Cortico-cortical evoked potentials of language tracts in minimally invasive glioma surgery guided by Penfield stimulation.

• Cortico-cortical evoked potentials (CCEPs) were obtained in minimally invasive resection for glioma in awake and asleep patients. • Optimal stimulation and recording sites were guided by awake Penfield stimulation and analyzed in real time during surgery. • CCEP features were affected by tumor location and histopathology, and correlated with postoperative aphasia. We investigated the feasibility of recording cortico-cortical evoked potentials (CCEPs) in patients with low- and high-grade glioma. We compared CCEPs during awake and asleep surgery, as well as those stimulated from the functional Broca area and recorded from the functional Wernicke area (BtW), and vice versa (WtB). We also analyzed CCEP properties according to tumor location, histopathology, and aphasia. We included 20 patients who underwent minimally invasive surgery in an asleep-awake-asleep setting. Strip electrode placement was guided by classical Penfield stimulation of positive language sites and fiber tracking of the arcuate fascicle. CCEPs were elicited with alternating monophasic single pulses of 1.1 Hz frequency and recorded as averaged signals. Intraoperatively, there was no post-processing of the signal. Ninety-seven CCEPs from 19 patients were analyzed. There was no significant difference in CCEP properties when comparing awake versus asleep, nor BtW versus WtB. CCEP amplitude and latency were affected by tumor location and histopathology. CCEP features after tumor resection correlated with short- and long-term postoperative aphasia. CCEP recordings are feasible during minimally invasive surgery. CCEPs might be surrogate markers for altered connectivity of the language tracts. This study may guide the incorporation of CCEPs into intraoperative neurophysiological monitoring. [ABSTRACT FROM AUTHOR]