Endoscopic endonasal transpterygoid appoach to the pterygopalatine fossa and cavernous sinus: Anatomic landmarks and their relations on fresh cadavers

Objective The aim of this study was to investigate the course of neurovascular structures, anatomic landmarks of the pteryopalatine fossa and cavernous sinus and their relations with each other and further improve endoscopic approaches by the endoscopic transpterygoid approach on fresh cadavers. Methods This study was carried on at Ege University School of Medicine Otolaryngology Department between June 2014 and June 205. Ten fresh cadavers out of 15 were included. Twenty pterygopalatine fossa and cavernous sinuses of 10 cadavers were investigated with the endoscopic endonasal transpterygoid approach. The same procedure was implemented for each cadaver. These were: maxillary antrostomy, anterior and posterior ethmoidectomy, sphenoidotomy, transpterygoid pterygopalatine fossa dissection and cavernous sinus dissection. Results The mean distance from anterior nasal spine to the ethmoid crest of the palatine bone was 60.35 mm, SD: 1.31 mm with an angle of 21.7°. The mean distance between the sphenopalatine foramen and the superior part of choana was 18.30 mm, SD: 1.38 mm. The mean distance between the entry point of vidian (pterygoid) canal and the sphenopalatine foramen inferomedian to the vidian canal was 6.30 mm, SD: 0.47 mm. The rate of dehiscence on the bony canal of the cavernous internal carotid artery was 25%. Anterior carotid portion was prominent in 60%, posterior carotid portion was prominent in 35% and whole course of carotid artery in the lateral wall of the sphenoid sinus was prominent in 30% of the cases. The distance between the entry point of Eustachian tube and the petrous segment of the carotid arter was 19.50 mm, SD:1.05 mm. Conclusion Tracking the vidian nerve in the floor of the sphenoid sinüs was found as a reliable and safe method in finding cavernous internal carotid artery. The rate of carotid artery dehiscence was similar with previous reports. Key words: Pterygopalatine fossa, cavernous sinüs, transpterygoid, endoscopic