January 06, 2016
This video describes the techniques for resection of outer venous malformation that are located within or very close to the motor cortex. This is a 35 year old male who presented with a sudden onset seizure and my evaluation demonstrated a hemorrhagic mass with evidence of edema. An angiogram demonstrated the nidus of the malformation without any robust draining vein although there was a small draining vein joining the superior sagittal sinus. I suspected that one of the dominant draining veins must have acutely thrombozed in this patient leading to repeated hemorrhages and edema causing the seizure activity. The location of the hemorrhage and AVM is most likely related to the face area and potentially the hand area Patient underwent a craniotomy. Dura was opened at cruciate fashion, a strip electrode was placed close to the motor cortex so motor evoked potentials can be monitored using direct cortical stimulation. Due to the vital location of the malformation that's surrounding cortical areas, very wide colloidal dissection was used to identify the emphasized vessels and draining veins. Here's the location of the clot. A trans-sulcal approach was used to reach the malformation while preserving as much of the normal cortex as possible. Obviously a small part of the cortex that is infiltrated and affected by the malformation has to be removed. Here's the trans-sulcal approach to the malformation. Here's the clot within the sulcus and the emphasized vessels are also identified. This is part of the cortex affected by the malformation. Next, I evacuate as much of the clot as possible to create working space for identification of the malformation. Here's the clot and it's evacuation. The vessels to the malformation are disconnected, and the emphasized vessels at the depth of the sulcus are carefully protected. The trans-sulcal approach is extended. Again, the malformation with associated clot. Here's emphasized vessel through the sulcus that's protected. You can see it's just coming across the malformation without any significant contribution to the AVM. I continue to remove additional clot and circumferentially disconnect the malformation. The gliotic margin is apparent. Clot is removed. Here you can see the gliotic margin is gently cleaned out to maximize the chance of postoperative seizure freedom. A portion of AVM remains just in this location. Again, the emphasized vessels are being identified and protected. Here's part of the malformation within the cortex. Again, part of the cortex containing the malformation itself. Nidal vessels. This part of the cortex has to be removed for complete removal of the nidus. After the exact part of the cortex associated with a malformation is identified, the AVM and associated cortex is circumferentially disconnected. The draining vein is also isolated and protected, and circumferential disconnection of the malformation is continued. So here is the hematoma cavity. Here is the malformation itself. Again, all this information was possible after the clot was removed and the anatomy was carefully inspected. Here's the draining vein that is preserved until the end of our dissection. The AVM is nearly completely disconnected besides it's draining vein. Here's the draining vein. Temporal occlusion reveals no untoward signs and therefore the vein was also coagulated and sacrificed. After extraction of the AVM the resection cavity is further inspected. As you can see here no residual AVM is apparent, and the postoperative CT scan revealed no evidence of ischemia. The intraoperative angiogram also revealed complete exclusion of the malformation and this patient recovered from his surgery without any new neurological deficits. Thank you.
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