Chapter 27 - Surgical Management of Sphenoid Wing Meningiomas

Abstract

Sphenoid wing meningiomas (SWMs) are tumors that grow from the arachnoid cells located in the area of both sphenoid wings. They can be classified into two main groups: en-plaque and globoid. En-plaque refers to tumors, usually small and planar, which generate a marked bone reaction (or tumor invasion), located in the lateral wall of the orbit. The globoid type can be divided into pterional or lateral, alar or middle, and clinoidal or inner. Some authors consider a third kind of tumor, intradiploic or intraosseous meningiomas, which are those located in the diploë of the sphenoid wings, without any dural component. The most common clinical manifestation of en-plaque tumors is proptosis, which is usually asymptomatic. The clinical course of globoid tumors depend on their specific location. Clinoidal tumors present a more ample list of clinical manifestations because they grow close to the optic nerve, carotid artery, and cavernous sinus. Diagnosis of SWM is based initially on clinical manifestations and corroborated with imaging studies. Computed tomography is very useful in tumors that present bony reaction, particularly in en-plaque meningiomas, while magnetic resonance imaging (MRI) is more useful in globoid meningiomas and also for the correct assessment of the dural component of en-plaque tumors. Surgery is the best therapeutic option for SWM. The goal must be radical resection, which means total removal of the tumor, along with the dural implant (with a 1 cm free margin), and all bone components. This goal can be reached in the majority of cases but is almost impossible to achieve in clinoid tumors, especially when they invade the cavernous sinus. Even though removal of SWM is a very safe surgical procedure, there is a chance of complication. The postoperative problems most often mentioned are: epidural hematoma, cerebrospinal fluid leakage, seizures, infection, and cosmetic discomfort.