The surgical treatment of secondary epilepsy caused by glioma in the eloquent cortical areas

Abstract

Objective To investigate surgical methods,secure and curative effects under intraoperative awake anesthesia combined with a multimodal approach of cerebral functional localization for the resection of glioma and epileptogenic foci in eloquent Cortical area.Methods 31 Consecutive patients suffering from secondary epilepsy caused by glioma in the eloquent area were treated with the asleep-awake -asleep-technique.According to MRIs,DTT and functional MRIs design operative plans before the operations.Craniotomy was performed under general anesthesia with the laryngeal mask.Then,awake anesthesia,and functional mapping,such as sense,motion,and language zones,was judged via intraoperative neurophysiologic monitoring (IOM).Epileptogenic foci were localized by electrocorticography (ECoG) monitoring and assisted with an intra-operative real-time ultrasound to locate the anatomical boundary of the tumors.Surgical resected tumors and epileptogenic foci were performed under awake surgery.Finally,the skull was closed under general anesthesia.Results 28 patients underwent asleep-awake-asleep successfully in 31 cases; other than a short period of delirium post operation in older patients,no painful or dreaded experiences occurred before and after operations.18 patients remained on laryngeal masks,while 10 patients pulled out the laryngeal mask before language mapping and reinserted the mask after mapping was finished.23 patients' cerebral functional areas were located by IOM; in five cases,eloquent areas were not found.Epileptogenic foci were discovered in 21 cases through ECoG monitoring.Total resection was achieved in 21 patients and subtotal resection in 7.Preoperative dysfunctions aggravated in 17 cases 2 days after operation,but all patients recovered in one month; no permanent or new complications were noted.Pathology:astrocytoma Ⅰ ～ Ⅱ grade was noted in 14 patients,Ⅲ ～ Ⅳgrade in 3,oligodendroglioma in 4,oligodendroglioma and glioblastoma in 2,and other types in 3 respectively.All patients were followed-up from 8 months to 4.3 years.In 18 cases,epileptic seizures disappeared completely and severity decreased in10 patients.Consequently,the effective rate was 100％.Unfortunately,tumor recurrences were noted in 16 cases; operation was performed in 9 Cases,radiotherapy in 4,relinquishment of treatment in 2 and fatality in 2.Conclusion The combination of awake anesthesia and the modern,multimodal Cerebral functional localization monitoring technique for secondary epilepsy caused by glioma in eloquent areas is a safe,effective and microinvasive treatment method. Key words: Eloquent area; Glioma; Secondary epilepsy; Awake anaesthesia; Intraoperative neurophysiologic monitoring; Electrocorticography