Extended endoscopic endonasal approach to the pterygopalatine fossa: anatomic study.

Our aim in this study was to recognize the endoscopic anatomy of the pterygopalatine fossa (PPF) and the anatomic variations of the related neurovascular structures, to define the endoscopic endonasal approach to this region.Six fresh adult cadavers were studied (N=6) by endoscopic endonasal approach. To reach the pterygopalatine fossa endonasally, we performed the middle meatus transpalatine approach in 2 cadavers, the middle meatus transnasal approach in 2 cadavers and the inferior turbinatectomy transnasal approach in 2 cadavers. The superior and posterior walls of the maxillary sinus were defined and studied. The sphenopalatine foramen is widened by drilling the orbital process of the foramen and the sphenopalatine artery was exposed. The posterior wall of maxillary sinus was opened to expose the pterygopalatine fossa and its neurovascular contents, which were studied and documented.The PPF was easily approached by endoscopic transnasal transmaxillary approach. The PPF region was best exposed by the middle meatus tranasal approach. In the PPF; infraorbital nerve, vidian nerve, major palatine nerve, the infraorbital artery, internal maxillary artery, sphenopalatine artery, descending palatine artery, posterior superior alveolar artery and buccal artery were exposed. According Morton and Khan morphologic classification of the third portion of the internal maxillary artery we found intermediate type in 2 cadavers (33.3%), M' type in 2 cadavers (33.3%), T' type in 1 cadaver (16.7%) and Y' type in 1 cadaver (16.7%). Also, according to Chio and Park classification of the branching type of the infraorbital artery, posterior superior alveolar artery and deep palatine artery, we found type I in 4 cadavers (66%) and type II in 2 cadavers (33%).During the endoscopic transnasal transmaxillary approach to the PPF, it is possible to face wide range of variations in every phase of the approach. Understanding the anatomy of this region and the neurovascular relations from the endoscopic view by cadaver dissections will help us to performed more controlled and safe surgery.