Olfactory Groove Meningiomas: Comparison of Extent of Frontal Lobe Changes after Lateral and Bifrontal Approaches

Abstract Objective Olfactory groove meningiomas are often behaviorally silent. Numerous surgical approaches have been described in the literature for successful removal of these meningiomas. Lateral (pterional/ frontolateral) and anterior (bifrontal/ fronto-orbito-basal) approaches with their various modifications remain the two major corridors in resecting them. In this study, we discuss our experience in microsurgical treatment of these tumors at our institution and assess the extent of frontal lobe damage after the resection of tumor. Methods We reviewed the medical records of patients who underwent surgical excision of olfactory groove meningiomas from 1990 to 2014. To measure the extent of frontal lobe damage via lateral and anterior approaches, we measured the volume of porencephalic cave in the post-operative MRI in Brainlab software. The ratio of volume of porencephalic cave to tumor was measured between two sides and two approaches. Results Fifty-seven patients with olfactory groove meningiomas, who underwent 62 microsurgical resection procedures in 1990-2014, were included in the study (74% were more than 5 cm at presentation). Pterional and bifrontal craniotomies were the most commonly used approaches. At follow-up, the volume of porencephalic cave after lateral approach was significantly less in the side contralateral to craniotomy irrespective of tumor size. The difference between ratio of volume of porencephalic cave and initial tumor was significantly less after lateral approaches, when compared to anterior approaches. Conclusions Lateral approaches (pterional/ fronto-lateral) resulted in less frontal lobe change and better olfactory preservation in comparison to anterior approaches in present series.