PMC6024506_01
(a) Preoperative three-dimensional CT angiogram, superoinferior view, showing a saccular aneurysm (AN) arising from the trifurcation of the accessory ACA (black arrows), the branching point of the ACoA with fenestration, and the right A1 or A2 segment of the ACA. Aneurysmal fundus projects superolaterally to the right. Lt: left; Rt: right; BA: basilar artery. (b) Left lateral view of the three-dimensional CT angiogram, showing the accessory ACA (white arrows) arising from the posterior surface of the ACoA and running around the genu of the corpus callosum, parallel to bilateral pericallosal arteries, which distributed branches to the medial frontal lobes
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F1
Three-dimensional CT angiography revealed an anomalous artery originating from the posterior surface of the ACoA and a saccular aneurysm arising from the trifurcation of the anomalous artery, the branching point of the ACoA with fenestration, and the right A1or A2 segment of the ACA [Figure 1a]. The anomalous artery arose from the posterior surface of the ACoA and ran around the genu of the corpus callosum, parallel to bilateral pericallosal arteries, which distributed branches to the m edial frontal lobes [Figure 1b].
Intraoperative photographs showing the aneurysm (dotted arrows) and its relationship to bilateral A1 and A2 segments of the anterior cerebral artery (ACA), and the accessory ACA. (a) Partial resection of the ipsilateral gyrus rectus, allowing visualization of the aneurysm fundus behind the ipsilateral A2 segment of the ACA. (b) Gently pushing the aneurysm (dotted arrows) forward using the spatula to the corner of the ACoA, allowing visualization of the accessory ACA, working between the right frontal lobe and right A2 segment of the ACA. (c) The aneurysm is occluded by a straight fenestrated clip placed with the aperture around the ipsilateral A2 segment of the ACA, preserving the accessory ACA (white arrowheads). (d) Intraoperative indocyanine green angiogram showing patency of both the right A2 segment of the ACA and the accessory ACA (*), and disappearance of the aneurysm. Lt: left; Rt: right; CN: cranial nerve; Lt CN: left cranial nerve
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F2
A2 segments of the ACA, and the anterior surface of the ACoA were exposed [Figure 2a]. After partial resection of the ipsilateral gyrus rectus, the aneurysmal fundus was found behind the ipsilateral A2 segment of the ACA, which hid the accessory ACA. After gently pushing the aneurysm forward by spatula to the corner of the ACoA, the distal artery of the accessory ACA and its origin were confirmed, working between the right frontal lobe and the right A2 segment of the ACA [Figure 2b]. A straight fenestrated Yasargil titanium clip (No. FT598T; blade length 4 mm, fenestration diameter 3.5 mm) was applied across the ipsilateral A2 segment of the ACA and toward the accessory ACA from the ACoA origin, parallel to the ACoA [Figure 2c]. Complete aneurysm occlusion and patency of the ipsilateral A2 segment of the ACA and the accessory ACA were confirmed intraoper atively under indocyanine green angiography [Figure 2d].
Postoperative three-dimensional computed tomography angiography (superoinferior view) showing patency of both the right A2 segment of the ACA and the accessory ACA (black arrow), resulting in disappearance of the aneurysm. Lt: left; Rt: right, BA: basilar artery
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F3
Postoperative three-dimensional CT angiography revealed patency of both the right A2 segment of the ACA and the accessory ACA, resulting in disappearance of the aneurysm [Figure 3].