Postoperative ischemia and neurological deficits after glioma resection: A systematic review and meta-analysis

Background. Postoperative ischemia is a known complication of glioma resection that is registered by diffusion-weighted MRI (DWI) and can lead to new neurological deficits. The aim of this review was to assess the incidence of ischemia after glioma resection and identify potential risk factors and consequences. Methods: A systematic review was conducted according to the PRISMA guidelines. Cohort studies reporting surgeries for WHO grade II-IV gliomas followed by postoperative DWI within 72 h were included. Pooled, weighted incidences for postoperative ischemia and neurological deficits were calculated with a binary random-effects model. Results: In total, 29 studies were included in this review, of which 25 studies with 2729 cases were included for meta-analysis. Pooled incidence was 48% (95% confidence interval [CI]: 36%-59%) for postoperative ischemia and 32% (95% CI: 23%-41%) for postoperative transient and persistent neurological deficits. Postoperative ischemia with any neurological deficits occurred in 15% (95% CI: 10%-20%) of patients, postoperative ischemia without neurological sequelae in 26% (95% CI: 17%-35%), and 41% (95% CI: 30%-52%) of patients with postoperative ischemia experienced neurological deterioration. Postoperative ischemia was associated with opercular, insular, or temporal tumor locations, proximity to and infiltration of perforating arteries, prior radiotherapy, age and intraoperative hemodynamic decline, among others. Postoperative ischemia was related to neurological deterioration, recurrence, and overall survival in some studies. Conclusion: Postoperative ischemia is a quite frequent complication of glioma resection affecting functional outcome and disease progression. Potential risk factors may give insight in preventive measures and future studies with precise spatial analyses could identify vulnerable brain regions.