Endovascular Embolization of Sinonasal Tumors: A Report of Two Cases and a Technical Review.

Hypervascular sinonasal tumors frequently cause recurrent epistaxis and pose a risk of significant intraoperative bleeding during resection. Preoperative embolization can improve operative visualization and safety; however, optimal technical strategies remain incompletely defined, particularly regarding embolic particle size and adjunctive flow-control techniques. We describe a structured preoperative embolization approach for two patients with hypervascular sinonasal tumors. In both cases, superselective microcatheterization of sphenopalatine artery feeders was performed after confirming the absence of internal carotid artery (ICA) anastomoses. Embolization using 300-500 µm Embosphere particles (Merit Medical, South Jordan, UT, USA), combined with adjunctive proximal coil deployment, achieved complete devascularization. This protocol provided both distal tumor penetration and proximal flow control, serving, additionally, as an intraoperative landmark during endoscopic skull-base surgery. These cases highlight a practical stepwise embolization strategy for sinonasal tumors, emphasizing careful angiographic assessment, appropriate particle sizing, and adjunctive coil placement. This technique supports safe and effective tumor devascularization and facilitates complete surgical resection in the endoscopic skull-base setting.