L’imagerie pour la stratégie d’approche chirurgicale des méningiomes du sinus caverneux

Abstract

The treatment of cavernous sinus meningiomas remains controversial. However, at present, the general consensus is that only tumors with extracavernous extensions should be operated on and that resection is performed only on the extracavernous portions. Since these tumors are deep-seated and in the vicinity of vital and highly functional neurovascular structures, surgery remains difficult and dangerous. To achieve the gross total removal of the extracavernous extensions with minimal sequelae, the operative strategy must take into account the location of the tumor extension, not only in the basal cisterns but also into the skull base structures, the vascularization of the tumor with its feeders, as well as the venous drainage pathways. These anatomical and surgical data are collected from preoperative imaging, which includes CT-scan with bony windows and consecutive fine sections, MRI, angio-MR, and DSA angiography performed with selective arteriography including late venous phases. The operative plan must define the type of craniotomy and complementary osteotomy, the usefulness of an anterior clinoidectomy with skeletonization of the optic nerve, and determine whether extensive exposure of the cerebral middle fossa is necessary to ensure substantial devascularization of the tumor and proximal control of the internal carotid artery at its intrapetrosal portion. In addition, the possible need for an extra-intracranial bypass prior to tumor removal should be evaluated. The high number of neuroimaging investigations is the guarantee of surgical accuracy and safety.