Endoscopic Endonasal Supra-Rosenmueller Fossa Approach to the Inferior Petrous Apex and Jugular Tubercle

Background: Approach to the inferior petrous apex (IPA) and adjacent jugular tubercle (JT) is still challenging. In this presentation, the authors demonstrate the surgical anatomy and clinical cases of endoscopic endonasal approach to the IPA and JT, especially emphasizing the importance of dissecting the mucosa over the Rosenmuller fossa, creating the route above and behind the orifice of the eustachian tube. Methods: The anatomical dissection was performed in three formalin fixed adult cadaver head simulating the actual endonasal surgery. After wide sphenoidotomy, the basopharyngeal fascia was stripped down to the superior clival line and the sphenoid sinus floor was flattened. The paraclival carotid artery was skeletonized and the anterior genu was freed from the foramen lacerum. The main hindering factor to approach laterally at this stage was found to be the eustachian tube. Thus, the mucosa over the Rosenmuller fossa was cut and reflected downward to create a route above and behind the eustachian tube. The technique was used in five cases with chordomas/chondrosarcoma. Results: Using the route over the Rosenmuller fossa, the IPS and JT can be approached with straight and slightly curved instruments allowing intensive surgical maneuver until the medial aspect of the jugular foramen and carotid canal. In clinical cases, the tumor at those areas could be removed without approach-related complication.