Background The extensive anastomotic network between ECA-ICA plays an important role in extra- and intracranial vascular pathologies, such as arteriovenous shunts, skull base tumors as well as various steno-occlusive diseases.^{1 2} When performing endovascular treatment (EVT), especially in the skull base region, lacking knowledge of this network can be potentially hazardous and associated with serious complications. Often referred to as ‘dangerous anastomoses’, their identification is crucial to avoid non-target embolization from proximal catheter positions. We present the unusual case of a rare anastomotic branch between the infraorbital and the dorsal nasal arteries which could be successfully used for safe and effective embolization.

Material and Methods A 16-year-old girl with a previously embolized frontal scalp arteriovenous fistula (AVF) presented recurrent symptoms and swelling in her forehead. A control DSA revealed the residual AV shunting supplied by branches of the ophthalmic artery (OA) and distal internal maxillary artery (IMA). The OA was only moderately enlarged, its frontal branch coursing upwards to the AV shunt connected also with an anastomotic loop arising from the infraorbital artery (IOA) and the dorsal nasal artery. Because of the small caliber of the OA, and thus elevated risks of spasm or thromboembolic complications with potential visual impairment, this anastomotic loop was chosen. Using a triaxial approach (NeuronMAX 90, 5F Sofia) allowed navigation of a 1.3F Headway Duo (MicroVention) into the distal IMA, IOA, and through the anastomoses into the frontal branch of the OA. From here, PHIL 25% (MicroVention) was injected until complete occlusion of the residual shunting was observed. The patient woke up without new neurological or visual symptoms.

Summary This case illustrates the value of understanding functional vascular anatomy between distal ICA and ECA territory in the EVT of craniofacial lesions. Using low-profile microcatheters, even very small anastomoses may nowadays be used to perform distal catheter navigation for safe and effective embolizations.

References

1. Bracco S, et al. Transorbital anastomotic pathways between the external and internal carotid systems in children affected by intraocular retinoblastoma. Surg Radiol Anat. 2016.

2. Geibprasert S, et al. Dangerous extracranial-intracranial anastomoses and supply to the cranial nerves: vessels the neurointerventionalist needs to know. AJNR Am J Neuroradiol. 2009.

Disclosures R. Dahl: None. G. Benndorf: None.