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Lateral Temporal AVM: Commando Operation

April 29, 2016


This video describes resection of a lateral temporal arteriovenous malformation. In the process of resection, you can see an injury occurred to the draining vein, which required an immediate resection of the nidus to avoid massive intraoperative blood loss and control the AVM premature rupture. This is a 40 year-old male who presented with a single seizure. CT angiogram, as well as MRI revealed a lateral temporal arteriovenous malformation, primarily felt by the MCA branches and a draining vein traveling more posteriorly towards the sigmoid and transverse sinuses. And arteriogram again, demonstrates the feeding vessels from the distal MCA branches from the inferior branches of the MCA. The large draining vein, which is most likely a hypertrophied vein of Labbé is also noted. There are some small feeding branches from the distal PCA as well. Patient underwent a right side of temporal craniotomy. A linear incision was utilized. You can see the exposure in this case, the large draining vein traveling posteriorly. Majority of the AVM is located here. The initial steps involve dissection of the feeding arteries and skeletonization of the draining vein. Obviously the vein is carefully protected and the superficial anatomy of the malformation is included. I like to use jeweler forceps to gently disconnect the thick, superficial arachnoid bands. In this case, I wanted to better define the feeding arteries just around the vein. So as I'm disconnecting them, I can protect the vein itself. Part of the nidus may be located under the vein. This pathoanatomy can complicate removal of the malformation and potentially lead the surgeon to enter the nidus prematurely. I went ahead and disconnect to some of these superficial arterio feeders to the malformation. Again, my goal is protecting the vein and disconnecting as many other feeders around the vein as possible. Obviously the distal inferior branches of the MCA enter the malformation in this region. I intermittently encountered some bleeding that I was able to control effectively in a timely fashion. Now that the more superficial distal M2 and M3 branches, their feeder malformation are disconnected. I diverted my attention to the inferior pole of the tumor. And the more posterior aspect of the nidus. Here is further dissection to disconnect the deeper portion of the nidus. You saw a feeding vessel, most likely from the posterior circulation, from the PCA that will be disconnected as well. Now, moving more inferiorly and disconnecting the nidus again, preserving the draining vein traveling along the lateral aspect of the middle cranial fossa. Here are some of the feeding vessels from the inferior aspect of the nidus that are being disconnected. Again, working around the vein. I do suspect that I got into the nidus at this juncture as I was overzealously, trying to protect the vein. I entered the nidus and did not stay on the periphery of the nidus, since I believe the margin of the nidus was covered by the vein. I could have dissected on the other side of the vein and protected some part of the nidus that was located just underneath the vein. Some of the deep white matter feeders are very difficult to control. As you can see, despite their coagulation they continue to resist, collapse and they pop and continue bleeding. Here's the draining vein that is exiting the nidus and joining the more larger dominant, superficial draining vein. I've continued to preserve the drainage. There's often a dominant feeding vessel close to the vein that has to be carefully coagulated and cut. I continue to disconnect the feeding vessels while protecting the draining vein. I ran into some bleeding here from a feeding artery. As I attempted to control this artery, I inadvertently injured the vein. This led to significant amount of bleeding, obviously not all the AVM is disconnected at this time. And this so-called commando operation is necessary to remove the malformation, to avoid brain swelling and excessive blood loss. I continued to coagulate the error of the bleeding, but I was not successful. As you can see, I'm focusing my attention primarily at the side of the bleeding, rather than trying to take the entire AVM out. Next I focused my attention or removing the entire AVM and that led to control of the bleeding. So once the bleeding is encountered from the dominant vein, one has to efficiently and quickly focus on his or her attention of removing the entire nidus under these circumstances. You can see the vein is quite dark blue now. The nidus is being disconnected thoroughly at this time and is ready for delivery. Further hemostasis is achieved at the bit of the resection cavity. Here's the final result. Again, a very dark draining vein, brain appears very relaxed. I continued to coagulate the surrounding advance to minimize the risk of any residual nidus. Postoperative angiogram demonstrated the complete removal of the malformation, without an evidence of AV shunting and the three months MRI revealed no complicating features, and this patient may then exhume recovery. Thank you.

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