Surgical strategy for meningioma extension into the optic canal.

Neuroimaging of the extension of meningioma into the optic canal was evaluated for planning the surgical strategy. Intracanalicular extension and localization were retrospectively analyzed in 13 patients with frontal base meningioma near the optic canal, based on the findings of visual field defects, magnetic resonance (MR) imaging, and surgical observations. MR imaging confirmed intracanalicular localization in one of three patients with tumors extending into the optic canals, and indicated the tumor in the others. The visual field defect did not precisely correspond to the tumor localization. Unroofing of the optic canal was performed in four patients and no adverse effects were observed. The interhemispheric approach was employed for tumors localized medially in the canal, and the pterional approach for tumors localized laterally. MR imaging is useful to evaluate the intracanalicular extension, but aggressive confirmation during surgery is essential. Tailored unroofing of the optic canal and removal of the intracanalicular tumor can be performed with few adverse effects and results in good tumor control.