E-115 Pterygovaginal artery: a less recognized recurrent branch from the distal internal maxillary artery

Introduction The pterygovaginal artery (PtVA) is one of the recurrent branches from the distal part of the internal maxillary artery (IMA), which courses through the pterygovaginal canal (PtVC) that connects the pterygopalatine fossa and the nasopharynx. Less attention has been paid to this artery in spite of its unique anatomical features and important anastomoses around the eustachian tube because on angiography this minute artery can be hardly distinguished due to overlaps of many IMA branches. Nevertheless, widespread utilization of cone beam computed tomography (CBCT) has enabled us depicting even extremely small arteries. In cases with hypervascular lesions, PtVA is often enlarged and can be identified with attentive observation. We present three cases of tumor embolization before endonasal endoscopic approach and underscore its clinical implications in neurointerventional surgery. Case 1 (Sinonasal renal cell-like adenocarcinoma) A 66-year-old woman with a history of von Hippel-Lindau disease and multiple surgeries for intracranial hemangioblastomas was scheduled for a resection of an enlarging mass extending around the ethmoid and sphenoid sinuses. Along with branches from the left sphenopalatine artery (SPA), the left PtVA, branching from the most distal part of the IMA, was embolized selectively with 40% n-butyl cyanoacrylate. Case 2 (Sphenoid Sinus Hemangioma) A 20-year-old man presented with the right abducens nerve palsy. MRI showed an enhancing mass around the sphenoid sinus extending to the cavernous sinus. CBCT revealed that the main feeder from the IMA was the PtVA, branching from a relatively proximal portion of IMA, lateral to the pterygomaxillary fissure. The selective angiography from the PtVA showed a tumor stain and a branch to the nasopharyngeal roof anastomosing with the ascending pharyngeal artery (APhA) and ascending palatine artery. After the microcatheter was further advanced close to the lesion, embospheres of 300−500μm were cautiously injected and platinum coils were deployed in the PtVA. Post-embolization CBCT showed coils in the PtVC. Case 3 (Pituicytoma) A 69-year-old woman with a large sellar tumor underwent a preoperative embolization. The distal IMA, middle meningeal arteries, accessory meningeal artery, APhAs were embolized with coils. The tumor stain from the distal IMA was specifically derived from the PtVA, the Vidian artery, and the artery of the foramen rotundum. Conclusion The PtVA has a medial or lateral origin from the distal IMA and anatomical knowledge for this artery is essential in neurointervention. Embolization should be performed with precaution to avoid unintended migration through dangerous anastomoses. Disclosures K. Yoshida: None. T. Akiyama: None.