January 08, 2016
And important consideration during a resection of pineal region masses is the location of deep veins, including the vein of Galen and the veins of Rosenthal. In this video, I'm going to illustrate the variations and the configurations of these veins. This is a hemorrhagic pineal region tumor. And the patient presented with severe headache and subsequently collapsed. Initial imaging in the emergency room demonstrated acute hydrocephalus and a hemorrhagic mass in the area of the tectum and parapineal region. An MRI demonstrates a relatively hemorrhagic mass again in the area of the pineal region. An important consideration in this case, is the location of the planes. Further study of the T2 axial images demonstrates the mass to be actually originating from the pulvinar and posterior thalamus, and the sagittal enhanced images elucidate the fact that the deep veins, including the veins of Rosenthal, are mobilized posteriorly. This configuration places the veins between the tumor and the surgeon. During the surgical approach via the supracerebellar route, the location of veins should be kept in mind. The patient underwent a left paramedian supracerebellar trajectory and craniotomy for exposure of the mass. I prefer a paramedian approach versus the midline supracerebellar approach, since the paramedian variant is less disruptive and provides adequate exposure of the midline, via a cross-court trajectory. A ventricular catheter was placed at the time of the admission. The craniotomy, as you can see, is relatively small. This is the left transverse sinus, transverse sigmoid junction. Small extent of the dura, above the sinus is exposed. So the transverse sinus can be mobilized superiorly using retention sutures. And here's the dura over the superior posterior cerebella. A coronal dural incision is used. The supracerebellar operative trajectory is developed. You can see that the cerebellum is tight in the region. Here's the falx cerebelli. Two stitches were placed along the posterior aspect of the cerebellum, to mobilize the transfer sinus superiorly and expand the operative corridor through this supracerebellar trajectory. You can see the hemorrhagic mass is even early. Small cortical incision is made and the tumor is interred. You can see the hemorrhagic mass. Again, an important consideration is the location of the deep veins. That could be very much engulfed by the tumor. Small cuts are made to assure that no important neurovascular structure is endangered. Here is the capsule, the tumor on left side that is being exposed. As you can see here, I try to take a bite of the tumor, relatively blindly. And in a moment you can see one of the veins. Just about there. Was very much close to be caught within the jaws of the pituitary rongeurs. Again, this is an important point to remember, that in the tumors that are primarily anterior to the veins within the tectum potentially or thalamus and pushed the veins posteriorly, the deep veins can be between the surgeon and the tumor, and can be easily injured if they're not looked for. Something that I have repeatedly mentioned to my fellows and residents, that it's best to say, there it is and be wrong hundred times, but it's not appropriate or acceptable to say, there it was and be right even once. So the deep veins have to be very much looked for and protected, because of their importance in draining the diencephalic structures. I was lucky enough to avoid any injury to the vein. I continued the resection of the tumor more anteriorly, moving cross-court from left to right to remove the tumor, keeping the veins in view, until the posterior aspect of the third ventricle is encountered. You can see other veins more anteriorly, that are smaller in caliber. Obviously this tumor is not resectable in a gross total fashion, since it infiltrates the posterior thalamus. Tumor was somewhat hemorrhagic and very suckable, obviously because it's hemorrhaged into itself. The final pathology of the tumor was consistent with a pilocytic astrocytoma. Here you can see the resection cavity looks relatively clean. This is the contralateral tectum across falx cerebelli. Here is CSF draining through the posterior third ventricle. It's a good sign that I have reached the anterior extents of my resection cavity. Manipulation of the posterior third ventricle walls is avoided. Hemostasis is secured. Here's the posterior aspect of the thalamus. No further hemorrhage of tumor is evident. Here's some more, the deep veins, including vein of Galen along the midline. Aggressive coagulation along the thalamus is avoided and pieces of thrombin soaked cotton are used to apply gentle tamponade and reach hemostasis. A very much blind spot of the surgeon is along the posterior aspect of the resection cavity and inferiorly along the lip of the cerebellum, over which the surgeon is working. I'll continue to explore this area. Again, this is falx cerebelli. Further inspection of the resection cavity does not reveal any obvious tumor. Here's the posterior aspect of the third ventricle. I'm looking into the ventricle. As you can see, these are both of the walls. The internal cerebral veins would be located just along the roof here. This is rather disorienting, because the approach is different from the standard midline supracerebellar approach. Here you can see the inferior aspect of the resection cavity within my blind spot, that I do not see any more tumor. Contralaterally everything looks clean. I'm relatively satisfied with the extent of resection. Here's the final look of the operative field under minimum magnification. Three months, MRI demonstrates adequate resection of the parapineal mass. Obviously the tumor that was invading the thalamus was left behind. This patient made an excellent recovery and has returned to college without any deficits. Again, the especially important learning point here is, always identifying the configuration of deep veins. Sometimes additional vascular imaging may be necessary, especially for tumors that originate anterior to the veins, the veins can be mobilized posteriorly between the surgeon and the tumor. Alternative operative routes may be necessary if the veins make the supracerebellar trajectory toward the tumor unsafe. Thank you.
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