The Anatomy Of Endoscopic Transsphenoidal Approach To Cavernous Sinus

Objective : The endoscopic surgical anatomy of the medial wall of the cavernous sinus was studied to establish an anatomic basis for tumors treatment involving in the medial wall of the cavernous sinus.Materials and methods: Eight adult (16 sides) cadaveric heads were studied under endoscope 0 and 70 degree 4-mm rod-lens. The posterior wall of the sphenoidal sinus was operated via a middle meatal approach. The exposure of the posterior wall of the sphenoidal sinus was followed by an anterior sphenoidaotomy. To measure and photograph the structures after cut the bony floor.Results: 1. The cavernous sinus is network structure of thickness ranging, repeatedly branches and convergences, not cysts. These mesh structure and ICA adjacent to each other, and under in a complete separation the operating microscope, so that it is possible for removing the rumors invading cavernous sinus surgeon removed the tumor cavernous possible.2. The medial wall of the cavernous sinus is actually issued by the diaphragma sellae fibers consisting of thin-walled.The collagen fibers in the medial wall of the cavernous sinus is significantly less than those in the superior and lateral wall of the cavernous sinus. It is actually originated from the diaphragma sellae fibers thin-walled structure and to be the border of the pituitary gland and cavernous sinus.3. The posterior bony wall of the sphenoidal sinus is subdivided into five vertical compartments: midline, bilateral paramedian, and bilateral lateral. 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 carotid artery protuberance. The lateral vertical compartment contains four bony protuberances (optic, cavernous sinus apex, maxillary, and mandibular) and three depressions (carotico-optic, ophthalmomaxillary [V1-V2], and maxillomandibular [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 nerve); the V1-V2 triangle; and the V2-V3 triangle. The paraclival ICA segment can be further subdivided into two parts: the lacerum segment caudally (the extracavernous sinus) and the trigeminal segment rostrally (the intracavemous sinus). When the mucosa of the sphenoidal sinus is removed, the lacerum segment of the ICA can be identified as a bare artery if fibrocartilage is absent.4. The parasellar segment of the ICA is C-shaped, with the convexity of the "C" facing anterolaterally when it is viewed from the medial aspect. It is subdivided into four parts in a caudal-to-rostral order: the "hidden segment," the inferior horizontal segment, the anterior vertical segment, and the superior horizontal segment.Conclusions: 1. The cavernous sinus is an irregular venous plexus which is composed with thickness ranging from vein, a branch line repeatedly, not entirely enveloping the ICA. 2 The medial wall of the cavernous sinus is formed by the dura propria that covers the pituitary gland. Trans the posterior wall of the sphenoid sinus under the endoscopy can access to the medial wall of the cavernous sinus and the ICA. It is possible for doctors to remove tumors involving the lateral wall of cavernous sinus without neurovascular injury.