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Large Medial Temporal/Choroidal AVM

January 07, 2016

Transcript

AVMs fed by the anterior choroidal artery can be quite challenging to resect. These malformations typically include temporal horn malformations and medial temporal lobe malformations. In this video, I'll describe the techniques for resection of a relatively large temporal horn or medial temporal arterioveous malformation through the transventricular transchoroidal route. This is a 32 year old male who presented with repeated hemorrhages, related to his four centimeter arteriovenous malformation, fed primarily by anterior choroidal artery. You can see the size of the malformation, its location, along the medial temporal lobe, invading some of it dying cephalic structures. This patient had previously undergone treatment with radiosurgery without any productive effect. Further imaging demonstrates the angio architecture of this malformation and it's feeding vessels and draining veins. This artery as expected should have both cortical and deep venous drainage. As you can see here, the feeding vessels are primarily from the anterior choroidal artery and draining veins are either superficial through the arterialized sylvian veins or deep brain veins through the veins of Rosenthal, to the vein of Galen. Due to the large size of the lesion, a left sided Pterional craniotomy was completed. A large question mark incision was used, to elevate a sizeable bone flap, and intra medial temporal lobectomy was completed. This is also another view of the posterior circulation, demonstrating relatively less robust feeders from the posterior circulation. Here's the arterialized Sylvian vein. Here's the intra medial temporal lobe resection. Here's the transmeatal trickle approach and identification of the choroid plexus through the Sylvian fissure. Again, redirecting our attention, you can see the internal choroidal artery and the large hypertrophied anterior choroidal artery over the poster clinoid process. I was able to isolate this large anterior choroidal artery early on for proximal control. The artery, as you can see, is intimately associated with a posterior clinoid process through the Sylvian fissure again. Now, I redirect my attention through the temporal horn or the feeders from choroid plexus are identified. The route of anterior choroid artery at the tip of my arrow, is evident directly ending into the malformation. Here you can see choroid plexus, enter a choroidal artery and the malformation intimately associated with the choroid plexus. Now, the angio architecture of the malformation is more evident, you can see the route of anterior carotid artery and the feeders are one by one isolated. I go around the malformation after some of the basal feeders are disconnected. I stay very close to the malformation, just above the malformation, close to the basal ganglia. The deep white matter feeders from the basal ganglia are coagulated and cut. As expected, these white matter feeders can be quite problematic and their walls are relatively incompetent. Therefore, their bipolar coagulation is often complicated by further bleeding and persistent work to ultimately control the lumen of these vessels. The periodic margin of the malformation is followed. Here are some of the feeders from the anterior temporal artery, along the tip of the temporal lobe. Here's the malformation, some of it draining vein anteriorly. I continued to dissect the malformation along its capsule and margins posteriorly into the ventricle. You can see the hippocampus here, the tail of the malformation, just above the tail of the hippocampus. You can see the vein is somewhat, darkened. I go ahead and temporarily occlude the vein. You can see the malformation continues to swell. Obviously, this means that I have to devascularize the malformation further. I believe some of the feeders along the midbrain have to be disconnected. Here is the anterior choroidal artery feeder. I temporarily occlude the vessel, to make sure that there are no evasage vessels that are forgotten. Originating from the anterior choroidal artery, another temporary occlusion of the vein, demonstrated a further filling of the malformation. Here are the feeding vessels from their posterior circulation lateral to the midbrain that are being disconnected. I clearly identify the feeders going into the malformation before they are sacrificed. Here is the transchoroidal corridor. The malformation is more disconnected posteriorly and along its space. The third trial of temporary occlusion of the vein reveals no further AVM swelling. I continue to disconnect some of the more posterior connections, subsequently the anterior choroidal artery was disconnected just at its entry point into the nidus. Next, the vein was coagulated and disconnected. And the malformation was delivered. The stump of the anterior choroidal artery as it entered the nidus was coagulated and cut. You can see the Sylvian vein is now completely, darkened. Here's the intraoperative angiogram, which demonstrates or store resection of the malformation without any early intro venous shunting. This patient recovered from his surgery well, although his right upper extremity weakness, worsened after surgery, this weakness resolved at six months follow up. Thank you.

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