Key Points: Figures 1 and 2 illustrates the important venous structures that need to be considered when approaching a lesion in the pineal region.
Figure 1: Top: A labeled diagram of the posterior fossa veins. See text for full explanation. Bottom: Schematic view of the deep cerebral venous system as seen from a posterolateral view. 1: inferior sagittal sinus; 2: straight sinus; 3: internal cerebral vein; 4: vein of Galen; 5: basal vein of Rosenthal; 6: thalamostriate vein; 7: transverse sinus; 8: superior sagittal sinus Figures taken from Microneurosurgery by Yasargil; top: Volume IIIA, p 332; bottom: Volume IIIB, p 207
Figure 2: Schematic view of the deep venous system in relationship to the pineal region. 1. septum pellucidum; 2: fornix; 3: pineal recess third ventricle; 4: pulvinar; 5: pineal gland; 6: superior colliculi; 7: inferior colliculi; 8: trochlear nerve Figure taken from Atlas of Neurosurgery: Basic Approaches to Cranial and Vascular Procedures by Meyer (ref 1); p.171
* The basal vein of Rosenthal: formed by the anterior and deep middle cerebral veins and small branches from the insula and cerebral peduncles; as the basal vein of Rosenthal (BVR) goes posteriorly around the cerebral peduncle, it receives tributaries from the temporal horn and the medial medial temporal lobe and is joined by the inferior striate veins, which drain part of the basal ganglia. The BVR may also receive blood from the lateral mesencephalic vein; the BVR curves posteriorly around the cerebral peduncle and collicular (tectal) plate to join the vein of Galen
* The vein of Galen: receives both internal cerebral veins, both basal veins of Rosenthal, the occipital veins, small tributaries from the corpus callosum (posterior callosal vein), the mesencephalon and the cerebellum. The vein of Galen (VG) is short and U-shaped as it curves posteriorly and superiorly around the splenium of the corpus callosum. The VG ends at the apex of the tentorial notch by joining the inferior sagittal sinus to form the straight sinus. An important landmark is the midline precentral cerebellar vein that extends from the cerebellum to the underside of the vein of Galen.
* Septal and thalamostriate veins join alng the inferior aspect of the foramen of Monro to form the paired internal cerebral veins. Each internal cerebral vein (ICV) penetrates the subarachnoid space to run just lateral to the midline in the velum interpositum. As the ICV goes posteriorly, small subependymal veins and the posterior septal veins join it; just inferior to the splenium of the corpus callosum, the paired ICVs join the paired BVR to form the VG (see above).
* Pineal tumors: if the pineal neoplasm has a significant caudal extension toward the fourth ventricle, it may be advantageous to approach the tumor through a parieto-occipital trans- tentorial interhemipsheric approach. On the other hand, if the majority of the tumor lies above the tentorium, a suboocipital craniotomy/craniectomy with a supracerebellar/ infra-tentorial approach may be better.