Applied Anatomy Study Of Extended Transsphenoidal Approach

This study was conducted to observe and measure the correlative anatomic structure along the extended transsphenoidal approach and provide some reference data for the clinical application. Six skull specimens and 15 adult cadaveric heads were dissected under microscope through an extended transsphenoidal approach. We studied factors which affect the bone window expansion and examined the endoscopic anatomy of the surgical corridor along the cavernous sinus, supersellar region of anterior cranial fossa and clivus.The results showed that the anterior region of aperture of sphenoidal sinus has a direct impact on the exposure of bone window. The windowing range of anterior region of sphenoidal sinus aperture is the key point for the exposure of the upper, lower and lateral wall of sphenoidal sinus. Bone removal can be extended to the supra-lateral and infer-lateral areas in operation. The cavernous portion of internal carotid artery and its branches and cranial nerves in cavernous sinus could be seen when extending toward cavernous sinus and cutting open the medial wall of cavernous sinus. The internal carotid artery and abducent nerve may be susceptible to intraoperative damage. Posterior ethmoid sinus has a direct impact on the exposure of operation field. Excision of posterior ethmoid sinus improves the exposure of super-and external region of sphenoid sinus. Extending toward the supersellar region of anterior cranial fossa through the extended transsphenoidal approach helps to expose optic nerve, optical chiasm, supraclinoid portion of internal carotid artery and the anterior communicating artery complex. The distance between posterior edge of sieve plate and the frontal edge of tuberculum sellae form should less than 15mm. Extend toward the clivus, the pons, medulla oblongata, basilar artery and its branches could be seen. To protect nerves and blood vessels effectively the width of grinding slope of bone should less than 20mm.The extended transsphenoidal approach to the cavernous sinus is suitable for lesions which invade the cavernous sinus. The extended transsphenoidal approach to the anterior sellar and the anterior cranial fossa is suitable for reasonably suprasellar lesions. The extended transsphenoidal approach to theclivus is suitable for lesions which invade along the midline.