[Collateral venous channels in occlusion of deep cerebral veins and sinuses].

The authors report on the relationship between occlusion or stenosis of the deep cerebral veins and sinuses and the development of collateral venous channels in pineal region tumors. Five cases of meningioma arising from the falcotentorial junction were the subject of this study. There were two males and three females with an average age of 51.2 years (range: 26-67). The straight sinus (SS) and posterior part of the great vein of Galen (GVG) were included in the occlusion or stenosis of the deep cerebral veins and sinuses in 3 cases, the GVG, SS and posterior part of the internal cerebral vein in 1, and the SS alone in 1. The various types of collateral venous channels following the occlusion could be classified a type 1, from the basal vein of Rosenthal (BVR) to the petrosal vein via the lateral mesencephalic and/or anterior pontomesencephalic veins; type 2, via the veins on the medial surface of the parietal and/or occipital lobe to the superior sagittal sinus (SSS); type 3, dilated superficial anastomotic veins; type 4, via the posterior fossa venous circulation to the transverse sinus or the SS; and type 5, via the falcian veins to the SSS. The first three types of collateral venous channels seem to be important following occlusion or stenosis of deep cerebral veins and sinuses. Stereoscopic angiograms are essential to analyze deep venous channels around deep-seated tumors. Clear identification of occlusion or stenosis and the development of venous system collaterals on angiograms is important to the surgical treatment of pineal region tumors.