Risk factors and surgical maneuvers to decrease recurrences of olfactory groove meningiomas: institutional case series and systematic literature review

Background: Recurrences of olfactory groove meningiomas (OGMs) sometimes occur even after gross total resection. The present study discusses the risk factors of recurrences and the most important surgical steps at initial surgery to reduce the recurrence rate. Methods: A monoinstitutional series of 60 patients with OGMs operated through microsurgical transcranial approaches and a comprehensive systematic literature review on recurrent OGMs operated via transcranial approaches (TCAs) (Group A) or endoscopic endonasal approach (EEA) (Group B) were retrospectively and separately analyzed. The analyzed factors included patient age, prior surgeries, tumor size, extent of resection at initial surgery, management of basal bone invasion, dural attachment, optic canals invasion, anterior cerebral arteries (ACAs) encasement, follow-up. All these data were statistically correlated with the recurrence rate. The review investigation followed a prespecified protocol registered on PROSPERO (PROSPERO 2024 CRD420250655908). Results: 48 studies met the inclusion criteria for an overall sample of 1498 patients, of which 1377 (38 studies) belonging to the group A and 121 (10 studies) belonging to group B. The overall recurrence rate was 6.6% after TCAs and 7.4% after EEA (p > 0.9); however, the median follow up was longer in group A (72.5 ± 29.6 months) compared to group B (32.3 ± 12.9 months) (p < 0.01). Studies of patients treated by TCAs showed higher median values of gross total resection (GTR) (92.5%) than studies on patients treated by EEA (67.7%) (p < 0.01). The median recurrence rate after GTR was 4.7% in group A and 5.6% in group B (p > 0.9). In group A the resection of the dural attachment (reported in 46% of the reviewed patients) resulted in further decrease of the recurrence rate (3.2%). Optic canal extension was significantly more frequent in group A (57.3%) than in group B (21.5%) (p < 0.01). Conclusion: Resection of infiltrated basal bone and dural attachment during TCAs, mainly in young anosmic patients, may reduce the recurrence rate. Residual intracranial tumor nodules and peripheral dural infiltration must be avoided during the EEA. Decompression of the optic nerves and resection of tumor extending into the optic canals is mandatory in both approaches to minimize the recurrence risk. Clinical trial number: Not applicable.