Endoscopic Endonasal Transphenoidal Approaches To The Sellar Region: Anatomic Study And Clinical Application

ObjectivesTo establish the anatomic basis for the endoscopic endonasal transphenoidal approaches to the sellar region.Methods15 adult cadaveric heads were studied: 13 were fixed with formalin, 8 of them were artery-injected with red latex, 2 fresh cadaveric heads were not fixed nor artery-injected. 0? 30? and 70?angled 4-mm rod-lens endoscopes were used. The anatomy of three different operating approaches were studied: midline approach (paraseptal appraoch), lateral approach (middle turbinectomy), and far lateral approach (resection of uncinate process and ethmoidal bulla plus middle turbinectomy) both combined with postero-septum dislocation approach.Results1. The superior and posterior bony wall of sphenoidal sinus is subdivided into five vertical compartments: midline, bilateral paramedian, and bilateral lateral.(1) Midline vertical compartment is formed with planum sphenoidale, tuberculum sellae and clivus notch.(2) Bilateral paramedian compartments are composed of the medial 1/3 part of optic canal, the presellar, parasellar, and postsellar protuberances of 1C A.(3) Bilateral lateral compartments comprised 4 bony protuberances (optic, roof of cavernous sinus, maxillary nerve and mandibular nerve) and 3 bony depressions (carotico-optic, ophthalmomaxillary [V1-V2], and maxillomandibular [V2-V3].2. The anatomy of 3 different endoscopic endonasal combined approaches via one nostril are studied: midline, lateral and farlateral plus postero-septum dislocation approaches. The operating field of 0?angeled endoscope is used as thefocus of operation. 30?,70?angled endoscopes can be used to observe the anatomic area outside the operating field but was difficult for operating.(1) Midline approach is described as the paraseptal plus postero-septum dislocation approach. The operating route is located between the nasal septum and the middle turbinate. The center of 0 ? endoscope is midline and contralateral vertical compartments. It can give access to planum sphenoidale superiorly and clivus inferiorly and thus can achieve the anatomic observation and operation.(2) Lateral approach is the combined rout of middle turbinectomy plus septum dislocation. The operating channel is in the middle meatus between the exterior wall of nasal cavity and middle turbinate. The center of 0?endoscope field is the ipsilateral lateral and midline vertical compartments and could accomplish the anatomy observation and operation of this area. Because of the superior restriction of the middle turbinate remainder and inferior restriction of inferior turbinate, the endoscope could not move vertically freely. But it provide the transversal space for the movement of endoscope and was in favor of observation and operation for the ipsilaterl operating field.(3) Far lateral approach is the combined route of uncinate process and ethmoidal bulla resection plus middle turbinectomy .The operating channel is in the middle meatus between ethmoid plate and septum. This approach can give broader space for the transversal movement of endoscope. The superior and posterior walls of sphenoidal sinus are both in the operating field and it is better for the operation in ipsilateral lateral vertical compartment.3. The application of nasal speculum offeres a trumpetlike operating space and is in favour of the protection of nasal mucosa. It alleviates the limitation of longitudinal movement of endoscope but restricts the transversal movement.4. After the accomplishment of observation and dissection of cavernous sinus under or with the aid of endoscope , it is possible to resect the tumor in the cavernous sinus or infiltrating it through medial or inferior wall.5. Having confirmed sthe anatomic landmark of transphenoidal approach: middle turbinate, middle nasal meatus, posterior nasal apertures, ostium of sphenoidal sinus,IVprotuberance of sellar floor, clivus indentation and operating routes.6. The 0 ? angled endoscope is better used in operative procedure...