PMC

Stepwise dissection of the EETPA. Pictures obtained with a 0-degree endoscope. ( A ) The vertical plate, sphenoid process, and orbital process of the palatine bone are localized. The anterior margin of the torus tubarius of the Eustachian tube is identified posteromedially to the medial pterygoid plate of the pterygoid process. The sphenopalatine artery is divided, the submucosal dissection is continued posteriorly, and the lateral portion of the anterior margin of the sphenoid floor is exposed. ( B ) By drilling the sphenoid floor and the sphenoid process of the palatine bone, proceeding in a medial to lateral direction, the pharyngeal artery within its canal, the vidian canal with its contents, and the PPF contents protected by its periosteum are progressively exposed. ( C ) The palatovaginal canal (or palatosphenoidal canal) communicates the PPF with the roof of the nasopharynx and contains the pharyngeal artery and neural branches from the pterygopalatine ganglion. The pharyngeal artery is identified within the palatovaginal canal along its course from the PPF to the roof of the nasopharynx. ( D ) The pharyngeal artery is divided and the palatovaginal canal is drilled out, better defining the medial and inferior limits of the vidian canal. The vidian canal travels within the base of the pterygoid, with a medial to lateral direction, and it connects the PPF with the middle cranial fossa. It contains the vidian artery and nerve. In all cadaveric dissections of this study, the vidian artery has been consistently identified. ( E ) Using a 90-degree dissector, the vidian is completely isolated from the vidian canal. The entry point of the vidian canal on the PPF and the proximal portion of the vidian nerve are better defined. ( F ) The orbital process of the palatine bone, the perpendicular plate of the palatine bone, and the posterior wall of the maxillary sinus are progressively drilled out, better exposing the periosteum of the PPF in its anterior, medial, and superior limits. ( G ) The PPF, still protected by its periosteum, is lateralized. ( H ) The anteromedial portion of the base of the pterygoid is drilled out. ( I ) The vidian artery is divided. ( J ) Subsequently, the vidian nerve is divided. This maneuver allows easier lateralization of the PPF contents and the exposure of the medial margin of the foramen rotundum at the superoposterior limit of the PPF. ( K ) The pterygoid base is completely removed, exposing the floor of the middle cranial fossa. ( L ) The medial and lateral pterygoid plates are drilled out (excluding the distal portion of the lateral pterygoid plate), and the passage of V3 through the foramen ovale and its anterior and posterior division with the respective main branches are identified. ( M ) The PPF contents are carefully dissected. V2 and the muscular and pterygopalatine MAX with their main branches are identified. Starting from a standard transpterygoid access, different surgical corridors can be followed from medial to lateral: the midclivus, lacerum and cavernous ICA, lateral compartment of the cavernous sinus, the floor of the middle cranial fossa, Meckel's cave, petrous apex and petrous bone, PPF, and medial portion of the ITF. ( N ) The neurovascular contents of the PPF are transposed inferolaterally better showing the relation between the PPF and ITF neurovascular structures. ( O ) Closer view on V3 along its intracranial passage through the foramen ovale. The relation between the lingual process, V3, and vidian nerve are highlighted. ( P ) The medial portion of the greater sphenoid wing between V2 and V3 is removed, up to the level of the foramen spinosum. The MMA is isolated along its extra- to intracranial segments. ( Q ) Access to the middle cranial fossa is gained in an extradural fashion. The superolateral surface of the Meckel's cave is exposed. The greater superficial petrosal nerve is isolated from the anterior surface of the petrosal process of the sphenoid bone to its entry point into the vidian canal. ( R ) The temporal dura is incised and the inferomesial portion of the right temporal lobe is exposed. AAA, alveolar antral artery; B., bone; br., branch; DPA, descending palatine artery; DPB, descending palatine bundle; EETPA, endoscopic endonasal transpterygoid approach; FL, foramen lacerum; GSPN, greater superficial petrosal nerve; ICA, internal carotid artery; MAX, maxillary artery; inf., inferior; IOA, infraorbital artery; ION, infraorbital nerve; IT, inferior turbinate; lat., lateral; LPM, lateral pterygoid muscle; MMA, middle meningeal artery; MS, maxillary sinus; N., nerve; orb., orbital; PB, palatine bone; PN, palatine nerve; post., posterior; PPF, pterygopalatine fossa; pr., process; PSAA, posterior superior alveolar artery; PVC, palatovaginal canal; SPA, sphenopalatine artery; sphen., sphenoidal; sphenopal., sphenopalatine; temp., temporal; tens., tensor; V2, maxillary nerve; V3, mandibular nerve; VA, vidian artery; VC, vidian canal; vert., vertical; VN, vidian nerve.

Demonstrative case, Part 1: (A) Pre-embolization subtracted angiogram of left ICA and left ECA circulations (coronal and sagittal views) shows a large left posterior nasal cavity tumor measuring 43.5 mm×44.1 mm×55.7 mm with a blood supply from distal branches of the left sphenopalatine artery, left accessory meningeal artery, left middle meningeal artery, left inferior lateral trunk, and left vidian artery. (B) Embolization of ECA feeders (balloon inflated but not visualized). (C) Unsubtracted angiogram showing Onyx cast with evidence of deep penetration to peripheral feeders. (D) Subtracted angiogram of ICA after ECA embolization shows persistent vascularization supplied by vidian artery. (E) Roadmap showing microcatheter in distal vidian artery protected by balloon. (F) Embolization of Vidian artery feeders under balloon protection. (G) Post-embolization subtracted angiogram shows reduction of tumor blush by >90%. ICA, internal carotid artery; ECA, external carotid artery.

Angiogram from a patient with a juvenile nasopharyngeal angiofibroma (JNA) demonstrating subtle anastomosis between the external and internal carotid arteries via the Vidian artery. The left internal maxillary artery (white arrow) supplies a JNA as demonstrated by the left external carotid artery (ECA) injection (A) and the left internal carotid artery (ICA) injection with reflux (B). A Vidian artery is noted (white arrowheads) in the early arterial phase left ICA injection on lateral (B) and anteroposterior (C) injections. Faint opacification of the tumor arises from the Vidian artery in the capillary phase of the same ICA injection (D). Post-embolization ECA injection (E) demonstrates complete devascularization. Post-embolization, the Vidian artery opacification is attenuated (F).

Right ICA (A) and right ECA (B) angiograms in lateral view, posttransvenous coiling of a cavernous dural arteriovenous malformation, demonstrate the anastomosis between the vidian artery from the distal IMA to the vidian branch of the mandibular artery. The vidian artery has a characteristic horizontal course on the lateral view (black arrows), thus differentiating it from the more inferior course of the pterygovaginal artery (white arrows), which also anastomoses with a branch of the mandibular artery (black arrowhead) and the superior pharyngeal artery (white arrowhead) around the eustachian tube.