Introduction In 2011, the treatment of retinoblastoma was revolutionized by the introduction of intra-arterial chemotherapy, involving the catheterization of the ophthalmic artery (OA) for direct drug delivery to the eye with minimal systemic or ocular toxicity. As intra-arterial chemotherapy becomes established as a first line therapy for retinoblastoma, it is important to understand the potential technical pitfalls and anatomical challenges that can be encountered with drug delivery to the ophthalmic artery.

Materials and Methods An institutional retrospective review of 60 patients who underwent intraarterial chemotherapy for management retinoblastoma was performed. Procedure reports and imaging data were reviewed for patient demographics, OA anatomy, microcatheter and microwire selection, technical challenges, and solutions to such obstacles with ophthalmic artery catheterization.

Results Among 60 patients, a total of 226 OA catheterizations (116 right and 110 left) were performed between February 2011 and February 2024. Median patient age was 19 months. Standard approach was via femoral access and catheterization of the OA origin from the internal carotid artery (ICA) using a flow-directed 1.2 or 1.5 French Magic microcatheter (Balt, Montmorency, France) with a 0.008’ Asahi Chikai (Asahi, Irvine, California) or Mirage (Medtronic, Minneapolis, MN) microwire. The microwire was typically positioned within the microcatheter in the ICA proximal to the OA origin. 41 patients had conventional anatomy of the OA arising anteriorly from the C6 segment of the ICA. 19 patients (31%) had OA origin variants that increased the difficulty of OA catheterization. Of these, 10 had a more medial origin of the ophthalmic artery, 4 of which were high-medial origins. 6 patients had a small caliber origin either due to vasospasm or stenosis, and 3 had acute angulation or proximal tortuosity at the origin. In 3 patients, the OA was catheterized by selecting the OA origin first with the microwire. In 9 patients, the external carotid artery collaterals to the OA were catheterized. Of these, 7 were the meningolacrimal (MLA) branch of the middle meningeal artery (MMA), 1 was the orbital branch of the anterior temporal artery, and 1 was the accessory meningeal artery. Of the 7 patients that received chemotherapy via the MLA, 4 underwent distal MMA branch embolization to augment flow to the OA. In one case with stenosis of the OA origin and vasospasm of the MMA, chemotherapy was successfully delivered to the OA using balloon-assisted occlusion of the ICA distal to the OA.

Conclusion As intraarterial chemotherapy gains popularity as a first-line therapy for the treatment of retinoblastoma, it is important to be aware of the potential technical challenges that variant OA anatomy. In our institutional cohort, we demonstrate a history of success with OA catheterization using a 1.2 or 1.5 French Magic microcatheter and a 0.008’ Asahi or Mirage microwire. In cases where drug delivery to the OA from the ICA was not feasible, catheterization of the MLA collateral was the most common alternative approach, with coil embolization of distal MMA branches to augment flow to the OA.

Disclosures K. Ding: None. R. Matthay: None. S. Hetts: None.