Transcript

This video describes the methodology for resection of a complex large, vermian hemangioblastoma, quite a challenging case. This is a 52 year old male who presented with imbalance and MRI evaluation revealed a cystic relatively enhancing mass within the floor of the fourth ventricle. You can see the location of the mass relative to the lower brainstem and talavilar approach would be ideal for this approach while preserving the normal cerebellum, as much as possible because of the relatively dense homogeneous enhancement of the non histic part of this tumor. I suspected a hemangioblastoma and therefore a preoperative angiogram was completed. Here's the preoperative T2 images, demonstrating evidence of edema within the cerebellum, the mass is relatively intimately associated with the floor of the fourth ventricle. But I suspected preoperatively that the tumor would not be very adherent to the floor and a good restore resection should be feasible. Here's the preoperative angiogram, early arterial phase. You can see the feeding vessels from the PICA, here's a later phase or a venous phase of the angiogram that you can see the draining vein proceeding posteriorly and superiorly. Obviously this draining vein has to be protected during the stages of dissection and devascularization, it's also very important to only devascularize the lesion by disconnecting those vessels that are directly ending in hemangioblastoma, one has to protect the emphasized vessels very carefully. You can see some of the distal PICA branches are draping over the superior pole of the tumor. I'm going to essentially treat this lesion a very highly vascular hemangioblastoma like an R two venous malformation. Let's go ahead and investigate the inter operative findings. Patient underwent resection in the latter position. Here's the dura over the cerebellum. You can see C1 here, suboccipital bone was resected and here's the lower edge of the transfer sinus, dura was opened. You can see the arachnoid over a cisterna magna. I'll go ahead and gently tear open the arachnoid, very efficient technique to disclose the lesion. Here you can see the arterialized draining vein very early on during our exposure. I'll go ahead and execute the to reveal our approach and find the floor or the fourth ventricle very early on. This is an important strategy so that we can always keep the floor of the fourth ventricle in mind, during a resection of a mass and understand the level of the floor to protect it. If significant bleeding is evident. So the floor is found, piece of cottonoid is placed for surgical orientation, and I'll go ahead and circumferentially disconnect the malformation while preserving the draining vein more superiorly. Initially the mass did not appear very vascular, but I knew that this situation would for sure change later in the operation, you can using a marisol cottonoid. That's not very adherent along the floor between the mass and the floor in order to protect the floor from any inadvertent quiet coagulation. Here's the capsule of the mass that was coagulated and de vascularized, I'll go ahead now, circumferentially disconnect the malformation. You can see it surface here at the tip of the arrow, and I stay on the capsule and use the bipolar forceps to disconnect the normal tissue from the capsule of the malformation. Here, you can see the very obvious surface of the hemangioblastoma. You can see normal cerebellum and the interface. Obviously just as in the case of our tunous malformations, it's best to avoid getting into the hemangioblastoma. Here you can see getting around the capsule of the tumor and reaching one of the cysts most likely. So far torrential bleeding is not present. Now going to the right side and repeating the same steps here. You can see some feeding vessels potentially to the hemangioblastoma. Here you can see the interface between the cerebellum and the capsule, on the other side, some of the feeding vessels, smaller ones are coagulated and disconnected. Some of the more dominant and larger feeders should be more anteriorly closer to the floor of the fourth ventricle. You can go on around the capsule, exposing some of the cysts and draining them. Continuous irrigation is used to keep the planes and the interface between the hemangioblastoma and the cerebellum obvious and evident in all times, again, appreciating the level of the floor of the fourth ventricle, protecting it at all times. And now that good portion of the capsule on its lateral parts have been de vascularized I can come over, find the floor of the fourth and now work from the fourth up in order to eliminate any risk of inadvertent, coagulation of the floor of the fourth ventricle. You can see a section of chord plexus, again, working from the floor up rather than the other way around. So that one always has the surgical orientation, right? In terms of protecting the very vital and functional floor of the fourth ventricle. You can see the interface, coagulation and sharp dissection are continued. This is the more easy part of the