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Validity of the frontolateral approach as a minimally invasive corridor for olfactory groove meningiomas
1Department of Neurosurgery, Ain Shams University, Cairo, Egypt. khaledbahy@yahoo.com
Background:
Several approaches are described for olfactory groove meningiomas (OGMs) varying from a very wide bifrontal craniotomy to minimally invasive endoscopic techniques. The goal of this study was to evaluate the results of the frontolateral approach for olfactory groove meningioma. Pitfalls related to this corridor will be described. The impact of tumor size and encasement of the anterior cerebral artery complex on the degree of tumor removal will be described on the basis of experience with 18 cases.
Methods:
Eighteen patients with OGM underwent microsurgical removal using the frontolateral approach. A retrospective study was conducted by analyzing clinical data, neuroimaging studies, operative findings, clinical outcome, and degree of tumor removal.
Findings:
The patients were classified into group A with tumor size less than 4 cm in diameter (7 out of 18 cases, 38.9%) and group B with tumor size more than 4 cm in diameter (11 out of 18 cases, 61.1%). CSF rhinorrhea was observed in three patients (16.7%). Postoperative left frontal intracerebral hematoma occurred in one patient (5.6%) belonging to group A. In another patient (5.6%) belonging to group B, marked right frontal lobe swelling was evident after dural opening, which necessitated partial right frontal pole resection. Total tumor removal (Simpson grade 1 and 2) was achieved in 14 out of 18 patients (77.8%), while subtotal removal (Simpson grade 3 and 4) was achieved in 4 patients (22.2%). In the 14 patients in whom total removal was achieved, 7 belonged to group A (all 7 patients of group A with 100% removal), while the remaining 7 patients belonged to group B (7 out of 11 patients, 63.6% removal; one of them had anterior cerebral artery complex encasement). The four patients in whom subtotal removal was achieved belonged to group B; three of them showed anterior cerebral artery complex encasement, and one elderly patient had non-extensive paranasal sinus involvement. One patient (5.6%) in group B died from cerebral infarction after subtotal tumor removal with anterior cerebral artery injury during its dissection from the tumor capsule.
Conclusion:
The frontolateral approach has the advantages of both the pterional and conventional bifrontal approaches. The frontolateral approach allows quick and minimally invasive access to OGMs less than 4 cm in diameter, and also to tumors more than 4 cm in diameter without encasement of the anterior cerebral artery complex. Tumor size more than 4 cm in diameter and encasement of the anterior cerebral artery complex are limiting factors for the frontolateral approach if radical tumor removal is considered.
Insights
The frontolateral approach is effective for olfactory groove meningiomas (OGMs) under 4 cm. Larger OGMs or those encasing the anterior cerebral artery complex present challenges for complete removal using this technique.
Area of Science:
- Neurosurgery
- Oncology
Background:
- Olfactory groove meningiomas (OGMs) can be treated with various surgical approaches, from bifrontal craniotomy to endoscopic methods.
- The frontolateral approach offers a distinct surgical corridor for OGM resection.
Purpose of the Study:
- To evaluate the efficacy and outcomes of the frontolateral approach for olfactory groove meningioma (OGM) resection.
- To identify potential pitfalls and limiting factors associated with this surgical corridor.
Main Methods:
- Retrospective analysis of 18 patients who underwent microsurgical OGM removal via the frontolateral approach.
- Evaluation of clinical data, neuroimaging, operative findings, and extent of tumor removal.
Main Results:
- Total tumor removal (Simpson grade 1-2) was achieved in 77.8% of patients.
- Tumor size >4 cm and anterior cerebral artery complex encasement were associated with lower rates of complete resection.
- Complications included CSF rhinorrhea (16.7%) and, in one case, cerebral infarction after anterior cerebral artery injury.
Conclusions:
- The frontolateral approach provides advantages for OGM resection, combining benefits of pterional and bifrontal methods.
- This approach is suitable for smaller OGMs (<4 cm) and larger ones without anterior cerebral artery complex encasement.
- Tumor size and anterior cerebral artery encasement are critical factors limiting radical resection with the frontolateral approach.
