Intraoperative subcortical stimulation and fiber tracking: Does the stimulation current predict the distance to subcortical fibers?

Objective: In subcortical glioma surgery, preservation of fibers originating in the precentral gyrus is still challenging. Preoperative DTI based fiber tracking allows an approximation of the course of fibers but is intraoperatively limited due to brain shift. Therefore the intraoperative cortical and subcortical elicitation of motor evoked potentials (MEP) is commonly used to localize and continuously evaluate in real time the function and integrity of these fibers. The disappearance of MEP or the increase of the motor threshold is a strong predictor for postoperative morbidity. The correlation between stimulat…