Comparison of the asleep-awake-asleep technique and monitored anesthesia care during awake craniotomy: a systematic review and meta-analysis

Awake craniotomy (AC) is the preferred surgical option for intractable epilepsy and resection of tumors adjacent to or within eloquent cortical areas. Monitored anesthesia care (MAC) or an asleep-awake-asleep (SAS) technique is most widely used during AC. We used a random-effects modeled meta-analysis to synthesize the most recent evidence to determine whether MAC or SAS is safer and more effective for AC. We included randomized controlled trials and observational studies that explored the incidence of AC failure, duration of surgery, and hospital length of stay in adult patients undergoing AC. Eighteen studies were included in the final analysis. MAC was associated with a lower risk of AC failure when compared with SAS (global pooled proportion MAC vs. SAS 1% vs. 4%; odds ratio [ORs]: 0.28; 95% confidence interval [CI]: 0.11-0.71; P=0.007) and shorter surgical procedure time (global pooled mean MAC vs. SAS 224.44 vs. 327.94 min; mean difference, -48.76 min; 95% CI: -61.55 to -35.97; P<0.00001). SAS was associated with fewer intraoperative seizures (global pooled proportion MAC vs. SAS 10% vs. 4%; OR: 2.38; 95% CI: 1.05-5.39; P=0.04). There were no differences in intraoperative nausea and vomiting between the techniques (global pooled proportion MAC vs. SAS: 4% vs. 8%; OR: 0.86; 95% CI: 0.30-2.45; P=0.78). Length of stay was shorter in the MAC group (MAC vs. SAS 3.96 vs. 6.75 days; mean difference, -1.30; 95% CI: -2.69 to 0.10; P=0.07). In summary, MAC was associated with lower AC failure rates and shorter procedure time compared with SAS, whereas SAS was associated with a lower incidence of intraoperative seizures. However, there was a high risk of bias and other limitations in the studies included in this review, so the superiority of 1 technique over the other needs to be confirmed in larger randomized studies