Intraoperative Electrocorticography Monitoring Research Articles

Surgery guided with intraoperative electrocorticography in patients with low-grade glioma and refractory seizures.

OBJECTIVE Using intraoperative electrocorticography (ECoG) to identify epileptogenic areas and improve postoperative seizure control in patients with low-grade gliomas (LGGs) remains inconclusive. In this study the authors retrospectively report on a surgery strategy that is based on intraoperative ECoG monitoring. METHODS A total of 108 patients with LGGs presenting at the onset of refractory seizures were included. Patients were divided into 2 groups. In Group I, all patients underwent gross-total resection (GTR) combined with resection of epilepsy areas guided by intraoperative ECoG, while patients in Group II underwent only GTR. Tumor location, tumor side, tumor size, seizure-onset features, seizure frequency, seizure duration, preoperative antiepileptic drug therapy, intraoperative electrophysiological monitoring, postoperative Engel class, and histological tumor type were compared between the 2 groups. RESULTS Univariate analysis demonstrated that tumor location and intraoperative ECoG monitoring correlated with seizure control. There were 30 temporal lobe tumors, 22 frontal lobe tumors, and 2 parietal lobe tumors in Group I, with 18, 24, and 12 tumors in those same lobes, respectively, in Group II (p < 0.05). In Group I, 74.07% of patients were completely seizure free (Engel Class I), while 38.89% in Group II (p < 0.05). In Group I, 96.30% of the patients achieved satisfactory postoperative seizure control (Engel Class I or II), compared with 77.78% in Group II (p < 0.05). Intraoperative ECoG monitoring indicated that in patients with temporal lobe tumors, most of the epileptic discharges (86.7%) were detected at the anterior part of the temporal lobe. In these patients with epilepsy discharges located at the anterior part of the temporal lobe, satisfactory postoperative seizure control (93.3%) was achieved after resection of the tumor and the anterior part of the temporal lobe. CONCLUSIONS Intraoperative ECoG monitoring provided the exact location of epileptogenic areas and significantly improved postoperative seizure control of LGGs. In patients with temporal lobe LGGs, resection of the anterior temporal lobe with epileptic discharges was sufficient to control seizures.

Surgical Treatment of MRI-Negative Temporal Lobe Epilepsy Based on PET: A Retrospective Cohort Study

Introduction: Using retrospective and comparative methods, we aim to discuss the surgical treatment of magnetic resonance imaging (MRI)-negative temporal lobe epilepsy (TLE) presented with positive positron emission tomography (PET) results. Methods: From the viewpoint of semiology, demography, surgical treatment and prognosis evaluation, we compared 19 MRI-negative, PET-positive TLE patients to 41 TLE with hippocampal sclerosis patients, and then statistically analyzed the differences between these 2 cohorts. Results: Under intraoperative electrocorticography monitoring, all patients underwent successful standard anterior temporal lobectomy. It appears that there is no significant difference between the surgical outcome of MRI-negative/PET-positive TLE (Engle class I: 68.4%, Engle class I + II: 84.2%) and TLE with hippocampal sclerosis (Engle class I: 68.3%, Engle class I + II: 80.5%). The analysis also shows that to some extent MRI-negative, PET-positive TLE might be distinct from TLE with hippocampal sclerosis as a clinical entity, i.e. the former is not a subtype of the latter. History of febrile convulsion and occurrence of secondary generalized tonic-clonic seizure may possibly differentiate them from each other. Conclusion: Successful resective surgery of MRI-negative TLE based on PET can yield similar favorable results to TLE with hippocampal sclerosis. This study demonstrates that with reasonable presurgical workup, such TLE subtypes can be surgically treated without invasive intracranial electrode implantation.

Dysembryoplastic Neuroepithelial Tumor

Dysembryoplastic neuroepithelial tumors are rare, surgically curable, neuronal-glial neoplasms affecting young patients with intractable epilepsy. Its recognition is needed to avoid unnecessary adjuvant therapy. The authors reviewed the records of 15 patients with dysembryoplastic neuroepithelial tumors who underwent epilepsy surgery using intraoperative electrocorticography monitoring, including 8 males and 7 females (mean age, 15.8 years). Neuroimaging showed a predominantly intracortical location, the presence of septations, a triangular pattern of distribution, a lack of contrast enhancement, and an absence of peritumoral edema. Eleven cases were classified as complex type, 3 as simple type, and 1 as "nonspecific" type. Associated cortical dysplasia was found in 5 cases and leptomeningeal involvement in 1 case. Its immunophenotype suggested a pluripotential neuroepithelial origin. The mean follow-up was 37.5 months; 2 patients had tumor recurrence. Although they are generally benign neoplasms, recurrences sometimes occur. Complete resection of the tumor with the epileptogenic zone is important for a favorable outcome.

Surgical Treatment of Epilepsy with Chronic Cerebral Granuloma Caused by Schistosoma japonicum

To study the surgical treatment of epilepsy with cerebral granuloma caused by Schistosoma japonicum. Two hundred fifty cases of epilepsy caused by cerebral schistosomiasis from 1955 to 2004 were analyzed retrospectively. There were no deaths. Follow-up of 196 cases for 4-5 years after operation demonstrated that 180 cases (92%) were seizure-free or well-controlled. Surgical treatment should be considered when drug therapy fails to control epilepsy or the lesion shows mass effect. Intraoperative electrocorticography monitoring is helpful to define the extent of the resection of the lesion.