Optimizing the extent of resection in eloquently located gliomas by combining intraoperative MRI guidance with intraoperative neurophysiological monitoring

Several methods have been introduced to improve the extent of resection in glioma surgery. Yet, radical tumor resections must not be attempted at the cost of neurological deterioration. We sought to assess whether the use of an intraoperative MRI (iMRI) in combination with multimodal neurophysiological monitoring is suitable to increase the extent of resection without endangering neurological function in patients with eloquently located gliomas. Fifty-four patients were included in this study. In 21 patients (38.9 %), iMRI led to additional tumor resection. A radiologically complete resection was achieved in 31 patients (57.4 %), while in 12 of these, iMRI had depicted residual tumor tissue before resection was continued. The mean extent of resection was 92.1 % according to volumetric analyses. Postoperatively, 13 patients (24.1 %) showed new or worsening of pre-existing sensory motor deficits. They were severe in 4 patients (7.4 %). There was no correlation between the occurrence of either any new (P = 0.77) or severe (P = 1.0) sensory motor deficit and continued resection after intraoperative image acquisition. Likewise, tumor location, histology, and tumor recurrence did not influence complication rate on uni- and multivariate analysis. We conclude that the combination of iMRI guidance with multimodal neurophysiological monitoring allows for extended resections in glioma surgery without inducing higher rates of neurological deficits, even in patients with eloquently located tumors.