Transorbital anastomotic pathways between the external and internal carotid systems in children affected by intraocular retinoblastoma

Abstract

When properly searched, anastomoses between the ophthalmic artery and the external carotid artery are almost constant in children. Depending on the clinical scenario, they can represent dangers or valuable alternative routes for collateral circulations and intraarterial chemotherapy.

Hemodynamic and Anatomic Variations Require an Adaptable Approach during Intra-Arterial Chemotherapy for Intraocular Retinoblastoma: Alternative Routes, Strategies, and Follow-Up

“…Indeed, the reflux of contrast medium into the ICA is likely secondary to an inversion of the blood flow within the OA due to several possible anastomoses with the ECA, which may provide alternative pathways for the orbital blood supply. 12,15 In such cases, balloon occlusion of the ICA with drug infusion just below the block may not be as effective as the use of alternative routes through the ECA because the blood supply to the orbit comes just from the latter source. In children, the hemodynamic balance between the OA and the ECA may be subtle.…”

“…Our study shows that 16.29% of procedures occurred via 1 of the many alternative pathways previously described and involving branches of the ECA. 12 This adaptable approach allowed us to increase the number of successful sessions of IAC. In particular, we calculated that 24.52% of eyes could have skipped at least 1 session of IAC if we had not looked for anastomotic pathways.…”

“…However, several anastomoses connecting the MMA with the OA were used for drug delivery: the direct anastomosis between the 2 vessels (meningo-ophthalmic artery) was used in 14 eyes (38 sessions); the anastomosis between the MMA and the lacrimal artery was used in 9 orbits (24 sessions); and finally, in 1 orbit (2 sessions), we used an unusual anastomosis between the MMA and the supraorbital artery. 12 Less frequently, the arteries used for delivering the antitumoral drugs were periorbital vessels that anastomosed with arteries running in the anterior orbit and were identified following previously published criteria, 13 such as the dorsal nasal artery anastomosed with the angular artery (1 eye, 1 session), 12 the frontal branch of the superficial temporal artery that anastomosed with the supratrochlear artery (1 eye, 1 session), 12 the zygomatico-orbital artery anastomosed with the lacrimal artery (1 eye, 2 sessions), 12 and the anterior deep temporal artery connected to the lacrimal artery (3 eyes, 5 sessions). 12 Seven patients (7 eyes affected by grade D tumors) abandoned the treatment after just 1 session (1 patient treated via a branch of the ECA and 6 via the OA).…”

“…12 Less frequently, the arteries used for delivering the antitumoral drugs were periorbital vessels that anastomosed with arteries running in the anterior orbit and were identified following previously published criteria, 13 such as the dorsal nasal artery anastomosed with the angular artery (1 eye, 1 session), 12 the frontal branch of the superficial temporal artery that anastomosed with the supratrochlear artery (1 eye, 1 session), 12 the zygomatico-orbital artery anastomosed with the lacrimal artery (1 eye, 2 sessions), 12 and the anterior deep temporal artery connected to the lacrimal artery (3 eyes, 5 sessions). 12 Seven patients (7 eyes affected by grade D tumors) abandoned the treatment after just 1 session (1 patient treated via a branch of the ECA and 6 via the OA). In 4 of these 7 patients, the ophthalmologic evaluation showed a poor response or the progression of the disease; in the remaining patients, a massive tumor necrotic fragmentation involving the whole vitreous cavity occurred.…”

An update on the variations of the orbital blood supply and hemodynamic

“…Novel data on the anastomoses occurring between the external carotid artery (ECA) and the internal carotid artery (ICA) via the ophthalmic artery (OA) have been produced. In addition to their angiographic demonstration, a survey on the frequency of visualization has been produced for the first time [10]. Knowledge of the incidence that characterizes a certain vascular pattern provides clinicians and neurovascular interventionalists with a useful reference when searching for connections between the internal and external carotid systems.…”