Awake vs. asleep motor mapping for glioma resection: a systematic review and meta-analysis

Background: Intraoperative stimulation (IS) mapping has become the preferred standard treatment for eloquent tumors as it permits a more accurate identification of functional areas, allowing surgeons to achieve higher extents of resection (EOR) and decrease postoperative morbidity. For lesions adjacent to the perirolandic area and descending motor tracts, mapping can be done with both awake craniotomy (AC) and under general anesthesia (GA). Objective: We aimed to determine which anesthetic protocol—AC vs. GA—provides better patient outcomes by comparing EOR and postoperative morbidity for surgeries using IS mapping in gliomas located near or in motor areas of the brain. Methods: A systematic literature search was carried out to identify relevant studies from 1983 to 2019. Seven databases were screened. A total of 2351 glioma patients from 17 studies were analyzed. Results: A random-effects meta-analysis revealed a trend towards a higher mean EOR in AC [90.1% (95% C.I. 85.8–93.8)] than with GA [81.7% (95% C.I. 72.4–89.7)] (p = 0.06). Neurological deficits were divided by timing and severity for analysis. There was no significant difference in early neurological deficits [20.9% (95% C.I. 4.1–45.0) vs. 25.4% (95% C.I. 13.6–39.2)] (p = 0.74), late neurological deficits [17.1% (95% C.I. 0.0–50.0) vs. 3.8% (95% C.I. 1.1–7.6)] (p = 0.06), or in non-severe [28.4% (95% C.I. 0.0–88.5) vs. 20.1% (95% C.I. 7.1–32.2)] (p = 0.72), and severe morbidity [2.6% (95% C.I. 0.0–15.5) vs. 4.5% (95% C.I. 1.1–9.6)] (p = 0.89) between patients who underwent AC versus GA, respectively. Conclusion: Mapping during resection of gliomas located in or near the perirolandic area and descending motor tracts can be safely carried out with both AC and GA.