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Insular AVM: Techniques for Resection

October 28, 2019


This video describes a resection of hemorrhagic Insular AVMs. This is an unfortunate 32 year-old male who presented with large intercerebral hemorrhage related to an insular AVM. You can see the dominant location of this malformation associated large blood clot more immediately with extension into the ventricle. This AVM had multiple episodes of hemorrhage previously and was observed in an outside institution. This patient had previously hadn't done insertion of a ventriculoperitoneal shunt. As expected, this AVM is primarily fed from the branches of the MCA and potentially some of the lenticulostriate arteries that are not evident on the CT angiogram. The strategy would be a left frontal temporal craniotomy and entering the hematoma cavity through the left inferior frontal gyrus, removing the clot, achieving decompression, and then circumferential disconnection of the malformation. You can see that the draining vein is a dominant one, more posterior along the nidus. And we're going to watch for that during the operation. Here's the angiogram again, demonstrating the relatively diffused nature of this malformation. Its main feeders are from the MCA branches. There are definitely some feeders from the deep structures that can be quite challenging. These deep white matter feeders are the most difficult part of the operation and the draining vein more posteriorly as expected. After left front temporal craniotomy, the duro was reflected. You can see that the hemorrhage led to significant amount of a clearance between the brain and the duro. Here's the temporal lobe. Here's the frontal lobe, anterior and fairy frontal lobe. Went ahead and enter the hemorrhagic cavity, just anterior to the AVM and removed as much clot as possible to decompress the brain and be able to manipulate the nidus more effectively during the later stages of the operation. Removing more clot. Here's some of the deep white matter feeders. They're encountered usually after the clot is evacuated. These were coagulated and here's a view of the malformation more posteriorly. I went ahead and extended to coat ecodomy more posteriorly, and here's the draining vein. As we expected posterior to the malformation. Here's the malformation located here. Again the draining vein is over here and we'll go ahead and circumferentially disconnect the malformation as we're doing right now. Obviously we have to carefully look for the MCA branches and protect them. I'm going to stay right on the surface of the nidus and then also disconnect the deep white matter feeders at the depth of the nidus. Here working around the superior pole of the malformation and other potential draining vein here that we also noted during the preoperative angiogram. Again, staying right on the nidus making sure none of the emphasized vessels is sacrificed. Here's the draining vein posteriorly. Again, more clots around the underneath surface of the malformation. Here's the malformation Nidus. Removing the clot, preserving the draining vein and then working circumferentially around the nidus until it is removed in entirety. Here is a branch of the MCA moving more posteriorly that was protected Under the tip of my arrow. You can see that right there. Here reaching along the posterior pole of the malformation, removing more clot and then disconnecting any of the vessels more inferiorly. I'll go ahead and achieve more hemostasis more immediately from the deep white matter feeders. And then mobilize the malformation out of our resection cavity. Here's inferiorly disconnecting the feeders from the MCA to the malformation. Here staying right on the surface of the malformation. This allowed me to minimize the amount of time necessary to dissect the MCA vessels. If this malformation was unruptured, it may have been reasonable to dissect the MCA branches much more effectively and identify them early on before the malformation is disconnected. Here again, disconnection of the malformation. There is a draining veins still left behind. I don't see any swelling of the malformation upon temporary occlusion of the vein. This tells me that the malformation is essentially devascularized. Here is a large, deep white matter that has been also coagulated. I think the malformation is mostly now circumferentially disconnected. Temporary occlusion of the vein did not reveal any findings and therefore the vein was also sacrificed and the nidus was then removed. Next I'm going to inspect a resection cavity very carefully to make sure there's no remarkable findings. Careful. Hemostasis is critical. I try to minimize any significant coagulation as this can often lead to more bleeding from the very friable wall of the resection cavity. Patience and irrigation with pure thrombus solution can be quite effective for those oozing areas. Here's the postoperative angiogram demonstrating complete exclusion of the malformation without any AV shunting. Here's the three months postoperative CT scan, which reveals resolution of the hemorrhage. And this patient actually made very nice recovery and has primarily returned to a functional status. Thank you.

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