gms | German Medical Science

Objective: The preoperative assessment of medial sphenoid wing meningiomas concerning their involvement of the optic canal is still demanding. It is quite challenging to predict tumour extension into the optic foramen based on MRI. To evaluate this hypothetic discrepancy, we present a series of medial sphenoid wing meningiomas with intraoperative evidence of intracanalicular tumour extension not reflected by preoperative imaging.

Methods: From 2004-2007 400 meningiomas have been operated on at the Department of Neurosurgery. Fifty-eight medial sphenoid wing meningiomas were evaluated prospectively by computed tomography and MRI before the operation. In all patients the intraoperative video, a questionnaire from the surgeon and postoperative imaging were evaluated in respect to tumour infiltration and/or extension into the optic canal and extent of decompression.

Results: On the preoperative MRI, 38 patients did not show any tumour infiltration of the optic canal in coronal fat-suppressed MRI sequences. In 50% of these patients, the optic canal was nevertheless opened for decompression and intracanalicular tumour was found in 17/19 of these cases. None of the patients with an opened optic canal sustained visual loss or any morbidity due to the bony decompression.

Conclusions: Extension of medial sphenoid wing meningiomas into the optic canal is not sufficiently predictable by neuroimaging despite fat-suppression techniques. We therefore recommend meticulous inspection of the optic foramen and generous opening of the bony margins for decompression of the optic nerve.