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Complex Large ACoA Aneurysm: Tenets

December 02, 2015


Large complex fusiform ACoA aneurysms can be quite challenging to clip ligate. Let's review the intraoperative events for a 52-year-old female who presented with an incidental 15-millimeter relatively fusiform complex ACoA aneurysm. Preoperative 3D cerebral arteriogram demonstrates the multilobulated nature of this aneurysm. The aneurysm incorporates the entire ACoA complex and also incorporates part of the proximal part of the right A2. The left A1 was dominant in this case. Therefore, the aneurysm was approached via a left-sided frontotemporal craniotomy. However, I expected to have some difficulty with applying the clip across enough to exclude the aneurysm completely, but preserving the origin of the contralateral A2. Obviously reconstruction of the ACoA is mandatory in this case. Small part of the gyrus rectus was removed. Here is the dominant left A1 artery of Heubner. Continue dissection more distally until ipsilateral A2 is exposed. Contralaterally, I looked over the chiasm to find the contralateral A1. Temporary clip was placed on the dominant left A1. Further dissection was completed across the aneurysm neck until the contralateral A2 is exposed. Here is contralateral A1, ipsilateral A1 aneurysm. Further dissection was necessarily to be able to find the contralateral A2. Further dissection over the dome to completely recognize the route of A2 and protect it during definitive clip application. Sharp dissection is used to avoid intraoperative premature rupture. Again, working around the lobules of the aneurysm. Here's placement of a temporary clip on contralateral A1 and ipsilateral A1. So now the aneurysm can be deflated and I can look around the entire extent of the posterior wall of aneurysm, including around the lobules safely so that the contralateral A2 can be at least estimated. You can see the aneurysm is somewhat deflatable. I can look across. However, the contralateral A2 is not evident. I can only see it anterior to the aneurysm sac but not necessarily posteriorly. In other words, the final clip application has to be slightly performed blindly, especially along the length of the posterior clip blade, while preserving the contralateral A2. My initial impression was placement of a straight clip. However, as you can see, the clip is going to leave a dog-ear and I'm unable to see the distal clip light adequately. Also it appeared that the clip would slide and occlude the ACoA as you can see here. So a tandem clip configuration is more appropriate. A portion of the aneurysm sac distally continues to be unclipped. Here's a fenestrated clip to close the distal end of the aneurysm. I deflate the aneurysm via its puncture so I can place a more definitive clip while the compression of the aneurysm adequately preserving the origin of the contralateral A2. Here is a longer fenestrated clip trying to preserve the lumen of ACoA while avoiding any compromise of the origin of the A2. And it appears that the tip of the clip blades could potentially compromise the origin of the contralateral A2. I continue to play with the clip blades hoping for a more desirable configuration here. You can see the contralateral A2 appears patent, however, part of the neck remains unclipped. Place the second tandem clip fenestrated straight parallel to the first one, catching the distal neck. However, inspection revealed most likely compromise of the contralateral A2. The brain appeared and remained healthy. You can see the small amount of gyrus rectus that was removed. Here is the distal part of the neck that remains free and it's unclipped. I cannot see the origin of the contralateral A2. I placed a second fenestrated clip. This time, turning my hand slightly counter-clockwise. It's hard to see the origin of A2 but the aneurism sac appeared or completely occluded. Again, the proximal of A2 appear to be compromised, so I reposition the clip just short of the distal neck of the aneurysm to preserve the lumen of contralateral A2. This configuration was further inspected. The contralateral A2 appears intact. Further manipulation led to intraoperative bleeding from the aneurysm sac. Obviously, the aneurysm is not completely occluded. Therefore, I advance the clip using a straight one and was happy with the final construct. The contralateral A2 appeared patent. Small part of the sac remained unclipped, therefore I repositioned this clip one last time. And this final repositioning did the trick. The contralateral A2 appeared patent and the sac was completely excluded. The postoperative angiogram demonstrated good exclusion of the aneurysm sac. There may have been a small residual aneurysm neck, which was necessary to remain the contralateral A2 patent. Patient did not suffer from any ischemia post-operatively and made a nice recovery. Thank you.

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