Importance of Epidural Microsurgical Working in Surgery for Medial Sphenoid Wing Meningiomas

Objective: Epidural microsurgical working (EMW) technique including the removal of anterior clinoid process, opening the optic canal, and coagulation of the fine feeding arteries could decompress the optic nerve and decrease subdural hemorrhage before the tumor manipulation. It seems to be the good technique for medial sphenoid wing meningiomas (SWM), which are usually fed by internal carotid artery (ICA), recurrent meningeal artery, middle meningeal artery, and inferolateral trunk. Here, we have explored whether EMW influence the functional recovery of the optic nerve and tumor radicality in patients with medial SWM, by comparing the surgical results between groups with and without EMW. Methods: Total 65 patients with medial SWM affected optic nerve were analyzed. The consecutive series of patients were divided into two groups; without EMW in 14 and with EMW in 51 patients. Prognostic factors were statistically assessed using univariate analysis between two groups. Results: In the group without EMW, 9 of 14 patients (64.3%) had visual disturbance preoperatively and only 1 (of 9, 11.1%) improved. On the other hand, 30 of 51 (58.8%) had visual disturbance preoperatively and 25 of 31 (83.3%) postoperatively showed improvement in the group with EMW (p < 0.01). Epidural ACP resection increased the tumor radicality by exposing the tumor base around the optic canal and ICA. Conclusions: Introduction of EMW dramatically improved the patient's visual function and tumor radicality.