In skull base surgery, and especially in the posterior skull base approaches, it is of paramount importance to manage the dural sinuses, bridging veins (e.g., tentorial, petrosal), and the vein of Labbé.

Whenever possible, aim to preserve the sinuses and bridging veins, as occlusion may lead to a number of often unpredictable events, despite the use of pre- and intraoperative tests. A meningioma with a dominant sinus invasion may be best managed by subtotal-partial resection followed by radiotherapy of the intrasinus component; in rare situations and in expert hands, a total resection with venous reconstruction may be achievable.

• Preoperative magnetic resonance imaging (MRI), magnetic resonance venography (MRV), computed tomography venography (CTV), or cerebral angiogram are used to determine the involvement of the dural sinuses in the different pathologies (e.g., meningioma invasion of the sinus vs. compression of the wall), as well as the different anatomic variations of size and dominancy of the sinuses and the collateral drainage of the occluded sinuses.

• Preservation of the sinuses/veins is the main goal of surgery. Their reconstruction or their sacrifice are dependent on the existence of outflow collaterals, in order to avoid brain/cerebellum venous infarct and/or swelling.

Anatomic variations of the dural sinuses, vein of Labbé, and bridging veins should be studied in detail before deciding on the appropriate treatment (e.g., surgery vs. radiosurgery) and on the appropriate lateral approaches to the middle and posterior skull base (e.g., subtemporal/transpetrous approaches).

Anatomy of the Dural Sinuses and Vein of Labbé

• In general, occlusion of one cavernous sinus, superior petrosal sinuses, and nondominant transverse and sigmoid sinuses is well tolerated by patients. Occlusion of the anterior third of the superior sagittal sinus is generally tolerated when the anterior cortical veins have collaterals; otherwise, there is still the risk of frontal lobe venous infarction/edema.