Endoscopic endonasal cavernous sinus surgery: An anatomic study

OBJECTIVE: The endoscopic surgical anatomy of the cavernous sinus was studi ed to establish an anatomic basis for endoscopic endonasal cavernous sinus surgery. METHODS: Five adult cadaveric heads were studied with 0-, 30-, and 70-degre e 4-mm rod-lens endoscopes. The posterior wall of the sphenoidal sinus was approached via a paraseptal, middle turbinectomy, or middle meatal approach . RESULTS: The posterior bony wall of the sphenoidal sinus is subdivided into five vertical compartments: midline, bilateral paramedian, and bilateral l ateral. The midline vertical compartment consists of the planum sphenoidale , tuberculum sellae, sella, and clival indentation. The paramedian vertical compartment is composed of the medial third of the optic canal and the car otid artery protuberance, The lateral vertical compartment contains four bo ny protuberances (optic, cavernous sinus apex, maxillary, and mandibular) a nd three depressions (carotico-optic, ophthalmomaxillary [V1-V2], and maxil lomandibular [V2-V3]). The three depressions form anatomic triangles at the lateral vertical compartment: the optic strut triangle, which is bordered by the optic nerve, carotid artery, and oculomotor nerve (IIIrd cranial ner ve); the V1-V2 triangle; and the V2-V3 triangle, The internal carotid arter y at the posterior wall of the sphenoidal sinus can be subdivided into two main segments: the parasellar and the paraclival. The vidian canal is a lan dmark that leads to the foramen lacerum, the mandibular nerve, and the pter ygopalatine fossa. CONCLUSION: Endoscopic anatomy of the cavernous sinus has been studied via an endonasal route in cadaveric specimens to provide an anatomic basis for endoscopic endonasal cavernous sinus surgery.