Microsurgical anatomy of the extended transnasal transsphenoidal approach to the inferior wall of cavernous sinus

Objective:Toprovideanatomicreferencesfortheextendedtransnasaltranssphenoidalapproach to the inferior wall of cavernous sinus.Methods: Simulating surgeries of the extended transnasal transsphenoidal approach were performed under microscope in 10 formalin fixed cadaveric heads, and correlated anatomic structures were observed and measured.Results: (1) The direct working pathway to expose the inferior wall of cavernous sinus could be established through the extended transnasal transsphenoidal approach.(2) The visible field of the inferior wall of cavernous sinus was the irregular shape of quadrangle, with the length of anterior and medial edge of (11.95±2.01)mm (8.66~15.15 mm),and (14.02±1.68)mm (11.47~17.66 mm)respectively.(3) The whole antero-inferior and medial compartments of cavernous sinus,as well most parts of lateral compartment and lateral wall could be observed.Conclusions: The extended transnasal transsphenoidal approach to expose the inferior wall of cavernous sinus could be established by removing upper and middle nasal concha and posterior ethmoid sinus. The advantages of this approach include direct visualization and minimal invasion.