Diffuse Peri-Atrial AVM: Superior Parietal Lobule Approach

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Let's talk about resection of diffused, peri-atrial arteriovenous malformation, and pitfalls related to underestimating the AVM size, during the operation and managing the resultant inter operative bleeding. This is a 52 year old female with a spontaneous intracranial hemorrhage. You can see the location of the hemorrhage and the associated peri-atrial arteriovenous malformation. Shonda , when the resection of this malformation in a delayed fashion after her hemorrhage, a cerebral arteriogram demonstrated the nidus in the pre atrial region with a draining vein leading to the transfer sinus. Unfortunately, before the surgery, I estimated the size of the nidus to be relatively small around the edges of my arrow here. However, further inspection after surgery and retrospective review , revealed numerous small vessels that actually made up the nidus. And this AVM is much larger than evident here. Could be that the hematoma that was still resolving had compressed a portion of the nidus, and therefore, I underestimated the size of the malformation. This under estimation unfortunately led to entry into the nidus of the malformation prematurely and excessive intra operative blood loss. You can see the location of the head of the patient and positioning and the linear incision and the location of the superior sagittal sinus. Neuro navigation was used inter operably, you can see the interhemispheric quarter was entered. And I initially attempted to use the interhemispheric corridor, and ipsilateral operative trajectory to reach this malformation. But since the malformation was farther from the midline than desired, I proceeded in terms of using a corticotomy and entering the malformation or exposing it using a corticotomy within the superior pridal labial. Here again is my initial attempt for interhemispheric approach. I abandoned that attempt after I investigated the location of the malformation using inter operative stealth CT angiogram. Here's my dissection through the white matter of the superior pridal labial, you can see the, some of the gliosis and hematoma resolving after the white matter was further transected. I continued to use neuro navigation to move toward the malformation. And my initial plan was to be able to find a malformation, go around it and ultimately expose the atrium of the lateral ventricle. Here's a small corkscrew vessel. Here's part of the malformation. I felt that I'm just about the superior pole of the malformation If I just stay around the nidus and continue controlling the bleeding and disconnecting the malformation, I should be successful to circumferentially disconnect the nidus. However, my initial attempt was faced with torrential bleeding. I found myself inside the nidus of the malformation and partly related to the fact that I underestimated the exact nidus or the malformation. So essentially I ended up removing this nidus from inside out, which is obviously very undesirable. So the whole operation continued to be very difficult, technically challenging associated with significant amount of bleeding. Here is the choroid plexus leading to the atrium. I wanted to control the bleeding as soon as possible to minimize the amount of blood that was entering the atrium. Some hemostasis was secured. I felt better. There is no significant amount of blood within the atrium. However, as it continued to remove the malformation in the area surrounding the atrium , I led to causing more bleeding. Piece of carotenoid was used to cover the atrium and minimize the amount of blood that was entering the ventricular system. The brain appeared somewhere tense in this area. I suspect that there is a portion of the AVM that I have transected. Therefore, I immediately entered this area and removed the part of the malformation that was trapped and was causing intracranial hemorrhage. You can see the tense part of the brain associated with this part of the surgery. Here, the AVM is essentially being removed piecemeal. Some further vessels are apparent especially along the lateral aspect of the atrium. I continued to work close to these vessels. Again, remove the nidus piece by piece. Since I'm not very clear where the exact border of the malformation is. You can see the portion of the nidus that is intact and has been disconnected. Obviously very unsettling feeling to continue the malformation resection without exactly recognizing the borders of the nidus. Here, I encountered some normal white matter, good news that I'm most likely reaching the borders of the malformation. And when I remove the malformation, the bleeding should also stop. You can see, as the malformation is disconnected, hemostasis is immediately reached. Except in this small area where I had to continue dissect further and remove additional small piece of the nidus. Brain is very relaxed. Further inspection reveals no significant source of bleeding. The atrium was inspected. Any blood within the atrium was removed. Post-operative CT scan revealed only small amount of blood within the ventricular system. In addition to post-operative angiogram confirmed complete removal of the nidus without any evidence of A-V shunting. And this patient made an excellent recovery from her surgery. Thank you.

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