The Blood Supply of Intracavernous Cranial Nerves: An Anatomic Study and Its Implications for Transcranial and Endoscopic Cavernous Sinus Surgery

Background: Tumors with cavernous sinus (CS) invasion present a neurosurgical challenge. Despite improvements in microscopic and endoscopic surgical techniques, cranial nerve (CN) deficits remain the most frequent cause of disability following CS surgery. In this study, we evaluate the anatomic variations and clinical implications of the blood supply of intracavernous CNs when approaching the CS region from transcranial and endonasal routes. A detailed understanding of the blood supply of intracavernous CNs is essential for improving outcomes when operating on lesions involving the CS.

Methods: The origin, course, diameter, and pattern of the cavernous internal carotid artery (Cav-ICA) branches vascularizing intracavernous CNs were studied in 10 specimens (20 sides) from transcranial and endonasal perspectives. Three tumors with CS invasion were selected to illustrate the surgical application of the findings.

Results: The most common branches of the Cav-ICA were the meningohypophyseal trunk (MHT; present in 100% of the specimens); the inferolateral trunk (ILT; 85%); and McConnel's capsular arteries (20%). The proximal segment of the oculomotor nerve received blood from the ILT and superolateral trunk in 100 and 10% of the specimens, respectively; the distal segment was supplied by the ILT only. The proximal trochlear nerve received blood supply from the ILT and tentorial artery in 75 and 25% of the specimens, respectively; the distal segment was exclusively supplied by the superior orbital branch. The proximal third of the abducens nerve, at the level of Dorelo's canal, received blood only from the dorsal meningeal artery. However, the middle and distal thirds received blood from the ILT. The ophthalmic and proximal maxillary segments of the trigeminal nerve also received blood from the ILT. The distal maxillary segment was supplied by the artery of the foramen rotundum. The medial half of the Gasserian ganglion received blood from the ILT and the tentorial artery; the lateral half was supplied by the artery of the foramen rotundum and the dorsal branches of the middle meningeal artery. All ILT trunk branches were located on the inferomedial aspects of the intracavernous CNs; the MHT branches were located on the posterior compartment of the CS. The superior orbital branch supplied blood to the distal segments of all CNs passing through the superior orbital fissure. From a transcranial perspective, all Cav-ICA branches were found on the lateral wall of the CS, except the dorsal meningeal artery which was located in the posterior wall. From an endoscopic endonasal perspective, the tentorial artery and dorsal meningeal artery were found in the superior compartment and posterior compartment of the CS, respectively. The ILT was found in the lateral and inferior compartment of the CS.

Conclusion: ILT branches supply blood to all intracavernous CNs except the proximal segment of the abducens nerve at the level of the Dorelo's canal. MHT branches supply the proximal segment of the abducens nerve and the medial aspect of the Gasserian ganglion. Middle meningeal artery branches supply the lateral aspect of the Gasserian ganglion. Understanding the anatomy of Cav-ICA branches is important to improve the surgical outcome of lesions involving the CS.

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Publication History

Article published online:
12 February 2021