Nuances of Olfactory Groove Meningioma Surgery: 2-Dimensional Operative Video.

Olfactory groove meningiomas frequently present as large or giant-size tumors associated with marked frontal lobe edema and significant frontal lobe dysfunction. Simpson grade I removal was rare in early reports due to their invasion of the ethmoid sinuses and skull base bone,1 which resulted in high recurrence rates.2,3 Indeed, recurrence occurred in the most celebrated case of olfactory groove meningioma.4,5  To achieve Simpson grade I removal (tumor, dura, bone), protect the frontal lobes from additional injury, and provide the best chance for recovery, we demonstrate a few nuances for olfactory groove meningioma surgery: Utilizing a skull base approach with a low dural opening, the frontal veins are preserved, and the frontal lobe is protected from retraction, manipulation, and venous injury. By the time of diagnosis, although the patient's olfaction is often absent, there still remains a role to preserve at least 1 olfactory tract, which might yield some preservation in a limited number of patients. Emphasis has been rightly made on the preservation of the A2 segments, which can be dissected using microsurgical technique. Lastly, multilayer reconstruction of the skull base is required, using an inlay graft, resting on a vascularized pericranial flap, and occlusion of the sinuses with a fat graft. The endonasal endoscopic approach has fallen out of favor due to limitations for complete tumor resection and higher complication rates.6  We present a case of a relatively small olfactory groove meningioma in a 36-yr-old male with partial olfactory loss. The patient consented for surgery.  Images at 2:07, 2:29, and 2:54 from Al-Mefty O, Operative Atlas of Meningiomas, © LWW, 1997, with permission. Image at 8:31 public domain by age.