Angiographic characteristics of unruptured middle cerebral artery aneurysms predicting perforator injuries

The aim of the present study was to delineate preoperative factors that may predict perforator injuries following open surgery for an unruptured middle cerebral artery (MCA) aneurysm.

The authors conducted a retrospective review of 85 consecutive patients who underwent surgical clipping of 91 unruptured MCA aneurysms. In addition to demographic profiles, angiographic characteristics of aneurysms, which included the side, size, projection, height from the origin of the ophthalmic artery, and distance between the internal carotid artery (ICA) bifurcation and the aneurysm origin, were analysed and correlated with perforator injuries. Compared with the preoperative CT and/or MRI, any newly-developed infarctions in the striatocapsular area were regarded as perforator injuries even if they were very small and asymptomatic.

A perforator injury was found in 14 out of 91 cases (15%). Although the majority of them remained asymptomatic, neurological deterioration occurred in four patients. Of the analysed variables, both the height (from the origin of the ophthalmic artery) and the distance (between the ICA bifurcation and the aneurysm origin) were significantly associated with perforator injuries. A stepwise increment of the risk was observed as the position of aneurysms became higher or as the distance to the ICA bifurcation became shorter.

These results would be helpful in estimating surgical risks for an unruptured MCA aneurysm, one of the most commonly encountered aneurysms in the neurosurgical field.