An Anatomic Feasibility Study for Revascularization of the Ophthalmic Artery, Part I: Intracanalicular Segment

The anatomico-functional complexity of the ophthalmic segment aneurysms is attributable to the presence of critical neurovascular structures in the surgical field. Surgical clipping of the ophthalmic artery (OpA) aneurysms can result in postoperative visual deficit due to the complexity of the aneurysm, vasospasm, or optic nerve manipulation. In this study, we aimed to characterize the feasibility of an intracanalicular OpA (iOpA) revascularization with 2 donor vessels: an intracranial-intracranial (IC-IC) bypass using the anterior temporal artery (ATA) and an extracranial-intracranial (EC-IC) bypass using the superficial temporal artery (STA). We further discuss their potential role in "unclippable" OpA aneurysms.

Twenty cadaveric specimens were used to evaluate the operative exposure of the intradural and intracanalicular OpA segments using an extradural-intradural intracanalicular approach. The arterial caliber and length at the anastomotic sites and required donor artery lengths were measured. The feasibility of the bypass using both donors was assessed.

The average length of the intradural and intracanalicular segment of the OpA was 9.5 ± 1.6 mm. The mean caliber of the iOpA was 1.5 ± 0.2 mm. The mean ATA length required for an ATA-OpA anastomosis was 26.7 ± 8.9 mm, with a mean caliber of 1.0 ± 0.1 mm. The mean length of STA required for the bypass was 89.9 ± 9.7 mm, with a mean caliber of 1.92 ± 0.4 mm.

This study confirms the feasibility of iOpA revascularization using IC-IC and EC-IC bypasses. These techniques could potentially be used for prophylactic or therapeutic neuroprotection from retinal ischemic injury while treating complex OpA aneurysms, infiltrative tumors, or intraoperative arterial injuries.