August 13, 2016
This lengthier video describes the Principles of AVM Resection and more specifically for a funnel AVM. This is a 32-year-old female who presented with seizures. MRI evaluation revealed a lateral, right-funnel arteriovenous malformation. An angiogram further studied the angioarchitecture of the malformation. As expected most of the feeding vessels are from the MCA and the draining vein moves more medially to join their superior sagittal sinus. There are obvious a number of deep white-matter feeders at the depth of the resection cavity during surgery. Right frontal temporal craniotomy was accomplished. You can see the draining vein, the nidus of the malformation. Subarachnoid and transulcal dissection exposed some of the feeding vessels at the depth of the sulcus. The vein was also skeletonized. Typically there is a number of relatively prominent veins accompanying the vein. It's best to isolate these arteries ahead of time so in the face of bleeding the artery can be easily recognized, coagulated and cut. Here's this artery, very intimately associated with a draining vein. Here's the transulcal dissection. This maneuver and dissection technique allows differentiation between the empisage as well as the feeding arteries. The draining veins are protected and the dissection continues around them. The superficial feeding vessels are coagulated and cut. Along the posterior capsule of the tumor transulcal dissection was not feasible and the pure membranes were coagulated, and transparenchymal dissection allowed isolation of the AVM. Here's another more superficial feeding artery that has been coagulated and cut. There's a good sulcal boundary along this part of the AVM. I exploit the transulcal trajectory to protect as many of the peel surfaces as possible. Here are some of the corkscrew vessels within the sulcus. More superficial feeding vessel. I continue circumferential disconnection of the malformation in a cylindrical fashion. Deep white matter feeders become more of an issue as dissection continues within the white matter. Here's a more demagnified view of the operative space. And the feeding vessels, they're typically corkscrew are isolated and coagulated just at the periphery of the malformation. Here are some of the white matter feeders. They typically lack a robust wall. One has to remember that the AVM has labials of its nidus that invades the surrounding white matter and therefore the nidus should be mistaken for white matter feeders. And here's one of the white matter feeding vessels that's bleeding. The vessel should be followed and coagulated at it's more distal segment away from the nidus. Here's another white matter feeder. We're reaching the apex of the malformation. This is part of the nidus. Try to stay away from it as much as possible. The nidus should not be entered. Heres a white matter feeder bleeding. I continue to remove a little bit of normal brain around it away from the nidus until a relatively more normal vessel is encountered which is more amenable to bipolar coagulation. So, I again, this section continues in a circumferential fashion while staying outside the nidus of the malformation. Another white matter feeder that is been followed and coagulated. Packing the area is not necessarily as effective and may lead to remote hemorrhages and cerebral swelling. Here is dissection just around the nidus and attempting to stay outside of the nidus and avoid entry or immature entry it the nidus itself. Most of the nidus is now primarily disconnected. The vein appears relatively collapsed. Here are some of the final feeders to the apex of the malformation that are also being coagulated and cut. Here's another view along the entry aspect of the malformation and rolling out the malformation from their resection cavity. Next I plan to temporary occlude the venous drainage and assure that no nidal swelling is evident. Before doing so, some of the arterial feeders hiding underneath the vein are being coagulated and cut. And the draining vein is quite collapsed, assuring the surgeon that most of the feeding vessels to the nidus are disconnected. Here's the temporary occlusion test. Obviously there's no evidence of nidal swelling. The draining vein is coagulated and cut. The nidus is removed. Adequate hemostasis is secured. The resection cavity is carefully inspected to make sure no evidence of a residual malformation is evident. Any occult bleeding typically leads one to believe that a residual nidus is hidden somewhere within the resection cavity. Here's the post operative angiogram which demonstrates complete exclusion of the malformation. There are some stasis within the large feeding vessels leading to the malformation but it gave no evidence of Av shunting and postoperative CT scan reveals no evidence of ischemia and this patient made an excellent recovery without any complication. Thank you.
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