ARTICLE | doi:10.20944/preprints202307.0469.v1
Subject: Medicine And Pharmacology, Anatomy And Physiology Keywords: cavernous sinus triangles; endoscopic transorbital; extended endoscopic endonasal; fronto-temporo-orbito-zygomatic; middle fossa.
Online: 7 July 2023 (07:30:31 CEST)
Background: The cavernous sinus (CS) is a highly vulnerable anatomical space, mainly for the neurovascular structures which it contains, therefore a detailed knowledge of its anatomy is mandatory for the surgical unlocking. To compare the anatomy of this region from different endoscopic and microsurgical operative corridors, also focusing on the corresponding anatomic landmarks met along these routes. Furthermore, we tried to define the safe entry zones to this venous space from these three different operative corridors and provide indications regarding the optimal approach according to the lesion location. Methods: Five embalmed and injected adult cadaveric specimens (10 sides) separately underwent dissection and exposure of the CS via superior eyelid endoscopic transorbital (SETOA), extended endoscopic endonasal transsphenoidal-transethmoidal (EEEA) and microsurgical transcranial fronto-temporo-orbito-zygomatic (FTOZ) approaches. The anatomical landmarks and the content of this venous space have been described and compared from these surgical perspectives. Results: The SETOA allowed the exposure of the entire lateral wall of the CS without entering its neurovascular structures and part of the posterior wall; furthermore, thanks to its anteroposterior trajectory, it allowed to disclose in a minimally invasive fashion, also the posterior ascending segment of the cavernous ICA with the related sympathetic plexus through the Mullan’s triangle. Through the anterolateral triangle, the transorbital corridor allowed to expose the lateral 180 degrees of vidian nerve and artery in the homonymous canal, the anterolateral aspect of the lacerum segment of the ICA, at its the transition zone from the petrous horizontal to the ascending posterior cavernous segment, surrounded by the carotid sympathetic plexus, and the medial Meckel’s cave. Conclusion: Different regions of the cavernous sinus are better exposed by different surgical corridors. The relationship of tumor and cranial nerves in the lateral wall guides the selection of the approach to cavernous sinus lesions. The transorbital endoscopic approach can be considered a safe and minimally invasive complementary surgical corridor to the well-established transcranial and endoscopic endonasal routes in the exposure of the cavernous sinus. Nevertheless, peer knowledge of the anatomy and a surgical learning curve are required.