Original ArticlesNeurophysiological Mapping of Functional Systems With an Emphasis on Language Localization During Glioma ResectionSanai, Nader MD; Berger, Mitchel S. MD Author Information Department of Neurological Surgery, Brain Tumor Research Center, University of California at San Francisco, CA The authors declare that they are not involved in any relationships with companies that make products related to this study. Reprints: Mitchel S. Berger, MD, Department of Neurological Surgery, UCSF, 505 Parnassus Avenue, M779, Box 0112, San Francisco, CA 94143 (e-mail: [email protected]). Neurosurgery Quarterly: December 2009 - Volume 19 - Issue 4 - p 255-263 doi: 10.1097/WNQ.0b013e3181bd42d8 Buy Metrics Abstract Refinement of neurosurgical technique has enabled safer operations with more aggressive outcomes. One cornerstone of modern-day practice is the usage of intraoperative stimulation mapping. In addition to identifying critical motor pathways, this technique can be adapted to reliable identify language pathways, as well. Given the individual variability of cortical language localization, such awake language mapping is essential to minimize the language deficits following tumor resection. Our experience suggests that cortical language mapping is a safe and efficient adjunct to optimize tumor resection while preserving essential language sites, even in the setting of negative mapping data. However, the value of maximizing glioma resections remains surprisingly unclear, as there is no general consensus in the literature regarding the efficacy of extent of glioma resection in improving patient outcome. While the importance of resection in obtaining tissue diagnosis and to alleviate symptoms is clear, a lack of class 1 evidence prevents similar certainty in assessing the influence of extent of resection. Beyond an analysis of modern intraoperative mapping techniques, we examine every major clinical publication since 1990 on the role of extent of resection in glioma outcome. The mounting evidence suggests that, despite persistent limitations in the quality of available studies, a more extensive surgical resection is associated with longer life expectancy for both low-grade and high-grade gliomas. © 2009 Lippincott Williams & Wilkins, Inc.