Resection of Gliomas with and without Neuropsychological Support during Awake Craniotomy—Effects on Surgery and Clinical Outcome

Language sites in the cortex of the brain vary among patients. Language mapping while the patient is awake is an intraoperative technique designed to minimize language deficits associated with brain-tumor resection. To study language function after brain-tumor resection with language mapping, we examined 250 consecutive patients with gliomas. Positive language sites (i.e., language regions in the cortex of the brain, 1 cm by 1 cm, which were temporarily inactivated by means of a bipolar electrode) were identified and categorized into cortical language maps. The tumors were resected up to 1 cm from the cortical areas where intraoperative stimulation produced a disturbance in language. Our resection strategy did not require identification of the stimulation-induced language sites within the field of exposure. A total of 145 of the 250 patients (58.0%) had at least one site with an intraoperative stimulation-induced speech arrest, 82 patients had anomia, and 23 patients had alexia. Overall, 3094 of 3281 cortical sites (94.3%) were not associated with stimulation-induced language deficits. A total of 159 patients (63.6%) had intact speech preoperatively. One week after surgery, baseline language function remained in 194 patients (77.6%), it worsened in 21 patients (8.4%), and 35 patients (14.0%) had new speech deficits. However, 6 months after surgery, only 4 of 243 surviving patients (1.6%) had a persistent language deficit. Cortical maps generated with intraoperative language data also showed surprising variability in language localization within the dominant hemisphere. Craniotomies tailored to limit cortical exposure, even without localization of positive language sites, permit most gliomas to be aggressively resected without language deficits. The composite language maps generated in our study suggest that our current models of human language organization insufficiently account for observed language function. Copyright 2008 Massachusetts Medical Society.

Surgical resection plays a central role in the management of gliomas. In this study, we review the evidence in support of extent of resection to improve survival, symptom management, and time to malignant transformation in low- and high-grade gliomas, and summarize the findings from our literature search regarding the role of extent of resection and intraoperative practices to maximize safety. There is a growing body of evidence supporting improved overall survival, improved progression-free survival, and superior quality of life with greater extent of resection. Additionally, a better understanding of central nervous system plasticity allows for a staged approach to the surgical management of low- and intermediate-grade gliomas. A number of intraoperative techniques have been utilized to offer safer glioma surgery with greater extent of resection. Approaches such as awake brain tumor surgery can be safely performed with low failure rates and excellent long-term functional outcomes.

Despite the growing use of intraoperative functional mapping in supratentorial low grade glioma (LGG) surgery, few studies have compared series of patients operated on without and with direct electrical stimulation (DES) by the same team. The present study compared the rate of LGG surgery performed in eloquent areas, the rate of postoperative sequelae, and the quality of resection during two consecutive periods in the same department-the first without and the second with the use of intraoperative electrophysiology. Between 1985 and 1996, 100 patients harbouring a supratentorial LGG underwent surgery with no functional mapping (S1). Between 1996 and 2003, 122 patients were operated on in the same department for a supratentorial LGG using intraoperative cortico-subcortical DES (S2). Comparison between the two series showed that 35% of LGGs were operated on in eloquent areas in S1 versus 62% in S2 (p<0.0001), with 17% severe permanent deficits in S1 versus 6.5% in S2 (p<0.019). On postoperative MRI, 37% of resections were subtotal and 6% total in S1 versus 50.8% and 25.4%, respectively, in S2 (p<0.001). In both groups, survival was significantly related to the quality of resection. The results of the present study allow, for the first time, quantification of the contribution of intraoperative DES in LGG resection. Indeed, the use of this method leads to the extension of indications of LGG surgery within eloquent areas; to a decrease in the risk of sequelae; and to improvement of the quality of tumour resection, with an impact on survival.