Preoperative assessment of eloquence in neurosurgery: a systematic review.

BACKGROUND AND OBJECTIVES: Tumor location and eloquence are two crucial preoperative factors when deciding on the optimal treatment choice in glioma management. Consensus is currently lacking regarding the preoperative assessment and definition of eloquent areas. This systematic review aims to evaluate the existing definitions and assessment methods of eloquent areas that are used in current clinical practice. METHODS: A computer-aided search of Embase, Medline (OvidSP), and Google Scholar was performed to identify relevant studies. This review includes articles describing preoperative definitions of eloquence in the study's Methods section. These definitions were compared and categorized by anatomical structure. Additionally, various techniques to preoperatively assess tumor eloquence were extracted, along with their benefits, drawbacks and ease of use. RESULTS: This review covers 98 articles including 12,714 participants. Evaluation of these studies indicated considerable variability in defining eloquence. Categorization of these definitions yielded a list of 32 brain regions that were considered eloquent. The most commonly used methods to preoperatively determine tumor eloquence were anatomical classification systems and structural MRI, followed by DTI-FT, functional MRI and nTMS. CONCLUSIONS: There were major differences in the definitions and assessment methods of eloquence, and none of them proved to be satisfactory to express eloquence as an objective, quantifiable, preoperative factor to use in glioma decision making. Therefore, we propose the development of a novel, objective, reliable, preoperative classification system to assess eloquence. This should in the future aid neurosurgeons in their preoperative decision making to facilitate personalized treatment paradigms and to improve surgical outcomes.

Impact of dedicated neuro-anesthesia management on clinical outcomes in glioblastoma patients: A single-institution cohort study.

BACKGROUND: Glioblastomas are mostly resected under general anesthesia under the supervision of a general anesthesiologist. Currently, it is largely unkown if clinical outcomes of GBM patients can be improved by appointing a neuro-anesthesiologist for their cases. We aimed to evaluate whether the assignment of dedicated neuro-anesthesiologists improves the outcomes of these patients. We also investigated the value of dedicated neuro-oncological surgical teams as an independent variable in both groups. METHODS: A cohort consisting of 401 GBM patients who had undergone resection was retrospectively investigated. Primary outcomes were postoperative neurological complications, fluid balance, length-of-stay and overall survival. Secondary outcomes were blood loss, anesthesia modality, extent of resection, total admission costs, and duration of surgery. RESULTS: 320 versus 81 patients were operated under the anesthesiological supervision of a general anesthesiologist and a dedicated neuro-anesthesiologist, respectively. Dedicated neuro-anesthesiologists yielded significant superior outcomes in 1) postoperative neurological complications (early: p = 0.002, OR = 2.54; late: p = 0.003, OR = 2.24); 2) fluid balance (p<0.0001); 3) length-of-stay (p = 0.0006) and 4) total admission costs (p = 0.0006). In a subanalysis of the GBM resections performed by an oncological neurosurgeon (n = 231), the assignment of a dedicated neuro-anesthesiologist independently improved postoperative neurological complications (early minor: p = 0.0162; early major: p = 0.00780; late minor: p = 0.00250; late major: p = 0.0364). The assignment of a dedicated neuro-oncological team improved extent of resection additionally (p = 0.0416). CONCLUSION: GBM resections with anesthesiological supervision of a dedicated neuro-anesthesiologists are associated with improved patient outcomes. Prospective evidence is needed to further investigate the usefulness of the dedicated neuro-anesthesiologist in different settings.

Awake craniotomy versus craniotomy under general anesthesia without surgery adjuncts for supratentorial glioblastoma in eloquent areas: a retrospective matched case-control study.

BACKGROUND: Awake craniotomy with electrocortical and subcortical mapping (AC) has become the mainstay of surgical treatment of supratentorial low-grade gliomas in eloquent areas, but not as much for glioblastomas. OBJECTIVE: This retrospective controlled-matched study aims to determine whether AC increases gross total resections (GTR) and decreases neurological morbidity in glioblastoma patients as compared to resection under general anesthesia (GA, conventional). METHODS: Thirty-seven patients with glioblastoma undergoing AC were 1:3 controlled-matched with 111 patients undergoing GA for glioblastoma resection. The two groups were matched for age, gender, preoperative Karnofsky Performance Score (KPS), preoperative tumor volume, tumor location, and type of adjuvant treatment. Primary outcomes were extent of resection and the rate of postoperative complications. The secondary outcome was overall postoperative survival. RESULTS: After matching, there were no significant differences in clinical variables between groups. Extent of resection was significantly higher in the AC group: mean extent of resection in the AC group was 94.89% (SD = 10.57) as compared to 70.30% (SD = 28.37) in the GA group (p = 0.0001). Furthermore, the mean rate of late minor postoperative complications in the AC group (0.03; SD = - 0.16) was significantly lower than in the GA group (0.15; SD = 0.39) (p = 0.05). No significant differences between groups were found for the other subgroups of postoperative complications. Moreover, overall postoperative survival did not differ between groups (p = 0.297). CONCLUSION: These findings suggest that resection of glioblastoma using AC is associated with significantly greater extent of resection and less late minor postoperative complications as compared with craniotomy under GA without the use of surgery adjuncts. However, due to certain limitations inherent to our study design (selection bias) and the absence of the use of surgery adjuncts in the GA group, we advocate for a prospective study to further build upon this evidence and study the use of AC in glioblastoma patients.