Is it safe to sacrifice the superior hypophyseal artery in aneurysm clipping? A report of two cases.

Clipping of paraclinoid internal carotid artery aneurysms related to the superior hypophyseal artery (SHA) carries risk of occlusion of this artery when originating distal to the neck of the aneurysm. Sometimes it is inevitable to sacrifice the artery to achieve total aneurysm occlusion. Otherwise a residual aneurysm would remain, which may lead to aneurysm regrowth and subsequent rupture. However, consequences of SHA sacrifice are rarely reported in the literature. In the two presented cases, the SHA was found originating distal to the neck and within the wall of the aneurysm, making the optimal clipping of the aneurysm at the neck unfeasible without trapping of the SHA. Intraoperative indocyanine green (ICG) angiography revealed a retrograde blood flow in the SHA distal to the clip in both patients, indicating some collateral circulation. No endocrinologic deficits were encountered after surgery. The vision was not affected in one patient. In the other patient, bilateral visual field defects occurred, which improved partially in the follow-up 2 months after surgery. The consequences of SHA occlusion are difficult to predict. A large variety of anatomical variations of the vascular anatomy exists. Intraoperative ICG angiography may help to estimate collateral blood flow but is not able to predict visual decline. Although final conclusions cannot be drawn from two patients, it seems that in case of multiplicity of superior hypophyseal complex, sacrifice of one even larger branch is safe. However, visual sequelae have to be taken into consideration when a single SHA has to be sacrificed for total aneurysm clipping.