Background: Glioma is associated with high recurrence and poor survival, despite the success of tumor resection surgery. This may be partly because the immune microenvironment within a glioma is susceptible to perioperative immunosuppression. Therefore, intraoperative anesthesia-related immunomodulators, such as scalp block, intravenous anesthesia, the opioid dosage administered, and transfusions, may influence oncological outcomes among patients with glioma. The aim of this retrospective study was to investigate the influence of anesthetic techniques on oncological outcomes after craniotomy for glioma resection, particularly the effects of scalp block, intravenous anesthesia, and inhalation anesthesia.Methods: Consecutive patients who underwent primary glioma resection surgeries between January 2010 and December 2017 were analyzed to compare postcraniotomy oncological outcomes (progression-free survival [PFS] and overall survival) by using the Kaplan-Meier method and multivariate Cox regression analysis. A propensity score-matched regression analysis including prognostic covariates was also conducted to analyze the selected relevant anesthetic factors of the unmatched regression model.Results: A total of 230 patients were included in the final analysis. No analyzed anesthetic factor was associated with overall survival. Patients who received scalp block had a more favorable median (95% confidence interval [CI]) PFS (55.37 [95% CI,] mo; P = 0.0053). Scalp block was associated with improved PFS before (hazard ratio, 0.465; 95% CI, 0.272-0.794; P = 0.0050) and after (hazard ratio, 0.367; 95% CI, 0.173-0.779; P = 0.0091) propensity scorematched Cox regression analysis. By contrast, intravenous anesthesia, amount of opioid consumed, and transfusion were not associated with PFS. Conclusions:The study results suggest that the scalp block improves the recurrence profiles of patients receiving primary glioma resection.

Background: The bispectral index (BIS) may be unreliable to gauge anesthetic depth when dexmedetomidine is administered. By comparison, the electroencephalogram (EEG) spectrogram enables the visualization of the brain response during anesthesia and may prevent unnecessary anesthetic consumption. Methods: This retrospective study included 140 adult patients undergoing elective craniotomy who received total intravenous anesthesia using a combination of propofol and dexmedetomidine infusions. Patients were equally matched to the spectrogram group (maintaining the robust EEG alpha power during surgery) or the index group (maintaining the BIS score between 40 and 60 during surgery) based on the propensity score of age and surgical type. The primary outcome was the propofol dose. Secondary outcome was the postoperative neurological profile.Results: Patients in the spectrogram group received significantly less propofol (1585 ± 581 vs. 2314 ± 810 mg, P < 0.001). Fewer patients in the spectrogram group exhibited delayed emergence (1.4% vs. 11.4%, P = 0.033). The postoperative delirium profile was similar between the groups (profile P = 0.227). Patients in the spectrogram group exhibited better in-hospital Barthel’s index scores changes (admission state: 83.6 ± 27.6 vs. 91.6 ± 17.1; discharge state: 86.4 ± 24.3 vs. 85.1 ± 21.5; group–time interaction P = 0.008). However, the incidence of postoperative neurological complications was similar between the groups.Conclusions: EEG spectrogram–guided anesthesia prevents unnecessary anesthetic consumption during elective craniotomy. This may also prevent delayed emergence and improve postoperative Barthel index scores.

High-grade gliomas are notorious for a high recurrence rate even after curative resection surgery. Studies regarding the influence of scalp block on high-grade gliomas have been inconclusive, possibly because the condition’s most important genetic mutation profile, namely the isocitrate dehydrogenase 1 (IDH1) mutation, had not been analyzed. Therefore, we conducted a single-center study including patients with high-grade glioma who underwent tumor resection between January 2014 and December 2019. Kaplan–Meier survival analysis revealed that scalp block was associated with longer progression-free survival (PFS; 15.17 vs. 10.77 months, p = 0.0018), as was the IDH1 mutation (37.37 vs. 10.90 months, p = 0.0149). Multivariate Cox regression analysis revealed that scalp block (hazard ratio: 0.436, 95% confidence interval: 0.236–0.807, p = 0.0082), gross total resection (hazard ratio: 0.405, 95% confidence interval: 0.227–0.721, p = 0.0021), and IDH1 mutation (hazard ratio: 0.304, 95% confidence interval: 0.118–0.784, p = 0.0138) were associated with better PFS. Our results demonstrate that application of scalp block, regardless of IDH1 profile, is an independent factor associated with longer PFS for patients with high-grade glioma.