Therapeutic Clip Occlusion of the Anterior Choroidal Artery Involved with Partially Thrombosed Fusiform Aneurysm: A Case Report

Background We describe a rare case with partially thrombosed fusiform anterior choroidal artery (AchA) aneurysm successfully treated with therapeutic occlusion of the AchA. Clinical presentation A 58-year-old man presented with transient mild hemiparesis of the right side. Magnetic resonance imaging (MRI) showed an ischemic lesion in the posterior limb of the left internal capsule. Digital subtraction angiography (DSA) revealed a left internal carotid artery saccular aneurysm (14.5-mm diameter) arising from the supraclinoid segment. The left AchA was not detected in the initial DSA, and MRI showed the aneurysm to be partially thrombosed. The second DSA performed 2 weeks after the onset showed recanalization of the thrombosed portion of the aneurysm with the left AchA apparently arising from its tip. The aneurysm was diagnosed as a partially thrombosed fusiform AchA aneurysm. Results Open surgery was performed and a titanium clip was applied to the base of the fusiform aneurysm under motor evoked potential monitoring, which remained unchanged after clipping. Occlusion of the aneurysm was confirmed by Doppler ultrasound and intraoperative fluorescence angiography. Furthermore, Doppler ultrasound and fluorescence angiography showed that the blood flow supplying the pyramidal tract was reconstituted by the retrograde collateral flow from the choroidal segment. The aneurysm was completely obliterated in postoperative DSA, which demonstrated retrograde filling of the AchA through the posterior circulation. The patient manifested transient weakness of the right side postoperatively, which was completely recovered after short-term rehabilitation. Conclusions This case illustrates the unique clinical course of a rare partially thrombosed fusiform AchA aneurysm, successfully treated with therapeutic clip occlusion of the AchA under the multimodal monitoring.