Motor mapping to enable resections of peri-rolandic diffuse gliomas

Intraoperative motor mapping is essential for maximum safe resection of peri-Rolandic gliomas. While both awake and asleep techniques have demonstrated efficacy in preserving neurological function, comparative outcomes across WHO 2021 molecular tumor subtypes remain poorly defined. We compare outcomes between these mapping modalities in glioblastoma (GBM) and IDH-mutant gliomas.

A 130-patient cohort undergoing peri-Rolandic glioma resection with intraoperative motor mapping at a single institution was analyzed. Patients were stratified by mapping modality (awake n = 54, asleep n = 76) and tumor subtype (WHO 2021). Within the asleep cohort, handheld probe (HHP-DCS, n = 61) and subdural electrode direct cortical stimulation (SDE-DCS, n = 12) were compared. The primary outcome was new or worsening neurological deficits at 3 months. Secondary outcomes included Karnofsky Performance Status (KPS), hospital length of stay, discharge disposition, and survival in GBM patients.

Three-month deficit rates were comparable between awake and asleep mapping (5.6% vs. 5.3%, p = 1.000). In GBM patients, pre- and postoperative KPS were significantly lower in the asleep group (p < 0.001 and p = 0.002), though delta KPS and 3-month deficit rates did not differ. No deficits occurred in either group among IDH-mutant gliomas. Progression-free and overall survival were comparable between mapping modalities in GBM. HHP-DCS and SDE-DCS produced similar 3-month deficit rates (3.3% vs. 16.7%, p = 0.124).

Awake and asleep motor mapping were associated with comparable neurological outcomes across glioma subtypes, supporting asleep mapping as a reasonable alternative when awake craniotomy is not feasible, though these retrospective data do not establish statistical equivalence. HHP-DCS and SDE-DCS appear comparable in safety. Larger prospective studies are needed to confirm these findings.