Superior Hypophyseal Artery Anatomy: A Ventral Perspective

Background: The role of the superior hypophyseal artery (SHA) has been previously reported with respect to the pituitary gland and as a source of aneurysm formation. However, little is documented with regards to its role in vascular supply to the optic apparatus. The limited reports addressing this latter aspect do so from a transcranial perspective. In this report we document the origin and course of the SHA from the ventral endonasal endoscopic vantage point with a specific emphasis on its role of supplying the optic apparatus. We provide a cadaveric anatomic study with clinical correlations.

Methods: Fifteen injected anatomic specimens were dissected and correlated with surgical findings. The anatomic architecture of the SHA as well as its relationship with the ophthalmic, posterior communicating artery and the distal dural ring of the ICA was noted. This was then correlated with intraoperative findings and surgical lesions located in the prechiasmatic, subchiasmatic and retrochiasmatic space.

Results: Identification of the superior hypophyseal artery was possible in all specimens. It was found to arise from the posteromedial wall of the ICA. We noted that the SHA had a main trunk and three consistent branches: the descending branch that runs parallel to the pituitary stalk, the infundibular branch that forms a network with the contralateral SHA around the infundibulum and chiasm, and the recurrent optic branch that travels anteriorly with the ipsilateral optic nerve. In two-third of the specimens an additional separate artery, the infero-lateral chiasmatic artery, was identified supplying the region of the optic tract and genu immediately posterior to SHA.

Conclusion: A complete knowledge of the course and distribution of the SHA is important when pursuing surgery in the suprasellar space. A ventral route to resect lesions located in the suprasellar space allows direct visualization of the superior hypophyseal arteries reminding when we are doing surgeries to meningiomas SHA will be displaced posteriorly and to craniopharingeomas it will be displaced anteriorly, which ultimately is the most important factor for their intraoperative preservation.