Strategies for resection of gliomas in eloquent areas of the brain

A critical review of the recent literature shows, that the extent of surgical resection is a key factor for overall survival and progression-free survival in the treatment of gliomos. The level of evidence is even better in high-grade than in low-grade gliomas. A distinct challenge is therefore the maximum resection of gliomas in functionally important i.e. eloquent areas of the brain, because the principle of "nihil nocere" should not be violated. Several technologies were recently developed in order to allow a maximum of tumour resection and avoid functional damage. These devices can be subdivided into tools for localization/resection and for functional guidance. Among the first group is neuronavigation with integration of functional MRI, fiber tracking, ultrasound, tumour fluorescence etc. as well as intra-operative MRI and CT. The latter comprises all types of intra-operative electrophysiology, which is still the gold standard for intra-operative monitoring, because functional image-guidance does not have a sufficient reliability for the time being. Using a combination of these technologies and an adequate microsurgical technique, it is possible to safely resect intrinsic brain tumours in eloquent areas of the brain, which were deemed inoperable only recently.