functional brain mapping, interictal and ictal monitoring of seizures, as well as thorough neuropsychological assessments were performed prior to resection in all cases. Outcome with regard to seizures, tumor recurrence, and neurological deficits was assessed with a mean follow-up period of 3.1 years. There was universal freedom from seizures postoperatively in 11 patients in whom complete or near-complete resection of epileptogenic cortex was achieved. In one patient in whom complete tumor resection and subtotal removal of epileptogenic cortex was achieved, a 95% reduction in seizure frequency was identified. No tumor recurrence or neurological deficits were observed. In a subset of four patients, neuropsychological and cognitive function were evaluated pre- and postoperatively. In these four, a clear trend toward improvement was noted in most functions. Thus, resection of epileptogenic cortex along with tumor may improve seizure outcome in selected patients with tumor-associated epilepsy without engendering identifiable neurological or cognitive deficits attributable to the incremental resection.

Patients with Epileptic Seizures and Cerebral Lesions Who Underwent Lesionectomy Restricted to or Associated with the Adjacent Irritative Area

“…According to Fried and Cascino (19), there is no standard surgical treatment for patients with epileptic seizures and cerebral lesions, but there are four surgical procedures that are frequently performed: restricted resection of the lesion; resection of the lesion associated with the adjacent area; resection of the lesion and of the distant epileptiform focus; and resection of the focus without lesionectomy, which is performed in cases in which the lesion is in areas that may result in neurologic sequelae if resected. Other authors (5,6,(8)(9)(10)(11)17) also describe lobectomies containing the lesion. Blume et al (20) and Fried and Cascino (19) stated that it is possible to control seizures even when resection of the cerebral lesion is partial, if resection of the irritative area, as identified by ECoG is also performed.…”

Merging Tradition with Innovation: Intraoperative Corticography and 7 Tesla Magnetic Resonance Imaging Sparing Chronic Intracranial Electrode Implantation in "Non-Lesional" Epilepsy Surgery

“…The semiology is variable, the epileptogenic zone is frequently broad and may coexist with hippocampal sclerosis ("dual pathology"), the interictal and ictal patterns multifocal, absent and occasional misleading and the imaging studies often unrevealing [8]. Most of the literature pertaining on the use of ECoG in extratemporal epilepsy stems from lesional cases [9][10][11][12], although prospective studies are lacking [13]. For non lesionalextratemporal resections the data is sparse [14].…”

Intractable Temporal Lobe Epilepsy from Benign and Malignant Amygdalo-hippocampal Anglioglioma; Icroneurosurgical Management. A Report of Two Cases with Short Literature Review

“…3,4 In certain developmental tumors, e.g., gangliogliomas and dysembryoplastic neuroepithelial tumors, which can be treated with excellent seizure-control rates in most patients. 16 Also, certain types of low-grade gliomas (e.g., isomorphic subtype of low-grade astrocytoma, pilocytic astrocytoma) can be operated on with excellent results. 17-20&21 In a series limited to preoperatively tailored resections for lesional (nonsclerotic) mesial TLE, satisfactory seizure control was obtained in 86% of patients.…”