title: Functional plasticity of language confirmed with intraoperative electrical stimulations and updated neuronavigation: case report of low-grade glioma of the left inferior frontal gyrus.
abstract: Removal of glioma from the dominant side of the inferior frontal gyrus (IFG) is associated with a risk of permanent language dysfunction. While intraoperative cortical and subcortical electrical stimulations can be used for functional language mapping in an effort to reduce the risk of postoperative neurological impairment, the extent of resection is limited by the functional boundaries. Recent reports proposed that a two-stage surgical approach for low-grade glioma in eloquent areas could avoid permanent deficits via the functional plasticity that occurs between the two operations. The report describes a patient with World Health Organization (WHO) grade II oligoastrocytoma in the left IFG, in functional plasticity of language occurred in the interval between two consecutive surgeries. Intraoperative electrical stimulations suggested that a language area and related subcortical fiber crossed the pre-central sulcus during tumor progression owing to functional plasticity. In the present case, we integrated neurophysiological data into the intraoperative neuronavigation system. We also confirmed the peri-lesional shift of language area and related subcortical fiber on image findings. Consequently, the tumor was sub-totally removed with two separate resections. Permanent language disturbance did not occur, and this favorable outcome was attributed to functional plasticity. The present experience sustains the multistage approach for low-grade gliomas in the language area. A combination of intraoperative electrical stimulations and updated neuronavigation may facilitate the characterization of brain functional plasticity.
authors.affiliation: Department of Neurosurgery, Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University.
authors.forename: Taiichi
authors.initials: T
authors.lastname: Saito
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Muragaki
authors.forename: Isamu
authors.initials: I
authors.lastname: Miura
authors.forename: Manabu
authors.initials: M
authors.lastname: Tamura
authors.forename: Takashi
authors.initials: T
authors.lastname: Maruyama
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nitta
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kurisu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iseki
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Okada
mesh_terms: D001254:Astrocytoma / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D001931:Brain Mapping / Q000379:methods*; D001932:Brain Neoplasms / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D004292:Dominance, Cerebral / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods*; D006801:Humans; D007806:Language Disorders / Q000503:physiopathology* / Q000517:prevention & control*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D009412:Nerve Fibers / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D038361:Neuronavigation / Q000379:methods*; D011183:Postoperative Complications / Q000503:physiopathology* / Q000517:prevention & control*; D017397:Prefrontal Cortex / Q000503:physiopathology* / Q000601:surgery*; D012086:Reoperation