An Anatomical Feasibility Study for Revascularization of the Ophthalmic Artery. Part II: Intraorbital Segment.

ABSTRACT

INTRODUCTION: Distal ophthalmic artery (OpA) aneurysms are a rare subset of vascular lesions with lack of optimal treatment. The management of these aneurysms may require complete occlusion of the parent vessel, carrying a risk of permanent visual impairment due to individual variations of extracranial collateral flow to the intraorbital ophthalmic artery (iOpA). OBJECTIVE: To test the feasibility of a superficial temporal artery (STA) to iOpA bypass to prevent acute ischemic retinal injury. Two different transorbital corridors (superomedial and posterolateral approaches) for this bypass were evaluated. METHODS: Each approach was carried out in 10 specimens each (n = 20). The corridors were compared to achieve the optimal exposure of the iOpA until the central retinal artery origin was visualized. An end-to-end anastomosis was performed from STA-to-iOpA. The arterial caliber and length at the anastomotic sites, required donor artery length, and intraorbital surgical area were measured. RESULTS: STA-iOpA bypasses were performed in all specimens. For the posterolateral transorbital approach, the mean caliber of STA was 1.8 ± 0.2 mm, and that of iOpA was 1.7 ± 0.5 mm. The required STA graft length was 78.3 ± 1 mm with lateral iOpA transposition of 8.2 ± 1.1 mm. For the superomedial approach, the average STA length required for an intraorbital bypass was 130.8 ± 14.0 mm. The mean calibers of iOpA and STA were 1.5 ± 0.1 mm and 1.5 ± 0.1 mm, respectively. CONCLUSIONS: This study demonstrates the feasibility of a novel revascularization technique of the iOpA using 2 different transorbital approaches. These techniques can be used in the management of intraorbital lesions such as OpA aneurysms, tumoral infiltrations, or intraoperative injuries.