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ICA Bifurcation Aneurysm

January 29, 2016


Let's review another demonstration, for clip ligation of carotid bifurcation aneurysms. This is a 32 year old female who presented with worsening headaches and on evaluation was noted to have approximately nine millimeter, right-sided internal carotid artery bifurcation aneurism. The morphology of the aneurysm is demonstrated, on this 3D reconstruction. A right frontal temporal craniotomy was completed. You can see the turn of the head, for approximately 30 degrees. The sphenoid wing and the area of the pterion, are thoroughly drilled away. In addition the roof of the orbit, is also drilled flat, with the lateral edge of the craniotomy. These two maneuvers allow an unobstructed view of the sub frontal area, toward the ICA bifurcation. You can see the flat trajectory flush with the roof of the orbit. Next, the dura is incised in the Calvin-linear fashion. Sutures are placed along the root of the dura, so the dura can be efficiently, moved out of the operating corridor. Following the use of a round arachnoid yard knife, I use jeweler forceps to gently spread the superficial thick arachnoid bands, of the sylvian fissure. The spreading action of the bipolar forceps, carefully dissects the, thin arachnoid bands within the fissure. The fissure is opened in the inside-to-outside technique, as you can see here, the deep part of the fissure is exposed distally, and then I work within the fissure, from the deep to superficial manner, to widely split the fissure. The arachnoid bands over the chiasm are also dissected, so the frontal lobe can be mobilized under the action and effect of the gravity. The ICA bifurcation is found after the M1 is followed within the fissure. Here is the ICA at level of the skull base. There is a small aneurysm, at the level of the PCoA. Here is more generous dissection of the arachnoid bands. Avoidance of fixed retraction provides very, a traumatic dissection of the fissure, you can see the neck of aneurism, the internal carotid artery, the PCoA and this small associated aneurism. Next, I dissect the medial wall of the neck, in order to protect the perforators, at the level the ICA bifurcation during passage of the clip blades. The clip blades should not perform, any of the dissection, blindly. I look again behind the ICA bifurcation to assure, that none of the perforating vessels will be at risk. Now the A1 is exposed as you can see, M1, A1, the aneurysm, the perforating vessels just behind the neck. Temporary clip is used to further dissect, these fine perforating vessels, from the neck of the aneurysm. Temporary occlusion of the ICA allows more high risk maneuvers on the aneurysm sack, to mobilize the perforating vessels. You can see those vessels are now mobilized. We're about ready to deploy the clip. I look on both sides of the MCA origin, off of the ICA bifurcation, here is another small perforating vessel, that's also being dissected from the aneurysm neck. A straight clip is deployed across the neck of the aneurysm, while preserving the origin of the MCA. You can see the MCA origin is rather small. Intraoperative fluorescein angiography, reveals adequate exclusion of the aneurysm, with patency of all the perforating vessels behind the aneurysm. This finding is also confirmed based on ICG. Again, you can see, the healthy status and condition of the brain using generous arachnoidal shripe dissection and dynamic retraction. And finally, the postoperative 3D arteriogram, demonstrates complete exclusion of the aneurysm, without any complicating features. This small PCoA aneurysm was too small, to be amenable to clip ligation. The postoperative CT scan also demonstrates, no evidence of ischemia, and this patient recovered very nicely from her surgery. Thank you.

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