Middle Cerebral Artery Aneurysm: Incidental Small Saccular MCA Aneurysm with Complex Geometry in a Patient with Ischemic Pontine Stroke – Microsurgical Clipping of the Saccular Aneurysm and Wrapping of a Blister Aneurysm on the Inferior MCA Branch (Postoperative DSA Confirmed the Complete Occlusion of the Saccular Aneurysm and Patency of Both Efferent MCA Branches – Development of a High-Grade Stenosis of the Inferior Trunk of the MCA, Possibly Induced by Muslin Gauze, and Eventually Formation of a De Novo Aneurysm)
A 59-year-old female patient presented with a brainstem ischemia due to an ectatic basilar artery. Diagnostic imaging revealed an incidental small aneurysm of the left middle cerebral artery (MCA) bifurcation with two separate lobules. Both lobules on this aneurysm were clipped. During this operation, a blister aneurysm was observed on the inferior trunk of the left MCA, and this artery was wrapped with muslin gauze. The operation in general was straightforward. Temporary clipping was not required and intraoperative hemorrhage did not occur. Postoperative DSA on day 4 confirmed the complete exclusion of the saccular aneurysm from blood circulation. The MCA bifurcation was otherwise well reconstructed, and both efferent branches had a normal caliber and vessel contour. The next follow-up DSA examination 13 weeks later, which was carried out when the patient was undergoing endovascular treatment to implant a flow diverter into the basilar artery, revealed a high-grade stenosis of the inferior branch of the left MCA. Subsequent DSA examinations at annual intervals confirmed the stenosis of the said artery, which remained clinically asymptomatic due to parenchymal supply via leptomeningeal collaterals. The latest follow-up examinations 4 years after the surgical clipping and wrapping showed a de novo aneurysm formation underneath the clip and a new, most likely inflammatory lesion of the adjacent temporal lobe. Possible explanations for these unusual findings are discussed apropos of the case description. An inflammatory reaction of the vessel wall to muslin gauze wrapped around it is the main topic of this chapter.
KeywordsMiddle cerebral artery Clip Blister aneurysm Aneurysm wrapping Muslin gauze Vessel wall inflammation Arterial stenosis De novo aneurysm formation
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