Neurological outcomes following awake and asleep craniotomies with motor mapping for eloquent tumor resection

Objective: Cortical mapping has been used as a tool to ensure maximal safe resection of intracranial tumors for several decades. Post-surgical motor and language deficits, including seizures, weakness, aphasia, and dysarthria have been well-documented in patients undergoing these operations, particularly on eloquent cortical regions. However, it is not known whether awake versus asleep cortical mapping contributes to differences in postoperative neurological deficits. Methods: A comprehensive review of the literature utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was completed for articles describing cortical mapping for tumor resection. We critically assessed all articles published in the last 20 years describing complications of patients who had undergone either awake or asleep motor mapping for eloquent brain tumor resection. Studies were analyzed for number of patients, follow-up duration, rates of transient and permanent motor and sensory deficits in the perioperative period, and outcomes at one-month follow-up. Results: Thirty-one studies met inclusion criteria, 24 of which reported long-term post-operative follow-up data. Follow-up among selected studies ranged from one month to four years. Nine of the 31 studies directly compared the postoperative outcomes of awake versus asleep mapping. The rate of transient deficits among patients who underwent awake and asleep mapping was 31.6% and 32.7%, respectively. The rate of permanent deficits was 10.8% in awake mapping patients and 12.7% in asleep mapping patients. Qualitative analysis showed that motor and sensory complications occurred at similar rates. Conclusions: Review of the current evidence suggests that the rates of transient and permanent postoperative neurologic deficits among awake versus asleep cortical mapping groups are similar. Thus, use of both techniques is reasonable to minimize perioperative morbidity.