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Medial Temporal AVM

December 01, 2015


Let's review the methodologies for clip ligation of medial temporal, or uncal arteriovenus malformations. This is a 54 year old female who was found down, and was later diagnosed with spontaneous intraventricular and medial temporal lobe ICH and IVH. Here's the location of the medial temporal lobe hemorrhage. Small Arteriovenous malformation along the medial temporal lobe was suspected. You can see the extent of intraventricular hemorrhage related to this small arteriovenous malformation. Preoperative arteriogram demonstrated the nidus of the malformation, along the medial of temporal lobe related to a small draining vein, traveling posterially. Branches of the posterior communicating artery, as well as posterior cerebral artery are the predominant feeding vessels to this malformation. Patient underwent a left fronto-temporal craniotomy. The Sylvian fissure was generously dissected, I did not feel an orbitozygomatic craniotomy would be necessary. Here's the roof of the orbit, here's the optic nerve. Let's go ahead and review the basic techniques and dissection in this area more thoroughly before getting to the malformation. This subfrontal area is being released, and dissected away from the optic apparatus. You can see the internal carotid artery, the origin of the PCoA, and the origin of the anterior carotid artery which most likely is providing some small feeding vessels to the malformation as well. Here's the M1, here's the draining vein traveling posterially in this location. Here's the branch on the anterior temporal artery, so the surrounding anatomy is thoroughly understood. Here again, is the anterior carotid artery moving medially and posteriorly. The malformation is located along the area of the ankus, is the draining vein moving posterially. Here's the area of the IC bifurcation, no obvious feeding vessel traveling toward the malformation is seen. Here's the third nerve, very nice anatomy of the basal cistern and its contents. Here's the A1 traveling anteriorly underneath the frontal lobe, and we're just about ready to start circumferential disconnection of the malformation within the area of the medial temporal lobe. Here's the basal artery at the depth of our dissection through the membrane of Liliequist, the third nerve was disconnected and released from the medial part of the AVM, so that during bipolar coagulation the nerve is not placed at risk. The medial part of the temporal lobe is now very thoroughly disconnected from the surrounding structures. Here's the draining vein, I continue circumferential coagulation and disconnection of the malformation superficially while preserving the draining vein. Here's a branch of the anterior temporal artery, here's the MC bifurcation more distally. Here's the draining vein moving posteriorly it is relatively arterialized. Coagulation along the lateral wall of the malformation starts there. Circumferential disconnection of the malformation I continue to coagulate the feeding vessels within the parenchyma onto lateral border of the malformation. Here, you can see disconnection of the malformation more anteriorly. Again, the draining veins over the roof of the ankus are protected. Here's the third nerve, here's the medial border of the ankus. I encountered some bleeding during disconnection of the posterior border of the malformation. You can see the draining vein is starting to appear slightly darker. Here's further dissection and control of the fitting vessels within the posterior part of the malformation. The AVM was isolated from branch of the anterior temporal artery. Here's further disconnection of the malformation more posteriorly. A feeding artery from the posterior circulation was encountered. It's important for the surgeon to remain patient, control the bleeding and avoid aggressive and premature in a vertant and indiscriminate coagualtion. This bleeding point was controlled in a timely fashion. Again, here is the nidus continuing disconnection more medially. So, location of the third nerve, some of the feeding vessels from the anterior carotid artery and the posterior communicating artery are also controlled. Now, I change my angle of view from the frontal side toward the temporal side in attempt to disconnect some of the additional branches, and feeding vessels from the posterior cerebral artery. This disconnection is occurring along the edge of the tentorium. The fourth nerve has to be protected. Aggressive coagulation in this area is avoided since the bleeding was not very torrential I placed a small piece of cotton and achieved hemostasis via gentle tamponade. Here is disconnection of some of the branches from the P2 and P3. Here again is the anterior temporal artery. The malformation is almost disconnected in its entirety. Here's the edge of the tentorium. Again, the third nerve for your orientation. The last connections to the capsule of the malformation are being transected. Here's the malformation being delivered around the anterior of temporal artery. This is the final resection cavity, the third nerve carotid artery virpavin soak gel foam was used to bathe the anterior temporal artery and surrounding emphasized vessels. And the postoperative angiogram revealed complete exclusion of the malformation, and CT scans reveal no evidence of ischemia, and this patient made an excellent recovery from her hemorrhage and her operation. Thank you.

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