August 17, 2016
It's sometimes or even often difficult to predict what's the best treatment modality for ruptured dissecting pseudoaneurysm of the vertebral artery also affecting the origin of the PICA. This is a 60 year old male presented with diffuse subarachnoid hemorrhage. You can see the location of the subarachnoid hemorrhage also entering into the fourth ventricle. An angiogram demonstrated dissecting aneurysm of the vertebral artery, also extending into the origin of the PICA. You can see this dissecting aneurysm is quite complex, and definitely involves the origin of the PICA. Obviously, the primary clip ligation of this aneurysm or aneurysms is not possible. My first thought would be performance of a PICA to PICA side to side bypass, and entrapment of the effected segment of the vertebral artery and PICA. Midline suboccipital craniotomy was completed. The tonsils were mobilized gently, and both PICAs were exposed. Here is the entry into the fourth ventricle, foramen of Magendie. You can see the proximal vertebral artery, the aneurysm affecting the origin of the PICA. I went ahead and inspected the need for a PICA-PICA side to side bypass. Here's the right PICA. The left PICA is more dominant. On initial inspection, it appeared that the right PICA is not really feeling vigorously. You can see the size difference between the two, therefore intraoperative ICG angiogram was completed to assist the flow within the PICA. You can see the right PICA is barely filling. However, the left PICA is very healthy. I therefore did not feel that a PICA to PICA bypass would be necessary. Patient did not have any obvious stroke in the PICA distribution preoperatively. On turning, ligation of the vertebral artery appeared to be a reasonable method to deal with the aneurysms. Microdoppler ultrasonography, again confirmed minimal flow within the right-sided PICA. Here's the proximal vertebral artery that is not affected by the dissection. Permanent clip was placed. Here's the distal part of the vertebral artery affected by the dissection. Here's the very prominent aneurysm, which is probably the source of subarachnoid hemorrhage. I inspected the viability of clip ligating the ruptured point. Further dissection around this aneurysm revealed that this is very fusiform and has affected the origin of the PICA significantly and primary ligation of any part of it, is now feasible. Here you can see the origin of the PICA curving more anteriorly and inferiorly. Entrapment was not performed to avoid any compromise of the flow within the perforating vessels, to the brain stem from the PICA. Here's the distal part of the vert, going around the anterior aspect of the brain stem. Again, the aneurysm located there. Another look at distal vert origin of the PICA. So essentially, these aneurysms were treated via anterior ligation of the vertebral artery, obviously proximal to the origin of the dissection process. This proved to be an effective therapy as the one month angiogram revealed significant healing of the aneurysm, and a CT scan revealed no endo ischemia and this patient made an excellent recovery. Again, you can see that the PICA is filling on the right side. The aneurysm is exceedingly small or non-existent, and the dissection process within the vertebral artery has significantly healed. Thank you.
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