Intraoperative Stimulation Mapping in Neurosurgery for Anesthesiologists—Part 1: The Technical Nuances

Brain mapping has evolved tremendously in the past decade, fueled by advances in functional neuroimaging technology in neuro-oncology and epilepsy surgery. Despite this, wide anatomic-functional interindividual variability and intraoperative brain shift continue to challenge neurosurgeons performing surgery within or near eloquent brain regions. As such, intraoperative direct cortical and subcortical stimulation mapping remains the gold standard for localizing eloquent brain regions with precision for a safe and tailored resection. Intraoperative stimulation mapping (ISM) allows for maximizing the extent of resection while minimizing postoperative neurological deficits, resulting in better patient outcomes. Understanding the technical nuances of ISM is imperative for the anesthesiologist to provide better anesthetic management tailored to the surgery and stimulation mapping planned. A comprehensive search was performed on electronic databases to identify articles describing intraoperative cortical and subcortical mapping, language, and motor mapping. In the first part of this narrative review, we summarize the salient technical aspects of ISM and the common neurophysiological tasks assessed intraoperatively relevant to the anesthesiologist.