The neuropsychological outcome of patients undergoing intraoperative MRI surgery for insular infiltrating gliomas

Maximal surgical resection remains the gold standard for diffuse gliomas. However, the procedure may be complex, especially in insular infiltrating lesions associated with a higher risk of morbidity. In these cases, an awake phase, coupled with other adjuvants (such as intraoperative MRI or ultrasound), can be considered. However, during the last decade, an increasing amount of scientific literature has led to the belief that awake surgery is mandatory to preserve cognition during low grade gliomas surgery. In this study, we evaluated neuropsychological outcomes following intraoperative MRI-guided resection of gliomas infiltrating the insula without intraoperative neuropsychological testing. We undertook a retrospective analysis of prospectively collected data including all patients operated in the intraoperative MRI for insular infiltrating gliomas (University Hospital of Lille, France, 2014–2022). Awake phase was not conducted in patients with a tumor in the non-dominant hemisphere. Awake phase was conducted in patients with a tumor in the dominant hemisphere for language preservation. Clinical, surgical, radiological and neuropsychological data were analyzed. Neuropsychological evaluation was carried out before and after surgery. Tumor volumes, extent of resection, overall survival and progression-free survival were estimated. Thirty-four patients were included, with a mean age of 37 years. Left hemispheric dominance was recognized in 11 patients. No statistically significant neuropsychological changes were found, except for mental flexibility (p = 0.046). This difference was not significant in subgroup analysis (dominant versus non-dominant hemisphere). The mean extent of resection was 92.9%. The WHO 2021 classifications allowed confirmation of a diffuse glioma: grade 2 (68%) and grade 3 (32%). Among these, 88.2% were alive at the end of our follow-up (mean 67 months). Intraoperative MRI-guided resection surgery without awake extensive neuropsychological tests for gliomas with insular components might enable optimal removal without jeopardizing neuropsychological functions.