operation. However, as we go further more bleeding is most likely possible. If I get into the capsule inadvertently, I coagulate the area of the bleeding and hemangioblastomas are usually easier to coagulate than MVA nitis is, and bleeding can be controlled relatively easily. Now working on the left side to find the floor. And again, working deep to superficial in order to protect the floor of the fourth ventricle. Now you can see some of the larger vessels anterior to the mass. Again, one has to be extremely careful to only coagulate the ones that are entering to the tumor. Very obviously like this one, rather than coagulating any emphasized vessels that are irrigating the cerebellum. Hemostasis is quite important for identifying these feeding vessels and avoiding inadvertent, coagulation in the neurovascular structures because of torrential bleeding. You can see some of the vessels on the floor of the fourth ventricle. Again, one has to follow these vessels and make sure they're ending exactly in the hemangioblastoma and not elsewhere before they are sacrificed. Here's a larger one, anterior to the mass. Bleeding into the fourth ventricle should be meticulously controlled. You can see how hemostasis is maintained. So all the planes of the neurovascular structures are carefully identified. Normal vessels are evident. They are kept intact until the mass is more thoroughly and circumferentially disconnected. You can see how the traction of the suction on the capsule is used to mobilize the mass and although it's M block dissection. High magnification and illumination of the micro score are exploited, you can see another potentially embosaged vessel. However, this one appeared to be going into the mass and therefore was sacrificed and disconnected. You can see the operative corridor is very narrow. And here you can see one of the vessels, most likely entering the hemangioblastoma, however, we'll continue to monitor this vessel. Here you can see at least at branch of it going into the hemangioblastoma, Some of these branches can pop just like deep white matters of the AVM. Here is a branch that is vigorously bleeding and how one has to be patient and maintain her or his composure in order to achieve hemostasis. Suction is used just on the exact point of bleeding. So the operative field is cleared. Inadvertent and indiscriminate coagulation of the neurovascular structures should be avoided. Patience is quite important in these moments. So one can make good decisions and not rushed ones. Based on the preoperative angiogram the superior pole of the tumor appeared to be the most difficult part for dissection. And that's when and where most of the effort was placed during the operation to disconnect the hemangioblastoma, More superficial vessels are disconnected. So I can see at the depth and control other points of bleeding. I continue disconnection layer by layer and always keep the floor of the fourth ventricle in mind, you can see another feeding artery to their malformation that's being coagulated and cut sharply. Piece of chord plexus is within the resection cavity. So the fourth ventricle should be close by. You can see it right there. Here's another vessel that appears to be entering the hemangioblastoma, it quickly is placed on this one and it's followed to make sure that it's clearly feeding the malformation and not other structure before it's disconnected. Here you can see it's definitely entering the malformation and therefore it was coagulated and cut. And you can see the floor, posteriolateral brainstem, where the lesion was more adherent. The posteriolateral brainstem is much more forgiving in terms of its mild invasion. However, the floor or the fourth is definitely a non forgiving by any means and should be extremely carefully protected. We're coming around most of the superior pole of the tumor and rolling the mass inferiorly. Here you can see the floor, more de magnified view for surgical orientation. The mass was therefore disconnected completely and excised. The cottonoid is being also removed and the floor of the fourth inspected to make sure it's intact. I'm very satisfied with the extent of resection. The clip was removed since the feeding vessel was coagulated. Here's the final product. And the post operative imaging revealed gross total resection of the hemangioblastoma. This patient did very well after surgery, had some nausea that subsequently improved. So the technical pearls in this video, are the importance of understanding the angio architecture of hemangioblastoma via preoperative imaging, obviously it's important to recognize the possibility of hemangioblastoma, based on its imaging features and perform a preoperative angiogram and protected draining veins. Also another technical pearl is avoidance of the fourth ventricle and circumferential disconnection of hemangioblastoma while keeping the operative planes very clear so that the feeding vessels are carefully identified and cut and the emphasized vessels are protected. Thank you.

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