This video reviews techniques for resection of complex spinal cord arteriovenous malformation, and more specifically the epipial technique for resection of these malformations in the spinal cord. This is a 48-year-old female who presented with left lower extremity weakness and numbness, which was relatively progressive, and she was known to have this arteriovenous malformation previously. On the MRI, this malformation is located at the level of T8 and T9, and on the axial images, it gives you the appearance that the malformation is potentially all localized to the epipial space, but as would expect, there are going to be feeders and a small part of the malformation is in the deep, white matter feeders, which will be embedded in the parenchyma of the malformation. Due to the progressive nature of her symptoms, she subsequently underwent a T7 through T9 laminectomy; however, before we proceeded with the procedure, we went ahead and obtained an angiogram, which confirmed our findings that the T8 radicular artery, two of them were the main feeding vessels to this relatively compact glomus malformation with evidence of a large draining vein. Knowing this information, we will plan to pursue disconnection of these feeders initially after the exposure of the malformation intraoperatively. So after performance of the laminectomy, the dura was opened in the midline. Interestingly, there was a layer of calcified, separate dural layer, just next to the dura proper that we removed in order to be able to open the dura. Next, we inspected our malformation here. This is caudal. This is cranial. And obviously we targeted those big feeders that were noted to be along the inferior aspect of the malformation first. Somatosensory evoked potentials and motor evoked potentials were used during this procedure. You can see a permanent clip was placed on those inferior feeders first. The feeders were subsequently resected, coagulated and transected. You can see the gliotic plane along the epipial space. I continued to direct my attention to the epipial space. I did not violate the gliotic margin within the parenchyma of the spinal cord. You can see the nerve roots intimately associated with a malformation. My repeated attempts here to stay epipial, disconnect the feeders to the malformation, however, leave a portion of the malformation within the parenchyma intact. Patient tolerate this partial AVM removal within the spinal cord very well. This is not consistent with our findings in the intracranial lesions and AVMs where partial AVM removal can be catastrophic. So here is the portion of the AVM that is intraparenchymal. I continue to cut across the malformation. This portion is intraparenchymal. This portion is epipial or subpial, and I continue to remove the AVM that is resectable without entering the spinal cord. Now we have this portion of the spinal cord within the parenchyma. The vein was obviously disconnected after removal of the epipial component of the tumor, and I'll continue to coagulate, but not necessarily aggressively manipulate the intraparenchymal portion of the malformation to prevent any neurological deficits that will be new. During the dissection of malformation we had some changes in our motor evoked potentials in the left lower extremity, along the superior portion of the resection, which was noted to be very mild. This is a post-operative angiogram, which demonstrates gross total resection of the malformation without any early draining veins. The patient awoke from the anesthetic with a slight left lower extremity weakness, consistent with our intraoperative mild findings based on motor evoked potential monitoring. The patient recovered well from this deficit at the six months evaluation and since has done very well and returned to work. Thank you.
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