Extent Of Glioma Resection Research Articles

Maximizing the Extent of Resection in Gliomas: Intraoperative Awake Mapping Versus Intraoperative Imaging

Maximizing the Extent of Resection in Gliomas: Intraoperative Awake Mapping Versus Intraoperative Imaging

The Value of Glioma Extent of Resection in the Modern Neurosurgical Era

Objective: There remains no general consensus in the neurosurgical oncology literature regarding the role of extent of glioma resection in improving patient outcome. Although the value of resection in establishing a diagnosis and alleviating mass effect is clear, there is less certainty in ascertaining the influence of extent of resection (EOR). Here, we review the recent literature to synthesize a comprehensive review of the value of extent of resection for gliomas in the modern neurosurgical era. Methods: We reviewed every major peer-reviewed clinical publication since 1990 on the role of EOR in glioma outcome. Results: Thirty-two high-grade glioma articles and 11 low-grade glioma articles were examined in terms of quality of evidence, expected EOR, and survival benefit. Conclusion: Despite limitations in the quality of data, mounting evidence suggests that more extensive surgical resection is associated with longer life expectancy for both low- and high-grade newly diagnosed gliomas.

Intraoperative confocal microscopy in the visualization of 5-aminolevulinic acid fluorescence in low-grade gliomas

Greater extent of resection (EOR) for patients with low-grade glioma (LGG) corresponds with improved clinical outcome, yet remains a central challenge to the neurosurgical oncologist. Although 5-aminolevulinic acid (5-ALA)-induced tumor fluorescence is a strategy that can improve EOR in gliomas, only glioblastomas routinely fluoresce following 5-ALA administration. Intraoperative confocal microscopy adapts conventional confocal technology to a handheld probe that provides real-time fluorescent imaging at up to 1000× magnification. The authors report a combined approach in which intraoperative confocal microscopy is used to visualize 5-ALA tumor fluorescence in LGGs during the course of microsurgical resection. Following 5-ALA administration, patients with newly diagnosed LGG underwent microsurgical resection. Intraoperative confocal microscopy was conducted at the following points: 1) initial encounter with the tumor; 2) the midpoint of tumor resection; and 3) the presumed brain-tumor interface. Histopathological analysis of these sites correlated tumor infiltration with intraoperative cellular tumor fluorescence. Ten consecutive patients with WHO Grades I and II gliomas underwent microsurgical resection with 5-ALA and intraoperative confocal microscopy. Macroscopic tumor fluorescence was not evident in any patient. However, in each case, intraoperative confocal microscopy identified tumor fluorescence at a cellular level, a finding that corresponded to tumor infiltration on matched histological analyses. Intraoperative confocal microscopy can visualize cellular 5-ALA-induced tumor fluorescence within LGGs and at the brain-tumor interface. To assess the clinical value of 5-ALA for high-grade gliomas in conjunction with neuronavigation, and for LGGs in combination with intraoperative confocal microscopy and neuronavigation, a Phase IIIa randomized placebo-controlled trial (BALANCE) is underway at the authors' institution.

Neurophysiological Mapping of Functional Systems With an Emphasis on Language Localization During Glioma Resection

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.

GLIOMA EXTENT OF RESECTION AND ITS IMPACT ON PATIENT OUTCOME

There is still no general consensus in the literature regarding the role of extent of glioma resection in improving patient outcome. Although the importance of resection in obtaining tissue diagnosis and alleviating symptoms is clear, a lack of Class I evidence prevents similar certainty in assessing the influence of extent of resection. We reviewed every major clinical publication since 1990 on the role of extent of resection in glioma outcome. Twenty-eight high-grade glioma articles and 10 low-grade glioma articles were examined in terms of quality of evidence, expected extent of resection, and survival benefit. Despite persistent limitations in the quality of data, mounting evidence suggests that more extensive surgical resection is associated with longer life expectancy for both low- and high-grade gliomas.

Functional neuronavigation and intraoperative MRI.

Our concept of computer assisted surgery is based on the combination of intraoperative magnetic resonance (MR) imaging with microscope-based neuronavigation, providing anatomical and functional guidance simultaneously. Intraoperative imaging evaluates the extent of a resection, while the additional use of functional neuronavigation, which displays the position of eloquent brain areas in the operative field, prevents increasing neurological deficits, which would otherwise result from extended resections. Up to mid 2001 we performed intraoperative MR imaging using a low-field 0.2 Tesla scanner in 330 patients. The main indications were the evaluation of the extent of resection in gliomas, pituitary tumours, and in epilepsy surgery. Intraoperative MR imaging proved to serve as intraoperative quality control with the possibility of an immediate modification of the surgical strategy, i.e. extension of the resection. Integrated use of functional neuronavigation prevented increased neurological deficits. Compared to routine pre- or postoperative imaging being performed with high-Tesla machines, intraoperative image quality and sequence spectrum could not compete. This led to the development of the concept to adapt a high-field MR scanner to the operating environment, preserving the benefits of using standard microsurgical equipment and microscope-based neuronavigational guidance with integrated functional data, which was successfully implemented by April 2002. Up to the end of 2002, 95 patients were investigated with the new setup. Improved image quality, intraoperative workflow, as well as enhanced sophisticated intraoperative imaging possibilities are the major benefits of the high-field setup.