The aim of this study is to examine morphology of intracranial aneurysm with neck indistinguishable from surrounding artery branches by cerebral angiography and discuss whether such aneurysms can be treated by interventional embolization. 6 patients who had not been treated by embolization due to irregular wide-necked aneurysms indistinguishable from surrounding artery branches by cerebral angiography received craniotomy for aneurysm clipping. The operations succeeded. Morphologically, neck width and location of the aneurysms were carefully observed and photographed from different directions and multi-angles during operation. The intraoperative findings were compared with the preoperative CTA and DSA images. Walls of the 6 patients’ aneurysms tightly clung to or adhered to surrounding branches and oppressed the branches into arcs, similar to the aneurysm walls in shape, and arterial branches and aneurysm walls suffered from segmental adhesion. In addition, abnormalities of communicating arteries to vary degrees were observed in 4 patients. However, after successful surgical clipping, it was revealed that the aneurysms would have been better treated by embolization since they are basically saccular aneurysms with regular sizes. Deformations in preoperative angiography may be due to anatomical variations of surrounding vessels near the aneurysms, aneurysm wall oppression or incomplete adhesion of surrounding arterial branches. Such deformations can be recognized by careful observation in preoperative angiography from different directions and multi-angles.
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