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Challenging Atherosclerotic PICA Aneurysm


This is a challenging case of an atherosclerotic PICA aneurysm. This is a 61 year old male, who presented with subarachnoid hemorrhage, as well as fourth ventricular hemorrhage. Sagittal CT angiogram demonstrated the presence of a PICA aneurysm. Preoperative cerebral arteriogram also demonstrated the morphology of the PICA aneurysm. The PICA itself was originating from the neck of the aneurysm and therefore endovascular therapy was noted to be somewhat risky. Left lateral suboccipital craniotomy was completed. The arachnoid membranes around the tonsils were dissected. Distal PICA was recognized, as you can see at the tip of my arrow. Further dissection was pursued over the PICA until this artery joined the vertebral artery. Here's further mobilization of the cerebellum, more medially. Cranial nerves including the 11th cranial nerve was dissected within the arachnoid bands. You can see the PICA again, being followed to its origin, were the aneurysm would be residing. Here is part of the aneurysm, you can see the part of the aneurysm associated with the origin of PICA is quite atherosclerotic. Here's a temporary clip on the vertebral artery. Atherosclerotic changes across the origin of the PICA. Now I'm dissecting around the neck of aneurysm trying to find the distal vert. The distal vert was not readily identifiable along the medial aspect of the vessel, but lateral to the vertebral artery, I was able to identify that distal vert curving around the aneurysm and moving medially. Here's the distal neck of the aneurysm. The challenging part of this case would be application of clips around and over the atherosclerotic plaque, without compromising the origin of the very small PICA artery. Here, you can see the origin of PICA. Again, a more magnified view of the atherosclerotic plaque, very intimately associated with the origin of the PICA. The artery was further mobilized, so the clipped blades can be passed just underneath the PICA. Here's another look at the distal vert, distal neck of the aneurysm. I'm relatively happy with the circumferential dissection around the neck. Before applying any clips, I measured the flow using a micro-Doppler ultrasound device, because of the significant atherosclerosis at the neck of the aneurysm, the tandem clipping technique was initially attempted. A fenestrated straight clip was applied, however, even the first clip occluded the PICA, based on micro-Doppler ultrasonography. The clip was removed. There was evidence of flow within PICA, after the removal of the clip. This time I placed the straight clip across the neck, away from the area of the plaque, hoping that the PICA would be speared. Again, there was no flow within the PICA, after application of this clip. Obviously, a more elaborate clip application is necessary to preserve the origin of the PICA in this case. My next attempt involved moving the clip more distally across the neck of aneurysm, to leave some space for the origin of the PICA. Again, this attempt was also futile and there was no flow within the PICA. Here's another view of the distal vert, now more medially, Distal part of the neck is also evident. Here's a clip, just very distal on the aneurysm. Again, the PICA did not appear to have adequate flow within it. Papaverine soaked Gelfoam was used. This maneuver was again, not able to restore flow within the PICA. This clip was obviously also removed. Fenestrated clip was applied, now a little bit more distal to the plaque, leaving some of the aneurysm close to the fenestration. It's across the entire neck of aneurysm. Straight clip was applied in a tandem fashion. Unfortunately the second clip occluded the flow within the PICA. So this clip was again removed. Now I applied a second fenestrated clip, just leaving a little bit of the aneurysm close to the plaque and this maneuver preserved flow within the PICA. No flow within the aneurysm was detected using micro-Doppler ultrasonography. Again, you can see the clips are all the way across, the PICA is nicely filling on fluorescein angiography and the aneurysm is obliterated. I'm satisfied with the result. The construction up here is adequate. Postoperative angiogram demonstrated complete exclusion of the aneurysm with patency of the PICA. CTI scan revealed no evidence of ischemia, and this patient made an excellent recovery. Again, this video demonstrates the challenges in terms of clip ligating atherosclerotic aneurysms. The intraluminal compromise could be significantly underestimated during extraluminal examination of the aneurysm or the vessel. Thank you.

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