Innovations in intraoperative image guidance for intrinsic brain tumors

Modern intraaxial tumor surgery has evolved from static three-dimensional point localization within the cranium with frame-based systems into highly accurate, user-friendly frameless stereotactic systems. However, brain shift was realized early on as a limitation which renders frameless stereotaxy less useful toward the later stages of tumor resection. Intraoperative MRI has proven to be useful in updating intraoperative images and thus maintaining the accuracy of navigation. The exploitation of tumor cell biochemistry led to adaptation of tumor fluorescence-guided surgery and has revolutionized high-grade glioma surgery. Furthermore, direct cell visualization techniques in tumor margins, such as with Raman spectroscopy or confocal microscopy, are exciting prospects that have the potential to take navigation-based tumor surgery to the next level. Future advances in intraaxial tumor navigation are likely from integration of multimodal MRI (including functional MRI and tractography) with intraoperative brain shift correction, awake functional mapping, and augmented reality platforms.