Arterial wall fragment embolism following balloon-assisted coiling: A case report.

Arterial wall fragment embolism is a rare complication of balloon-assisted coiling, and its underlying mechanism remains poorly understood. We report a histopathologically confirmed case of arterial wall fragment embolism during balloon-assisted coiling for a ruptured aneurysm. A 74-year-old woman presented with World Federation of Neurosurgical Societies grade V subarachnoid hemorrhage caused by a ruptured aneurysm at the junction of the right vertebral artery and the posterior inferior cerebellar artery. During balloon-assisted coiling, a contrast-filling defect at the aneurysm neck and irregularity of the parent artery wall were observed, followed by embolization to the basilar artery, resulting in acute occlusion. Histopathological examination of the retrieved embolus demonstrated arterial wall components, including the intima, internal elastic lamina, and media with smooth muscle cells, indicating that the embolus originated from the injured parent artery rather than representing thrombus. This case highlights that arterial wall fragment embolism should be considered in the differential diagnosis, in addition to thrombosis, when a contrast-filling defect and arterial wall irregularity develop during balloon-assisted coiling.