Introduction: The endoscopic endonasal approach (EEA) has become a routine corridor to the suprasellar region. The superior hypophyseal arteries (SHA) are intimately related to lesions in the suprasellar space, such as craniopharygiomas and meningiomas. Here we aim to investigate the surgical anatomy and variations of the SHA from the endoscopic endonasal perspective.

Methods: Thirty anatomical specimens with vascular injection were used for endoscopic endonasal dissection. Number of SHAs, origin, course, branching, anastomoses, and area of supply were collected and analyzed.

Results: We found a total of 192 SHAs arising from 60 internal carotid arteries (ICA) for an average of 3.2 SHAs arising from each ICA. The first SHA was the primary SHA in almost all cases (98%) as it supplied the infundibulum, optic chiasm, and proximal optic nerve. Two thirds of the first SHAs originated proximal to the distal dural ring, with 50% arising from the carotid cave and 50% from the proximal clinoidal ICA segment. The typical “candelabra” pattern in 3 branches (infundibular, recurrent optic, and descending) was found in just a third of primary SHA. The most common was a tree-like pattern (50%) with 3 or more branches; the descending branch supplied the diaphragm in 48%, the gland in 41%, both in 7%, and was absent in 25%. Circuminfundibular vascular anastomoses were found in all but one specimen.

Conclusions: The first SHA constantly supplies the optic chiasm and proximal optic nerve. Compromising this artery may cause a visual deficit. Unilateral injury to the primary SHA will likely not affect the infundibulum given the almost universal circuminfundibular anastomoses. Sacrifice of the descending branch will have no consequences when irrigating the diaphragm. Detailed understanding of the surgical anatomy of the SHAs is essential for safe and effective surgery in the suprasellar region.

Patient Care: This research provides detailed anatomy of superior hypophyseal artery which is critical in avoidance visual complication during surgery in suprasellar area.

Learning Objectives: Anatomy of superior hypophyseal arteries and clinical relevance.

References: Gibo H, Koyama T, Koyama J, Ito K, Hokama M, Osawa M, et al: The superior hypophyseal artery: Microsurgical anatomy. Clinical Neurology and Neurosurgery 99:S48, 1997 Krisht AF, Barrow DL, Barnett DW, Bonner GD, Shengalaia G: The microsurgical anatomy of the superior hypophyseal artery. Neurosurgery 35:899-903; discussion 903, 1994 McConnell EM: The arterial blood supply of the human hypophysis cerebri. Anat Rec 115:175-203, 1953 Hitotsumatsu T, Natori Y, Matsushima T, Fukui M, Tateishi J: Micro-anatomical study of the carotid cave. Acta Neurochirurgica 139:869-874, 1997