Endoscopic anatomy and approaches of the cavernous sinus: cadaver study

The objectives of this study were to recognize the endoscopic anatomy of the cavernous sinus and to understand the standard, purely endoscopic endonasal approaches to this anatomic structure. This basic information will facilitate our surgical procedures and decrease the rate of surgical complications. Seven fresh adult cadavers were studied bilaterally (n = 14). We used Karl Storz 0 and 30A degrees, 4 mm, 18 cm and 30 cm rod lens rigid endoscope in our dissections. After cadaver preparation, extended endoscopic endonasal approaches were performed to access the cavernous sinus. In the seven cadavers, the cavernous sinus and superior orbital fissure, on both sides, were widely exposed with extended endoscopic endonasal approach. The antero-inferior portion of the cavernous sinus was exposed by removing the superior and the middle turbinates and the posterior ethmoidal cells (extended endoscopic endonasal transsphenoidal approach); the whole lateral wall of the cavernous sinus was exposed by removing the anterior and the posterior ethmoidal cells (endonasal ethmoido-pterygo-sphenoidal approach: far lateral); and the medial wall of the cavernous sinus was exposed by introducing the 30A degrees endoscope from the contralateral nostril (contralateral endoscopic endonasal transsphenoidal approach). According to the neurovascular architecture, the lateral wall of the cavernous sinus is divided into the superior triangular area, the superior quadrangular area and the inferior quadrangular area. This division can facilitate understanding of the anatomic relations of the cavernous sinus from the endoscopic view. Knowledge of the anatomy of the cavernous sinus obtained with an endoscopic view of cadaver dissections is an essential step in the learning curve of endoscopic skull base surgery, and is important for endoscopic treatment of various pathologies in this region. In this anatomic study, we reviewed the approaches to the cavernous sinus with an endoscopic view and identified the neurovascular relations. This approach will help in performing safer and minimally invasive surgery.