Transopercular Resection of IDH–Mutated Insular Glioma: A Critical Appraisal of an Initial Experience

Abstract

Recent data suggest a favorable benefit/risk ratio for insular glioma surgery. However, it remains unknown if this is also applicable in the learning period of this expertise. Moreover, little is known about the neuropsychological outcomes after resection of insular glioma. To report an initial experience of isocitrate dehydrogenase (IDH)-mutated insular glioma resection and to contribute to our knowledge of neuropsychological outcomes after insular glioma resection. A consecutive series of 12 patients operated on for an IDH-mutated insular glioma was retrospectively reviewed. Surgery was performed through a transopercular approach. In 10 of the 12 patients, brain mapping with electric stimulation in an awake patient guided the resection. The extent of resection was assessed by volumetric measures of postoperative fluid-attenuated inversion recovery magnetic resonance imaging. Areas of postoperative ischemia were detected by diffusion imaging. Neurologic, neuropsychological, and professional outcomes were retrieved from medical files. The median extent of resection was 94% (range, 80%-100%). None of the patients had permanent speech or motor deficits. Areas of ischemia were observed in 75% of patients. Neuropsychological evaluations showed slight deterioration regarding lexical abilities and verbal memory in patients with left-sided tumors. Patients' performances in cognitive flexibility also commonly declined, regardless of the tumor side. Eight of the 9 patients working at the time of the surgery were able to resume their professional activity. Resecting insular glioma under brain mapping techniques is a safe option, even during the learning period. Patients should be informed about the risk of mild deterioration of lexical abilities and cognitive flexibility.