Predictors of Insufficient Awakening During Awake Surgery: A Single-Center Retrospective Study

BACKGROUND AND OBJECTIVES: Awake surgery (AS) is widely performed for the resection of brain tumors and for epilepsy surgery. However, a non-negligible proportion of patients experience insufficient intraoperative awakening, leading to inadequate neurological monitoring. This retrospective study investigated predictive factors associated with insufficient intraoperative awakening. METHODS: We retrospectively reviewed 78 consecutive AS procedures for brain tumors and epilepsy performed at our institution between 2021 and 2024. Previously reported predictive factors for AS failure and contraindications for AS were evaluated, along with the presence of basal ganglionic involvement (BGI), defined as a high-intensity area on fluid-attenuated inversion recovery imaging involving the striatum and globus pallidus. RESULTS: Insufficient intraoperative awakening occurred in 13 cases (16.7%). Age (odds ratio [OR] per year, 1.04; 95% CI, 1.00-1.08), aphasia (OR, 4.18; 95% CI, 1.23-15.5), midline shift (OR, 7.85; 95% CI, 2.22-30.6), and BGI (OR, 118; 95% CI, 18.7-2352.2) were identified as factors associated with insufficient awakening using univariate logistic regression analysis. In multivariate logistic regression analysis, BGI remained independently associated with insufficient awakening (OR, 104.7; 95% CI, 16.4-2098.1). Preoperative corticosteroids were administered to 11 patients with glioblastoma to reduce peritumoral edema. Among 7 patients with glioblastoma and BGI at admission, BGI resolved preoperatively in 2 patients after corticosteroid therapy, and AS was successfully performed in both cases. Betamethasone was predominantly used, at a median dose of 4 mg/day and median preoperative treatment duration of 14 days. In both cases with resolved BGI, betamethasone was administered at 8 mg/day for more than 10 days. CONCLUSION: BGI may be one of the independent predictors of insufficient intraoperative awakening across a broader AS population. Preoperative administration of an adequate course of betamethasone may facilitate sufficient intraoperative awakening in patients with glioblastoma and BGI. Further multicenter studies are warranted.