Bone Invasion in Skull Base Meningiomas Resected by Expanded Endonasal Endoscopic Approaches

Background: Degrees of resection and bone invasion by skull base meningiomas are known prognostic factors. Endonasal endoscopic techniques allow early bone removal during the approach itself.

Objective: The purpose of this study was to analyze evidence of bone invasion in a series of skull base meningiomas treated with endonasal endoscopic techniques.

Methods: All imaging and pathology reports of 48 consecutive skull base meningiomas operated on endonasally by the senior author (DMP) in conjunction with the skull base team were retrospectively reviewed. Confirmation of bone invasion was based in pathologic analysis. Cases for which pathologic review of bone invasion was not recorded were discarded.

Results: Twenty-three of 48 skull base meningiomas were evaluated for histologic evidence of bone invasion. Tumor location was distributed as follows: the olfactory groove (n = 9), tuberculum sellae (n = 7), sphenopetroclival (n = 2), and sphenocavernous (n = 5) regions. Microscopic analysis identified 20 WHO grade I tumors and 3 grade II lesions; there were no malignant meningiomas. Twenty-two (95.65%) of the 23 analyzed patients were positive for bone invasion.

Conclusions: Regardless of the route used, surgeons tackling skull base meningiomas must be aware of the high rate of bone invasion related to this pathologic group and address it accordingly. Further prospective studies are necessary to determine whether complete bone removal will render lower rates of recurrence.