内側頭蓋底海綿静脈洞への経蝶形骨洞アプローチによる海綿静脈洞内内頚動脈への到達：顕微鏡解剖学的検討

Background The cavernous sinus (CS) is a complex and deep-seated structure that requires extensive anatomical knowledge and microsurgical training. Direct microsurgical repair of the intracavernous internal carotid artery (IC-ICA) pathologies has been largely avoided, favoring other treatment options, such as endovascular or bypass procedures. Expanding our understanding of microsurgical anatomy could improve the direct surgical options for IC-ICA pathologies. Objective We describe the IC-ICA access triangles and perform a quantitative comparative analysis. Methods Thirteen cadaveric heads were subjected to a pretemporal transcavernous approach. The clinoidal triangle (CT), infratrochlear triangle (ITT), and anteromedial triangle (AMT) were exposed. Triangle areas and IC-ICA lengths exposed within each triangle were determined under the microscope. Results A total of 25 CSs were successfully analyzed. The triangle areas measured 56.3 ± 29.4 mm², 48.9 ± 27.3 mm², and 44.1 ± 19.6 mm² for ITT, AMT, and CT, respectively (p=0.403). The IC-ICA lengths exposed measured 11.3 ± 4.3 mm, 7.4 ± 3.9 mm, and 7.7 ± 3.5 mm for ITT, AMT, and CT, respectively (p=0.002). Conclusions The ITT is a CS window that provides wide access to the IC-ICA. This window can be used to directly repair various IC-ICA pathologies, such as aneurysms or carotid cavernous fistulas.