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Ruptured Medial Occipital AVM

August 13, 2016


Here's another case of a ruptured medial occipital arteriovenous malformation. This is a 42 year old male who presented with acute right-sided subdural hematoma, which required emergent evacuation. Here's the initial CT scan on presentation. You can see the large intracerebral hemorrhage within the right medial occipital lobe associated with a large right-sided subdural hematoma. Patient made a reasonable recovery after evacuation of the hematoma and adenoma resection of his medial occipital AVM a month later. CT angiogram again demonstrates the location of the malformation. The coronal image more clearly defines the location of the mass just at the junction of the posterior superior sagittal sinus and the transverse sinus. Angiogram was completed. As expected, most feeders are coming from the anterior aspect of the malformation. These feeders are the distal branches of the PCA. The draining vein joins the trochlear and the more medial aspect of the transverse sinus. Here is patient positioning for resection of the malformation. Right side of the head was placed in the dependent position so that gravity retraction can be exploited. A lumbar drain was also inserted. I'll go back and also demonstrate the placement of the skull clamp. Obviously patient previously underwent a large right-sided craniotomy for evacuation of the hematoma, the pins should not be placed on the bone flap therefore one has to pay special attention to the pin sites of the skull clamp as demonstrated here so that the incision is not affected by the pin sites and the previous bone flap is also not influenced by the pin sites. Here's the exposure, midline is located here. The bone over the posterior superior sagittal sinus and the trochlear was removed. The dura was incised based over the superior sagittal sinus. Again, the right occipital lobe is in the dependent position. CSF was drained through the lumbar drain. Here's the malformation hematoma cavity. The gliotic margins are identified and the malformation is disconnected circumferentially. I expect most feeders coming interiorly along the pial surfaces, just close to the area of the falx. Dissection is relatively straightforward here until the deep white matter feeders are encountered. Again, the draining vein toward the trochlear is preserved. The feeding vessels on the surface of the falx which are the distal branches of the PCA are found coagulated and cut. Here's the falx, other feeders are found isolated and sacrificed. Here's the more anterior surface of the malformation. Here some of the feeders still present on the pial surface. Here you can see the distal PCA branches. I continue to disconnect these distal PCA branches leading to the malformation. You can see one here. Posterior falx is apparent. Last feeding vessels are disconnected. This patient did not undergo preoperative embolization. Now that the malformation is circumferentially disconnected, the draining vein joining the dura is disconnected and cut. The nidus is removed. Pial surface, both anteriorly and posteriorly is recoralized. Hemostasis is secured. Postoperative angiogram revealed complete exclusion of the malformation without any evidence of early A-V shunting and the postoperative CT scan confirmed absence of any complicating features. Thank you.

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