Introduction: Intraoperative stimulation mapping (ISM) using electrocortical and subcortical mapping (awake craniotomy, AC) or evoked potentials has become a solid option for the resection of supratentorial low-grade gliomas in eloquent areas, but not as much for high-grade gliomas. This meta-analysis aims to determine whether ISM and AC improve overall survival and decrease neurological morbidity in patients with high-grade glioma as compared to resection under general anethesia (GA).
Methods: A systematic search was performed to identify relevant studies. Only adult patients were included who had undergone craniotomy for high-grade glioma (WHO grade III or IV) using ISM (among which AC) or GA. Primary outcomes were the rate of postoperative complications and overall postoperative survival. Secondary outcomes were extent of resection and percentage of eloquent areas.
Results: Review of 2,049 articles led tot the inclusion of 53 studies in the analysis, including 9,102 patients. The overall postoperative median survival in the AC group was significantly longer (16.87 versus 12.04 months; p<0.001) and the postoperative complication rate was significantly lower (0.13 versus 0.21; p<0.001). Extent of resection and preoperative patient KPS were indicated as prognostic factors, whereas patient KPS and the involvement of eloquent areas were identified as predictive factors.
Conclusions: These findings suggest that resection of high-grade glioma in eloquent areas using AC is associated with a significantly longer overall postoperative survival and a lower rate of postoperative complications. These data suggest that in these patients ISM and AC should be implemented in standard treatment. A prospective randomized study is therefore warranted.
Patient Care: Aggressive surgery is warrented in glioblastoma surgery, since the extent of resection improves survival in this patient group. However, since the majority of glioblastomas are located in eloquent areas, operating aggressively is often impossible due to imminent negative consequences for survival and quality of life (QoL). Hence, a surgical technique optimizing resection percentage of these tumors while preventing neurological deficits is necessary. Implementation of intraoperative stimulation mapping (ISM) and awake craniotomy (AC) made this endeavor possible in eloquently located low-grade glioma. Therefore, these techniques may be beneficial for resecting glioblastoma in eloquent areas as well. The current literature regarding the use of these techniques in glioblastoma surgery is insufficient. Our study advances current research by summarizing the evidence for the use of these techniques in glioblastoma surgery by investigating more than 9,000 patients, hereby laying the foundation for further research regarding the evidence-based use of these techniques in glioblastoma surgery.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Describe the value of ISM and AC in high-grade glioma surgery in a concise manner
2) Describe and discuss the opportunities for further research regarding the use of these techniques in high-grade glioma surgery