Algorithm for evaluating ophthalmic artery pseudo-occlusion during intra-arterial chemotherapy for retinoblastoma

Background and importance: Intra-arterial chemotherapy infusion for retinoblastoma is typically performed via selective catheterization of the ophthalmic artery. Anastomoses between the external carotid and the ophthalmic arteries have also been utilized when the ophthalmic artery cannot be catheterized directly. However, these are not present in every patient.Clinical presentation: A 10-month-old boy presented with bilateral retinoblastoma and underwent one round of intra-arterial chemotherapy (IAC) via direct catheterization of the ophthalmic arteries. Combined with adjuvant laser therapy, they experienced symptomatic improvement and tumour regression. However, during subsequent treatment sessions both ophthalmic arteries did not have anterograde flow and attempts to catheterize their origin were unsuccessful. Unfortunately, no targetable anastomoses between the external carotid and ophthalmic arteries were identified for drug delivery. Due to the patient's anatomy, balloon occlusion of the ECA was felt to be unsafe. As a salvage technique, a balloon was inflated in the left internal carotid artery (ICA) distal to the ophthalmic take-off to redirect flow into the ophthalmic. Repeat angiography with the distal ICA occluded showed improved flow into the ipsilateral ophthalmic artery. IAC was then successfully delivered through the left ICA.Conclusion: This case illustrates the importance of utilizing creative endovascular techniques for targeted intra-arterial drug delivery when other conventional measures fail as these patients often have limited, and potentially higher risk, therapeutic alternatives.