Purpose: Awake surgery of low-grade gliomas (LGG) resulted in a prolonged overall survival (OS) ≥ 20 years with long-lasting preservation of quality of life (less than 1% of permanent neurological deficits [PND] and > 93% of return to work [RTW]). Since intraoperative MRI (iMRI) was used worldwide in the two past decades, the question arises regarding its actual usefulness on long-term results in LGG patients. Here, we reviewed the literature on iMRI in LGG surgery by analyzing the onco-functional outcomes.
Methods: A systematic review was performed about iMRI in glioma surgery. We selected series that included at least 10 LGG patients, with ≥ 40% of patients with LGG in studies also comprising high-grade gliomas.
Results: From 1605 articles identified from database, we reviewed 19 studies on iMRI, with or without functional MRI, including a total of 1,463 LGG patients. The median age was 37 years (range 32-43.8 years). The mean duration of surgery was 6.2 h (4.3-9 h). The mean extent of resection (EOR) was 92.2% (range 81.3-95.7%), with an average rate of postoperative PND of 9% (range 3.4-13%) (described in 11 articles). The mean RTW rate was 64.8% (range 45-84.6%). The mean duration of follow-up was 3.8 years (range 1-10 years), available in 9 studies. Only two studies reported progression-free survival (5.6 and 8.5 years). Three studies provided OS, with a mean of 14.5 years (range 7.1-21 years). The estimated additional cost was $3 millions.
Conclusion: The percentage of PND is high after LGG resection with iMRI (mean 9%). Cognitive scores and RTW were exceptionally assessed. Most of series described only the EOR, with few considerations regarding the long-term follow-up, especially OS. Moreover, iMRI is expensive, not widely accessible, with an increased time of surgery. Therefore, the actual benefit of iMRI on the long-run onco-functional outcomes is not demonstrated in LGG patients.
Clinical trial number: Not applicable.
Keywords: Awake mapping; Functional outcomes; Intraoperative MRI; Low-grade glioma; Surgery.
© 2026. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.