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Parietal AVM: Partially Thrombosed

February 10, 2015


This is a nice video describing the events surrounding resection of a partially thrombosed arteriovenous malformation. This is a 44 year-old male who present with a seizure. MRI evaluation revealed an arteriovenous malformation in the the parasagittal area, with potentially draining vein toward the superior sagittal sinus. An arteriogram demonstrated this posterior parietal arteriovenous malformation, primarily fed by the distal branches of the anterior cerebral artery. Interestingly, there is no large draining vein joining the superior sagittal sinus. I suspected that the vein most likely acutely thrombosed leading to hemodynamic changes within the AVM, potentially some minor edema and therefore acute seizure activity. Here's another view of this malformation. However, in this view, there is evidence of a draining vein, cortically joining the straight sinus. Patient underwent a right-sided parietal parasagittal craniotomy. You can see the position of the patient in the prone position, the location of the head within the skull clamp and this skull flap used for wide exposure of this malformation. Here are other photos, demonstrating dissection of the scalp flap, two burr holes over the superior sagittal sinus. The dura was incised based over the sinus and the malformation was apparent. You can see that this large draining vein joining the superior sagittal sinus appears completely thrombosed as suspected preoperatively. The removal of this malformation is relatively straightforward. Here's the interhemispheric corridor. I started dissection along the anterior border of the malformation using intra-operative CT angiogram navigation. Here you can see the thrombosed vein joining a portion of the nidus. Here's one of the feeding arteries. Toward the malformation, I continued to circumferentially disconnect the nidus and stay outside the nidus so that the malformation can be reliably disconnected. Interhemispherically, you can again see the falx cerebri. The AVM is being circumferentially disconnected in this area. You can see the thrombose draining vein joining the superior sagittal sinus more posteriorly. No additional large feeding vessels are apparent as expected in this area. The peeled surfaces along the interhemispheric corridor are coagulated. Some of the venous bleeding can be quite effectively controlled by using gel foam packing. It's bleeding is most likely from the area of the falx. In this case, bipolar coagulation was quite effective. Some of the adhesions from the malformation to the falx were apparent. I continue lateral white matter dissection. I expect to run into some deep white matter of feeders in this area. Here's the nidus of the malformation, quite apparent. Continue bipolar coagulation and disconnection of the white matter. The malformation is being mobilized away from the brain. Malformation appears more disconnected. Here's disconnection of the malformation from the pia along the medial hemisphere. Since most of the malformation is completely disconnected, the thrombose draining vein is also being transected. The AVM was subsequently removed. Here is the final result of the resection cavity and the postoperative angiogram revealed complete removal of the malformation. And the three months MRI evaluation revealed no complicating features, and this patient made an excellent recovery from his operation. Thank you.

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