Morphometric Mapping of the Parapharyngeal Internal Carotid Artery via a Transoral Endoscopic Corridor: A Cadaveric Study Based on a Novel Proposed Modular Classification

Objective: The parapharyngeal internal carotid artery (ppICA) represents a key surgical landmark within the parapharyngeal space (PPS), where its deep location and close neurovascular relationships make inadvertent injury potentially catastrophic. Transoral endoscopic approach is increasingly used for styloid process resection in Eagle’s syndrome and management of PPF tumors (e.g., pleomorphic adenoma and paraganglioma). Using a novel modular subdivision of the ppICA into three surgical segments— infrapetrous or upper ppICA (UppICA), extending from its entry into the carotid canal to the stylo-muscular complex; stylo-muscular or middle ppICA (MppICA), at the level of the styloid process and stylopharyngeal diaphragm; and infra-styloid lower ppICA (LppICA), from this intersection to the most caudal point accessible transorally—we performed a systematic morphometric analysis, with emphasis on spatial relationships, surgical depth, and vascular variations. Methods: Five cadaveric heads (10 sides) underwent endoscopic-assisted transoral dissection through a retromolar trigone approach (navigation accuracy