Full endoscopic endonasal extreme far-medial approach: Eustachian tube transposition.

The complex anatomical relationships within the skull base have been described from an endoscopic point of view. However, systematic surgical, not just anatomical, management of the eustachian tube (ET) and the approach to the styloid and parapharyngeal spaces have not yet been described. The authors describe the full endoscopic endonasal extreme far-medial approach used in their surgical practice and show how they applied it to a case. To the authors' knowledge, from a strictly surgical viewpoint, this work is the first to describe a fundamental endonasal approach to the inferior clivus, the condylar and tubercular compartments, the prestyloid and poststyloid spaces, and ET transposition to expose the aforementioned structures without disrupting the ET. For lesions with mediolateral growth patterns, the authors consider the extreme far-medial approach to be superior to the pure transmaxillary approach. Additional cases and more evidence are needed to refine this surgical technique.